TRANSMISSIVE IMAGING AND RELATED APPARATUS AND METHODS

• US 20130116561A1
• Filed: 10/17/2012
• Published: 05/09/2013
• Est. Priority Date: 10/17/2011
• Status: Active Grant

• Current Assignee: Butterfly Network, Inc.
• Original Assignee: Butterfly Network, Inc.
• Inventors: Rothberg, Jonathan M., Charvat, Gregory, Sanchez, Nevada, Ralston, Tyler
• Granted Patent: US 8,852,103 B2
• Time in Patent Office: Days
• US Class Current: 600/438
• CPC Class Codes: A61B 2017/320069 for ablating tissue
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 2562/164 the sensor is mounted in or on a conformable substrate or carrier
• CPC Class Codes: A61B 5/015 By temperature mapping of body part
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: A61B 8/13 Tomography A61B8/10, A61B8/12 take precedence; tomography for radiation diagnosis A61B6/02
• CPC Class Codes: A61B 8/4209 by using holders, e.g. positioning frames
• CPC Class Codes: A61B 8/4245 involving determining the position of the probe, e.g. with respect to an external reference frame or to the patient
• CPC Class Codes: A61B 8/4254 using sensors mounted on the probe
• CPC Class Codes: A61B 8/4263 using sensors not mounted on the probe, e.g. mounted on an external reference frame
• CPC Class Codes: A61B 8/4477 using several separate ultrasound transducers or probes
• CPC Class Codes: A61B 8/4483 characterised by features of the ultrasound transducer
• CPC Class Codes: A61B 8/4488 the transducer being a phased array
• CPC Class Codes: A61B 8/4494 characterised by the arrangement of the transducer elements devices for short-range imaging using particular transducer elements arrangements under G01S15/8909; arrangements of transducers in generation of mechanical vibrations of infrasonic, sonic or ultrasonic frequency B06B1/0607
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data
• CPC Class Codes: A61B 8/5207 involving processing of raw data to produce diagnostic data, e.g. for generating an image reconstruction G06T11/00
• CPC Class Codes: A61B 8/56 Details of data transmission or power supply
• CPC Class Codes: A61B 8/565 involving data transmission via a network
• CPC Class Codes: A61N 2007/0078 with multiple treatment transducers
• CPC Class Codes: A61N 7/00 Ultrasound therapy lithotripsy A61B17/22, A61B17/225; massage using supersonic vibration A61H23/00 ; using ultrasound for introducing media into the body A61M37/0092
• CPC Class Codes: A61N 7/02 : Localised ultrasound hyperthermia hyperthermia in general A61F7/00
• CPC Class Codes: H04J 13/00 : Code division multiplex systems for frequency hopping H04B1/713

Abstract

Apparatus and methods are described that include ultrasound imaging devices, which may operate in a transmissive ultrasound imaging modality, and which may be used to detect properties of interest of a subject such as index of refraction, density and/or speed of sound. Devices suitable for performing high intensity focused ultrasound (HIFU), as well as HIFU and ultrasound imaging, are also described.

Claims

1. An apparatus, comprising:

a plurality of radiation sources comprising a first radiation source, a second radiation source, and a third radiation source;

a first radiation sensor and a second radiation sensor; and

processing circuitry coupled to the first radiation sensor and the second radiation sensor and configured to receive and discriminate between, for each of the first and second radiation sensors, respective source signals emitted by the first, second, and third radiation sources,

wherein the first radiation source, the second radiation source, and the first radiation sensor lie in a first plane, and

wherein the second radiation source, the third radiation source, and the second radiation sensor lie in a second plane different than the first plane.

2. The apparatus of claim 1, wherein the first radiation source is an ultrasound source.

3. The apparatus of claim 2, wherein the first radiation sensor and the second radiation sensor are ultrasound radiation sensors.

4. The apparatus of claim 1, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least ten radiation sources of the plurality of radiation sources.

5. The apparatus of claim 4, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 100 radiation sources of the plurality of radiation sources.

6. The apparatus of claim 5, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 1,000 radiation sources of the plurality of radiation sources.

7. The apparatus of claim 4, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by between ten radiation sources and 10,000 radiation sources of the plurality of radiation sources.

8. The apparatus of claim 1, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 1% of the radiation sources of the plurality of radiation sources.

9. The apparatus of claim 8, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 10% of the radiation sources of the plurality of radiation sources.

10. The apparatus of claim 9, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 25% of the radiation sources of the plurality of radiation sources.

11. The apparatus of claim 10, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 50% of the radiation sources of the plurality of radiation sources.

12. The apparatus of claim 11, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 75% of the radiation sources of the plurality of radiation sources.

13. The apparatus of claim 12, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 90% of the radiation sources of the plurality of radiation sources.

14. The apparatus of claim 13, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by all radiation sources of the apparatus.

15. The apparatus of claim 14, wherein the plurality of radiation sources comprises at least fifty radiation sources.

16. The apparatus of claim 1, wherein the plurality of radiation sources is arranged in three dimensions.

17. The apparatus of claim 1, wherein the plurality of radiation sources forms an array of at least two dimensions in which the plurality of radiation sources adopts a regular spacing.

18. The apparatus of claim 17, wherein the plurality of radiation sources is arranged in three dimensions.

19. The apparatus of claim 1, further comprising a plurality of radiation sensors including the first and second radiation sensors, wherein the plurality of radiation sensors is arranged in at least two dimensions.

20. The apparatus of claim 19, wherein the plurality of radiation sensors is arranged in three dimensions.

21. The apparatus of claim 19, wherein the plurality of radiation sensors forms an array of at least two dimensions in which the plurality of radiation sensors adopts a regular spacing.

22. The apparatus of claim 19, wherein the plurality of radiation sources forms an array of at least two dimensions, and wherein the plurality of radiation sensors forms an array of at least two dimensions.

23. The apparatus of claim 1, wherein the plurality of radiation sources and the first and second radiation sensors are configured to remain static during operation.

24. The apparatus of claim 1, wherein at least some radiation sources of the plurality of radiation sources are not spaced at regular intervals with respect to neighboring radiation sources.

25. The apparatus of claim 1, further comprising a plurality of radiation sensors including the first and second radiation sensors, wherein at least some radiation sensors of the plurality of radiation sensors are not spaced at regular intervals with respect to neighboring radiation sensors.

26. The apparatus of claim 1, wherein the plurality of radiation sources are physically coupled to a first mount and wherein the first and second radiation sensors are physically coupled to a second mount.

27. The apparatus of claim 26, wherein the first mount is flexible.

28. The apparatus of claim 26, wherein the first and second mounts are configured to be independently movable.

29. The apparatus of claim 28, further comprising a detector configured to detect an orientation and/or position of one or more of the plurality of radiation sources relative to one or both of the first and second radiation sensors.

30. The apparatus of claim 1, wherein the first and second radiation sensors are disposed on a first side of a plane and wherein the plurality of radiation sources are disposed on a second side of the plane.

31. The apparatus of claim 1, wherein the first, second, and third radiation sources and the first and second radiation sensors are collectively configured to operate in a transmissive modality.

32. The apparatus of claim 1, wherein directivity vectors of the first, second, and third radiation sources are incident upon the first and second radiation sensors.

33. The apparatus of claim 1, wherein at least one of the first, second, and third radiation sources is configured to alternately operate as a radiation source and a radiation sensor.

34. The apparatus of claim 33, wherein the first, second, and third radiation sources are coupled to the processing circuitry via parallel transmit and receive signal paths, and wherein the apparatus further comprises a switch for switchably coupling the first, second, and third radiation sources to either the transmit signal path or the receive signal path.

35. The apparatus of claim 1, wherein the plurality of radiation sources comprises at least two distinct arrays of radiation sources.

36. The apparatus of claim 35, wherein the at least two distinct arrays of radiation sources comprises three or more distinct arrays of radiation sources.

37. The apparatus of claim 36, wherein the processing circuitry coupled to the first radiation sensor and the second radiation sensor is configured to receive and discriminate between, for each of the first and second radiation sensors, respective source signals emitted by at least one radiation source in each of three distinct arrays of the three or more distinct arrays of radiation sources.

38. The apparatus of claim 1, wherein the processing circuitry is configured to perform a heterodyning function to receive and discriminate between the respective source signals emitted by the first, second, and third radiation sources.

39. The apparatus of claim 38, wherein the processing circuitry comprises a multiplier configured to receive an output signal from the first radiation sensor and a transmission signal to be emitted from the first radiation source, and wherein the multiplier is configured to provide an output signal to an analog-to-digital converter.

40. The apparatus of claim 1, wherein the processing circuitry comprises analog pulse compression circuitry configured to perform analog pulse compression on the respective source signals emitted by the first, second, and third radiation sources and received by the first and second radiation sensors.

