RADIATION THERAPY TREATMENT PLAN IMPROVEMENT THROUGH USE OF KNOWLEDGE BASE

• US 20130077752A1
• Filed: 09/28/2011
• Published: 03/28/2013
• Est. Priority Date: 09/28/2011
• Status: Active Grant

• Current Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Original Assignee: Corey Zankowski
• Inventors: ZANKOWSKI, Corey
• Granted Patent: US 8,774,358 B2
• Time in Patent Office: Days
• US Class Current: 378/65
• CPC Class Codes: A61N 2005/1041 using a library of previously administered radiation treatment applied to other patients
• CPC Class Codes: A61N 5/1031 using a specific method of dose optimization
• CPC Class Codes: A61N 5/1039 using functional images, e.g. PET or MRI

Abstract

A radiation therapy dose distribution method starts with selecting a treatment type. Then an organ at risk (OAR) distance to target map is determined. The OAR distance to target map comprises distances to a target organ for portions of an OAR. The OAR distances are determined from at least one segmented patient organ image. A cohort average dose distance to target histogram is selected. A dose value to the portions of the OAR are assigned to form a first 3D dose distribution map. The dose values are from the selected cohort average dose distance to target histogram. A second 3D dose distribution map is determined based on a field arrangement determined by the treatment type and the first 3D dose distribution map. A dose distance to target histogram is calculated using the second 3D dose distribution map and the distance to target map.

Claims

1. A method for determining a radiation therapy dose distribution, comprising:

selecting and downloading a treatment type for a patient from a database;

determining an organ at risk (OAR) distance to target map, wherein the OAR distance to target map comprises distances to a target organ for respective portions of at least one OAR, and wherein the OAR distances are determined from at least one segmented patient organ image;

selecting and downloading a cohort average dose distance to target histogram from the database;

assigning a dose value to each of the portions of the at least one OAR to form a first 3D dose distribution map, wherein the assigned dose values are from the selected cohort average dose distance to target histogram;

determining a second 3D dose distribution map based on a field arrangement determined by the selected treatment type and the first 3D dose distribution map; and

calculating a dose distance to target histogram for the patient using the second 3D dose distribution map and the distance to target map.

2. The method of claim 1 further comprising optimizing the second 3D dose distribution map to generate a third 3D dose distribution map, wherein the dose distance to target histogram is calculated using the third 3D dose distribution map.

3. The method of claim 2, wherein optimizing the second 3D dose distribution map uses at least one OAR objective comprising at least one of:

an average OAR dose volume histogram, a cohort average OAR dose volume histogram, 2D penalty maps, biological objectives, and a dose distance to target histogram.

4. The method of claim 3, further comprising:

optimizing the third 3D dose distribution map to generate a fourth 3D dose distribution map using adjusted OAR objectives to drive a dose volume histogram in a desired direction, wherein calculating the dose distance to target histogram uses the fourth 3D dose distribution map and the distance to target map.

5. The method of claim 3, further comprising:

updating the database, wherein population and cohort populations are updated with current patient information, and wherein updating the database comprises updating the plurality of OAR objectives.

6. The method of claim 1, wherein the selected cohort average dose distance to target histogram is based on a patient'"'"'s meta-data, the selected treatment type, and the OAR distance to target map.

7. The method of claim 6, wherein the selected cohort average OAR dose volume histogram has an average distance to target for the OAR that is similar to the average distance to target for the OAR of the patient.

8. The method of claim 6, wherein the cohort average dose distance to target histogram is an average of a plurality of dose distance to target histograms of radiation therapy dose distribution plans with similar meta-data and organ at risk distance to target maps.

9. The method of claim 1, wherein the portions of a plurality of organs at risk comprise individual pixels.

10. The method of claim 1, wherein the distance to the target organ is the shortest distance to the target organ.

11. The method of claim 1, wherein the selection of the treatment type is based on a patient'"'"'s meta-data.

12. The method of claim 10, wherein the treatment type selected is the most frequently selected treatment type for the meta-data.

