Shiba Shintaro, Saitoh Jun-Ichi, Irie Daisuke, Shirai Katsuyuki, Abe Takanori, Kubota Yoshiki, Sakai Makoto, Okada Ryosuke, Ohno Tatsuya, Nakano Takashi
Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma, Japan.
Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma, Japan
Anticancer Res. 2017 Oct;37(10):5673-5680. doi: 10.21873/anticanres.12003.
BACKGROUND/AIM: To analyze the accuracy of patient positioning and dose distribution quality using a fiducial marker-matching technique in carbon-ion radiotherapy (C-ion RT) for stage I lung cancer.
Thirteen patients with 26 fiducial markers and 104 radiation fields were examined. Change in the fiducial marker position coordinates from the gross tumor volume center (Δm), and change in the water-equivalent path length of the chest wall (ΔWEL) were measured in each radiation field. Criterion for an acceptable change in dose distribution was defined as the percentage of D95 (%D95) at gross tumor volume greater than 90% of the prescribed dose.
Thirteen radiation fields (12.5%) were classified as unacceptable. Δm and ΔWEL had significant negative correlations with %D95 and thus were significant factors related to unacceptable irradiation fields.
Patient positioning using a fiducial marker-matching technique resulted in 12.5% of radiation fields demonstrating unacceptable degradation due to Δm and ΔWEL.
背景/目的：分析在Ⅰ期肺癌碳离子放疗（C离子放疗）中使用基准标记匹配技术时患者摆位的准确性和剂量分布质量。
对13例患者的26个基准标记和104个照射野进行了检查。在每个照射野中测量基准标记位置坐标相对于大体肿瘤体积中心的变化（Δm）以及胸壁水等效路径长度的变化（ΔWEL）。剂量分布可接受变化的标准定义为大体肿瘤体积处D95（%D95）大于处方剂量的90%。
13个照射野（12.5%）被归类为不可接受。Δm和ΔWEL与%D95呈显著负相关，因此是与不可接受照射野相关的显著因素。
使用基准标记匹配技术进行患者摆位时，12.5%的照射野因Δm和ΔWEL出现了不可接受的剂量分布退化。
