A multiple-source photon beam model and its commissioning process for VMC++ Monte Carlo code

Tillikainen, L; Siljamäki, S.

doi:10.1088/1742-6596/102/1/012024

Cited by 4 publications

(7 citation statements)

References 5 publications

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“…We used the following parameters for the simulation: grid size = 0.5 cm, ECUT = 0.500 MeV (electron/positron minimum transport energy) and PCUT = 0.05 MeV (photon minimum transport energy). The particle sampling for the VMC++ calculation was performed as described in Tillikainen and Siljamäki (2008) for the primary photon source.…”

Section: Reference Dose Calculations Using Vmc++mentioning

confidence: 99%

A 3D pencil-beam-based superposition algorithm for photon dose calculation in heterogeneous media

Tillikainen¹,

Helminen²,

Torsti³

et al. 2008

Phys. Med. Biol.

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129

105

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In this work, a novel three-dimensional superposition algorithm for photon dose calculation is presented. The dose calculation is performed as a superposition of pencil beams, which are modified based on tissue electron densities. The pencil beams have been derived from Monte Carlo simulations, and are separated into lateral and depth-directed components. The lateral component is modeled using exponential functions, which allows accurate modeling of lateral scatter in heterogeneous tissues. The depth-directed component represents the total energy deposited on each plane, which is spread out using the lateral scatter functions. Finally, convolution in the depth direction is applied to account for tissue interface effects. The method can be used with the previously introduced multiple-source model for clinical settings. The method was compared against Monte Carlo simulations in several phantoms including lung- and bone-type heterogeneities. Comparisons were made for several field sizes for 6 and 18 MV energies. The deviations were generally within (2%, 2 mm) of the field central axis d(max). Significantly larger deviations (up to 8%) were found only for the smallest field in the lung slab phantom for 18 MV. The presented method was found to be accurate in a wide range of conditions making it suitable for clinical planning purposes.

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Section: Reference Dose Calculations Using Vmc++mentioning

confidence: 99%

A 3D pencil-beam-based superposition algorithm for photon dose calculation in heterogeneous media

Tillikainen¹,

Helminen²,

Torsti³

et al. 2008

Phys. Med. Biol.

Self Cite

129

105

View full text Add to dashboard Cite

show abstract

“…The calculation plane was located at 10‐cm depth from the phantom surface in the layer of the lung material. The particle generator of the proposed model was based on the MC sampling techniques . The direction and energy of the secondary photons was determined from the those of the initial photons by Kahn's method .…”

Section: Methodsmentioning

confidence: 99%

“…The particle generator of the proposed model was based on the MC sampling techniques. 8 The direction and energy of the secondary photons was determined from the those of the initial photons by Kahn's method. 19,20 To evaluate the agreement on the dose curves between the model and PSD, we calculated the passing rate of the gamma index with 1%/1 mm criteria.…”

Section: C2 Model Dose Curve Comparison With Reference Datamentioning

confidence: 99%

“…Traditional source models offer the following two approaches: (a) the accelerator simulation model and (b) the analytical function model . The accelerator simulation model reproduces the radiation output by full MC simulation in the accelerator head and provides the phase space data (PSD) of the particles that pass through the head components.…”

Section: Introductionmentioning

confidence: 99%

“…Traditional source models offer the following two approaches: (a) the accelerator simulation model [3][4][5] and (b) the analytical function model. [6][7][8] The accelerator simulation model reproduces the radiation output by full MC simulation in the accelerator head and provides the phase space data (PSD) of the particles that pass through the head components. Although the PSD could be an accurate source model reflecting the physical processes of the particle transport in the accelerator head, its construction requires the optimization of the incident parameters of the accelerated electrons and the detailed geometrical information of the head components.…”

Section: Introductionmentioning

confidence: 99%

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A photon source model based on particle transport in a parameterized accelerator structure for Monte Carlo dose calculations

Ishizawa

Dobashi²,

Ito³

et al. 2018

Medical Physics

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Toward a web-based real-time radiation treatment planning system in a cloud computing environment

Na¹,

Suh²,

Kapp³

et al. 2013

Phys. Med. Biol.

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To exploit the potential dosimetric advantages of intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), an in-depth approach is required to provide efficient computing methods. This needs to incorporate clinically related organ specific constraints, Monte Carlo (MC) dose calculations, and large-scale plan optimization. This paper describes our first steps toward a web-based real-time radiation treatment planning system in a cloud computing environment (CCE). The Amazon Elastic Compute Cloud (EC2) with a master node (named m2.xlarge containing 17.1 GB of memory, two virtual cores with 3.25 EC2 Compute Units each, 420 GB of instance storage, 64-bit platform) is used as the backbone of cloud computing for dose calculation and plan optimization. The master node is able to scale the workers on an 'on-demand' basis. MC dose calculation is employed to generate accurate beamlet dose kernels by parallel tasks. The intensity modulation optimization uses total-variation regularization (TVR) and generates piecewise constant fluence maps for each initial beam direction in a distributed manner over the CCE. The optimized fluence maps are segmented into deliverable apertures. The shape of each aperture is iteratively rectified to be a sequence of arcs using the manufacture's constraints. The output plan file from the EC2 is sent to the simple storage service. Three de-identified clinical cancer treatment plans have been studied for evaluating the performance of the new planning platform with 6 MV flattening filter free beams (40 × 40 cm(2)) from the Varian TrueBeam(TM) STx linear accelerator. A CCE leads to speed-ups of up to 14-fold for both dose kernel calculations and plan optimizations in the head and neck, lung, and prostate cancer cases considered in this study. The proposed system relies on a CCE that is able to provide an infrastructure for parallel and distributed computing. The resultant plans from the cloud computing are identical to PC-based IMRT and VMAT plans, confirming the reliability of the cloud computing platform. This cloud computing infrastructure has been established for a radiation treatment planning. It substantially improves the speed of inverse planning and makes future on-treatment adaptive re-planning possible.

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A multiple-source photon beam model and its commissioning process for VMC++ Monte Carlo code

Cited by 4 publications

References 5 publications

A 3D pencil-beam-based superposition algorithm for photon dose calculation in heterogeneous media

A 3D pencil-beam-based superposition algorithm for photon dose calculation in heterogeneous media

A photon source model based on particle transport in a parameterized accelerator structure for Monte Carlo dose calculations

Toward a web-based real-time radiation treatment planning system in a cloud computing environment

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