41. The apparatus of claim 1, wherein the processing circuitry comprises an amplification stage coupled directly to a detector.

42. The apparatus of claim 1, wherein the processing circuitry comprises an amplification stage coupled to an input of an analog-to-digital converter (ADC).

43. The apparatus of claim 1, wherein the plurality of radiation sources and the first and second radiation sensors are configured to characterize a volume, and wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) image of the volume based at least partially on the respective source signals emitted by the first, second, and third radiation sources and received by the first and second radiation sensors.

44. The apparatus of claim 43, wherein the processor comprises the processing circuitry.

45. The apparatus of claim 1, wherein the plurality of radiation sources and the first and second radiation sensors are configured to characterize a volume, and wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) temperature profile of the volume based at least partially on the respective source signals emitted by the first, second, and third radiation sources.

46. The apparatus of claim 45, wherein the processor comprises the processing circuitry.

47. The apparatus of claim 1, further comprising a plurality of radiation sensors in addition to the first and second radiations sensors, wherein the plurality of radiation sources, the first and second radiation sensors, and the plurality of radiation sensors in addition to the first and second radiation sensors collectively form a structure into which a subject may be inserted.

48. The apparatus of claim 47, wherein the structure is substantially a box with an open side via which the subject may be inserted, and wherein the first and second radiation sensors together with the plurality of radiation sensors in addition to the first and second radiation sensors form a side of the box.

49. The apparatus of claim 1, wherein the apparatus further comprises at least one radiation sensor in addition to the first and second radiation sensors, the at least one radiation sensor in addition to the first and second radiation sensors being coupled to the processing circuitry.

50. The apparatus of claim 1, further comprising a plurality of ultrasound elements configured as high intensity focused ultrasound (HIFU) elements configured to apply HIFU.

51. The apparatus of claim 50, further comprising a support on which the plurality of radiation sources and the HIFU elements are disposed.

52. The apparatus of claim 1, wherein the first radiation source and the first radiation sensor are formed of different materials.

53. The apparatus of claim 52, wherein the first radiation source is an ultrasound source comprising lead zirconate titanate (PZT) and wherein the first radiation sensor is an ultrasound sensor comprising polyvinylidene difluoride (PVDF).

54. The apparatus of claim 43, wherein the at least one processor is configured to construct the 3D image of the volume by:

generating a 3D image of the volume from a plurality of measurements by using a compressive sensing image reconstruction process, the plurality of measurements obtained based at least partially on the respective source signals.

55. The apparatus of claim 54, wherein using the compressive sensing image reconstruction process comprises identifying a solution to a system of linear equations relating the plurality of measurements to a property of the volume being imaged.

56. The apparatus of claim 55, wherein the system of linear equations represents a linear approximation to a forward operator of a three-dimensional wave propagation equation.

57. An apparatus, comprising:

a plurality of radiation sources comprising a first radiation source, a second radiation source, and a third radiation source;

a first radiation sensor and a second radiation sensor; and

processing circuitry coupled to the first radiation sensor and the second radiation sensor and configured to receive and discriminate between, for each of the first and second radiation sensors, respective source signals emitted by the first, the second, and the third radiation sources,

wherein respective center points of the first radiation source, the second radiation source, the third radiation source, and the first radiation sensor define a first non-zero solid angle having its vertex positioned at the center point of the first radiation sensor, and

wherein the respective center points of the first radiation source, the second radiation source, and the third radiation source, together with a center point of the second radiation sensor define a second non-zero solid angle having its vertex positioned at the center point of the second radiation sensor.

58. The apparatus of claim 57, wherein the first radiation source is an ultrasound source.

59. The apparatus of claim 58, wherein the first radiation sensor and the second radiation are ultrasound radiation sensors.

60. The apparatus of claim 57, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least ten radiation sources of the plurality of radiation sources.

61. The apparatus of claim 60, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 100 radiation sources of the plurality of radiation sources.

62. The apparatus of claim 61, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 1,000 radiation sources of the plurality of radiation sources.

63. The apparatus of claim 60, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by between ten radiation sources and 10,000 radiation sources of the plurality of radiation sources.

64. The apparatus of claim 57, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 1% of the radiation sources of the plurality of radiation sources.

65. The apparatus of claim 64, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 10% of the radiation sources of the plurality of radiation sources.

66. The apparatus of claim 65, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 25% of the radiation sources of the plurality of radiation sources.

67. The apparatus of claim 66, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 50% of the radiation sources of the plurality of radiation sources.

68. The apparatus of claim 67, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 75% of the radiation sources of the plurality of radiation sources.

69. The apparatus of claim 68, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by at least 90% of the radiation sources of the plurality of radiation sources.

70. The apparatus of claim 69, wherein the processing circuitry is configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source signals emitted by all radiation sources of the apparatus.

71. The apparatus of claim 70, wherein the plurality of radiation sources comprises at least fifty radiation sources.

72. The apparatus of claim 57, wherein the plurality of radiation sources is arranged in three dimensions.

73. The apparatus of claim 57, wherein the plurality of radiation sources forms an array of at least two dimensions in which the plurality of radiation sources adopts a regular spacing.

74. The apparatus of claim 73, wherein the plurality of radiation sources is arranged in three dimensions.

75. The apparatus of claim 57, further comprising a plurality of radiation sensors including the first and second radiation sensors, wherein the plurality of radiation sensors is arranged in at least two dimensions.

76. The apparatus of claim 75, wherein the plurality of radiation sensors is arranged in three dimensions.

77. The apparatus of claim 75, wherein the plurality of radiation sensors forms an array of at least two dimensions in which the plurality of radiation sensors adopts a regular spacing.

78. The apparatus of claim 75, wherein the plurality of radiation sources forms an array of at least two dimensions, and wherein the plurality of radiation sensors forms an array of at least two dimensions.

79. The apparatus of claim 57, wherein the plurality of radiation sources and the first and second radiation sensors are configured to remain static during operation.

80. The apparatus of claim 57, wherein at least some radiation sources of the plurality of radiation sources are not spaced at regular intervals with respect to neighboring radiation sources.

81. The apparatus of claim 57, further comprising a plurality of radiation sensors including the first and second radiation sensors, wherein at least some radiation sensors of the plurality of radiation sensors are not spaced at regular intervals with respect to neighboring radiation sensors.

82. The apparatus of claim 57, wherein the plurality of radiation sources are physically coupled to a first mount and wherein the first and second radiation sensors are physically coupled to a second mount.

83. The apparatus of claim 82, wherein the first mount is flexible.

84. The apparatus of claim 82, wherein the first and second mounts are configured to be independently movable.

85. The apparatus of claim 84, further comprising a detector configured to detect an orientation and/or position of one or more of the plurality of radiation sources relative to one or both of the first and second radiation sensors.

86. The apparatus of claim 57, wherein the first and second radiation sensors are disposed on a first side of a plane and wherein the plurality of radiation sources are disposed on a second side of the plane.

87. The apparatus of claim 57, wherein the first, second, and third radiation sources and the first and second radiation sensors are collectively configured to operate in a transmissive modality.

88. The apparatus of claim 57, wherein directivity vectors of the first, second, and third radiation sources are incident upon the first and second radiation sensors.

89. The apparatus of claim 57, wherein at least one of the first, second, and third radiation sources is configured to alternately operate as a radiation source and a radiation sensor.

90. The apparatus of claim 89, wherein the first, second, and third radiation sources are coupled to the processing circuitry via parallel transmit and receive signal paths, and wherein the apparatus further comprises a switch for switchably coupling the first, second, and third radiation sources to either the transmit signal path or the receive signal path.

91. The apparatus of claim 57, wherein the plurality of radiation sources comprises at least two distinct arrays of radiation sources.

92. The apparatus of claim 91, wherein the at least two distinct arrays of radiation sources comprises three or more distinct arrays of radiation sources.

93. The apparatus of claim 92, wherein the processing circuitry coupled to the first radiation sensor and the second radiation sensor is configured to receive and discriminate between, for each of the first and second radiation sensors, respective source signals emitted by at least one radiation source in each of three distinct arrays of the three or more distinct arrays of radiation sources.

94. The apparatus of claim 57, wherein the processing circuitry is configured to perform a heterodyning function to receive and discriminate between the respective source signals.

95. The apparatus of claim 94, wherein the processing circuitry comprises a multiplier configured to receive an output signal from the first radiation sensor and a transmission signal to be emitted from the first radiation source, and wherein the multiplier is configured to provide an output signal to an analog-to-digital converter.

