@article{oai:repo.qst.go.jp:00045752,
 author = {Mori, Shinichiro and Yanagi, Takeshi and Hara, Ryusuke and Gregory, Sharp and Asakura, Hiroshi and Kumagai, Motoki and Kishimoto, Riwa and Yamada, Shigeru and Katou, Hirotoshi and Kandatsu, Susumu and Kamada, Tadashi and 森 慎一郎 and 柳 剛 and 原 竜介 and 浅倉 裕史 and 熊谷 始紀 and 岸本 理和 and 山田 滋 and 加藤 博敏 and 神立 進 and 鎌田 正},
 issue = {1},
 journal = {International Journal of Radiation Oncology Biology Physics},
 month = {Jan},
 note = {Purpose
We compared respiratory-gated and -ungated treatment strategies using 4D scattered carbon ion beam distribution in pancreatic 4DCT data sets.
Materials and Methods
Seven inpatients with pancreatic tumors underwent 4DCT scanning under free-breathing conditions using a rapidly rotating cone-beam CT (CBCT), which was integrated with a 256 slice detector, in cine mode. Two types of bolus for gated and ungated treatment were designed to cover the planning target volume (PTV) using 4DCT data sets in a 30% duty cycle around exhalation and a single respiratory cycle, respectively. Carbon ion beam distribution for each strategy was calculated as a function of respiratory phase by applying the compensating bolus to 4DCT at the respective phases. Smearing was not applied to the bolus, but consideration was given to drill diameter. The accumulated dose distributions were calculated by applying deformable registration and calculating the dose volume histogram (DVH).
Results
Doses to normal tissues in gated treatment were minimized mainly on the inferior aspect, which thereby minimized excessive doses to normal tissues. Over 95% of the dose, however, was delivered to the clinical target volume (CTV) at all phases for both treatment strategies. Maximum doses to the duodenum and pancreas averaged across all patients were 43.1/43.1 GyE (ungated/gated) and 43.2/43.2 GyE (ungated/gated), respectively.
Conclusions
Although gated treatment minimized excessive dosing to normal tissue, the difference between treatment strategies was small. Respiratory gating may not always be required in pancreatic treatment as long as dose distribution is assessed. Any application of our results to clinical use should be undertaken only after discussion with oncologists, particularly with regard to radiotherapy combined with chemotherapy.},
 pages = {303--312},
 title = {Comparison of Respiratory-gated and -ungated Planning in Scattered Carbon Ion Beam Treatment of the Pancreas Using Four-dimensional CT},
 volume = {76},
 year = {2010}
}