System and method for manufacturing bolus for radiotherapy using a three-dimensional printer

Patent metadata

Field	Value
Publication number	US-10350435-B2
Application number	US-201615157029-A
Country	US
Kind code	B2
Filing date	May 17, 2016
Priority date	Nov 27, 2013
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

Disclosed herein are systems, methods, and computer-readable storage devices for manufacturing patient-specific bolus for use in targeted radiotherapy treatment. Based on dose calculations without a bolus and based on three-dimensional scan data of a patient, the example system generates a model of a bolus for targeting radiotherapy treatment to a planning target volume or target region within the patient. The system can perform several iterations to generate a resulting model for the bolus. Then, the system can generate instructions for controlling a three-dimensional printer to generate the bolus that conforms to the patient's skin surface while also specifically targeting the planning target volume for the radiotherapy treatment. In this way, the amount of radiotherapy treatment administered to other tissue is reduced, while the costs, time, and human involvement in creating the bolus are significantly reduced.

First claim

We claim:

1. A method of fabricating a target bolus for use in radiation therapy, the method comprising:
processing data comprising (i) three-dimensional scan data associated with a patient, (ii) a planning target volume, and (iii) a first dose calculation associated with a treatment goal to obtain a target bolus model, wherein the target bolus model is an initial model, and wherein a patient-facing side of the target bolus model is shaped to conform to a skin surface of the patient;
performing a second dose calculation for the treatment goal, wherein the second dose calculation is performed based on the presence of the target bolus model;
determining that the second dose calculation fails to meet conditions associated with the treatment goal;
modifying the target bolus model until an additional dose calculation meets the conditions associated with the treatment goal; and
fabricating the target bolus according to the modified target model.

2. The method according to claim 1 wherein the dose calculations are performed according to a Monte Carlo algorithm.

3. The method according to claim 1 wherein the model is initially calculated as an approximate target bolus for achieving conformal coverage of the planning target volume.

4. The method according to claim 1 wherein modifying the model comprises reducing at least one hot spot or cool spot.

5. The method according to claim 1 wherein modifying the model comprises improving dose coverage relative to the planning target volume.

6. The method according to claim 1 wherein modifying the model comprises reducing surface irregularity.

7. The method according to claim 1 wherein modifying the model comprises modifying the model based on an analysis of a margin of the planning target volume.

8. The method according to claim 1 wherein modifying the model comprises improving conformity of the dose distribution at edges of the planning target volume.

9. The method according to claim 1 wherein obtaining the model further comprises processing the three-dimensional scan data to include an immobilization component, wherein the immobilization component is configured to immobilize a region of the patient proximate to the planning target volume, and wherein the immobilization component is further configured to rigidly support the target bolus relative to the planning target volume.

10. The method according to claim 9 wherein the target bolus and the immobilization component are fabricated such that the immobilization component is integrated with the target bolus.

11. The method according to claim 9 further comprising connecting a securing mechanism to the immobilization component after fabricating the immobilization component, such that the immobilization component can be secured relative to the patient by the securing mechanism during radiation treatment.

12. The method according to claim 11 wherein the securing mechanism comprises a strap.

13. The method according to claim 11 wherein the immobilization component further comprises one or more attachment mechanisms that are configured to facilitate attachment of the securing mechanism to the immobilization component.

14. The method according to claim 13 wherein the one or more attachment mechanisms are selected from the group consisting of brackets and grommets.

15. The method according to claim 9 wherein the immobilization component comprises a mesh.

16. The method according to claim 14 wherein the immobilization component is formed by controlling an effective electron density of the material forming the immobilization component.

17. The method according to claim 15 wherein the immobilization component is formed by controlling one or more of a density of the mesh, a thickness of lines forming the mesh, and an effective electron density of the material forming the mesh.

18. The method according to claim 9 wherein the immobilization component is configured to fit contours of the region to be immobilized.

19. The method according to claim 9 wherein the target bolus is configured for use in radiation therapy involving irradiation of a breast, and wherein the immobilization component is configured to support the breast.

20. The method according to claim 19 wherein the immobilization component is configured to avoid damage or irritation to an inframammary fold.

21. The method according to claim 1 wherein the model for the target bolus comprises a cavity configured to receive a radiation dosimeter.

22. The method according to claim 21 further comprising inserting the radiation dosimeter into the cavity after fabricating the target bolus.

23. The method according to claim 21 wherein the cavity is configured to accept a specific type of radiation dosimeter.

24. The method according to claim 21 wherein the target bolus is formed to include a restraining mechanism for retaining the radiation dosimeter in place after insertion of the radiation dosimeter into the cavity.

25. The method according to claim 21 wherein the cavity is formed such that when the radiation dosimeter is inserted into the cavity, the radiation dosimeter is located proximal to the skin surface when the target bolus is employed during radiation treatment.

26. The method according to claim 21 wherein the radiation dosimeter is selected from the group consisting of ionization chambers, diodes, metal-oxide semiconductor field-effect transistors (MOSFETs), radiographic film, radiochromic film, diamond detectors, optically stimulated luminescence dosimeters (OSLDs), and arrays thereof.

27. The method according to claim 1 wherein the target bolus comprises one or more scintillator materials.

28. The method according to claim 27 wherein the scintillator materials form a spatial pattern.

29. The method according to claim 1 wherein the model for the target bolus is initially selected from a template set of bolus shapes.

30. The method according to claim 1 wherein fabricating the target bolus comprises:
outputting the model for the target bolus to a fabrication device to produce a replica of the target bolus for use with the planning target volume of the patient.

31. The method according to claim 30 wherein the fabrication device comprises a three-dimensional printer.

32. The method according to claim 31 wherein the dose calculations are performed according to an electron Monte Carlo algorithm.

33. The method according to claim 1 wherein the dose calculations are performed for one of electron radiation therapy, megavoltage photon radiation therapy and proton radiation therapy.

34. The method according to claim 1 wherein a beam-incident side of the target bolus is shaped according to a regular geometric surface.

35. The method according to claim 1 further comprising generating and fabricating one or more additional target boluses, wherein each additional target bolus is respectively associated with a different stage of a treatment plan.

36. The method according to claim 35 wherein at least two additional target boluses are fabricated in advance of a plurality of subsequent stages of the treatment plan.

37. The method according to claim 35 wherein at least one of the one or more additional target boluses are fabricated

Assignees

• Univ Dalhousie

Inventors

• Robar James
• Su Shiqin

Classifications

• G16H50/30

  for calculating health indices; for individual health risk assessment · CPC title

• B29C64/393

  for controlling or regulating additive manufacturing processes · CPC title

• B29L2031/753

  Medical equipment; Accessories therefor (bloodbags, medical bags B29L2031/7148; artificial eyes B29L2011/0008) · CPC title

• A61N5/1075

  for testing, calibrating, or quality assurance of the radiation treatment apparatus · CPC title

• B33Y50/02

  for controlling or regulating additive manufacturing processes · CPC title