96. The apparatus of claim 57, wherein the processing circuitry comprises analog pulse compression circuitry configured to perform analog pulse compression on the respective source signals emitted by the first, second, and third radiation sources.

97. The apparatus of claim 57, wherein the processing circuitry comprises an amplification stage coupled directly to a detector.

98. The apparatus of claim 57, wherein the processing circuitry comprises an amplification stage coupled to an input of an analog-to-digital converter (ADC).

99. The apparatus of claim 57, wherein the plurality of radiation sources and the first and second radiation sensors are configured to characterize a volume, and wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) image of the volume based at least partially on the respective source signals emitted by the first, second, and third radiation sources and received by the first and second radiation sensors.

100. The apparatus of claim 99, wherein the processor comprises the processing circuitry.

101. The apparatus of claim 57, wherein the plurality of radiation sources and the first and second radiation sensors are configured to characterize a volume, and wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) temperature profile of the volume based at least partially on the respective source signals emitted by the first, second, and third radiation sources and received by the first and second radiation sensors.

102. The apparatus of claim 101, wherein the processor comprises the processing circuitry.

103. The apparatus of claim 57, wherein the first non-zero solid angle covers greater than π

/4 steradians.

104. The apparatus of claim 103, wherein the first non-zero angle covers greater than π

/2 steradians.

105. The apparatus of claim 103, wherein the second non-zero solid angle covers greater than π

/4 steradians.

106. The apparatus of claim 57, further comprising a plurality of radiation sensors in addition to the first and second radiations sensors, wherein the plurality of radiation sources, the first and second radiation sensors, and the plurality of radiation sensors in addition to the first and second radiation sensors collectively form a structure into which a subject may be inserted.

107. The apparatus of claim 106, wherein the structure is substantially a box with an open side via which the subject may be inserted, and wherein the first and second radiation sensors together with the plurality of radiation sensors in addition to the first and second radiation sensors form a side of the box.

108. The apparatus of claim 57, wherein the apparatus further comprises at least one radiation sensor in addition to the first and second radiation sensors, the at least one radiation sensor in addition to the first and second radiation sensors being coupled to the processing circuitry.

109. The apparatus of claim 57, further comprising a plurality of ultrasound elements configured as high intensity focused ultrasound (HIFU) elements configured to apply HIFU.

110. The apparatus of claim 109, further comprising a support on which the plurality of radiation sources and the HIFU elements are disposed.

111. The apparatus of claim 57, wherein the first radiation source and the first radiation sensor are formed of different materials.

112. The apparatus of claim 111, wherein the first radiation source is an ultrasound source comprising lead zirconate titanate (PZT) and wherein the first radiation sensor is an ultrasound sensor comprising polyvinylidene difluoride (PVDF).

113. The apparatus of claim 99, wherein the at least one processor is configured to construct the 3D image of the volume by:

generating a 3D image of the volume from a plurality of measurements by using a compressive sensing image reconstruction process, the plurality of measurements obtained based at least partially on the respective source signals.

114. The apparatus of claim 113, wherein using the compressive sensing image reconstruction process comprises identifying a solution to a system of linear equations relating the plurality of measurements to a property of the volume being imaged.

115. The apparatus of claim 114, wherein the system of linear equations represents a linear approximation to a forward operator of a three-dimensional wave propagation equation.

116. An apparatus, comprising:

a plurality of radiation sources configured to emit respective source radiation signals incident upon a volume to be characterized, the volume spanning orthogonal X, Y, and Z axes, the plurality of radiation sources occupying multiple locations in the X direction and multiple locations in the Y direction;

a plurality of radiation sensors separated from the plurality of radiation sources along the Z direction and configured to sense the respective source radiation signals emitted by the plurality of radiation sources, the plurality of radiation sensors occupying multiple locations in the X direction and multiple locations in the Y direction; and

processing circuitry coupled to the plurality of radiation sensors and configured to receive and discriminate between, for each of the plurality of radiation sensors, the respective source signals of the plurality of radiation sources.

117. The apparatus of claim 116, wherein the apparatus further comprises at least one additional radiation sensor in addition to the plurality of radiation sensors.

118. An apparatus, comprising:

a plurality of radiation sources configured to emit respective source radiation signals directed to be incident upon a subject such that the respective source radiation signals pass through the subject along paths bounding a volume;

a radiation sensor configured to receive the respective source radiation signals after they pass through the subject; and

processing circuitry coupled to the radiation sensor and configured to discriminate between the respective source radiation signals.

119. The apparatus of claim 118, wherein the plurality of radiation sources and the radiation sensor are static.

120. An apparatus, comprising:

a plurality of radiation sources configured to emit respective source radiation signals directed to be incident across a surface area of a subject;

first and second radiation sensors each configured to sense the respective source radiation signals; and

processing circuitry coupled to the first and second radiation sensors and configured to receive and discriminate between, for each of the first and second radiation sensors, the respective source radiation signals emitted by the plurality of radiation sources.

121. The apparatus of claim 120, wherein a first radiation source of the plurality of radiation sources is an ultrasound source.

122. The apparatus of claim 121, wherein the first radiation sensor and the second radiation are ultrasound radiation sensors.

123. The apparatus of claim 120, wherein the plurality of radiation sources comprises at least ten radiation sources.

124. The apparatus of claim 123, wherein the plurality of radiation sources comprises at least 100 radiation sources.

125. The apparatus of claim 124, wherein the plurality of radiation sources comprises at least 1,000 radiation sources.

126. The apparatus of claim 123, wherein the plurality of radiation sources comprises between ten radiation sources and 10,000 radiation sources.

127. The apparatus of claim 120, wherein the plurality of radiation sources is arranged in three dimensions.

128. The apparatus of claim 120, wherein the plurality of radiation sources forms an array of at least two dimensions in which the plurality of radiation sources adopts a regular spacing.

129. The apparatus of claim 128, wherein the plurality of radiation sources is arranged in three dimensions.

130. The apparatus of claim 120, further comprising a plurality of radiation sensors including the first and second radiation sensors, wherein the plurality of radiation sensors is arranged in at least two dimensions.

131. The apparatus of claim 130, wherein the plurality of radiation sensors is arranged in three dimensions.

132. The apparatus of claim 130, wherein the plurality of radiation sensors forms an array of at least two dimensions in which the plurality of radiation sensors adopts a regular spacing.

133. The apparatus of claim 130, wherein the plurality of radiation sources forms an array of at least two dimensions, and wherein the plurality of radiation sensors forms an array of at least two dimensions.

134. The apparatus of claim 120, wherein the plurality of radiation sources and the first and second radiation sensors are configured to remain static during operation.

135. The apparatus of claim 120, wherein at least some radiation sources of the plurality of radiation sources are not spaced at regular intervals with respect to neighboring radiation sources.

136. The apparatus of claim 120, further comprising a plurality of radiation sensors including the first and second radiation sensors, wherein at least some radiation sensors of the plurality of radiation sensors are not spaced at regular intervals with respect to neighboring radiation sensors.

137. The apparatus of claim 120, wherein the plurality of radiation sources are physically coupled to a first mount and wherein the first and second radiation sensors are physically coupled to a second mount.

138. The apparatus of claim 137, wherein the first mount is flexible.

139. The apparatus of claim 137, wherein the first and second mounts are configured to be independently movable.

140. The apparatus of claim 139, further comprising a detector configured to detect an orientation and/or position of the plurality of radiation sources relative to the first and second radiation sensors.

141. The apparatus of claim 120, wherein the first and second radiation sensors are disposed on a first side of a plane and wherein the plurality of radiation sources are disposed on a second side of the plane.

142. The apparatus of claim 120, wherein the plurality of radiation sources and the first and second radiation sensors are collectively configured to operate in a transmissive modality.

143. The apparatus of claim 120, wherein directivity vectors of first, second, and third radiation sources of the plurality of radiation sources are incident upon the first and second radiation sensors.

144. The apparatus of claim 120, wherein at least one radiation source of the plurality of radiation sources is configurable to alternately operate as a radiation source and a radiation sensor.

145. The apparatus of claim 144, wherein the at least one radiation source is coupled to the processing circuitry via parallel transmit and receive signal paths, and wherein the apparatus further comprises a switch for switchably coupling the at least one radiation source to either the transmit signal path or the receive signal path.

146. The apparatus of claim 120, wherein the plurality of radiation sources comprises at least two distinct arrays of radiation sources.

147. The apparatus of claim 146, wherein the at least two distinct arrays of radiation sources comprises three or more distinct arrays of radiation sources.

148. The apparatus of claim 147, wherein the processing circuitry coupled to the first radiation sensor and the second radiation sensor is configured to receive and discriminate between, for each of the first and second radiation sensors, respective source signals emitted by at least one radiation source in each of three distinct arrays of the three or more distinct arrays of radiation sources.

