@misc{oai:repo.qst.go.jp:00069534,
 author = {Mori, Shinichiro and Kumagai, Motoki and Asakura, Hiroshi and Yamada, Shigeru and Kishimoto, Riwa and Katou, Hirotoshi and Kandatsu, Susumu and 森 慎一郎 and 熊谷 始紀 and 浅倉 裕史 and 山田 滋 and 岸本 理和 and 加藤 博敏 and 神立 進},
 month = {Sep},
 note = {Purpose/Objective(s): Intrafractional motion affects the accuracy of the delivered dose in radiotherapy, particularly in carbon beam radiotherapy. Although recent studies using 4D-CT have focused on the thoracic region, evaluation of dose variation due to intrafractional respiratory motion is also necessary in abdominal regions, such as the liver and kidney, etc. However, the poor image quality in abdominal 4D-CT resulting from respiratory phase-based resorting process error hampers calculation of quantitative dose distribution. Here, we evaluated dose variation due to intrafractional motion using fast-rotate cone-beam CT and compared 4D dose assessments between respiratory-ungated and -gated charged particle pancreatic therapy.
Materials/Methods: Four-dimensional (4D) CT scan using a 256-multislice CT was performed in a patient with pancreatic cancer under free breathing conditions. Two range compensators previously designed to ensure sufficient carbon beam coverage of PTV for ungated and gated treatment strategies using 4D-CT data sets at respective phases were applied to 4D-CT, and then the carbon beam dose distribution was calculated with a pencil beam algorithm. 4D-DVHs for the two strategies were calculated and compared.
Results: Although abdominal region consists tissue density more than thoracic region, significant beam overshoot and undershoot were observed due to respiratory-induced intestinal gas bubble motion. Dose variation was minimized with respiratory-gated compared with ungated treatment. In contrast, DVHs incorporating respiratory function (4D-DVH) were similar.
Conclusions: We quantified 4D dose variation in the abdominal region using 4D-CT, which includes deformable registration. Dose assessments between the respiratory-ungated and -gated strategies did not greatly differ throughout treatment. 4D dose assessment more closely reflects actual clinical conditions than conventional planning, and is useful in defining treatment strategies., ASTRO 50Th Annual Meeting},
 title = {Four-dimensional Heavy Charged Particle Beam Radiotherapy in Pancreatic Cancer},
 year = {2008}
}