13. The method of claim 1, wherein the OAR distance to target map is determined from structure sets in a medical image, and wherein the structure sets are determined after segmentation of the medical image is complete.

14. The method of claim 1, wherein the selected cohort average dose distance to target histogram has a confidence level greater than a desired confidence level.

15. The method of claim 2, wherein optimizing the second 3D dose distribution map utilizes an optimizer that takes the field arrangements and the first 3D dose distribution map and calculates a set of fluences that provide the third 3D dose distribution map.

16. A computer readable storage media having computer-readable and computer-executable instructions embodied therein for causing a computer system to execute a method for determining a radiation therapy dose distribution, the computer-executable instructions comprising:

instructions to select and download a treatment type for a patient from a database;

instructions to determine an organ at risk (OAR) distance to target map, wherein the OAR distance to target map comprises distances to a target organ for respective portions of at least one OAR, and wherein the OAR distances are determined from at least one segmented patient organ image;

instructions to select and download a cohort average dose distance to target histogram from the database;

instructions to assign a dose value to each of the portions of the at least one OAR to form a first 3D dose distribution map, wherein the assigned dose values are from the selected cohort average dose distance to target histogram;

instructions to determine a second 3D dose distribution map based on a field arrangement determined by the selected treatment type and the first 3D dose distribution map; and

instructions to calculate a dose distance to target histogram for the patient using the second 3D dose distribution map and the distance to target map.

17. The method of claim 16 further comprising instructions to optimize the second 3D dose distribution map to generate a third 3D dose distribution map, wherein the dose distance to target histogram is calculated using the third 3D dose distribution map.

18. The method of claim 17, wherein optimizing the second 3D dose distribution map uses at least one OAR objective comprising at least one of:

an average OAR dose volume histogram, a cohort average OAR dose volume histogram, 2D penalty maps, biological objectives, and a dose distance to target histogram.

19. The method of claim 18, the computer-executable instructions further comprising:

instructions to optimize the third 3D dose distribution map to generate a fourth 3D dose distribution map using adjusted OAR objectives to drive a dose volume histogram in a desired direction, wherein calculating the dose distance to target histogram uses the fourth 3D dose distribution map and the distance to target map.

20. The method of claim 18, the computer-executable instructions further comprising:

instructions to update the database, wherein population and cohort populations are updated with current patient information, and wherein updating the database comprises updating the plurality of OAR objectives.

21. The method of claim 16, wherein the selected cohort average dose distance to target histogram is based on a patient'"'"'s meta-data, the selected treatment type, and the OAR distance to target map.

22. The method of claim 21, wherein the selected cohort average OAR dose volume histogram has an average distance to target for the OAR that is similar to the average distance to target for the OAR of the patient.

23. The method of claim 21, wherein the cohort average dose distance to target histogram is an average of a plurality of dose distance to target histograms of radiation therapy dose distribution plans with similar meta-data and organ at risk distance to target maps.

24. The method of claim 16, wherein the portions of a plurality of organs at risk comprise individual pixels.

25. The method of claim 16, wherein the distance to the target organ is the shortest distance to the target organ.

26. The method of claim 16, wherein the selection of the treatment type is based on a patient'"'"'s meta-data.

27. The method of claim 25, wherein the treatment type selected is the most frequently selected treatment type for the meta-data.

28. The method of claim 16, wherein the OAR distance to target map is determined from structure sets in a medical image, and wherein the structure sets are determined after segmentation of the medical image is complete.

29. The method of claim 16, wherein the selected cohort average dose distance to target histogram has a confidence level greater than a specified level of confidence.

30. The method of claim 17, wherein optimizing the second 3D dose distribution map utilizes an optimizer that takes the field arrangements and the first 3D dose distribution map and calculates a set of fluences that provide the third 3D dose distribution map.