■髓母细胞瘤是一种常见于儿科的中枢神经肿瘤。这种肿瘤类型的主要放射治疗技术是颅底照射(CSI),整个大脑和脊髓都暴露在辐射中。由于儿科健康器官的不成熟,放射性副作用,如第二癌症更严重。因此,本研究旨在评估CSI后健康器官发生继发性癌症的风险.
■七种危险器官(OAR),包括皮肤,眼透镜,甲状腺,肺,肝脏,胃,膀胱,结肠,并考虑了性腺,并通过TLD在拟人化RANDO体模内测量了每个OAR在CSI期间接受的剂量。然后,获得的每个器官的平均剂量用于根据特定器官的推荐癌症风险系数估计继发性恶性肿瘤发展的概率.
■结果表明,胃和结肠具有继发恶性肿瘤的高风险,而皮肤发生继发性癌症的概率最低。治疗过程后所有考虑的器官的总接受剂量低于相应的可耐受剂量水平。
■从结果来看,可以得出结论,CSI期间的一些OAR有很高的继发性癌症发展风险.由于儿科器官的不成熟,可能会加剧辐射暴露的放射源效应,因此这个问题可能令人担忧。因此,严格屏蔽的OAR在颅骨放射治疗和/或通过现代技术,如强子治疗使他们免受辐射领域是强烈建议。
UNASSIGNED: Medulloblastoma is a central nerves tumor that often occurs in pediatrics. The main radiotherapy technique for this tumor type is craniospinal irradiation (CSI), through which the whole brain and spinal cord are exposed to radiation. Due to the immaturity of healthy organs in pediatrics, radiogenic side effects such as second cancer are more severe. Accordingly, the current study aimed to evaluate the risk of secondary cancer development in healthy organs following CSI.
UNASSIGNED: Seven organs at risk (OARs) including skin, eye lens, thyroid, lung, liver, stomach, bladder, colon, and gonads were considered and the dose received by each OAR during CSI was measured inside an anthropomorphic RANDO phantom by TLDs. Then, the mean obtained dose for each organ was used to estimate the probability of secondary malignancy development according to the recommended cancer risk coefficients for specific organs.
UNASSIGNED: The results demonstrated that the stomach and colon are at high risk of secondary malignancy occurrence, while the skin has the lowest probability of secondary cancer development. The total received dose after the treatment course by all considered organs was lower than the corresponding tolerable dose levels.
UNASSIGNED: From the results, it can be concluded that some OARs during CSI are highly at risk of secondary cancer development. This issue may be of concern due to organ immaturity in pediatrics which can intensify the radiogenic effects of radiation exposure. Accordingly, strict shielding the OARs during craniospinal radiotherapy and/or sparing them from the radiation field through modern techniques such as hadron therapy is highly recommended.