Design and characterisation of a minibeam collimator utilising Monte Carlo simulation and a clinical linear accelerator.
Phys Med Biol
; 69(13)2024 Jun 19.
Article
em En
| MEDLINE
| ID: mdl-38759691
ABSTRACT
Objective.Spatially fractionated radiotherapy is showing promise as a treatment modality. Initial focus was on beams of photons at low energy produced from a synchrotron but more recently research has expanded to include applications in proton therapy. Interest in photon beams remains and this is the focus of this paperApproach.This study presents a 3D printed tungsten minibeam collimator intended to produce peak-to-valley dose ratios (PVDR) of between seven and ten with a 1 MV, bremsstrahlung generated, photon beam. The design of the collimator is motivated by a Monte Carlo study estimating the PVDR for different collimator designs at different energies. This collimator was characterised on a clinical linear accelerator (Elekta VersaHD) as well as an orthovoltage unit.Main results.The performance of the fabricated collimator was measured on Elekta VersaHD running in unflattened mode with a 6 MV beam. On the Elekta VersaHD units the PVDR was measured to be between approximately 1.5 and 2.0 at 3 cm deep. For measurements with the orthovoltage unit PVDRs of greater than 10 were observed at a depth of 4 cm.Significance.The results confirmed that the predictions from simulation could be reproduced on linear accelerators currently in clinical usage, producing PVDRs between 2-2.5. Using the model to predict PVDRs using 1 MV photon beams, the threshold considered to produce enhanced normal tissue dose tolerance (>7) was surpassed. This suggests the possibility of using such techniques with versions of existing Linac technology which have been modified to operate at low energy and high beam currents.
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Bases de dados:
MEDLINE
Assunto principal:
Aceleradores de Partículas
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Método de Monte Carlo
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Desenho de Equipamento
Limite:
Humans
Idioma:
En
Revista:
Phys Med Biol
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Reino Unido