Abstract ID: 83 Hybrid Monte Carlo for low-energy X-rays intraoperative radiation therapy dose calculation

García, Pilar; Villa-Abaunza, A.; Hinault, P.; Pérez, Nuria Yagües; Udı́as, J. M.

doi:10.1016/j.ejmp.2017.09.042

Cited by 2 publications

(3 citation statements)

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“…The XIORT-MC described in this work is a powerful tool for treatment planning with the INTRABEAM. [24][25][26][27][28]45 The user can select between CPU or GPU execution and between a MC or a HMC algorithm while keeping a high-dose prediction accuracy. The CPU-based version of the code already reaches a speed-up factor of about 50-100 when compared to a regular MC.…”

Section: Discussionmentioning

confidence: 99%

“…The XIORT‐MC described in this work is a powerful tool for treatment planning with the INTRABEAM 24–28,45 . The user can select between CPU or GPU execution and between a MC or a HMC algorithm while keeping a high‐dose prediction accuracy.…”

Section: Discussionmentioning

confidence: 99%

“…In previous works, we very briefly introduced a new algorithm running in CPU, named Hybrid MC (HMC), [24][25][26][27][28] to calculate dose deposited by the INTRA-BEAM device within minutes,fully taking into account the different tissues and structures of the patient, that is, as derived from a 3D Computed Tomography (CT) image. The HMC includes all the relevant physics of a regular MC minimizing the contribution of statistical noise, so dose distributions may be obtained in a CPU in a much shorter time than a regular full-MC simulation.…”

Section: Introductionmentioning

confidence: 99%

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XIORT‐MC: A real‐time MC‐based dose computation tool for low‐ energy X‐rays intraoperative radiation therapy

et al. 2021

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Purpose: The INTRABEAM system is a miniature accelerator for low-energy X-ray Intra-Operative Radiation Therapy (IORT), and it could benefit from a fast and accurate dose computation tool. With regards to accuracy, dose computed with Monte Carlo (MC) simulations are the gold standard, however, they require a large computational effort and consequently they are not suitable for realtime dose planning. This work presents a comparison of the implementation on Graphics Processing Unit (GPU) of two different dose calculation algorithms based on MC phase-space (PHSP) information to compute dose distributions for the INTRABEAM device within seconds and with the accuracy of realistic MC simulations. Methods: The MC-based algorithms we present incorporate photoelectric, Compton and Rayleigh effects for the interaction of low-energy X-rays. XIORT-MC (X-ray Intra-Operative Radiation Therapy Monte Carlo) includes two dose calculation algorithms; a Woodcock-based MC algorithm (WC-MC) and a Hybrid MC algorithm (HMC), and it is implemented in CPU and in GPU. Detailed MC simulations have been generated to validate our tool in homogeneous and heterogeneous conditions with all INTRABEAM applicators, including three clinically realistic CT-based simulations. A performance study has been done to determine the acceleration reached with the code, in both CPU and GPU implementations. Results: Dose distributions were obtained with the HMC and the WC-MC and compared to standard reference MC simulations with more than 95% voxels fulfilling a 7%-0.5 mm gamma evaluation in all the cases considered. The CPU-HMC is 100 times more efficient than the reference MC, and the CPU-WC-MC is about 50 times more efficient. With the GPU implementation, the particle tracking of the WC-MC is faster than the HMC, with the extraction of the particle's information from the PHSP file taking a major part of the time. However, thanks to the variance reduction techniques implemented in the HMC, up to 400 times less particles are needed in the HMC to reach the same level of noise than the WC-MC. Therefore, in our implementation for INTRABEAM energies, the HMC is about 1.3 times more efficient than the WC-MC in an NVIDIA GeForce GTX 1080 Ti card and about 5.5 times more efficient in an NVIDIA GeForce RTX 3090. Dose with noise below 5% has been obtained in realistic situations in less than 5 s with the WC-MC and in less than 0.5 s with the HMC. Conclusions:The XIORT-MC is a dose computation tool designed to take full advantage of modern GPUs, making possible to obtain MC-grade accurate dose distributions within seconds. Its high speed allows a real-time dose calculation that includes the realistic effects of the beam in voxelized geometries

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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XIORT‐MC: A real‐time MC‐based dose computation tool for low‐ energy X‐rays intraoperative radiation therapy

et al. 2021

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Fast optimized Monte Carlo phase-space generation and dose prediction for low energy x-ray intra-operative radiation therapy

et al. 2019

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Low energy X-ray Intra-Operative Radiation Therapy (IORT) is used mostly for breast cancer treatment with spherical applicators. X-ray IORT treatment delivered during surgery (ex: INTRABEAM®, Carl Zeiss) can benefit from accurate and fast dose prediction in a patient 3D volume. However, full Monte Carlo (MC) simulations are time-consuming and no commercial treatment planning system was available for this treatment delivery technique. Therefore, the aim of this work is to develop a dose computation tool based on MC phase space information, which computes fast and accurate dose distributions for spherical and needle INTRABEAM® applicators. First, a database of monoenergetic phasespace (PHSP) files and depth dose profiles (DDPs) in water for each applicator is generated at factory and stored for on-site use. During commissioning of a given INTRABEAM® unit, the proposed Fast and Optimized Phase-Space (FOPS) generation process creates a phasespace at the exit of the applicator considered, by fitting the energy spectrum of the source to a combination of the monoenergetic precomputed phase-spaces, by means of a genetic algorithm, with simple experimental data of depth dose profiles in water provided by the user. An in-house hybrid MC algorithm which takes into account condensed history simulations of photoelectric, Rayleigh and Compton interactions for X-rays up to 1 MeV computes the dose from the optimized phase-space file. The whole process has been validated against radiochromic films in water as well as reference MC simulations performed with penEasy in heterogeneous phantoms. From the pre-computed monoenergetic PHSP files and DDPs, building the PHSP file optimized to a particular depth-dose curve in water only takes a few minutes in a single core (i7@2.5 GHz), for all the applicators considered in this work, and this needs to be done only when the X-ray source is replaced. Once the phase-space file is ready, the hybrid Monte Carlo code is able to compute dose distributions within 10 minutes. For all the applicators, more than 95% of voxels from dose distributions computed with the FOPS+hybrid code agreed within 7%-0.5 mm with both reference MC simulations and measurements. The method proposed has been fully validated and it is now implemented into radiance (GMV SA, Spain), the first commercial IORT Treatment Planning System (TPS).

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Abstract ID: 83 Hybrid Monte Carlo for low-energy X-rays intraoperative radiation therapy dose calculation

Cited by 2 publications

References 2 publications

XIORT‐MC: A real‐time MC‐based dose computation tool for low‐ energy X‐rays intraoperative radiation therapy

XIORT‐MC: A real‐time MC‐based dose computation tool for low‐ energy X‐rays intraoperative radiation therapy

Fast optimized Monte Carlo phase-space generation and dose prediction for low energy x-ray intra-operative radiation therapy

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