Spatially-variant normal tissue objective for radiotherapy

• US 20080008291A1
• Filed: 01/25/2007
• Published: 01/10/2008
• Est. Priority Date: 07/06/2006
• Status: Abandoned Application

• Current Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Original Assignee: Varian Medical Systems International AG (Siemens AG)
• Inventors: Alakuijala, Jyrki Antero, Pesola, Katja Marika
• Application Number:
  US11/698,617
• Publication Number:
  US 20080008291A1
• Time in Patent Office: Days
• US Class Current: 378/65
• CPC Class Codes: A61N 5/103 Treatment planning systems
• CPC Class Codes: A61N 5/1042 with spatial modulation of the radiation beam within the treatment head

Abstract

A system for use to determine or evaluate a radiation treatment plan includes a processor configured for determining a spatially variable constraint, and imposing the spatially variable constraint on a healthy tissue. A system for use to determine or evaluate a radiation treatment plan includes a processor configured for determining a first position of a first healthy tissue, imposing a first constraint on the first healthy tissue based on the determined first position, determining a second position of a second healthy tissue, and imposing a second constraint on the second healthy tissue based on the determined second position, wherein the first constraint and the second constraint have different values. A radiation system includes a processor configured for determining a treatment plan using a spatially variable constraint on healthy tissue, and a radiation machine for performing a radiation procedure based on the determined treatment plan.

Claims

1. A method for use to determine or evaluate a radiation treatment plan, comprising:

determining a spatially variable constraint; and

imposing the spatially variable constraint on a healthy tissue.

2. The method of claim 1, further comprising determining a value of the spatially variable constraint based on a distance between the healthy tissue and a boundary of a target tissue.

3. The method of claim 2, wherein the target tissue is a point located in or on a Planning Target Volume.

4. The method of claim 2, wherein the target tissue is a point located in or on a Clinical Target Volume.

5. The method of claim 1, further comprising predicting a result of a radiation treatment based on the imposed spatially variable constraint.

6. The method of claim 1, further comprising determining a treatment plan based on the imposed spatially variable constraint.

7. The method of claim 1, further comprising determining a value of the spatially variable constraint using a process that includes:

determining a first position of a first target tissue;

determining a first target constraint value;

calculating a first value based on the first target constraint value;

determining a second position of a second target tissue;

determining a second target constraint value;

calculating a second value based on the second target constraint value; and

selecting a maximum of the first and second values.

8. The method of claim 7, wherein the first target constraint value is determined by:

determining a plurality of target constraint values;

determining a subset of the target constraint values having increasing radiation dose associated therewith; and

selecting a minimum value from the subset as the first target constraint.

9. The method of claim 1, wherein the spatially variable constraint is represented by a function that decreases linearly.

10. The method of claim 1, wherein the spatially variable constraint is represented by a function that decreases exponentially.

11. The method of claim 10, wherein the function comprises:

$f<br><br>\left(x\right)=\{\begin{array}{cc}{f}_o<br><br>{\mathrm{<br><br>}}^{-k<br><br>\left(x-x_{\mathrm{start}}\right)}+f_{\mathrm{\infty <br><br>}}<br><br>\left(1-{\mathrm{<br><br>}}^{-k<br><br>\left(x-x_{\mathrm{start}}\right)}\right),& x\ge <br><br>x_{\mathrm{start}}\\ f_o,& x\le <br><br>x_{\mathrm{start}}\end{array}$

12. The method of claim 1, wherein the spatially variable constraint is associated with a limit of radiation dose to be received by the healthy tissue.

13. The method of claim 1, wherein the healthy tissue comprises a mathematical model of a real healthy tissue.

14. A system for use to determine or evaluate a radiation treatment plan, comprising:

a processor configured for

determining a spatially variable constraint, and

imposing the spatially variable constraint on a healthy tissue.

15. A method for use to determine or evaluate a radiation treatment plan, comprising:

determining a first position of a first healthy tissue;

imposing a first constraint on the first healthy tissue based on the determined first position;

determining a second position of a second healthy tissue; and

imposing a second constraint on the second healthy tissue based on the determined second position, wherein the first constraint and the second constraint have different values.

16. The method of claim 15, wherein the first healthy tissue is closer to a target tissue than the second healthy tissue, and the value of the first constraint is higher than the value of the second constraint.

17. The method of claim 15, further comprising determining the value of the first constraint based on a distance between the first healthy tissue and a boundary of a target tissue.

