RADIATION THERAPY PLAN DOSE PERTURBATION SYSTEM AND METHOD

• US 20090252292A1
• Filed: 03/12/2009
• Published: 10/08/2009
• Est. Priority Date: 03/12/2008
• Status: Active Grant

• Current Assignee: Sun Nuclear Corporation (American Capital Limited)
• Original Assignee: Sun Nuclear Corporation (American Capital Limited)
• Inventors: Simon, William E., Nelms, Benjamin E.
• Granted Patent: US 7,945,022 B2
• Time in Patent Office: Days
• US Class Current: 378/65
• CPC Class Codes: A61N 2005/1034 Monte Carlo type methods; particle tracking
• CPC Class Codes: A61N 2005/1076 using a dummy object placed in the radiation field, e.g. phantom
• CPC Class Codes: A61N 5/1038 taking into account previously administered plans applied to the same patient, i.e. adaptive radiotherapy
• CPC Class Codes: A61N 5/1071 for verifying the dose delivered by the treatment plan

Abstract

A method of determining a patient dose during or prior to therapy from an external radiation beam includes determining a dose distribution from a patient plan as delivered in a QA phantom at each appropriate beam angle and comparing the dose distribution determined from measurements or calculations to a corresponding treatment planning system (TPS) dose modeled distribution in the QA phantom and providing a correction distribution when applied to the TPS dose modeled distribution results in the dose distribution determined. The correction distribution may optionally be interpolated to non-measured points for each beam angle and geometrically projected toward the source of radiation through a volume that equals a dose volume of the TPS for a patient beam for each beam angle. The correction distribution is applied to the TPS patient dose volume for each beam angle for providing a corrected dose distribution in the patient.

Claims

1. A method of determining a patient dose during or prior to therapy by an external radiation beam from a source of radiation, the method comprising:

determining a dose distribution from a patient plan as delivered in a QA phantom at each of a plurality of beam angles;

comparing the determined dose distribution at each beam angle to a corresponding treatment planning system (TPS) dose modeled distribution in the QA phantom, with the comparing resulting in a correction distribution that when applied to the TPS dose modeled distribution results in the determined dose distribution;

geometrically projecting the correction distribution relative to the source of radiation through a volume that represents a dose volume of the TPS for a patient beam for each beam angle; and

applying the correction distribution to the TPS patient dose volume for each beam angle for providing a corrected dose distribution in the patient for each beam angle.

2. The method of claim 1, wherein the determining comprises at least one of measuring and calculating.

3. The method of claim 2, wherein the calculating comprises at least one of MapCALC™

and Monte Carlo calculations for radiation transport in radiotherapy dosimetry and treatment planning.

4. The method of claim 2, wherein the dose distribution measuring comprises measuring dose with at least one of a film, a diode array, an ion chamber array, and an electronic portal imaging device (EPID).

5. The method of claim 2, wherein the dose distribution measuring comprises measuring dose with a three dimensional detector array.

6. The method of claim 2, further comprising interpolating the correction distribution from the measured dose to non-measured points for each beam angle, wherein the geometrically projecting comprises geometrically projecting the interpolated correction distribution, and wherein the correction distribution applying to the TPS patient dose volume comprises applying the interpolated correction distribution.

7. The method of claim 1, further comprising generating a dose error kernel for sub-beamlets of the beam based on the determined dose distribution;

and wherein the geometrically projecting comprises geometrically applying the dose error kernel divergently from the source.

8. The method of claim 1, further comprising comparing the corrected dose distribution to the TPS dose modeled distribution.

9. The method of claim 1, further comprising aggregating all beam angle corrected dose distributions into the total patient dose distribution.

10. The method of claim 9, further comprising comparing the corrected total dose distribution to the TPS total dose distribution.

11. The method of claim 9, further comprising reducing the corrected total dose distribution by patient structure analysis to dose volume histograms and comparing the dose volume histograms to TPS total dose volume histograms.

12. The method of claim 1, further comprising reducing the corrected dose distribution by patient structure analysis to dose volume histograms and comparing the dose volume histograms TPS dose volume histograms.

13. The method of claim 1, further comprising exporting the corrected dose distribution to the TPS for reviewing thereof.

14. The method of claim 1, further comprising providing the phantom having various materials simulating heterogeneities in the patient.

15. A system for determining a patient dose during or prior to therapy from an external radiation beam, the method comprising:

means for determining a dose distribution from a patient plan as delivered in a QA phantom at each of a plurality of beam angles;

means for comparing the determined dose distribution at each beam angle to a corresponding treatment planning system (TPS) dose modeled distribution in the QA phantom, with the comparing resulting in a correction distribution that when applied to the TPS dose modeled distribution results in the determined dose distribution;

means for geometrically projecting the correction distribution relative to the source through a volume that represents a dose volume of the TPS for a patent beam for each beam angle; and

means for applying the correction distribution to the TPS patient dose volume for each beam angle for providing a corrected dose distribution in the patient for each beam angle.

16. The system of claim 15, wherein the determining means comprises at least one of means for measuring and means for calculating.

17. The system of claim 16, wherein the dose distribution measuring means comprise at least one of a film, a diode array, an ion chamber array, a three dimensional detector array, and an electronic portal imaging device (EPID).

18. The system of claim 16, further comprising means for interpolating the correction distribution to non-measured points for each beam angle, wherein the means for geometrically projecting the correction distribution includes means for geometrically projecting the interpolated correction distribution, and wherein the means for applying the correction distribution includes means for applying the interpolated correction distribution.

19. The system of claim 16, wherein the calculating means comprises at least one of MapCALC calculation means and Monte Carlo calculation means for radiation transport in radiotherapy dosimetry and treatment planning.

20. The system claim 15, further comprising means for generating a dose error kernel for sub-beamlets of the beam based on the determined dose distribution;

and wherein the geometrically projecting means comprises means for geometrically applying the dose error kernel divergently from the source.

21. The system of claim 15, further comprising means for comparing the corrected dose distribution to the TPS dose modeled distribution.

22. The system of claim 15, further comprising means for aggregating all beam angle corrected dose distributions into the total patient dose distribution.

23. The system claim 22, further comprising means for comparing the corrected total dose distribution to the TPS total dose distribution.

24. The system of claim 22, further comprising means for reducing the corrected total dose distribution by patient structure analysis to dose volume histograms and comparing the dose volume histograms to TPS total dose volume histograms.

25. The system of claim 15, further comprising means for reducing the corrected dose distribution by patient structure analysis to dose volume histograms and comparing the dose volume histograms TPS dose volume histograms.

26. The system of claim 15, further comprising means for exporting the corrected dose distribution to the TPS for reviewing thereof.

27. The system of claim 15, wherein phantom comprises materials simulating heterogeneities in the patient.