Alignment of ultrasound transducer arrays and multiple aperture probe assembly

• US 9,510,806 B2
• Filed: 03/13/2014
• Issued: 12/06/2016
• Est. Priority Date: 03/13/2013
• Status: Active Grant

• Current Assignee: Maui Imaging, Inc.
• Original Assignee: Maui Imaging, Inc.
• Inventors: Smith, David M., Adam, Sharon L., Dietz, Dennis R.
• Primary Examiner(s): Murphy, Daniel L
• Application Number:
  US14/210,015
• Publication Number:
  US 20140269209A1
• Time in Patent Office: 999 Days
• Field of Search: 295/94, 297/29, 356/138, 367/140, 367/908
• US Class Current: 1/1
• CPC Class Codes: A61B 8/4461 Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe
• CPC Class Codes: A61B 8/4477 using several separate ultrasound transducers or probes
• 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 8/58 Testing, adjusting or calibrating the diagnostic device
• CPC Class Codes: A61B 8/587 Calibration phantoms models for medical purposes G09B23/28
• CPC Class Codes: G01S 15/8927 using simultaneously or sequentially two or more subarrays or subapertures
• CPC Class Codes: G01S 7/52079 Constructional features constructional features of transducers B06B; mounting transducers G10K11/00; constructional features of ultrasonic medical diagnostic devices A61B8/44
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/5313 Means to assemble electrical device

Abstract

The effective aperture of an ultrasound imaging probe can be increased by including more than one transducer array and using the transducer elements of all of the arrays to render an image can greatly improve the lateral resolution of the generated image. In order to render an image, the relative positions of all of the elements must be known precisely. Systems and methods for accurately calibrating and adjusting a multi-aperture ultrasound system are disclosed. The relative positions of the transducer elements can be computed and aligned prior to and during probe assembly.

Claims

1. A method of building a multiple aperture ultrasound probe, the method comprising the steps of:

forming a gasket with a first flowable solidifying material on a lower surface of a substantially planar precision alignment element;

securing the precision alignment element to a back surface of a transducer array with the gasket, the gasket having an enclosed perimeter shape and a thickness dimension extending away from the substantially planar precision alignment element;

evaluating and adjusting alignment of the transducer array relative to the precision alignment element; and

injecting a second flowable solidifying material through at least one hole in the precision alignment element to secure the transducer array to the precision alignment element.

2. The method of claim 1, wherein the injecting step comprises filling a volume defined by the back surface of the transducer array, the lower surface of the precision alignment element, and an inner circumferential surface of the gasket with the second flowable solidifying material.

3. The method of claim 1, further comprising allowing the second flowable solidifying material to solidify, and mounting the precision alignment element to a probe alignment bracket.

4. The method of claim 3, further comprising placing the probe alignment bracket into a probe housing, and injecting a third flowable solidifying material into a space between the transducer array and the probe housing.

5. The method of claim 4, wherein the injected third flowable solidifying material surrounds at least a portion of the precision alignment element or the probe alignment bracket.

6. The method of claim 1, wherein evaluating alignment of the transducer array relative to the precision alignment element comprises imaging a target with the transducer array and comparing a resulting image of the target with known information defining a geometry of the target.

7. The method of claim 6, wherein the target comprises a plurality of pins oriented in a known configuration relative to the precision alignment element.

8. The method of claim 7, wherein each of the pins has a flat surface substantially perpendicular to a longitudinal axis of the pins, the longitudinal axis being substantially perpendicular to an ultrasound wavefront transmitted from a single element of the transducer array and arriving at the pins.

9. The method of claim 1, wherein adjusting alignment of the transducer array relative to the precision alignment element comprises adjusting at least one set screw to mechanically move the transducer array relative to the precision alignment element.

10. The method of claim 1, further comprising allowing the first flowable solidifying material to solidify prior to evaluating and adjusting alignment of the transducer array relative to the precision alignment element.

11. The method of claim 1, wherein the first flowable solidifying material and the second flowable solidifying material are the same material.

