Characterisation of the half-field beam penumbra for a variety of blocking set-ups

8th International Conference on 3D Radiation Dosimetry

Smith, S.T.^1 ; Kairn, T.^1,2 ; Crowe, S.B.^1 ; Asena, A.^1 ; Trapp, J.V.^1

School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia^1

Genesis CancerCare Queensland, Brisbane, Australia^2

关键词: Beam divergence;    Blocking set;    Blocking technique;    Film measurement;    Measurements of;    Optimal results;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/573/1/012073/pdf
DOI  :  10.1088/1742-6596/573/1/012073

来源: IOP

【 摘 要 】

Measurements of half-field beam penumbra were taken using EBT2 film for a variety of blocking techniques. It was shown that minimizing the SSD reduces the penumbra as the effects of beam divergence are diminished. The addition of a lead block directly on the surface provides optimal results with a 10-90% penumbra of 0.53 ± 0.02 cm. To resolve the uncertainties encountered in film measurements, future Monte Carlo measurements of halffield penumbras are to be conducted.