Equipment and method for calibration and quality assurance of an ultrasonic bone anaylsis apparatus
DCFirst Claim
1. A phantom for an ultrasound bone analysis apparatus having a foot well and a plurality of transducer pads, comprising:
- a plug cast having a plurality of indentations located on a respective plurality of opposite sides thereof, the plurality of indentations having a respective plurality of shapes complementary to a respective plurality of shapes of the respective plurality of transducer pads, the plug also having an attenuation-versus-frequency profile that is substantially flat in a frequency range of between about 200 kHz and about 1000 kHz and a sound impedance that approximates that of soft human tissue.
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Abstract
An improvement to calibration and quality assurance of an ultrasonic bone analysis apparatus is achieved by using phantoms. A received ultrasound signal that passed through a first phantom is used as a baseline for calculating BUA. The first phantom has an attenuation-versus-frequency profile that is substantially flat in a frequency range of 200 to 1000 kHz and a sound impedance that approximates that of soft human tissue. A propagation time of the signal is used to calibrate a zero point of the apparatus. A second phantom has an attenuation in a frequency range of 200-1000 kHz which approximates that of a human foot, including an attenuation-versus-frequency profile that is substantially linear in the frequency range of 200-600 kHz and is approximately 1 dB/MHz per mm. A received ultrasound signal that passed through the second phantom is used to calibrate the apparatus for a BUA calculation, and can also be used for at least one of determining and correcting a drift of the apparatus. A third phantom has a predetermined SOS that is substantially independent of temperature. A received ultrasound signal that passed through the third phantom is used to calibrate the apparatus for a SOS calculation, and can also be used for at least one of determining and correcting instrument drift. An ultrasonic signal is transmitted through mutually touching transducer pads. The received signal is used as a baseline for calculating BUA. A measurement of the propagation time of the received signal is compared with a temporally-proximate measurement of an ultrasonic signal that passed through a patient'"'"'s heel to determine a time of propagation through the heel.
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Citations
61 Claims
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1. A phantom for an ultrasound bone analysis apparatus having a foot well and a plurality of transducer pads, comprising:
a plug cast having a plurality of indentations located on a respective plurality of opposite sides thereof, the plurality of indentations having a respective plurality of shapes complementary to a respective plurality of shapes of the respective plurality of transducer pads, the plug also having an attenuation-versus-frequency profile that is substantially flat in a frequency range of between about 200 kHz and about 1000 kHz and a sound impedance that approximates that of soft human tissue. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A phantom for an ultrasound bone analysis apparatus having a foot well and a plurality of transducer pads, comprising:
a block of material having a plurality of indentations located on a respective plurality of opposite sides thereof, the plurality of indentations having a respective plurality of shapes complementary to the respective plurality of transducer pads, and the block having an attenuation in a frequency range of between about 200 kHz and about 1000 kHz which approximates that of a human foot. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A phantom for an ultrasound bone analysis apparatus having a foot well and a plurality of transducer pads, comprising:
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a housing having a plurality of inner walls and a plurality of indentations located on a respective plurality of opposite sides of the housing, the plurality of indentations having a respective plurality of bottoms parallel to respective adjacent ones of the plurality of inner walls of the housing; and a mixture of ethyl alcohol and water which is contained by an air-tight receptacle formed from the plurality of inner walls of the housing, the mixture having a predetermined ratio of alcohol and water and a predetermined SOS that is substantially temperature-independent, and air-tight receptacle preventing a change in alcohol concentration by evaporation of the alcohol or absorption of water by the mixture. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method of calibrating an ultrasound bone analysis apparatus having a foot well and a plurality of transducer assemblies with a respective plurality of transducer pads, comprising the steps of:
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placing in the foot well a first phantom having an attenuation-versus-frequency profile that is substantially flat in a frequency range of between about 200 kHz and about 1000 kHz and a sound impedance that approximates that of soft human tissue; adjusting the plurality of transducer assemblies; transmitting through the first phantom via one of the plurality of transducer pads an ultrasound signal; receiving via another one of the plurality of transducer pads a signal that passed through the first phantom; and using the received signal that passed through the first phantom as a baseline for calculating a BUA. - View Dependent Claims (33, 34, 35, 36, 37)
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38. A method of calibrating an ultrasound bone analysis apparatus having a foot well and a plurality of transducer assemblies with a respective plurality of transducer pads, comprising the steps of:
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placing in the foot well a phantom having an attenuation in a frequency range of between about 200 kHz and about 1000 kHz which approximates that of a human foot, including an attenuation-versus-frequency profile that is substantially linear in a frequency range of between about 200 kHz and about 600 kHz and is approximately 1 dB/MHz per mm; adjusting the plurality of transducer assemblies; transmitting through the phantom via one of the plurality of transducer pads an ultrasound signal; receiving via another one of the plurality of transducer pads a signal that passed through the phantom; and using the received signal that passed through the phantom to calibrate the apparatus for a BUA calculation. - View Dependent Claims (39)
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40. A method of calibrating an ultrasound bone analysis apparatus having a foot well and a plurality of transducer assemblies with a respective plurality of transducer pads, comprising the steps of:
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placing in the foot well a phantom having a predetermined SOS that is substantially temperature-independent; adjusting the plurality of transducer assemblies; transmitting through the phantom via one of the plurality of transducer pads an ultrasound signal; receiving via another one of the plurality of transducer pads a signal that passed through the phantom; and using the received signal that passed through the phantom for at least one of determining and correcting a drift of the apparatus. - View Dependent Claims (41, 42)
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43. A method of calibrating an ultrasound bone analysis apparatus having a plurality of transducer assemblies with a respective plurality of transducers and a respective plurality of transducer pads, comprising the steps of:
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adjusting the plurality of transducer assemblies until the plurality of transducer pads are mutually in contact; transmitting an ultrasound signal through one of the plurality of transducers; and receiving a signal corresponding to the transmitted signal through another one of the plurality of transducers. - View Dependent Claims (44, 45, 46, 47, 48)
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49. An apparatus for performing ultrasonic bone analysis comprising:
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a foot well assembly having a foot well for resting a patient'"'"'s foot; a transducer drive mechanism including a plurality of transducer assemblies having a plurality of respective transducers and a plurality of respective coupling pads, at least one of the plurality of transducers supplying ultrasonic signals and at least another one of the plurality of transducers receiving ultrasonic signals corresponding to the transmitted signals, and the plurality of transducer assemblies being adjustable to respective positions such that the plurality of respective coupling pads are in mutual contact; and a controller for controlling the positioning of the plurality of transducer assemblies to achieve ultrasonic coupling, controlling the ultrasonic signals transmitted by at least the one of the plurality of transducers, performing calibration including calibrating a zero point of the apparatus, and performing quality assurance including at least one of determining and correcting a drift of the apparatus. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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61. A phantom for an ultrasound bone analysis apparatus having a foot well and a plurality of transducer pads, comprising:
a block of material having a predetermined SOS that is substantially temperature-independent and a sound impedance that approximates that of soft human tissue, and the block having at least one of an attenuation-versus-frequency profile that is substantially flat in a frequency range of between about 200 kHz and about 1000 kHz and an attenuation in a frequency range of between about 200 kHz and about 1000 kHz which approximates that of a human foot.
Specification