Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, Heraklion 71003, Crete, Greece.
Phys Med. 2013 Nov;29(6):650-5. doi: 10.1016/j.ejmp.2012.08.001. Epub 2012 Aug 22.
The purpose of this study was to measure the scattered dose to out-of-field organs from head and neck radiotherapy in pediatric patients and to estimate the risk for second cancer induction to individual organs. Radiotherapy for thalamic tumor, brain tumor, acute leukemia and Hodgkin's disease in the neck region was simulated on 5 and 10-year-old pediatric phantoms with a 6 MV photon beam. The radiation dose to thyroid, breast, lung, stomach, ovaries, bladder, liver, uterus, prostate and colon was measured using thermoluminescent dosimeters. The methodology, provided by the BEIR VII report was used for the second cancer risk estimations. Peripheral dose range for a simulated 5-year-old patient was 0.019%-1.572% of the given tumor dose. The corresponding range at the advanced patient age was reduced to 0.018%-1.468%. The second cancer risk per fraction for male patients varied from 3 to 215 per 1,000,000 patients depending upon the age at the time of exposure, primary cancer site and organ scattered dose. The corresponding risk for females was 1-1186 per 1,000,000 patients. The higher risk values were found for breast, thyroid and lung cancer development. The current data concerning the risk magnitude for developing subsequent neoplasms to various out-of-field organs may be of value for health care professionals in the follow-up studies of childhood cancer survivors.
本研究旨在测量头颈部放疗中离野器官的散射剂量，并估计个体器官发生第二癌症的风险。使用 6 MV 光子束对 5 岁和 10 岁儿童体模进行了丘脑肿瘤、脑肿瘤、急性白血病和颈部霍奇金病的放射治疗模拟。使用热释光剂量计测量了甲状腺、乳房、肺、胃、卵巢、膀胱、肝、子宫、前列腺和结肠的辐射剂量。第二癌症风险估算采用了 BEIR VII 报告提供的方法。模拟 5 岁患者的外周剂量范围为所给肿瘤剂量的 0.019%-1.572%。在患者年龄较大时，相应范围缩小到 0.018%-1.468%。男性患者每次分割的第二癌症风险因暴露时的年龄、原发性癌症部位和离野器官散射剂量而异，从每 100 万患者 3 到 215 不等。女性的相应风险为每 100 万患者 1-1186。乳腺癌、甲状腺癌和肺癌的发展风险较高。关于各种离野器官发生继发肿瘤风险幅度的当前数据可能对儿童癌症幸存者随访研究中的医疗保健专业人员有价值。
