Flux Glenn, Leek Francesca, Gape Paul, Gear Jonathan, Taprogge Jan
Department of Physics, Royal Marsden Hospital & Institute of Cancer Research, Sutton, UK.
Department of Physics, Royal Marsden Hospital & Institute of Cancer Research, Sutton, UK.
Semin Nucl Med. 2022 Mar;52(2):167-177. doi: 10.1053/j.semnuclmed.2021.11.002. Epub 2021 Dec 24.
Radioactive iodine was first used for the treatment of benign thyroid disease and thyroid cancer 80 years ago. I-131 mIBG was later developed for the treatment of adult and pediatric neuroendocrine tumors. Physicists were closely involved from the outset to measure retention, to quantify uptake and to calculate radiation dosimetry. As the treatment became widespread, contrasting treatment regimes were followed, either given with empirically derived fixed levels of activity or guided according to the radiation doses delivered. As for external beam radiotherapy, individualized treatments for both thyroid cancer and neuroendocrine tumors were developed based on the aim of maximizing the radiation doses delivered to target volumes while restricting the radiation doses delivered to organs-at-risk, particularly the bone marrow. The challenge of marrow dosimetry has been met by using surrogate measures, often the blood dose for thyroid treatments and the whole-body dose in the case of treatment of neuroblastoma with I-131 mIBG. A number of studies have sought to establish threshold absorbed doses to ensure therapeutic efficacy. Although different values have been postulated, it has nevertheless been conclusively demonstrated that a fixed activity approach leads to a wide range of absorbed doses delivered to target volumes and to normal organs. Personalized treatment planning is now technically feasible with ongoing multicenter clinical trials and investigations into image quantification, biokinetic modelling and radiobiology.
80年前，放射性碘首次用于治疗良性甲状腺疾病和甲状腺癌。后来，I-131 mIBG被开发用于治疗成人和儿童神经内分泌肿瘤。从一开始，物理学家就密切参与其中，以测量滞留情况、量化摄取量并计算辐射剂量学。随着这种治疗方法的广泛应用，出现了不同的治疗方案，要么给予经验性得出的固定活度水平，要么根据所输送的辐射剂量进行指导。与外照射放疗一样，针对甲状腺癌和神经内分泌肿瘤的个体化治疗是基于在限制输送到危险器官（特别是骨髓）的辐射剂量的同时，最大化输送到靶体积的辐射剂量这一目标而开发的。通过使用替代测量方法应对了骨髓剂量测定的挑战，对于甲状腺治疗通常是血液剂量，对于用I-131 mIBG治疗神经母细胞瘤的情况则是全身剂量。许多研究试图确定阈值吸收剂量以确保治疗效果。尽管提出了不同的值，但已经确凿地证明，固定活度方法会导致输送到靶体积和正常器官的吸收剂量范围很广。随着正在进行的多中心临床试验以及对图像量化、生物动力学建模和放射生物学的研究，个性化治疗计划目前在技术上是可行的。
