Medical apparatus for heating a heating volume defined by a surface

Patent metadata

Field	Value
Publication number	US-10016627-B2
Application number	US-201314406330-A
Country	US
Kind code	B2
Filing date	Jun 4, 2013
Priority date	Jun 11, 2012
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

The invention provides for a medical apparatus ( 300, 500, 600 ) comprising a high intensity focused ultrasound system ( 302 ), a memory containing instructions, and a processor. Execution of the instructions causes the processor to receive ( 100, 202 ) surface data ( 342 ) descriptive of the location of a surface ( 322 ). The surface data defines the location of the heating volume. Execution of the instructions further cause the processor to determine ( 102, 204 ) a set of transducer switching commands ( 344 ) using the heating location data and an ultrasound transducer element model ( 352 ) and control ( 104, 206 ) the high intensity focused ultrasound system with the set of transducer switching commands to heat the heating volume. The set of transducer switching commands comprises an intensity level for the multiple ultrasound transducer elements either above or below a predetermined intensity for controlling a cross sectional shape of the heating volume to encompass the surface.

First claim

The invention claimed is:

1. A medical apparatus comprising:
a high-intensity focused ultrasound (HIFU) therapy system, provided with an ultrasound transducer array configured to emit a volumetric ultrasound beam with a geometric focus to heat treat a surface area within a subject, the ultrasound transducer array includes a plurality of ultrasound transducer elements arranged in a geometrical pattern, wherein ultrasound transducer elements of the ultrasound transducer array are activated to emit the volumetric ultrasound beam;
a memory configured for storing machine executable instructions;
a processor configured to execute the machine executable instructions to:
receive surface data, wherein the surface data is indicative of a location and shape of the surface area to be treated relative to a location of the transducer array;
calculate a set of transducer switching commands to control transducer elements so as to emit the volumetric ultrasound beam based on the surface data;
control the ultrasound transducer array to orient a principal axis of the volumetric ultrasound beam along an ultrasound propagation direction intersecting the surface area to be treated;
control the ultrasound transducer array to focus the volumetric ultrasound beam such that:
(i) the volumetric ultrasound beam has a cross section in a near field of the volumetric ultrasound beam transverse to the principal axis at the surface area to be treated, the cross section corresponding to the location and shape of the surface area to be treated;
(ii) in the cross section corresponding to the surface area to be treated, the volumetric ultrasound beam is focused to achieve constructive interference to achieve an energy density exceeding a pre-set therapeutic threshold;
(iii) the volumetric ultrasound beam is defocused in a region behind the surface area to be treated to increase a volume of the geometric focus such that the constructive interference does not occur behind the surface area to be treated therefore does not resulted in areas of high energy densities increase behind the surface area to be treated and to avoid ultrasound hotspots; and

wherein the HIFU therapy system is controlled by the processor to deliver ultrasound therapy to the subject.

2. The medical apparatus as claimed in claim 1 wherein:
the processor is further configured to:
determine the set of transducer switching commands using an ultrasound transducer element model wherein the set of transducer switching commands comprises an intensity level for each of the ultrasound transducer elements either above or below a predetermined intensity for controlling the cross section of the volumetric ultrasound beam to encompass the surface area to be treated; and
control the high intensity focused ultrasound therapy system with the set of transducer switching commands to heat the surface area to be treated.

3. The medical apparatus of claim 2 , wherein the focus of the volumetric ultrasound beam is electronically controlled, and the set of transducer switching commands further comprise a phase value for each ultrasound transducer element of the transducer array, wherein execution of the instructions causes the processor to determine the phase value for each of the plurality of ultrasound transducer elements to defocus the electronically controllable focus.

4. The medical apparatus of claim 3 , wherein a selected transducer element of the transducer array has a nearest neighbor transducer element and the phase value of the selected transducer element and the phase value of the nearest neighbor transducer element are within a range of determined phase values for each of the plurality of ultrasound transducer elements.

5. The medical apparatus of claim 3 , wherein execution of the instructions further causes the processor to assign the phase values of the transducer elements to cause a predetermined gradient in the phase values across the ultrasound transducer array to cause the defocusing of the electronically controllable focus.

6. The medical apparatus of claim 3 , wherein execution of the instructions further causes the processor to divide the transducer elements into groups, and the phase value of each transducer element in a group is identical.

7. The medical apparatus of claim 3 , wherein the high intensity focused ultrasound therapy system further comprise a mechanical actuator configured to mechanically position the ultrasound transducer array, and the processor is further configured to:
determine actuator commands to position the actuator to concentrate ultrasonic energy in the surface area to be treated using the surface data and the ultrasound transducer elements; and
control the actuator using the actuator commands.

8. The medical apparatus of claim 7 , wherein the actuator commands cause the mechanical actuator to perform anyone of the following: move the actuator closer to the surface area to be treated, move and/or rotate the actuator to increase the cross section and shape of the volumetric ultrasound beam at the surface area to be treated, and combinations thereof.

9. The medical apparatus of claim 8 , wherein the processor is further configured to:
determine an incidence angle relative to the surface area to be treated for each of the ultrasound transducer elements using the ultrasound transducer element model; and
assign the intensity level below the predetermined intensity to each of the plurality of ultrasound transducer elements where the incidence angle is outside of a predetermined angular range.

10. The medical apparatus of claim 9 , wherein the processor is further configured to:
determine actuator commands to reduce how many of the ultrasound transducer elements have an incidence angle outside of the predetermined range; and
control the actuator using the actuator commands.

11. The medical apparatus of claim 10 , wherein the medical apparatus further includes a medical imaging system configured to acquire medical image data from an imaging volume, the imaging volume including a heating volume, and the processor is further configured to:
acquire the medical image data and receive the surface data by specifying a heating location in the medical image data.

12. The medical apparatus of claim 11 , wherein the medical imaging system is a magnetic resonance imaging system operable for acquiring thermal magnetic resonance data from at least a target volume, wherein each of the ultrasound transducer elements have an adjustable intensity, and the processor is further configured to:
receive a treatment plan contained in computer storage, the treatment plan descriptive of a target temperature of the surface area to be treated;
acquire the thermal magnetic resonance data;
calculate a thermal map using the thermal magnetic resonance data;
determine an intensity adjustment for each of the plurality of ultrasound transducer elements in accordance with the thermal map and the treatment plan; and
control the intensity of the plurality of ultrasound transducer element using the intensity adjustment.

13. A non-transitory computer readable medium carrying a computer program having computer executable code for execution by a processor controlling a medical apparatus, wherein the medical apparatus comprises a high intensity focused ultrasound system, wherein the high intensity focused ultrasound system comprises an ultrasound transducer array for heating a heating target volume, wherein the ultrasound transducer array comprises multiple ultrasound transducer elements, wherein execution of the instructions causes the processor to:
receive surface data descriptive of a location and shape of a surface

Assignees

• Koninklijke Philips Nv

Inventors

• Viitala Antti Johannes
• Ylihautala Mika Petri

Classifications

• A61B2090/374

  NMR or MRI · CPC title

• A61N2007/0091

  with moving parts, e.g. transducers, lenses, reflectors · CPC title

• A61B2018/00714

  Temperature · CPC title

• A61N2007/0095

  by modifying an excitation signal · CPC title

• A61N7/02 Primary

  Localised ultrasound hyperthermia · CPC title