Fraction‐variant beam orientation optimization for intensity‐modulated proton therapy

Gu, Weixing; O’Connor, Daniel; Ruan, Dan; Zou, W.; Dong, Lei; Sheng, Ke

doi:10.1002/mp.14340

Cited by 3 publications

(1 citation statement)

References 34 publications

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“…While global convergence is not guaranteed, we have observed in previous works that the non-convex norm of p = 0, allows for good convergence using FISTA and efficient elimination of candidate catheters, while still having an analytical proximal operator. 29,31 This observation is also supported by the successful use of this non-convex group sparsity in a series of external beam optimization problems 29,[35][36][37][38][39][40][41][42] and image processing. 43 Further,in this study,a comparison with the clinical plans shows that the locally optimal solutions are dosimetrically desirable.…”

Section: Discussionmentioning

confidence: 63%

Analytical HDR prostate brachytherapy planning with automatic catheter and isotope selection

Frank,

Ramesh,

Lyu

et al. 2023

Medical Physics

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BackgroundHigh dose rate (HDR) brachytherapy is commonly used to treat prostate cancer. Existing HDR planning systems solve the dwell time problem for predetermined catheters and a single energy source.PurposeAdditional degrees of freedom can be obtained by relaxing the catheters' pre‐designation and introducing more source types, and may have a dosimetric benefit, particularly in improving conformality to spare the urethra. This study presents a novel analytical approach to solving the corresponding HDR planning problem.MethodsThe catheter and dual‐energy source selection problem was formulated as a constrained optimization problem with a non‐convex group sparsity regularization. The optimization problem was solved using the fast‐iterative shrinkage‐thresholding algorithm (FISTA). Two isotopes were considered. The dose rates for the HDR 4140 Ytterbium (Yb‐169) source and the Elekta Iridium (Ir‐192) HDR Flexisource were modeled according to the TG‐43U1 formalism and benchmarked accordingly. Twenty‐two retrospective HDR prostate brachytherapy patients treated with Ir‐192 were considered. An Ir‐192 only (IRO), Yb‐169 only (YBO), and dual‐source (DS) plan with optimized catheter location was created for each patient with N catheters, where N is the number of catheters used in the clinically delivered plans. The DS plans jointly optimized Yb‐169 and Ir‐192 dwell times. All plans and the clinical plans were normalized to deliver a 15 Gy prescription (Rx) dose to 95% of the clinical treatment volume (CTV) and evaluated for the CTV D90%, V150%, and V200%, urethra D0.1cc and D1cc, bladder V75%, and rectum V75%. Dose‐volume histograms (DVHs) were generated for each structure.ResultsThe DS plans ubiquitously selected Ir‐192 as the only treatment source. IRO outperformed YBO in organ at risk (OARs) OAR sparing, reducing the urethra D0.1cc and D1cc by 0.98% () and 1.09% () of the Rx dose, respectively, and reducing the bladder and rectum V75% by 0.09 () and 0.13 cubic centimeters (cc) (), respectively. The YBO plans delivered a more homogenous dose to the CTV, with a smaller V150% and V200% by 3.20 () and 1.91 cc (), respectively, and a lower CTV D90% by 0.49% () of the prescription dose. The IRO plans reduce the urethral D1cc by 2.82% () of the Rx dose compared to the clinical plans, at the cost of increased bladder and rectal V75% by 0.57 () and 0.21 cc (), respectively, and increased CTV V150% by a mean of 1.46 cc () and CTV D90% by an average of 1.40% of the Rx dose (). While these differences are statistically significant, the clinical differences between the plans are minimal.ConclusionsThe proposed analytical HDR planning algorithm integrates catheter and isotope selection with dwell time optimization for varying clinical goals, including urethra sparing. The planning method can guide HDR implants and identify promising isotopes for specific HDR clinical goals, such as target conformality or OAR sparing.

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Section: Discussionmentioning

confidence: 63%

Analytical HDR prostate brachytherapy planning with automatic catheter and isotope selection

Frank,

Ramesh,

Lyu

et al. 2023

Medical Physics

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A systematic review on the usage of averaged LET in radiation biology for particle therapy

Kalholm

Grzanka

Traneus

et al. 2021

Radiotherapy and Oncology

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This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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A reinforcement learning application of a guided Monte Carlo Tree Search algorithm for beam orientation selection in radiation therapy

Barkousaraie¹,

Bohara²,

Jiang³

et al. 2021

Mach. Learn.: Sci. Technol.

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Current beam orientation optimization algorithms for radiotherapy, such as column generation (CG), are typically heuristic or greedy in nature because of the size of the combinatorial problem, which leads to suboptimal solutions. We propose a reinforcement learning strategy using a Monte Carlo Tree Search (MCTS) that can find a better beam orientation set in less time than CG. We utilize a reinforcement learning structure involving a supervised learning network to guide the MCTS and to explore the decision space of beam orientation selection problems. We previously trained a deep neural network (DNN) that takes in the patient anatomy, organ weights, and current beams, then approximates beam fitness values to indicate the next best beam to add. Here, we use this DNN to probabilistically guide the traversal of the branches of the Monte Carlo decision tree to add a new beam to the plan. To assess the feasibility of the algorithm, we used a test set of 13 prostate cancer patients, distinct from the 57 patients originally used to train and validate the DNN, to solve five-beam plans. To show the strength of the guided MCTS (GTS) compared to other search methods, we also provided the performances of Guided Search, Uniform Tree Search and Random Search algorithms. On average, GTS outperformed all the other methods. It found a better solution than CG in 237 s on average, compared to 360 s for CG, and outperformed all other methods in finding a solution with a lower objective function value in less than 1000 s. Using our GTS method, we could maintain planning target volume (PTV) coverage within 1% error similar to CG, while reducing the organ-at-risk mean dose for body, rectum, left and right femoral heads; the mean dose to bladder was 1% higher with GTS than with CG.

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Fraction‐variant beam orientation optimization for intensity‐modulated proton therapy

Cited by 3 publications

References 34 publications

Analytical HDR prostate brachytherapy planning with automatic catheter and isotope selection

Analytical HDR prostate brachytherapy planning with automatic catheter and isotope selection

A systematic review on the usage of averaged LET in radiation biology for particle therapy

A reinforcement learning application of a guided Monte Carlo Tree Search algorithm for beam orientation selection in radiation therapy

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