149. The apparatus of claim 120, wherein the processing circuitry is configured to perform a heterodyning function to detect and discriminate the respective source signals.

150. The apparatus of claim 149, wherein the processing circuitry comprises a multiplier configured to receive an output signal from the first radiation sensor and a transmission signal to be emitted from a first radiation source of the plurality of radiation sources, and wherein the multiplier is configured to provide an output signal to an analog-to-digital converter.

151. The apparatus of claim 120, wherein the processing circuitry comprises analog pulse compression circuitry configured to perform analog pulse compression on the respective source signals.

152. The apparatus of claim 120, wherein the processing circuitry comprises an amplification stage coupled directly to a detector.

153. The apparatus of claim 120, wherein the processing circuitry comprises an amplification stage coupled to an input of an analog-to-digital converter (ADC).

154. The apparatus of claim 120, wherein the plurality of radiation sources and the first and second radiation sensors are configured to characterize at least part of the subject, and wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) image of the part of the subject based at least partially on the respective source signals.

155. The apparatus of claim 154, wherein the processor comprises the processing circuitry.

156. The apparatus of claim 120, wherein the plurality of radiation sources and the first and second radiation sensors are configured to characterize at least part of the subject, and wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) temperature profile of the part of the subject based at least partially on the respective source signals.

157. The apparatus of claim 156, wherein the processor comprises the processing circuitry.

158. The apparatus of claim 120, wherein the surface area is between approximately 1 cm² and approximately 100 cm².

159. The apparatus of claim 158, wherein the surface area is between approximately 50 cm² and approximately 100 cm².

160. An apparatus, comprising:

three radiation sources arranged in a multi-dimensional, non-linear arrangement and configured to produce respective source signals;

a plurality of radiation sensors; and

processing circuitry coupled to the plurality of radiation sensors and configured to receive and discriminate between, for at least one radiation sensor of the plurality of radiation sensors, the respective source signals produced by the three radiation sources.

161. The apparatus of claim 160, wherein a first radiation source of the three radiation sources is an ultrasound source.

162. The apparatus of claim 161, wherein the at least one radiation sensor is an ultrasound radiation sensor.

163. The apparatus of claim 160, further comprising a plurality of radiation sources including the three radiation sources, and wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by at least ten radiation sources of the plurality of radiation sources.

164. The apparatus of claim 163, wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiations sensor, the respective source signals emitted by at least 100 radiation sources of the plurality of radiation sources.

165. The apparatus of claim 164, wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by at least 1,000 radiation sources of the plurality of radiation sources.

166. The apparatus of claim 163, wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by between ten radiation sources and 10,000 radiation sources of the plurality of radiation sources.

167. The apparatus of claim 160, further comprising a plurality of radiation sources including the three radiation sources, and wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by at least 1% of the radiation sources of the plurality of radiation sources.

168. The apparatus of claim 167, wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by at least 10% of the radiation sources of the plurality of radiation sources.

169. The apparatus of claim 168, wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by at least 25% of the radiation sources of the plurality of radiation sources.

170. The apparatus of claim 169, wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by at least 50% of the radiation sources of the plurality of radiation sources.

171. The apparatus of claim 170, wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by at least 75% of the radiation sources of the plurality of radiation sources.

172. The apparatus of claim 171, wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by at least 90% of the radiation sources of the plurality of radiation sources.

173. The apparatus of claim 172, wherein the processing circuitry is configured to receive and discriminate between, for the at least one radiation sensor, the respective source signals emitted by all radiation sources of the apparatus.

174. The apparatus of claim 173, wherein the plurality of radiation sources comprises at least fifty radiation sources.

175. The apparatus of claim 160, further comprising a fourth radiation source, wherein the four radiation sources are arranged in three dimensions.

176. The apparatus of claim 160, comprising a plurality of radiation sources including the three radiation sources, wherein the plurality of radiation sources forms an array of at least two dimensions in which the plurality of radiation sources adopts a regular spacing.

177. The apparatus of claim 176, wherein the plurality of radiation sources is arranged in three dimensions.

178. The apparatus of claim 160, wherein the plurality of radiation sensors is arranged in at least two dimensions.

179. The apparatus of claim 178, wherein the plurality of radiation sensors is arranged in three dimensions.

180. The apparatus of claim 178, wherein the plurality of radiation sensors forms an array of at least two dimensions in which the plurality of radiation sensors adopts a regular spacing.

181. The apparatus of claim 178, comprising a plurality of radiation sources including the three radiation sources, wherein the plurality of radiation sources forms an array of at least two dimensions, and wherein the plurality of radiation sensors forms an array of at least two dimensions.

182. The apparatus of claim 160, wherein the three radiation sources and the plurality of radiation sensors are configured to remain static during operation.

183. The apparatus of claim 160, comprising a plurality of radiation sources including the three radiation sources, wherein at least some radiation sources of the plurality of radiation sources are not spaced at regular intervals with respect to neighboring radiation sources.

184. The apparatus of claim 160, wherein at least some radiation sensors of the plurality of radiation sensors are not spaced at regular intervals with respect to neighboring radiation sensors.

185. The apparatus of claim 160, wherein the three radiation sources are physically coupled to a first mount and wherein the plurality of radiation sensors are physically coupled to a second mount.

186. The apparatus of claim 185, wherein the first mount is flexible.

187. The apparatus of claim 185, wherein the first and second mounts are configured to be independently movable.

188. The apparatus of claim 187, further comprising a detector configured to detect an orientation and/or position of the three radiation sources relative to the plurality of radiation sensors.

189. The apparatus of claim 160, wherein the plurality of radiation sensors are disposed on a first side of a plane and wherein the three radiation sources are disposed on a second side of the plane.

190. The apparatus of claim 160, wherein the three radiation sources and the plurality of radiation sensors are collectively configured to operate in a transmissive modality.

191. The apparatus of claim 160, wherein directivity vectors of the three radiation sources are incident upon first and second radiation sensors of the plurality of radiation sensors.

192. The apparatus of claim 160, wherein at least one radiation source of the three radiation sources is configurable to alternately operate as a radiation source and a radiation sensor.

193. The apparatus of claim 192, wherein the at least one radiation source is coupled to the processing circuitry via parallel transmit and receive signal paths, and wherein the apparatus further comprises a switch for switchably coupling the at least one radiation source to either the transmit signal path or the receive signal path.

194. The apparatus of claim 160, wherein the apparatus comprises at least two distinct arrays of radiation sources, and wherein each of the three radiation sources belongs to at least one of the at least two distinct arrays.

195. The apparatus of claim 194, wherein the at least two distinct arrays of radiation sources comprises three or more distinct arrays of radiation sources.

196. The apparatus of claim 195, wherein the processing circuitry coupled to the plurality of radiation sensors is configured to receive and discriminate between, for the at least one radiation sensor, respective source signals emitted by at least one radiation source in each of three distinct arrays of the three or more distinct arrays of radiation sources.

197. The apparatus of claim 160, wherein the processing circuitry is configured to perform a heterodyning function to detect and discriminate the respective source signals.

198. The apparatus of claim 196, wherein the processing circuitry comprises a multiplier configured to receive an output signal from a first radiation sensor of the plurality of radiation sensors and a transmission signal to be emitted from a first radiation source of the three radiation sources, and wherein the multiplier is configured to provide an output signal to an analog-to-digital converter.

199. The apparatus of claim 160, wherein the processing circuitry comprises analog pulse compression circuitry configured to perform analog pulse compression on the respective source signals.

200. The apparatus of claim 160, wherein the processing circuitry comprises an amplification stage coupled directly to a detector.

201. The apparatus of claim 160, wherein the processing circuitry comprises an amplification stage coupled to an input of an analog-to-digital converter (ADC).

202. The apparatus of claim 160, wherein the three radiation sources and the plurality of radiation sensors are configured to characterize at least part of a subject, and wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) image of the part of the subject based at least partially on the respective source signals.

203. The apparatus of claim 202, wherein the processor comprises the processing circuitry.

204. The apparatus of claim 160, wherein the three radiation sources and the plurality of radiation sensors are configured to characterize at least part of a subject, and wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) temperature profile of the part of the subject based at least partially on the respective source signals.

205. The apparatus of claim 204, wherein the processor comprises the processing circuitry.

206. An apparatus, comprising:

a plurality of radiation sources arranged nonlinearly in a first plane or three-dimensional space and configured to emit respective source signals through a volume to be characterized;

a plurality of radiation sensors arranged nonlinearly in a second plane or three-dimensional space and configured to oppose the first plane or three-dimensional space, and the volume, wherein each of the plurality of radiation sensors is configured to sense the source signals emitted by each of the plurality of radiation sources after the source signals pass through the volume; and

processing circuitry coupled to the plurality of radiation sensors and configured to receive and discriminate between the source signals sensed by the plurality of radiation sensors, the received signals being indicative of at least one characteristic of the volume.

