Robust optimization of intensity modulated proton therapy

Liu, Wei; Zhang, Xiaodong; Li, Yupeng; Mohan, Radhe

doi:10.1118/1.3679340

Cited by 312 publications

(399 citation statements)

References 23 publications

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“…Instead of attempting to improve the optimization algorithm of the TPS, which is clearly out of the control of a user, the proposed platform and the use of an out‐of‐the‐TPS decision function here allows us to imitate a planner's interactive planning process to search for the optimal solution that would otherwise require much more manual effort. The approach is quite general and should be applicable to facilitate the treatment planning of other modalities such as brachytherapy, (37) proton therapy, 38 , 39 station parameter optimized radiation therapy (SPORT), 29 , 40 gamma knife, (41) breast planning (42) or similar.…”

Section: Discussionmentioning

confidence: 99%

Application programming in C# environment with recorded user software interactions and its application in autopilot of VMAT/IMRT treatment planning

Wang

Liu

2016

J Applied Clin Med Phys

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An autopilot scheme of volumetric‐modulated arc therapy (VMAT)/intensity‐modulated radiation therapy (IMRT) planning with the guidance of prior knowledge is established with recorded interactions between a planner and a commercial treatment planning system (TPS). Microsoft (MS) Visual Studio Coded UI is applied to record some common planner‐TPS interactions as subroutines. The TPS used in this study is a Windows‐based Eclipse system. The interactions of our application program with Eclipse TPS are realized through a series of subroutines obtained by prerecording the mouse clicks or keyboard strokes of a planner in operating the TPS. A strategy to autopilot Eclipse VMAT/IMRT plan selection process is developed as a specific example of the proposed “scripting” method. The autopiloted planning is navigated by a decision function constructed with a reference plan that has the same prescription and similar anatomy with the case at hand. The calculation proceeds by alternating between the Eclipse optimization and the outer‐loop optimization independent of the Eclipse. In the C# program, the dosimetric characteristics of a reference treatment plan are used to assess and modify the Eclipse planning parameters and to guide the search for a clinically sensible treatment plan. The approach is applied to plan a head and neck (HN) VMAT case and a prostate IMRT case. Our study demonstrated the feasibility of application programming method in C# environment with recorded interactions of planner‐TPS. The process mimics a planner's planning process and automatically provides clinically sensible treatment plans that would otherwise require a large amount of manual trial and error of a planner. The proposed technique enables us to harness a commercial TPS by application programming via the use of recorded human computer interactions and provides an effective tool to greatly facilitate the treatment planning process.PACS number(s): 87.55.D‐, 87.55.kd, 87.55.de

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Section: Discussionmentioning

confidence: 99%

Application programming in C# environment with recorded user software interactions and its application in autopilot of VMAT/IMRT treatment planning

Wang

Liu

2016

J Applied Clin Med Phys

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“…This is because the extent of rectal displacement (≥ 9 mm) was significant enough for both field arrangements to observe similar benefits of the rectal spacers to reduce the volume receiving high dose to the rectum. Consequently, while there are some potential benefits of using anterior proton beams without a rectal spacer, LAT fields should be preferred with a rectal spacer especially because they are also more robust 25, 38. A rectal spacer may also be especially beneficial for prostate cancer patients with a hip prosthesis who receive proton therapy as an anterior beam is commonly used to avoid treating through the prosthesis, and the LAO/RAO configuration would then be preferred in such situations 39…”

Section: Discussionmentioning

confidence: 99%

Rectal dose to prostate cancer patients treated with proton therapy with or without rectal spacer

Chung

Polf

Badiyan

et al. 2016

J Applied Clin Med Phys

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The purpose of this study was to evaluate whether a spacer inserted in the prerectal space could reduce modeled rectal dose and toxicity rates for patients with prostate cancer treated in silico with pencil beam scanning (PBS) proton therapy. A total of 20 patients were included in this study who received photon therapy (12 with rectal spacer (DuraSeal™ gel) and 8 without). Two PBS treatment plans were retrospectively created for each patient using the following beam arrangements: (1) lateral‐opposed (LAT) fields and (2) left and right anterior oblique (LAO/RAO) fields. Dose volume histograms (DVH) were generated for the prostate, rectum, bladder, and right and left femoral heads. The normal tissue complication probability (NTCP) for ≥grade 2 rectal toxicity was calculated using the Lyman–Kutcher–Burman model and compared between patients with and without the rectal spacer. A significantly lower mean rectal DVH was achieved in patients with rectal spacer compared to those without. For LAT plans, the mean rectal V70 with and without rectal spacer was 4.19 and 13.5%, respectively. For LAO/RAO plans, the mean rectal V70 with and without rectal spacer was 5.07 and 13.5%, respectively. No significant differences were found in any rectal dosimetric parameters between the LAT and the LAO/RAO plans generated with the rectal spacers. We found that ≥ 9 mm space resulted in a significant decrease in NTCP modeled for ≥grade 2 rectal toxicity. Rectal spacers can significantly decrease modeled rectal dose and predicted ≥grade 2 rectal toxicity in prostate cancer patients treated in silico with PBS. A minimum of 9 mm separation between the prostate and anterior rectal wall yields the largest benefit.

