Fukumitsu Nobuyoshi, Takahashi Shinsei, Okumura Toshiyuki, Ishida Toshiki, Murofushi Keiko Nemoto, Ohnishi Kayoko, Aihara Teruhito, Ishikawa Hitoshi, Tsuboi Koji, Sakurai Hideyuki
Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8575, Japan.
Jpn J Radiol. 2018 Sep;36(9):559-565. doi: 10.1007/s11604-018-0757-9. Epub 2018 Jul 6.
Normal liver tissue changes after proton beam therapy (PBT) were investigated in patients at 1 and 2 years after the therapy.
Changes in normal liver tissue volume were examined. The dose distribution of the normal liver tissue was also simulated on the follow-up CTs.
The normal liver tissue volume was 1149 ± 215 cm before treatment, 1089 ± 188 cm at 1 year, and 1080 ± 236 cm at 2 years after treatment. The normal liver tissue volume was increased in 10 and decreased in 20 patients at 2 years and was smaller than that before the treatment in total (P = 0.03). The simulated volume that received more than 30 Gray equivalent [V30 (cm)] at 1 year was 258 ± 187 cm and that at 2 years (244 ± 171 cm) was smaller than that before treatment (297 ± 140 cm) (P = 0.03).
The changes in the shape and volume of normal liver tissue are not constant, which cause a large dose distribution discrepancy in the normal liver for 2 years. Therefore, careful consideration of the dose distribution of normal liver tissue is required when planning re-irradiation.
研究质子束治疗（PBT）后1年和2年患者正常肝组织的变化。
检查正常肝组织体积的变化。还在随访CT上模拟正常肝组织的剂量分布。
治疗前正常肝组织体积为1149±215cm³，治疗后1年为1089±188cm³，治疗后2年为1080±236cm³。2年时，10例患者正常肝组织体积增加，20例患者正常肝组织体积减小，总体上小于治疗前（P = 0.03）。1年时接受超过30格雷当量[V30（cm³）]的模拟体积为258±187cm³，2年时（244±171cm³）小于治疗前（297±140cm³）（P = 0.03）。
正常肝组织的形状和体积变化并不恒定，这导致2年内正常肝组织的剂量分布差异较大。因此，在计划再次放疗时，需要仔细考虑正常肝组织的剂量分布。