207. The apparatus of claim 206, wherein the plurality of radiation sources is arranged nonlinearly in a plane.

208. The apparatus of claim 207, wherein the plane is the first plane, and wherein the plurality of radiation sensors is arranged nonlinearly in the second plane.

209. The apparatus of claim 207, wherein the plurality of radiation sensors is arranged nonlinearly in a three-dimensional space.

210. The apparatus of claim 206, wherein the plurality of radiation sources is arranged nonlinearly in a three-dimensional space.

211. The apparatus of claim 210, wherein the plurality of radiation sensors is arranged nonlinearly in a plane.

212. The apparatus of claim 210, wherein the three-dimensional space is a first three-dimensional space, and wherein the plurality of radiation sensors is arranged nonlinearly in a second three-dimensional space.

213. The apparatus of claim 206, wherein:

the received signals are indicative of the appearance of the volume; and

the apparatus further comprises image processing circuitry configured to generate a three-dimensional image of the volume based on the received signals.

214. The apparatus of claim 206, wherein the at least one characteristic of the volume is a density of the volume.

215. The apparatus of claim 206, wherein the at least one characteristic of the volume is a refractive index of the volume.

216. The apparatus of claim 206, wherein the plurality of radiation sources includes between ten and 10,000 radiation sources.

217. The apparatus of claim 206, wherein the plurality of radiation sensors includes between ten and 10,000 radiation sensors.

218. The apparatus of claim 206, wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) image of the volume based at least partially on the received signals.

219. The apparatus of claim 218, wherein the processor comprises the processing circuitry.

220. The apparatus of claim 206, wherein the apparatus comprises a processor configured to construct a three-dimensional (3D) temperature profile of the volume based at least partially on the received signals.

221. The apparatus of claim 220, wherein the processor comprises the processing circuitry.

222. An apparatus comprising:

multiple arrays of ultrasound sources configured to emit respective source signals;

an array of ultrasound sensors configured to sense the respective source signals; and

processing circuitry coupled to the array of ultrasound sensors and configured to receive and discriminate between, for at least one ultrasound sensor of the array of ultrasound sensors, the respective source signals of at least one ultrasound source from each of at least two arrays of the multiple arrays of ultrasound sources.

223. The apparatus of claim 222, wherein the multiple arrays of ultrasound sources consist of two arrays of ultrasound sources.

224. The apparatus of claim 222, wherein the multiple arrays of ultrasound sources comprise three arrays of ultrasound sources.

225. The apparatus of claim 224, wherein the three arrays of ultrasound sources and the array of ultrasound sensors are configured, in combination, to substantially surround a subject.

226. The apparatus of claim 222, wherein the multiple arrays of ultrasound sources comprise four arrays of ultrasound sources.

227. The apparatus of claim 226, wherein the four arrays of ultrasound sources and the array of ultrasound sensors are configured, in combination, to substantially form an imaging structure configured to receive a subject.

228. An apparatus, comprising:

a plurality of ultrasound sensors forming a two-dimensional or three-dimensional ultrasound sensor arrangement; and

processing circuitry coupled to the plurality of ultrasound sensors and configured to process signals from the plurality of ultrasound sensors to produce ultrasound imaging data indicative of a subject imaged at least in part by the plurality of ultrasound sensors, wherein at least some ultrasound sensors of the plurality of ultrasound sensors are not spaced at regular intervals with respect to neighboring ultrasound sensors.

229. The apparatus of claim 228, wherein the at least some ultrasound sensors of the plurality of ultrasound sensors are not uniformly spaced along a line with respect to neighboring ultrasound sensors.

230. The apparatus of claim 228, wherein the at least some ultrasound sensors of the plurality of ultrasound sensors are not uniformly spaced relative to a grid.

231. The apparatus of claim 228, further comprising a support, wherein the plurality of ultrasound sensors are physically coupled to the support and configured in a fixed relationship with respect to each other.

232. The apparatus of claim 228, wherein spacing between neighboring ultrasound sensors of the plurality of ultrasound sensors is closer at an edge of the ultrasound sensor arrangement than at a center of the ultrasound sensor arrangement.

233. The apparatus of claim 228, wherein spacing between neighboring ultrasound sensors of the plurality of ultrasound sensors is closer at a center of the ultrasound sensor arrangement than at an edge of the ultrasound sensor arrangement.

234. The apparatus of claim 228, wherein the plurality of ultrasound sensors assume a substantially random layout.

235. The apparatus of claim 228, wherein the ultrasound sensor arrangement is substantially an array in which a substantial percentage of ultrasound sensors of the plurality of ultrasound sensors are spaced at regular intervals with respect to neighboring ultrasound sensors, and wherein placement of the at least some ultrasound sensors represents deviation from the array.

236. The apparatus of claim 235, wherein the ultrasound sensor arrangement is substantially planar, wherein the array substantially conforms to a grid, and wherein the placement of the at least some ultrasound sensors represents deviation from the grid.

237. The apparatus of claim 228, wherein a majority of the ultrasound sensors of the ultrasound sensor arrangement are not spaced at regular intervals with respect to neighboring ultrasound sensors.

238. The apparatus of claim 228, wherein a substantial percentage of ultrasound sensors of the ultrasound sensor arrangement are not spaced at regular intervals with respect to neighboring ultrasound sensors.

239. The apparatus of claim 228, further comprising a plurality of ultrasound sources forming a two-dimensional or three-dimensional ultrasound source arrangement, wherein spacing between at least some ultrasound sources of the ultrasound source arrangement differs from spacing between at least some ultrasound sensors of the ultrasound sensor arrangement.

240. The apparatus of claim 228, wherein the ultrasound sensor arrangement is formed on a first support and wherein the ultrasound source arrangement is formed on a second support distinct from the first support.

241. An apparatus, comprising:

a plurality of radiation sensors forming a two-dimensional or three-dimensional sensor arrangement and configured to receive radiation of wavelength λ

emitted by one or more radiation sources,

wherein a spacing between a first radiation sensor of the plurality of radiation sensors and its nearest neighboring radiation sensor of the plurality of radiation sensors is greater than λ

/2.

242. The apparatus of claim 241, wherein at least one radiation sensor of the plurality of radiation sensors is an ultrasound sensor.

243. The apparatus of claim 242, wherein the plurality of radiation sensors are ultrasound sensors.

244. The apparatus of claim 241, wherein the plurality of radiation sensors are arranged in a two-dimensional or three-dimensional array in which the plurality of radiation sensors are regularly spaced.

245. The apparatus of claim 244, wherein the plurality of radiation sensors are arranged in a three-dimensional array.

246. The apparatus of claim 244, wherein a minimum spacing between any radiation sensor of the plurality of radiation sensors and its nearest neighbor is greater than λ

/2.

247. The apparatus of claim 244, wherein the array is characterized by a pitch between radiation sensors, and wherein the pitch is greater than λ

/2.

248. The apparatus of claim 244, wherein the array is characterized by a non-uniform pitch between radiation sensors, and wherein a minimum pitch of the array is greater than λ

/2.

249. The apparatus of claim 241, wherein the wavelength λ

corresponds to a center frequency of the radiation.

250. The apparatus of claim 241, further comprising a plurality of radiation sources including the one or more radiation sources, wherein the plurality of radiation sources form a two-dimensional or three-dimensional arrangement of radiation sources and are configured to emit the radiation.

251. The apparatus of claim 250, wherein a spacing between a first radiation source of the plurality of radiation sources and its nearest neighboring radiation source of the plurality of radiation sources is greater than λ

/2.

252. The apparatus of claim 250, wherein a minimum spacing between any radiation source of the plurality of radiation sources and its nearest neighbor is greater than λ

/2.

253. The apparatus of claim 250, wherein the plurality of radiation sensors are coupled to a first support and wherein the plurality of radiation sources are coupled to a second support distinct from the first support.

254. The apparatus of claim 253, wherein the first and second supports are independently movable relative to each other.

255. The apparatus of claim 250, wherein the plurality of radiation sources are arranged in a substantially planar configuration in a first plane and wherein the plurality of radiation sensors are arranged in a substantially planar configuration in a second plane.

256. The apparatus of claim 250, wherein the plurality of radiation sources and the plurality of radiation sensors are configured in combination to characterize a volume at least in part based on the radiation emitted by the one or more radiation sources.

257. The apparatus of claim 256, further comprising processing circuitry coupled to the plurality of radiation sensors, wherein the processing circuitry is configured to construct a three-dimensional (3D) image of the volume based at least partially on the radiation emitted by the one or more radiation sources.

