In this study, the impact of anatomical changes on radiation dose variations of the prostate and bladder (as an organ at risk) was assessed for a potential scenario of magnetic resonance imaging-guided carbon-ion radiotherapy (MRgCT) of prostate cancer. To achieve this goal, carbon-ion beams perpendicular to a pelvis phantom affected by 1.5 T perpendicular magnetic field were simulated using the FLUKA code. Prostate diameter change from 6 to 1 cm leads to a prostate dose reduction of 88 %. Bladder diameter change from 10 to 5 cm leads to a reduction of 92 % in bladder dose. The set-up error of 5 mm leads to a decrease of 5 % in the prostate dose. Rectum diameter change from 5 to 3 cm leads to reductions of 20 % and 26 % in prostate and bladder dose, respectively. In conclusion, anatomical changes impact on dose variations in MRgCT of prostate cancer.

在这项研究中，针对磁共振成像引导的碳离子放射治疗（MRgCT）的潜在情况，评估了解剖变化对前列腺和膀胱（作为处于危险中的器官）的辐射剂量变化的影响。为了实现此目标，使用FLUKA代码模拟了垂直于受1.5 T垂直磁场影响的骨盆体模的碳离子束。前列腺直径从6厘米变化到1厘米导致前列腺剂量减少88％。膀胱直径从10厘米变化到5厘米可减少92％的膀胱剂量。5 mm的设定误差导致前列腺剂量减少5％。直肠直径从5厘米更改为3厘米可分别减少前列腺和膀胱剂量的20％和26％。结论，