STUDYING DOSIMETRIC IMPACT OF MOTION TO GENERATE ADAPTIVE PATIENT-SPECIFIC MARGINS IN EBRT PLANNING

• US 20140005464A1
• Filed: 03/13/2012
• Published: 01/02/2014
• Est. Priority Date: 03/15/2011
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V., Washington University In St Louis
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Parikh, Parag Jitendra, Bharat, Shyam, Bzdusek, Karl Antonin, Noel, Camille Elizabeth
• Granted Patent: US 9,744,379 B2
• Time in Patent Office: Days
• US Class Current: 600/1
• CPC Class Codes: A61N 2005/1072 taking into account movement of the target
• CPC Class Codes: A61N 5/1031 using a specific method of dose optimization
• CPC Class Codes: A61N 5/1037 taking into account the movement of the target, e.g. 4D-image based planning
• CPC Class Codes: G10L 21/0208 Noise filtering

Abstract

A treatment planning system (106) for generating patient-specific treatment margins. The system (106) includes one or more processors (142). The processors (142) are programmed to receive a radiation treatment plan (RTP) for irradiating a target (122) over the course of one or more treatment fractions. The RTP including one or more treatment margins around the target (122) and a planned dose distribution for the target (122). The processors (142) are further programmed to receive motion data for at least one of the treatment fractions of the RTP from one or more target surrogates (124), calculate a motion-compensated dose distribution for the target (122) using the motion data and the planned dose distribution, compare the motion-compensated dose distribution to the planned dose distribution, and adjust the treatment margins based on dosimetric differences between the motion-compensated dose distribution and the planned dose distribution.

Claims

1. A treatment planning system generating patient-specific treatment margins, said system comprising:

one or more processors programmed to;

receive a radiation treatment plan (RTP) for irradiating a target over the course of one or more treatment fractions, said RTP including one or more treatment margins around the target and a planned dose distribution to be delivered to the target;

receive motion data for at least one of the treatment fractions of the RTP;

calculate a motion-compensated dose distribution for the target using the motion data to adjust the planned dose distribution based on the received motion data;

compare the motion-compensated dose distribution to the planned dose distribution.

2. The system according to claim 1, wherein the processors are further operative to adjust the treatment margins based on dosimetric differences between the motion-compensated dose distribution and the planned dose distribution, the adjusting including:

identifying cold spots and/or hot spots between the motion-compensated dose distribution and the planned dose distribution;

in response to identifying a cold spot, increasing at least one of the treatment margins nearest the cold spot;

in response to identifying a hot spot, decreasing at least one of the treatment margins nearest the hot spot; and

,

in response to negligible dose differences between the motion-compensated dose distribution and the planned dose distribution, decreasing at least one of the treatment margins.

3. The system according to claim 2, wherein the adjusting is performed after one or more treatment fractions.

4. The system according to claim 2, wherein the adjusting is performed during a fraction,

5. The system according to claim 1, wherein the calculating includes:

creating one or more probability density functions (PDFs) from the motion data, each of said PDFs representing a cumulative motion pattern of the target during a treatment fraction.

6. The system according to claim 5, wherein the calculating farther includes:

convolving planned dose distributions with the PDFs to determine one or more motion-compensated doses indicative of the dose actually delivered to the target.

7. The system according to claim 1, further including:

a display;

wherein the comparing includes at least one of;

displaying the motion-compensated dose distribution adjacent to the planned dose distribution on the display; and

,

displaying the motion-compensated dose distribution overlaid on the planned dose distribution.

8. The system according to claim 1, wherein the comparing includes:

calculating a difference between the motion-compensated dose distribution and the planned dose distribution; and

/or

calculating at least one of dose volume histograms (DVH), maximum dose, mean dose, and minimum dose for each of the motion-compensated dose distribution and the planned dose distribution.

9. The system according to claim 1, wherein the RTP is optimized for one of external beam radiation therapy, proton therapy, ablation therapy and high-intensity focused ultrasound therapy.

10. A radiation therapy system, said system comprising:

one or more imaging modalities that obtain one or more planning images;

a planning system according to claim 1 that generates a radiation treatment plan (RTP) for irradiating a target over the course of one or more treatment fractions from the planning images, said RTP including one or more treatment margins around the target and a planned dose distribution for the target, and that generates patient-specific treatment margins from the RTP;

a radiation therapy apparatus for delivering radiation therapy in accordance with the RTP; and

,

a motion monitor generating the motion data from the target surrogates of the target.

11. A method for generating patient-specific treatment margins, said method comprising:

receiving a radiation treatment plan (RTP) for irradiating a target over the course of one or more treatment fractions, said RTP including one or more treatment margins around fee target and a planned dose distribution for the target;

receiving motion data for at least one of the treatment fractions of the RTP;

calculating a motion-compensated dose distribution for the target using the motion data to adjust the planned dose distribution based on the received motion data; and

,

comparing the motion-compensated dose distribution to the planned dose distribution.

12. The method according to claim 11, further including:

adjusting the treatment margins based on dosimetric differences between the motion-compensated dose distribution and the planned dose distribution.

13. The method according to claim 12, where the adjusting includes:

identifying cold spots and/or hot spots between the motion-compensated dose distribution and the planned dose distribution;

in response to identifying a cold spot, increasing at least one of the treatment margins nearest the cold spot;

in response to identifying a hot spot, decreasing at least one of the treatment margins nearest the hot spot;

in response to negligible dose differences between the motion-compensated dose distribution and the planned dose distribution, decreasing at least one of the treatment margins.

14. The method according to claim 11, wherein the calculating includes:

creating one or more probability density functions (PDFs) from the motion data, each of said PDFs representing a cumulative motion pattern of the target during a treatment fraction; and

,

convolving planned dose distributions with the PDFs to determine one or more motion-compensated doses indicative of the dose actually delivered to the target.

15. The method according to claim 14, wherein the calculating further includes:

accumulating the motion-compensated doses of the at least one of the treatment fractions.

16. The method according to claim 11, wherein the comparing includes at least one of:

displaying the motion-compensated dose distribution adjacent to the planned dose distribution;

displaying the motion-compensated dose distribution overlaid on the planned dose distribution; and

,

calculating a difference between the motion-compensated dose distribution and the planned dose distribution.

17. The method according to claim 11, wherein the comparing includes at least one of:

calculating at least one of dose volume histograms (DVH), maximum dose, mean dose, and minimum dose for each of the motion-compensated dose distribution and the planned dose distribution; and

,

calculating a dosimetric impact of motion on the RTP through a weighted combination of at least one of maximum dose, mean dose, and minimum dose for the motion-compensated dose distribution and/or the planned dose distribution.

18. A radiation therapy system comprising:

a radiation therapy apparatus for delivering radiation therapy in accordance with an RTP;

a motion monitor generating motion data from target surrogates of a target; and

,

one or more processors programmed to perform the method according to claim 11.

19. A computer medium carrying software which controls one or more processors to perform the method according to claim 11.

20. A radiation therapy system for irradiating a patient, said system comprising:

one or more processors programmed to;

generate a radiation treatment plan (RTF) for irradiating a target over the course of one or more treatment fractions, said RTP including a planned dose distribution to be delivered to the target;

receive motion data for at least one of the treatment fractions of the RTP;

calculate a motion-compensated dose distribution for the target using the motion data;

adjust the planned dose distribution based on dosimetric differences between the motion-compensated dose distribution and fee planned dose distribution; and

,

irradiate the patient using the adjusted planned dose distribution.