258. The apparatus of claim 256, further comprising processing circuitry coupled to the plurality of radiation sensors, wherein the processing circuitry is configured to construct a three-dimensional (3D) temperature profile of the volume based at least partially on the radiation emitted by the one or more radiation sources.

259. The apparatus of claim 241, wherein the plurality of radiation sensors and the one or more radiation sources are collectively configured to operate in a transmissive modality.

260. The apparatus of claim 259, wherein the plurality of radiation sensors are ultrasound sensors and wherein the one or more radiation sources are ultrasound sources, and wherein the plurality of radiations sensors and the one or more radiation sources are collectively configured to operate in a transmissive ultrasound modality.

261. The apparatus of claim 241, further comprising processing circuitry coupled to the plurality of radiation sensors and configured to receive and discriminate between, for at least one radiation sensor of the plurality of radiation sensors, the radiation of wavelength λ

emitted by the one or more radiation sources.

262. The apparatus of claim 241, wherein λ

represents a wavelength of a fundamental mode frequency of radiation emitted by the one or more radiation sources, and wherein the spacing between the first radiation sensor of the plurality of radiation sensors and its nearest neighboring radiation sensor of the plurality of radiation sensors is greater than 2λ

.

263. The apparatus of claim 262, wherein the spacing between the first radiation sensor of the plurality of radiation sensors and its nearest neighboring radiation sensor of the plurality of radiation sensors is greater than 3λ

.

264. An apparatus, comprising:

a plurality of N×

M radiation sources forming a two-dimensional or three-dimensional radiation source arrangement and configured to produce a first plurality of N×

M respective source signals, wherein N is greater than or equal to M;

a plurality of X×

Y radiation sensors forming a two-dimensional or three-dimensional radiation sensor arrangement; and

processing circuitry coupled to the plurality of radiation sensors and configured to discriminate between greater than (X×

Y×

N) received signals from the N×

M respective source signals.

265. The apparatus of claim 264, wherein at least one of the plurality of radiation sensors is an ultrasound sensor and wherein at least one of the (X×

Y×

N) received signals is an ultrasound signal.

266. The apparatus of claim 264, wherein the plurality of radiation sources is a plurality of ultrasound sources and wherein the plurality of radiation sensors is a plurality of ultrasound sensors.

267. The apparatus of claim 264, wherein the processing circuitry is configured to discriminate between up to (X×

Y×

N×

M) received signals from the N×

M respective source signals.

268. The apparatus of claim 267, wherein the processing circuitry is configured to discriminate between approximately (X×

Y×

N×

M) received signals from the N×

M respective source signals.

269. The apparatus of claim 267, wherein N=M =X =Y.

270. The apparatus of claim 264, wherein N=M =X =Y.

271. The apparatus of claim 264, wherein the plurality of N×

M radiation sources are configured to produce substantially concurrently the first plurality of N×

M respective source signals.

272. The apparatus of claim 264, comprising a processor configured to construct a three-dimensional (3D) image of a volume based at least partially on the received signals.

273. The apparatus of claim 272, wherein the processor comprises the processing circuitry.

274. The apparatus of claim 264, comprising a processor configured to construct a three-dimensional (3D) temperature profile of a volume based at least partially on the received signals.

275. The apparatus of claim 274, wherein the processor comprises the processing circuitry.

276. An apparatus, comprising:

a plurality of ultrasound elements in a fixed relationship with respect to each other and configured as ultrasound imaging elements; and

a detector configured to dynamically detect an orientation and/or position of the plurality of ultrasound elements.

277. The apparatus of claim 276, wherein the detector is located separately from the plurality of ultrasound elements.

278. The apparatus of claim 276, wherein the orientation and/or position of the plurality of ultrasound elements is a relative orientation and/or relative position relative to a second plurality of ultrasound elements.

279. The apparatus of claim 278, further comprising the second plurality of ultrasound elements, the second plurality of ultrasound elements being configured as ultrasound imaging elements.

280. The apparatus of claim 279, wherein the detector is located separately from the plurality and the second plurality of ultrasound elements.

281. The apparatus of claim 278, wherein the detector is configured to dynamically detect the relative orientation of the plurality of ultrasound elements relative to the second plurality of ultrasound elements.

282. The apparatus of claim 278, wherein the detector is configured to dynamically detect the relative position of the plurality of ultrasound elements relative to the second plurality of ultrasound elements.

283. The apparatus of claim 276, wherein the detector is integrated with the plurality of ultrasound elements.

284. The apparatus or claim 276, wherein the first plurality of ultrasound elements is physically coupled to a first support configured to maintain the plurality of ultrasound elements in the fixed relationship with respect to each other.

285. The apparatus of claim 284, wherein the detector is physically coupled to the first support.

286. The apparatus of claim 276, wherein the ultrasound elements are disposed on a flexible support.

287. The apparatus of claim 276, wherein the detector comprises an accelerometer.

288. The apparatus of claim 276, wherein the detector comprises a gyroscope.

289. The apparatus of claim 276, wherein the detector comprises an inertial navigation device.

290. The apparatus of claim 276, wherein the detector comprises a range finder.

291. The apparatus of claim 276, wherein the detector comprises an inclinometer.

292. The apparatus of claim 276, wherein the ultrasound elements are arranged in two dimensions.

293. The apparatus of claim 276, wherein the ultrasound elements are arranged in three dimensions.

294. The apparatus of claim 276, wherein the ultrasound elements are arranged in a substantially planar arrangement.

295. The apparatus of claim 276, wherein the ultrasound elements are arranged in an array in which the ultrasound elements are regularly spaced from each other.

296. A method, comprising:

accessing a plurality of measurements of a subject, the plurality of measurements resulting at least in part from the detection of ultrasound radiation by an ultrasound imaging device operating in a transmissive modality; and

generating, using at least one processor, at least one volumetric image of the subject from the plurality of measurements by using a compressive sensing image reconstruction process.

297. The method of claim 296, wherein said generating comprises identifying a solution to a system of linear equations relating the plurality of measurements to a property of the subject.

298. The method of claim 297, wherein identifying the solution to the system of linear equations comprises using a sparsity constraint to identify the solution.

299. The method of claim 297, wherein identifying the solution to the system of linear equations comprises using a three-dimensional basis.

300. The method of claim 299, wherein the three-dimensional basis is a three-dimensional discrete cosine basis, a three-dimensional discrete sine basis, or a three-dimensional wavelet basis.

301. The method of claim 297, wherein the ultrasound imaging device comprises at least one source and at least one sensor, wherein the method further comprises:

obtaining the system of linear equations based at least in part on geometry information indicating location of the at least one source and the at least one sensor.

302. The method of claim 297, wherein the ultrasound imaging device comprises a plurality of sources and a plurality of sensors, and wherein said generating comprises using geometry information indicating location of at least a first source in the plurality of sources and at least a first sensor in the plurality of sensors.

303. The method of claim 302, wherein the at least one volumetric image comprises a plurality of voxels, and wherein said generating comprises using the geometry information to calculate a value indicative of a length of a portion of a line through a voxel in the plurality of voxels, wherein the line intersects the voxel, and wherein the line connects the first source and the first sensor.

304. The method of claim 296, wherein the plurality of measurements comprises a plurality of time-of-flight measurements and/or a plurality of attenuation measurements.

305. The method of claim 296, wherein the plurality of measurements comprises the plurality of time-of-flight measurements and the plurality of attenuation measurements, and wherein said generating comprises using Kramers-Kronig relations to calculate the at least one volumetric image.

306. The method of claim 296, wherein the plurality of measurements resulted at least in part from the detection, by the ultrasound imaging device, of ultrasound radiation forward scattered from the subject.

307. A method, comprising:

accessing at least one volumetric image of a subject calculated using a plurality of measurements of the subject, the plurality of measurements resulting at least in part from the detection of ultrasound radiation by an ultrasound imaging device operating in a transmissive modality;

applying stereoscopic conversion to the at least one volumetric image to obtain a first stereoscopic image and a second stereoscopic image; and

displaying three-dimensionally, via a three-dimensional display, the first stereoscopic image and the second stereoscopic image to a viewer.

308. The method of claim 307, wherein the at least one volumetric image comprises an attenuation value for each of a first voxel and second voxel in the volumetric image, wherein the attenuation value for the first voxel is indicative of an amount of attenuation of an ultrasound signal passing through the first voxel.

309. The method of claim 307, wherein the at least one volumetric image comprises a speed of sound value for each of a first voxel and a second voxel in the volumetric image, wherein the speed of sound value for the first voxel is indicative of a speed of an ultrasound signal passing through the first voxel.