18. The method of claim 17, wherein the target tissue is a point located in or on a Planning Target Volume.

19. The method of claim 17, wherein the target tissue is a point located in or on a Clinical Target Volume.

20. The method of claim 15, further comprising predicting a result of a radiation treatment based on the first and second constraints.

21. The method of claim 15, further comprising determining a treatment plan based on the first and second constraints.

22. The method of claim 15, further comprising determining a value of the first constraint based on positions of at least two target tissues.

23. The method of claim 15, further comprising determining a value of the first constraint using a process that includes:

determining a first position of a first target tissue;

determining a first target constraint value;

calculating a first value based on the first target constraint value;

determining a second position of a second target tissue;

determining a second target constraint value;

calculating a second value based on the second target constraint value; and

selecting a maximum of the first and second values.

24. The method of claim 23, wherein the first target constraint value is determined by:

determining a plurality of target constraint values;

determining a subset of the target constraint values having increasing radiation dose associated therewith; and

selecting a minimum value from the subset as the first target constraint.

25. The method of claim 15, wherein the values of the first and second constraints lie on a curve in which x values represent distances from a boundary of a target tissue, and y values represent constraint values, the curve having a decreasing profile.

26. The method of claim 25, wherein the curve is represented by a function that decreases linearly.

27. The method of claim 25, wherein the curve is represented by a function that decreases exponentially.

28. The method of claim 27, wherein the function comprises:

$f<br><br>\left(x\right)=\{\begin{array}{cc}{f}_o<br><br>{\mathrm{<br><br>}}^{-k<br><br>\left(x-x_{\mathrm{start}}\right)}+f_{\mathrm{\infty <br><br>}}<br><br>\left(1-{\mathrm{<br><br>}}^{-k<br><br>\left(x-x_{\mathrm{start}}\right)}\right),& x\ge <br><br>x_{\mathrm{start}}\\ f_o,& x\le <br><br>x_{\mathrm{start}}\end{array}$

29. The method of claim 15, wherein the first constraint is associated with a limit of radiation dose to be received by the first healthy tissue.

30. The method of claim 15, wherein the first healthy tissue comprises a mathematical model of a real healthy tissue.

31. A system for use to determine or evaluate a radiation treatment plan, comprising:

a processor configured for

determining a first position of a first healthy tissue,

imposing a first constraint on the first healthy tissue based on the determined first position,

determining a second position of a second healthy tissue, and

imposing a second constraint on the second healthy tissue based on the determined second position, wherein the first constraint and the second constraint have different values.

32. A radiation process, comprising:

determining a treatment plan using a spatially variable constraint on healthy tissue; and

performing a radiation procedure based on the determined treatment plan.

33. The radiation process of claim 32, wherein the spatially variable constraint is represented by a function that decreases linearly.

34. The radiation process of claim 32, wherein the spatially variable constraint is represented by a function that decreases exponentially.

35. The radiation process of claim 34, wherein the function comprises:

$f<br><br>\left(x\right)=\{\begin{array}{cc}{f}_o<br><br>{\mathrm{<br><br>}}^{-k<br><br>\left(x-x_{\mathrm{start}}\right)}+f_{\mathrm{\infty <br><br>}}<br><br>\left(1-{\mathrm{<br><br>}}^{-k<br><br>\left(x-x_{\mathrm{start}}\right)}\right),& x\ge <br><br>x_{\mathrm{start}}\\ f_o,& x\le <br><br>x_{\mathrm{start}}\end{array}$

36. The radiation process of claim 32, wherein the spatially variable constraint is associated with a limit of radiation dose to be received by real healthy tissue.

37. The radiation process of claim 32, wherein the healthy tissue comprises a mathematical model of a real healthy tissue.

38. The radiation process of claim 32, wherein the treatment plan is determined after a first treatment session.

39. The radiation process of claim 32, wherein the radiation procedure comprises delivering radiation towards target tissue.

40. The radiation process of claim 32, wherein the radiation procedure comprises tracking movement of target tissue.

41. The radiation process of claim 32, wherein the radiation procedure comprises an intensity modulated radiation therapy.

42. The radiation process of claim 32, wherein the radiation procedure comprises tracking a movement of target tissue, and performing an intensity modulated radiation therapy on the target tissue.

43. A radiation system, comprising:

a processor configured for determining a treatment plan using a spatially variable constraint on healthy tissue; and

a radiation machine for performing a radiation procedure based on the determined treatment plan.