Compressional wave hyperthermia treating method and apparatus

• US 4,875,487 A
• Filed: 05/02/1986
• Issued: 10/24/1989
• Est. Priority Date: 05/02/1986
• Status: Expired due to Term

• Current Assignee: Varian Medical Systems Technologies Inc (Siemens AG)
• Original Assignee: Varian Associates, Inc. (Siemens AG)
• Inventors: Seppi, Edward J.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US06/860,281
• Time in Patent Office: 1,271 Days
• Field of Search: 128/399, 128/24 A, 128/804, 128/660, 128/660.03
• US Class Current: 600/439
• CPC Class Codes: A61B 2017/22028 arrays, e.g. phased arrays
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00
• CPC Class Codes: G10K 11/341 Circuits therefor

Abstract

A wide bandwidth compressional wave transducer array obtains information concerning tissue of a subject being treated and supplies hyperthermia compressional wave treating energy to a treated region of the subject. The array transducers are pulsed on and off with an on duty cycle portion of less than one. An array of compressional wave imaging transducers is in the center of the array of compressional wave hyperthermia focused far field transducers used to analyze and treat. The power and duty cycle of the compressional wave hyperthermia focused far field are varied to control the energy incident on certain regions in a treated subject. The ultrasonic frequencies of hyperthermia beams derived from individual transducers are randomly angle modulated so the energy of adjacent far field focused beams overlaps to a greater extent than focused coherent beams.

Claims

1. A method of treating a region of a subject with compressional wave energy derived from an array of ultrasonic transducers having a focused far field and a wide band pass frequency response and for analyzing matter of the subject in the path between the transducers and the region comprising the steps of from time to time exciting the transducers with pulse like ultrasonic electric energy having substantial frequency components in the band pass of the transducers, the transducers being excited while the region is in the focused far field of the array, the frequency and the transducer response being such that said frequency components are incident on the subject during said exciting step, the pulse like ultrasonic compressional wave energy from said transducers being reflected from certain regions internally of the subject back to the transducers while the transducers are no longer excited by the pulse like electric energy whereby the transducers derive electric signals having time positions and amplitudes together enabling information about different volumes in the subject between the array and the region to be determined, responding to the time positions of the derived electric signals to display the information, and supplying many cycles of treating hyperthermia ultrasonic electric energy to the transducers in the treating period between tow consecutive periods when the pulse like electric energy is exciting the transducers and the electric signals are being derived, the many cycles of ultrasonic electric energy being periodically disrupted for at least several cycles thereof and being supplied to the transducers while the region is in the focused far field and causing the transducers to be excited to derive in the subject many cycles of treating hyperthermia ultrasonic compressional wave energy having a frequency in the band pass of the transducers and having a duty cycle less than one, said method including the step of varying the duty cycle and amplitude of the compressional wave energy of at least one of said transducers in an inverse manner.

2. The method of claim 1 wherein the pulse like energy has a substantially single cycle sine wave like waveshape, further including the step of adjusting the periods of the single cycle and the treating energy so they are approximately the same while the same region is in the focused far field.

3. The method of claim 1 further comprising the step of incoherently modulating the far field by randomly phase modulating the treating ultrasonic electric energy applied to the transducers so that adjacent beams from different ones of said transducers in the focused far field spatially overlap to a greater extent than coherent adjacent focused far field beams.

4. The method of claim 1 further comprising the step of controlling the duty cycle of the treating compressional wave energy and the amplitude of the treating compressional wave energy derived from different transducers in the array to minimize pain experienced by the subject due to the compressional wave energy being incident on different portions of the subject while maintaining the energy of the treating compressional wave energy substantially constant.

5. The method of claim 1 wherein different ones of the transducers are excited in sequence whereby pulse like compressional wave energy from the different transducers is incident on the subject and reflected from the certain regions at different times, detecting the interval from the time one of said transducers derives one of the pulse like waves to the time said pulse like wave is reflected back to the array, detecting the amplitude of each pulse like wave reflected back to the array for each different one of said transducers, and displaying along mutually orthogonal first and second axes of an x-y display the number of each transducer deriving a pulse like wave of the compressional wave energy and the detected time interval associated with each numbered transducer respectively, and displaying on said display an indication of the detected amplitude associated with each numbered transducer.

6. The method of claim 5 further comprising adjusting the amplitude of the treating energy applied to each different transducer in response to the displayed information.

7. The method of claim 1 wherein different ones of the transducers are excited in sequence whereby pulse like compressional wave energy from the different transducers is incident on the subject and reflected from the certain regions at different times, detecting the amplitude of each pulse like wave reflected back to the array, and adjusting the amplitude of the treating energy applied to each different transducer in response to the detected amplitude for the associated different transducer.

8. A method of treating regions located close to and far from the surface of the skin of a subject with compressional wave energy from an array of ultrasonic transducers having a focused far field and a wide bandpass comprising the steps of treating a region close to the skin of the subject by focusing the far field of the array at one of said regions located close to the skin of said subject, and then exciting the transducers with electric energy such that the transducers derive in the subject many cycles of region treating ultrasonic compressional wave energy at a frequency within the band pass and relatively close to a high frequency cut off of the bandpass, treating a region far from the skin of the subject by focusing the far field of the array at one of said regions located far from the skin of said subject, and then exciting the transducers with electric energy such that the transducers derive in the subject many cycles of region treating ultrasonic compressional wave energy at a frequency within the band pass and relatively far from the high frequency cut off of the band pass, said method including the step of varying the duty cycle and amplitude of the compressional wave energy of at least one of said transducers in an inverse manner.

9. The method of claim 8 further comprising the step of controlling the duty cycle and the amplitude of the treating compressional wave energy of one or more of said transducers to minimize pain experienced by the subject due to the compressional wave energy being incident on different portions of the subject.

10. The method of claim 8 further comprising the step of controlling the duty cycle of the treating compressional wave energy and individually controlling the amplitude of the treating compressional wave energy derived from the transducers in the array to minimize pain experienced by the subject due to the compressional wave energy being incident on different portions of the subject.

11. The method of claim 10 further comprising the step of controlling the duty cycle of the treating compressional wave energy and the amplitude of the treating compressional wave energy derived from different transducers in the array to minimize pain experienced by the subject due to the compressional wave energy being incident on different portions of the subject while maintaining the energy of the treating compressional wave energy substantially constant.

12. A method of treating a region in a subject with treating hyperthermia compressional wave energy from an array of ultrasonic transducers having a focused far field comprising the steps of focusing the far field of the array at the region, and then simultaneously exciting transducers of the array with electric energy having a duty cycle considerably less than one such that each of the transducers derives in the subject a beam of hyperthermia treating focused far field ultrasonic compressional wave energy having said duty cycle, said method further including inversely varying the intensity and duty cycle of the treating energy applied to at least some of the transducers.

13. The method of claim 12 further comprising the step of incoherently modulating the far field by random phase modulating said electric energy so that adjacent beams from different ones of said transducers in the focused far field spatially overlap to a greater extent than coherent adjacent focused far field beams.

14. The method of claim 12 further comprising the step of controlling the duty cycle and the amplitude of the treating compressional wave energy to minimize pain experienced by the subject due to the compressional wave energy being incident on different portions of the subject.

15. A method of treating a region in a subject with treating hyperthermia compressional wave energy from an array of ultrasonic transducers having a focused far field comprising the steps of focusing the far field of the array at the region, supplying electric energy to said transducers, and varying the duty cycle and amplitude of said electric energy for at least one of said transducers in an inverse manner.