Heat surgery system monitored by real-time magnetic resonance temperature profiling
First Claim
1. A magnetic resonance (MR) pulsed heat system for allowing an operator to selectively heat tissue within a patient comprising:
- a) pulsed heat-producing means adapted for concentrating energy at an application point;
b) positioning means for positioning the application point of the pulsed heat-producing means in a specific tissue within the patient so as to create a heated region within the specified tissue;
c) operator responsive control means for enabling said operator to control the positioning means;
d) an MR imaging means comprising;
1. a radiofrequency (RF) transmitter for transmitting an RF excitation pulse and an RF refocussing pulse into said patient;
2. a gradient means for;
i. producing a time-varying magnetic field gradient in an "X" direction and time varying magnetic field gradient in a "Y" direction orthogonal to the "X" direction, both gradients applied simultaneously with the RF excitation pulse exciting longitudinal magnetization of an elongated excitation region in said patient,ii. applying a first set of diffusion gradients in the "X", "Y" directions and a "Z" direction orthogonal to both the "X" and "Y" directions after excitation of the excitation region and before application of the refocussing pulse,iii. applying a second set of diffusion gradients in the "X", "Y" and "Z" directions after application of the refocussing pulse, andiv. applying a readout gradient to the elongated excitation region along a direction for which a temperature-sensitive profile is desired;
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Accused Products
Abstract
Surgery is performed with a pulsed heat-producing device that selectively heats a region in a specific tissue within a patient destroying the tissue. The pulsed heat-producing device may be a coherent optical source that is guided by laser fiber to the tissue to be destroyed. In another embodiment, the pulsed heat-producing device is a focussed ultrasound transducer which concentrates ultrasonic energy at a focal point within the specific tissue. A magnetic resonance imaging system employing a real-time temperature-sensitive pulse sequence monitors the heated region of the tissue to provide temperature profiles allowing an operator to alter the position and size of the heated region.
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Citations
9 Claims
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1. A magnetic resonance (MR) pulsed heat system for allowing an operator to selectively heat tissue within a patient comprising:
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a) pulsed heat-producing means adapted for concentrating energy at an application point; b) positioning means for positioning the application point of the pulsed heat-producing means in a specific tissue within the patient so as to create a heated region within the specified tissue; c) operator responsive control means for enabling said operator to control the positioning means; d) an MR imaging means comprising; 1. a radiofrequency (RF) transmitter for transmitting an RF excitation pulse and an RF refocussing pulse into said patient; 2. a gradient means for; i. producing a time-varying magnetic field gradient in an "X" direction and time varying magnetic field gradient in a "Y" direction orthogonal to the "X" direction, both gradients applied simultaneously with the RF excitation pulse exciting longitudinal magnetization of an elongated excitation region in said patient, ii. applying a first set of diffusion gradients in the "X", "Y" directions and a "Z" direction orthogonal to both the "X" and "Y" directions after excitation of the excitation region and before application of the refocussing pulse, iii. applying a second set of diffusion gradients in the "X", "Y" and "Z" directions after application of the refocussing pulse, and iv. applying a readout gradient to the elongated excitation region along a direction for which a temperature-sensitive profile is desired; - View Dependent Claims (3, 5, 8, 9)
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2. receiver means for receiving an MR response signal from the elongated excitation region;
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4. computation means for computing a temperature vs. position profile along the readout gradient from the MR response signal from the receiver means, thereby creating a real-time temperature-sensitive MR image of the heated region; and e) display means for displaying the temperature-sensitive image to said operator. - View Dependent Claims (4)
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6. A method of performing heat surgery on a patient, as guided by magnetic resonance (MR) imaging comprising, the steps of:
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a) creating an internal image of tissues of said patient; b) determining the position of a specified tissue in the patient; c) applying pulsed heat at a predetermined pulse frequency to the specified tissue to create a heated region within the specified tissue; d) monitoring the heated region with an MR imaging device by;
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7. transmitting an RF excitation pulse into said patient;
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2. applying a time-varying magnetic field gradient in an "X" direction and a time-varying magnetic field gradient in a "Y" direction orthogonal to the "X" direction, both gradients applied simultaneously with the RF excitation pulse so as to excite longitudinal magnetization of an elongated excitation region in said patient; 3. applying to said patient a first set of diffusion gradients in the "X" and "Y" directions and a "Z" direction orthogonal to both the "X" and "Y" directions after excitation of the excitation region; 4. transmitting an RF refocussing pulse into said patient; 5. applying a second set of diffusion gradients in the "X", "Y" and "Z" directions after application of the RF refocussing pulse; 6. applying a readout gradient to said elongated excitation region in a direction which a temperature-sensitive profile is desired; 7. receiving an MR response signal from the elongated excitation region; and 8. computing a temperature vs. position profile along the readout gradient from the MR response signal; and e) adjusting the frequency and the position of the heated region so as to heat the specified tissue without substantial injury to adjacent tissue.
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Specification