Purpose: This study evaluated the properties of a scintillation sheet-based dosimetry system for beam monitoring
with high spatial resolution, including the effects of this system on the treatment beam. The dosimetric characteristics and feasibility of this system for clinical use were also evaluated.
Methods: The effects of the dosimetry system on the beam were evaluated by measuring the percentage depth
doses, dose profiles, and transmission factors. Fifteen treatment plans were created, and the influence of the
dosimetry system on these clinical treatment plans was evaluated. The performance of the system was assessed
by determining signal linearity, dose rate dependence, and reproducibility. The feasibility of the system for
clinical use was evaluated by comparing intensity distributions with reference intensity distributions verified by
quality assurance.
Results: The spatial resolution of the dosimetry system was found to be 0.43 mm/pixel when projected to the
isocenter plane. The dosimetry system attenuated the intensity of 6 MV beams by about 1.1%, without affecting
the percentage depth doses and dose profiles. The response of the dosimetry system was linear, independent of
the dose rate used in the clinic, and reproducible. Comparison of intensity distributions of evaluation treatment
fields with reference intensity distributions showed that the 1%/1 mm average gamma passing rate was 99.6%.
Conclusions: The dosimetry system did not significantly alter the beam characteristics, indicating that the system
could be implemented by using only a transmission factor. The dosimetry system is clinically suitable for
monitoring treatment beam delivery with higher spatial resolution than other transmission detectors.
Jaehyeon Seo, Hyunho Lee, Myonggeun Yoon*
Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea
Jaehyeon Seo
Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon, Republic of Korea
Hyunho Lee, Sung Hwan Ahn*
Department of Radiation Oncology, Samsung Medical Center, Seoul, Republic of Korea
Myonggeun Yoon*
FieldCure Ltd, Seoul, Republic of Korea