Voxel-based dose calculation of radionuclide imaging and therapy for preclinical studies using GEANT4 Monte Carlo simulation

Liu, H.; Geng, C.; Tang, X.; Tang, L.; Li, X.; Xu, P.

doi:10.52547/ijrr.20.2.9

Cited by 1 publication

(1 citation statement)

References 17 publications

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“…Monte Carlo (MC) simulations can provide an understanding of the phenomena that govern the characteristics of beam collimation used in radiotherapy applications as well as aid the development of treatment planning systems (Ahnesjö et al 1999, Rogers 2006, Korhonen 2009, Ojala et al 2014, Verhaegen et al 2021. The concept of phase space (PHSP) files has been extensively used in several medical applications (Fix et al 2001, Chetty et al 2007, Wang et al 2012, Perales et al 2017, Liu et al 2022 to speed up the calculations performed downstream of the fixed components in the treatment head. Each PHSP file includes a collection of all the particles and their kinematic characteristics at a location in the treatment head that is independent of the field size, accessories, and patient anatomy.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo modeling of Halcyon and Ethos radiotherapy beam using CAD geometry: validation and IAEA-compliant phase space

Laakkonen¹,

Lehtomäki²,

Cahill³

et al. 2023

Phys. Med. Biol.

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Objective: A Monte Carlo (MC) model of a Halcyon and Ethos (Varian Medical Systems, a Siemens Healthineers Company) radiotherapy beam was validated and field-independent phase space (PHSP) files were recorded above the dual-layer multileaf collimators (MLC). Approach: The treatment head geometry was modeled according to engineering drawings and the dual-layer MLC was imported from CAD (computer-aided design) files. The information for the incident electron beam was achieved from an iterative electromagnetic solver. The validation of the model was performed by comparing the dose delivered by the square MLC fields as well as complex field measurements. Main results: An electron phase space was generated from linac simulations and achieved improved MC results. The output factors for square fields were within 1% and the largest differences of 5% were found in the build-up region of PDDs and the penumbra region of profiles. With the more complicated MLC-shaped field (Fishbone), the largest differences of up to 8% were found in the MLC leaf tip region due to the uncertainty of the MLC positioning and the mechanical leaf gap (MLG) value. The impact of the collimator rotation on the PHSP solution has been assessed with both small and large fields, confirming negligible effects on in-field and out-of-field dose distributions. Significance: A computational model of the Halcyon and Ethos radiotherapy beam with a high accuracy implementation of the MLC was shown to be able to reproduce the radiation beam characteristics with square fields and more complex MLC-shaped fields. The field-independent PHSP files that were produced can be used as an accurate treatment head model above the MLC, and reduce the time to simulate particle transport through treatment head components.

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