12. A method of evaluating an alignment of an ultrasound transducer array relative to a precision alignment element, the method comprising the steps of;

flexibly securing the ultrasound transducer array to the precision alignment element;

mounting the precision alignment element in a fixed, known position and orientation relative to a target, the target having a plurality of reflectors in known reflector positions;

imaging the reflectors of the target with the array;

comparing imaged reflector positions with known reflector positions; and

identifying a corrective adjustment based on the comparing step.

13. The method of claim 12, further comprising comparing a brightness of the reflectors with expected brightness values.

14. The method of claim 12, further comprising visually comparing imaged reflector positions with known reflector positions using a graphical user interface in which a first image comprising the imaged reflector positions is displayed simultaneously with a second image comprising the known reflector positions.

15. The method of claim 14, wherein the graphical user interface further comprises a graphical representation of a brightness of imaged reflectors within a pre-determined radius of the known reflector positions.

16. An ultrasound probe alignment system, comprising:

a tank assembly comprising an ultrasound conducting material;

an array affixing and adjusting assembly at least partially within the tank assembly, the array affixing and adjusting assembly supporting a precision alignment element in a known position and orientation relative to a target assembly, the target assembly being disposed in the tank assembly and comprising a plurality of pins oriented with longitudinal axes that intersect at a single point.

17. The system of claim 16, further comprising a height adjustment assembly configured to adjust a distance between the array affixing and adjusting assembly and the target assembly.

18. The system of claim 16, wherein the plurality of pins are arranged with their longitudinal axes lying in a precisely aligned imaging plane of the ultrasound probe alignment system.

19. The system of claim 18, wherein the pins are arranged so as to be displaced from one another in two dimensions in the imaging plane of the ultrasound probe alignment system.

20. The system of claim 18, wherein the pins vary in length so as to lie on multiple different points of the imaging plane of the ultrasound probe alignment system.

21. The system of claim 20, wherein the plurality of pins comprises a center pin and at least one pair of pins equidistant from the center pin.

22. The system of claim 16, wherein the array affixing and adjusting assembly comprises structures for adjusting an orientation of an ultrasound transducer array relative to the precision alignment element.

23. A method of building a multiple aperture ultrasound probe, the method comprising the steps of:

forming a gasket with a first flowable solidifying material on a lower surface of a precision alignment element;

securing the precision alignment element to a back surface of a transducer array with the gasket;

evaluating and adjusting alignment of the transducer array relative to the precision alignment element by imaging a target with the transducer array and comparing a resulting image of the target with known information defining a geometry of the target, the target comprising a plurality of pins oriented with longitudinal axes that intersect at a single point and in a known configuration relative to the precision alignment element; and

injecting a second flowable solidifying material through at least one hole in the precision alignment element to secure the transducer array to the precision alignment element.

24. The method of claim 23, wherein the injecting step comprises filling a volume defined by the back surface of the transducer array, the lower surface of the precision alignment element, and an inner perimeter surface of the gasket with the second flowable solidifying material.

25. The method of claim 23, further comprising allowing the second flowable solidifying material to solidify, and mounting the precision alignment element to a probe alignment bracket.

26. The method of claim 25, further comprising placing the probe alignment bracket into a probe housing, and injecting a third flowable solidifying material into a space between the transducer array and the probe housing.

27. The method of claim 26, wherein the injected third flowable solidifying material surrounds at least a portion of the precision alignment element or the probe alignment bracket.

28. The method of claim 23, wherein each of the pins has a flat surface substantially perpendicular to a longitudinal axis of the pins, the longitudinal axis being substantially perpendicular to an ultrasound wavefront transmitted from a single element of the transducer array and arriving at the pins.

29. The method of claim 23, wherein adjusting alignment of the transducer array relative to the precision alignment element comprises adjusting at least one set screw to mechanically move the transducer array relative to the precision alignment element.

30. The method of claim 23, further comprising allowing the first flowable solidifying material to solidifyrior to evaluating and adjusting alignment of the transducer array relative to the precision alignment element.

31. The method of claim 23, wherein the first flowable solidifying material and the second flowable solidifying material are the same material.