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“…In the cancer literature, examples of analogous efforts for designing robust treatment protocols can be found in radiotherapy (51)(52)(53)(54). The challenges in designing a robust radiation treatment protocol can largely be attributed to geometric uncertainty and interpatient variability (54).…”

Section: Discussionmentioning

confidence: 99%

“…For the same beam arrangement, they computed a different dose distribution accounting for these uncertainties and compared this to the optimal dose distribution. They applied this approach to the lung, skull base and prostate and found that compared with IMPT plans optimized using conventional (nonrobust) methods, their method resulted in radiotherapy plans that are less sensitive to beamlet range and setup uncertainties (52). In a series of papers, robust optimization was used for planning intensity modulated radiation therapy for lung cancer in the face of uncertainty caused by breathing (51,55,56).…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have addressed the challenges posed by geometric uncertainty, including factors such as organ motion, variations in treatment setup, patient positioning errors, and fluctuations in machine output (54). For instance, Liu et al (52) used "worst-case robust optimization" to identify intensity modulated proton therapy (IMPT) plans that are robust to uncertainties in the beamlet range and equipment setup. For the same beam arrangement, they computed a different dose distribution accounting for these uncertainties and compared this to the optimal dose distribution.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluating optimal therapy robustness by virtual expansion of a sample population, with a case study in cancer immunotherapy

Barish

Ochs

Sontag

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Cancer is a highly heterogeneous disease, exhibiting spatial and temporal variations that pose challenges for designing robust therapies. Here, we propose the VEPART (Virtual Expansion of Populations for Analyzing Robustness of Therapies) technique as a platform that integrates experimental data, mathematical modeling, and statistical analyses for identifying robust optimal treatment protocols. VEPART begins with time course experimental data for a sample population, and a mathematical model fit to aggregate data from that sample population. Using nonparametric statistics, the sample population is amplified and used to create a large number of virtual populations. At the final step of VEPART, robustness is assessed by identifying and analyzing the optimal therapy (perhaps restricted to a set of clinically realizable protocols) across each virtual population. As proof of concept, we have applied the VEPART method to study the robustness of treatment response in a mouse model of melanoma subject to treatment with immunostimulatory oncolytic viruses and dendritic cell vaccines. Our analysis (i) showed that every scheduling variant of the experimentally used treatment protocol is fragile (nonrobust) and (ii) discovered an alternative region of dosing space (lower oncolytic virus dose, higher dendritic cell dose) for which a robust optimal protocol exists.robust therapies | cancer treatment | mathematical modeling | virotherapy | immunotherapy H eterogeneity is a defining feature of cancer (1, 2). Interpatient heterogeneity manifests clinically in variable disease progression and treatment response between patients with the same diagnosis, whereas intrapatient heterogeneity describes variations that exist between tumor cells in a single patient. Intrapatient heterogeneity can be broken down further into intratumor heterogeneity, intrametastatic heterogeneity, intermetastatic heterogeneity, and temporal heterogeneity (2, 3). Intratumor heterogeneity is evident through the presence of multiple genetic subclones within a primary tumor (2), which have even been shown to exist in spatially distinct regions of the primary tumor (4). Intrametastatic heterogeneity is similar to intratumor heterogeneity, but describes heterogeneity within a single metastatic lesion instead of within the primary tumor (2). Intermetastatic heterogeneity, on the other hand, describes variations in subclones between different metastases in the same patient (2). Finally, temporal heterogeneity is defined as changes that take place in the tumor over time, whether they are a result of genomic instability, natural selection, non-Darwinian evolution, or selective pressures imposed by treatment (4-6). Note that, in each case, heterogeneity need not be genetic but may also be epigenetic, phenotypic, or microenvironmental (2, 7, 8).For decades, cancer patients have been treated using standard of care, meaning they receive the best known treatment that has been deemed as efficacious and safe in epidemiological studies (9). However, in the face of such int...

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Robust optimization of intensity modulated proton therapy

Cited by 312 publications

References 23 publications

Application programming in C# environment with recorded user software interactions and its application in autopilot of VMAT/IMRT treatment planning

Application programming in C# environment with recorded user software interactions and its application in autopilot of VMAT/IMRT treatment planning

Rectal dose to prostate cancer patients treated with proton therapy with or without rectal spacer

Evaluating optimal therapy robustness by virtual expansion of a sample population, with a case study in cancer immunotherapy

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