310. The method of claim 307, wherein said accessing comprises accessing multiple time-dependent volumetric images of the subject, wherein said applying comprises applying the stereoscopic conversion algorithm to the multiple volumetric images to obtain multiple stereoscopic images including the first stereoscopic image and the second stereoscopic image, and wherein said displaying comprises displaying, via the three-dimensional display, the multiple stereoscopic images to a viewer in a time-dependent manner.

311. The method of claim 307, wherein the at least one volumetric image of the subject comprises accessing a plurality of volumetric images of the subject, wherein the method further comprises combining the plurality of volumetric images of the subject to form a fused volumetric image of the subject, and wherein said applying comprises applying the stereoscopic conversion to the fused volumetric image to obtain the first and the second stereoscopic images.

312. The method of claim 311, wherein combining the plurality of volumetric images comprises associating a first visual cue to values in the fused image originating from a first of the plurality of volumetric images and associating a second visual cue, different from the first visual cue, to values in the fused image originating from a second of the plurality of images.

313. The method of claim 307, further comprising:

applying at least one image analysis technique to the at least one volumetric image to identify at least one shape in the at least one volumetric image; and

updating the at least one volumetric image, prior to applying the stereoscopic conversation to the at least one volumetric image, so that the at least one volumetric image shows the identified at least one shape when displayed.

314. The method of claim 307, wherein the three-dimensional display is a lenticular display.

315. The method of claim 307, wherein said displaying comprises presenting the first stereoscopic image and the second stereoscopic image with different polarizations.

316. The method of claim 307, further comprising:

in response to said displaying, receiving input from the viewer specifying an update to how the at least one volumetric image is displayed; and

updating how the at least one volumetric is displayed three dimensionally, via the three-dimensional display, based on the received input.

317. A method, comprising:

accessing at least one volumetric image of a subject calculated using a plurality of measurements of the subject, the plurality of measurements resulting at least in part from the detection of radiation by an imaging device;

identifying a point of view within the subject, wherein identifying the point of view comprises identifying a location within the subject; and

displaying the at least one volumetric image to a viewer from the identified point of view.

318. The method of claim 317, wherein the imaging device is an ultrasound imaging device.

319. The method of claim 318, wherein the plurality of measurements resulted at least in part from the detection of ultrasound radiation by the ultrasound imaging device operating in a transmissive modality.

320. The method of claim 317, wherein said displaying comprises displaying three-dimensionally, via a three-dimensional display, the at least one volumetric image to the viewer from the identified point of view.

321. The method of claim 317, wherein said identifying comprises identifying a plurality of points of view within the subject, including the point of view, and wherein said displaying comprises displaying the at least one volumetric image to the viewer from at least two of the identified points of view.

322. The method of claim 321, wherein locations corresponding to the plurality of points of view lie along a path through the subject, and wherein said displaying comprises displaying the at least one volumetric image to the viewer in a sequence corresponding to an ordering of the locations along the path.

323. The method of claim 322, wherein said displaying comprises displaying, via a three-dimensional display, the at least one volumetric image from the at least two of the identified points of view.

324. The method of claim 317, wherein said identifying further comprises identifying an angle within the subject.

325. The method of claim 317, wherein said identifying comprises identifying the point of view based at least in part on input received from the viewer, wherein the input specifies the point of view.

326. The method of claim 317, wherein said identifying comprises automatically identifying the point of view at least in part by applying an image analysis technique to the at least one volumetric image.

327. A method, comprising:

displaying a volumetric image of a subject to a user three dimensionally via a three-dimensional display;

obtaining user input identifying at least one target point in the volumetric image corresponding to at least one location in the subject; and

applying high intensity focused ultrasound (HIFU) energy to the at least one location in the subject.

328. The method of claim 327, wherein said obtaining comprises obtaining the user input at least in part by detecting motion of the user and/or a pointing device of the user through the displayed volumetric image.

329. The method of claim 327, wherein said obtaining comprises identifying a plurality of target points in the volumetric image corresponding to a plurality of locations along a path through the subject.

330. The method of claim 327, wherein said applying comprises applying the HIFU energy based at least in part on at least one HIFU parameter, the method further comprising:

calculating the at least one HIFU control parameter.

331. The method of claim 330, comprising performing said calculating based at least in part on user input specifying an amount of energy and/or power to apply to the at least one location in the subject.

332. The method of claim 330, wherein the at least one HIFU control parameter specifies how to focus the HIFU energy to obtain a focused HIFU beam.

333. The method of claim 332, wherein performing said calculating comprises using a beamforming technique.

334. The method of claim 332, wherein performing said calculating comprises using a time-reversal technique.

335. The method of claim 327, wherein the three-dimensional display is a lenticular display.

336. The method of claim 327, wherein said displaying comprises applying stereoscopic conversion to the volumetric image to obtain a first stereoscopic image and a second stereoscopic image and displaying three-dimensionally, via the three-dimensional display, the first stereoscopic image and the second stereoscopic image to the user.

337. A method, comprising:

applying high intensity focused ultrasound (HIFU) energy to a subject;

identifying, based at least in part on an image of the subject, a first target point in the subject to which the HIFU energy was applied;

automatically determining whether to continue applying the HIFU energy to the first target point at least in part by comparing the first target point to a planned target point; and

continuing to apply the HIFU energy to the first target point based at least in part on the comparison.

338. The method of claim 337, further comprising:

applying the HIFU energy to the planned target point, based at least in part on determining a difference between the first target point and the planned target point as a result of the comparison.

339. The method of claim 337, wherein the image is a volumetric image obtained by an imaging device.

340. The method of claim 339, wherein the imaging device is an ultrasound imaging device operating in a transmissive modality.

341. The method of claim 340, wherein the ultrasound imaging device is further configured to perform said applying.

342. The method of claim 337, wherein said identifying is performed, automatically, by using a statistical inference technique.

343. The method of claim 337, wherein said automatically determining comprises determining whether a difference between a position of the first target point and a position of the planned target point is below a threshold.

344. A method, comprising:

accessing a plurality of measurements of a subject, the plurality of measurements resulting at least in part from the detection of ultrasound radiation by an ultrasound imaging device, the ultrasound imaging device comprising a plurality of ultrasound sources including a first ultrasound source and a plurality of ultrasound sensors including a first ultrasound sensor;

calculating, using at least one processor, a first image of the subject from the plurality of measurements by using first path length information for a path between the first ultrasound source and the first ultrasound sensor;

calculating, using the at least one processor, second path length information at least in part by computing refractive paths using the first image; and

calculating, using the at least one processor, a second image of the subject from the plurality of measurements by using the second path length information.

345. The method of claim 344, wherein said calculating the second path length information comprises computing refractive paths using Fermat'"'"'s principle.

346. The method of claim 345, wherein said calculating the second path length information further comprises obtaining a solution to a differential equation.

347. The method of claim 344, wherein said calculating the first image of the subject comprises calculating the first image by using a compressive sensing image reconstruction technique.

348. The method of claim 347, wherein said calculating the second image of the subject comprises calculating the second image by using the compressive sensing image reconstruction technique.

349. The method of claim 348, wherein using the compressive sensing image reconstruction technique to calculate the first image of the subject comprises identifying a solution to a first system of linear equations relating the plurality of measurements to a property of the subject, wherein the first system of linear equations was obtained based at least in part on first path length information.

350. The method of claim 349, wherein using the compressive sensing image reconstruction technique to calculate the second image of the subject comprises identifying a solution to a second system of linear equations relating the plurality of measurements to the property of the subject, wherein the second system of linear equations was obtained based at least in part on second path length information.

351. The method of claim 344, wherein the first image of the subject is a volumetric image of the subject.

352. The method of claim 344, wherein the second image of the subject is a volumetric image of the subject.

353. The method of claim 344, wherein the plurality of measurements was obtained by the ultrasound imaging device operating in a transmissive modality.

354. An apparatus, comprising:

a first ultrasound element configured as an ultrasound source;

transmit circuitry coupled to the ultrasound source and configured to provide to the ultrasound source a transmission signal to be emitted by the ultrasound source;

a second ultrasound element configured as an ultrasound sensor;

processing circuitry coupled to the ultrasound sensor and configured to process a signal emitted by the ultrasound source and received by the ultrasound sensor,

wherein the processing circuitry is configured to combine the signal received by the ultrasound sensor with a reference signal to produce a combined signal.

355. The apparatus of claim 354, wherein the reference signal is the transmission signal.

356. The apparatus of claim 354, wherein the reference signal is a chirp.

357. The apparatus of claim 354, wherein the processing circuitry is configured to generate the reference signal.

358. The apparatus of claim 357, wherein the processing circuitry is configured to generate the reference signal at least in part by using a local oscillator.

