Method and apparatus for using a multi-layer multi-leaf collimation system

1. A method for use with a radiation therapy treatment platform having a multi-layer multi-leaf collimation system wherein a first layer of collimation leaves are laterally offset with respect to a second layer of collimation leaves, the method comprising:

by a control circuit:

generating a preliminary radiation treatment plan using a model of a radiation therapy treatment platform comprising a single-layer multi-leaf collimation system having a single layer of collimation leaves that may be the same as or different than the first layer or the second layer of collimation leaves of the multi-layer multi-leaf collimation system;

using the preliminary radiation treatment plan to generate a final radiation treatment plan for the radiation therapy treatment platform that takes into account at least two layers of collimation leaves.

2. The method of claim 1 wherein the collimation leaves of the first layer have a same width as the collimation leaves of the second layer, and wherein the single-layer multi-leaf collimation system of the model of the radiation therapy treatment platform presumes that the single-layer multi-leaf collimation system has collimation leaves having a width that is less than the width of the collimation leaves of the first layer and the second layer.

3. The method of claim 2 wherein the width of the collimation leaves for the single-layer multi-leaf collimation system is approximately one half the width of the collimation leaves of the first layer and the second layer.

4. The method of claim 1 wherein the single-layer multi-leaf collimation system of the model of the radiation therapy treatment platform presumes that the single-layer multi-leaf collimation system has a greater number of collimation leaves than either of the first layer and the second layer.

5. The method of claim 4 wherein the single-layer multi-leaf collimation system of the model of the radiation therapy treatment platform presumes that the single-layer multi-leaf collimation system has at least twice as many collimation leaves as the first layer or the second layer.

6. The method of claim 1 wherein the single-layer multi-leaf collimation system of the model of the radiation therapy treatment platform presumes that the single-layer multi-leaf collimation system has collimation leaves that are less in width and greater in number than the collimation leaves of the first layer and the second layer.

7. The method of claim 6 wherein generating the final radiation treatment plan that takes into account a second layer of collimation leaves comprises, at least in part, modifying the preliminary radiation treatment plan to avoid apertures that the multi-layer multi-leaf collimation system cannot produce.

8. The method of claim 6 wherein generating the final radiation treatment plan that takes into account a second layer of collimation leaves comprises, at least in part, determining how to produce planned apertures formed by the single-layer multi-leaf collimation system using the multi-layer multi-leaf collimation system.

9. The method of claim 8 further comprising:

using the final radiation treatment plan to administer radiation to a patient using the multi-layer multi-leaf collimation system.

10. The method of claim 1 wherein the collimation leaves of the single-layer multi-leaf collimation system are presumed to have better transmission parameters than the collimation leaves of either the first layer or the second layer.

11. The method of claim 10 wherein generating the final radiation treatment plan that takes into account a second layer of collimation leaves comprises, at least in part, refining apertures defined in the preliminary radiation treatment plan to provide higher resolution by optimizing collimation leaf positions in the second layer of collimation leaves.

12. An apparatus comprising:

a control circuit configured to generate a radiation treatment plan by:

generating a preliminary version of the radiation treatment plan using a model of a radiation therapy treatment platform comprising a single-layer multi-leaf collimation system;

using the preliminary version of the radiation treatment plan to generate a final version of the radiation treatment plan that takes into account a second layer of collimation leaves.

13. The apparatus of claim 12 further comprising:

a multi-layer multi-leaf collimation system wherein a first layer of collimation leaves are laterally offset with respect to a second layer of collimation leaves, wherein the collimation leaves of the first layer have a same width as the collimation leaves of the second layer; and

wherein the single-layer multi-leaf collimation system of the model of the radiation therapy treatment platform presumes that the single-layer multi-leaf collimation system has collimation leaves having a width that is less than the width of the collimation leaves of the first layer and the second layer and that the single-layer multi-leaf collimation system has a greater number of collimation leaves than either of the first layer and the second layer.

14. The apparatus of claim 13 wherein the width of the collimation leaves for the single-layer multi-leaf collimation system is approximately one half the width of the collimation leaves of the first layer and the second layer.

15. The apparatus of claim 13 wherein the control circuit is configured to generate the final radiation treatment plan that takes into account a second layer of collimation leaves by, at least in part, modifying the preliminary radiation treatment plan to avoid apertures that the multi-layer multi-leaf collimation system cannot produce.

16. The method of claim 15 wherein the control circuit is configured to generate the final radiation treatment plan that takes into account a second layer of collimation leaves by, at least in part, determining how to produce planned apertures formed by the single-layer multi-leaf collimation system using the multi-layer multi-leaf collimation system.

17. The apparatus of claim 16 further comprising:

a radiation therapy treatment platform configured to use the final radiation treatment plan to administer radiation to a patient using the multi-layer multi-leaf collimation system.

18. The apparatus of claim 12 wherein the collimation leaves of the single-layer multi-leaf collimation system are presumed to have better transmission parameters than the collimation leaves of a multi-layer multi-leaf collimation system.

19. The apparatus of claim 18 wherein the control circuit is configured to generate the final radiation treatment plan that takes into account a second layer of collimation leaves by, at least in part, refining apertures defined in the preliminary radiation treatment plan to provide higher resolution by optimizing collimation leaf positions in the second layer of collimation leaves.