Kenta Kijima1, Anchali Krisanachinda2, Mikoto Tamura1, Yasumasa Nishimura3, Hajime Monzen4. 1. Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan. 2. Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. 3. Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osaka, Japan. 4. Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka, Japan hmon@med.kindai.ac.jp.
Abstract
BACKGROUND/AIM: Spatially fractionated radiotherapy (grid therapy) can control some bulky tumors which is challenging for conventional radiotherapy. This study aimed to investigate whether a novel tungsten contained rubber (TCR) grid collimator can be employed in electron grid therapy. MATERIALS AND METHODS: The TCR grid collimator placed on a solid water phantom, and percentage depth doses (PDDs) and lateral dose profiles were measured for 9 MeV electron beam with Gafchromic EBT3 films. At the lateral dose profile, the ratios of the dose in the areas with and without shielding (valley-to-peak ratios) were evaluated. RESULTS: The dmax values with the 1, 2 and 3 mm TCR grid collimators were 1.2, 1.1 and 0.7 cm, respectively, while the valley-to-peak ratios at each dmax were 0.566, 0.412 and 0.293, respectively. CONCLUSION: Only the 2 mm TCR grid collimator had adequate dosimetric features compared to the conventional grid collimator and could be substituted. Copyright
BACKGROUND/AIM: Spatially fractionated radiotherapy (grid therapy) can control some bulky tumors which is challenging for conventional radiotherapy. This study aimed to investigate whether a novel tungsten contained rubber (TCR) grid collimator can be employed in electron grid therapy. MATERIALS AND METHODS: The TCR grid collimator placed on a solid water phantom, and percentage depth doses (PDDs) and lateral dose profiles were measured for 9 MeV electron beam with Gafchromic EBT3 films. At the lateral dose profile, the ratios of the dose in the areas with and without shielding (valley-to-peak ratios) were evaluated. RESULTS: The dmax values with the 1, 2 and 3 mm TCR grid collimators were 1.2, 1.1 and 0.7 cm, respectively, while the valley-to-peak ratios at each dmax were 0.566, 0.412 and 0.293, respectively. CONCLUSION: Only the 2 mm TCR grid collimator had adequate dosimetric features compared to the conventional grid collimator and could be substituted. Copyright