359. The apparatus of claim 354, wherein the processing circuitry is configured to combine the signal received by the ultrasound sensor with the reference signal by multiplying the received signal with the reference signal to obtain the combined signal.

360. The apparatus of claim 354, wherein the processing circuitry comprises a mixer having a first input configured to receive the signal received by the ultrasound sensor and a second input configured to receive the transmission signal from the transmit circuitry.

361. The apparatus of claim 354, wherein the processing circuitry comprises a low pass filter configured to be applied to the combined signal.

362. The apparatus of claim 354, wherein the processing circuitry is configured to perform a Fourier transform on the combined signal.

363. The apparatus of claim 354, wherein the processing circuitry is configured to combine the received signal with the reference signal before the received signal is processed by an analog-to-digital converter.

364. An apparatus, comprising:

a support;

a first plurality of ultrasound elements configured as ultrasound imaging elements; and

a second plurality of ultrasound elements configured as high intensity focused ultrasound (HIFU) elements,

wherein the first plurality and second plurality of ultrasound elements are physically coupled to the first support, and

wherein at least some elements of the first plurality of ultrasound elements are arranged among at least some elements of the second plurality of ultrasound elements.

365. The apparatus of claim 364, wherein each of the first plurality of ultrasound imaging elements is configured to perform at least one of emission of a radiation source signal incident upon a volume to be imaged three-dimensionally or detection of such a radiation source signal.

366. The apparatus of claim 365, wherein the second plurality of ultrasound elements is configured to emit ultrasound radiation of sufficient intensity to induce a change in a tissue state of tissue located within the volume.

367. The apparatus of claim 364, wherein at least some elements of the first plurality of ultrasound elements are interspersed with at least some elements of the second plurality of ultrasound elements.

368. The apparatus of claim 364, wherein at least some elements of the first plurality of ultrasound elements are interleaved with at least some elements of the second plurality of ultrasound elements.

369. The apparatus of claim 364, wherein the first plurality of ultrasound elements and the second plurality of ultrasound elements are arranged in combination in a checkerboard pattern.

370. The apparatus of claim 364, wherein the second plurality of ultrasound elements are configured to collectively define a HIFU focal length movable in three dimensions.

371. The apparatus of claim 364, wherein at least one ultrasound element of the first plurality of ultrasound elements is configured to exhibit time-varying operation as an ultrasound imaging element and as a HIFU element.

372. The apparatus of claim 364, wherein at least one ultrasound element of the second plurality of ultrasound elements is configured to exhibit time-varying operation as a HIFU element and as an ultrasound imaging element.

373. The apparatus of claim 364, wherein the first plurality of ultrasound elements and/or the second plurality of ultrasound elements is arranged in at least two dimensions.

374. The apparatus of claim 373, wherein both the first plurality of ultrasound elements and second plurality of ultrasound elements are arranged in at least two dimensions.

375. The apparatus of claim 373, wherein the first plurality of ultrasound elements is arranged in at least two dimensions.

376. The apparatus of claim 375, wherein the first plurality of ultrasound elements is arranged in three dimensions.

377. The apparatus of claim 375, wherein the first plurality of ultrasound elements is arranged in an array of at least two dimensions in which the first plurality of ultrasound elements adopts a regular spacing.

378. The apparatus of claim 373, wherein the second plurality of ultrasound elements is arranged in at least two dimensions.

379. The apparatus of claim 378, wherein the second plurality of ultrasound elements is arranged in three dimensions.

380. The apparatus of claim 378, wherein the second plurality of ultrasound elements is arranged in an array of at least two dimensions.

381. The apparatus of claim 364, wherein the first plurality of ultrasound elements is configured to emit and/or receive ultrasound signals of wavelength λ

, and wherein a minimum spacing between nearest neighbor ultrasound elements of the first plurality of ultrasound imaging elements is greater than λ

/2.

382. The apparatus of claim 364, wherein the support is a first support, and wherein the apparatus further comprises:

a second support;

a third plurality of ultrasound elements configured as ultrasound imaging elements; and

a fourth plurality of ultrasound elements configured as HIFU elements,

wherein the third plurality and fourth plurality of ultrasound elements are physically coupled to the second support and wherein the third plurality and fourth plurality of ultrasound elements are in a substantially fixed relationship with respect to each other, and

wherein at least some elements of the third plurality of ultrasound elements are arranged among at least some elements of the fourth plurality of ultrasound elements.

383. The apparatus of claim 382, wherein the second support is a flexible support.

384. The apparatus of claim 382, wherein the first and second supports are moveable relative to each other, to change position and/or orientation of the first plurality of ultrasound elements relative to the third plurality of ultrasound imaging elements.

385. The apparatus of claim 384, further comprising at least one detector configured to detect position and/or orientation of the first plurality of ultrasound elements relative to the third plurality of ultrasound elements.

386. The apparatus of claim 385, wherein the at least one detector is configured to dynamically detect position and/or orientation during operation of the first plurality of ultrasound elements and/or the third plurality of ultrasound elements.

387. The apparatus of claim 385, wherein the at least one detector is physically coupled to the first support.

388. The apparatus of claim 384, further comprising circuitry configured to receive signals from the first plurality and/or third plurality of ultrasound elements and process the signals to determine position and/or orientation of the first plurality of ultrasound elements relative to the third plurality of ultrasound elements.

389. The apparatus of claim 364, wherein the first plurality and second plurality of ultrasound elements are in a substantially fixed relationship with respect to each other.

390. The apparatus of claim 364, wherein the support is a flexible support.

391. A system, comprising:

a first support;

a second support;

a first plurality of ultrasound elements configured as high intensity focused ultrasound (HIFU) elements and physically coupled to the first support and configured as a first source of HIFU;

a second plurality of ultrasound elements configured as ultrasound imaging elements and coupled to the first support and distinct from the first plurality of ultrasound elements;

a third plurality of ultrasound elements configured as HIFU elements and physically coupled to the second support and configured as a second source of HIFU; and

a fourth plurality of ultrasound elements configured as ultrasound imaging elements and coupled to the second support and distinct from the third plurality of ultrasound elements;

wherein the second plurality of ultrasound elements and the fourth plurality of ultrasound elements are configured to operate in combination in a transmissive ultrasound imaging modality.

392. The apparatus of claim 391, wherein the first support and second support are independently movable.

393. The apparatus of claim 391, further comprising control circuitry coupled to the first, second, third, and fourth pluralities of ultrasound elements and configured to control application of HIFU by the first and third pluralities of ultrasound elements and to control imaging operation of the second and fourth pluralities of ultrasound elements.

394. The apparatus of claim 391, further comprising a detector configured to detect relative position and/or orientation of the second plurality of ultrasound elements relative to the fourth plurality of ultrasound elements.

395. The apparatus of claim 391, wherein the second and fourth pluralities of ultrasound elements each include at least twenty-five ultrasound elements.

396. An apparatus, comprising;

a substrate;

a first plurality of ultrasound elements configured as ultrasound imaging elements coupled to the substrate; and

a second plurality of ultrasound elements configured as high intensity focused ultrasound (HIFU) elements coupled to the substrate.

397. The apparatus of claim 396, wherein the substrate is formed of an acoustically insulating material.

398. The apparatus of claim 396, wherein at least some elements of the first plurality of ultrasound elements are arranged among at least some elements of the second plurality of ultrasound elements.

399. The apparatus of claim 396, wherein at least some elements of the first plurality of ultrasound elements are interspersed with at least some elements of the second plurality of ultrasound elements.

400. The apparatus of claim 396, wherein at least some elements of the first plurality of ultrasound elements are interleaved with at least some elements of the second plurality of ultrasound elements.

401. The apparatus of claim 396, wherein the first plurality of ultrasound elements and the second plurality of ultrasound elements are arranged in combination in a checkerboard pattern.

402. The apparatus of claim 396, wherein each of the first plurality of ultrasound imaging elements is configured to perform at least one of emission of a radiation source signal incident upon a volume to be imaged three-dimensionally or detection of such a radiation source signal.

403. The apparatus of claim 402, wherein the second plurality of ultrasound elements is configured to emit ultrasound radiation of sufficient intensity to induce a change in a tissue state of tissue located within the volume.

404. The apparatus of claim 396, wherein the first plurality of ultrasound elements is configured to emit and/or receive ultrasound signals of wavelength λ

, and wherein a minimum spacing between nearest neighbor ultrasound elements of the first plurality of ultrasound imaging elements is greater than λ

/2.

405. The apparatus of claim 396, wherein the first plurality of ultrasound elements is disposed on the substrate, and wherein the second plurality of ultrasound elements is disposed on the substrate.