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Abstract：
Image-based dosimetry-guided radiopharmaceutical therapy has the potential to personalize treatment by limiting toxicity to organs at risk and maximizing the therapeutic effect. The 177Lu dosimetry challenge of the Society of Nuclear Medicine and Molecular Imaging consisted of 5 tasks assessing the variability in the dosimetry workflow. The fifth task investigated the variability associated with the last step, dose conversion, of the dosimetry workflow on which this study is based. Methods: Reference variability was assessed by 2 medical physicists using different software, methods, and all possible combinations of input segmentation formats and time points as provided in the challenge. General descriptive statistics for absorbed dose values from the global submissions from participants were calculated, and variability was measured using the quartile coefficient of dispersion. Results: For the liver, which included lesions with high uptake, variabilities of up to 36% were found. The baseline analysis showed a variability of 29% in absorbed dose results for the liver from datasets where lesions included and excluded were grouped, indicating that variation in how lesions in normal liver were treated was a significant source of variability. For other organs and lesions, variability was within 7%, independently of software used except for the local deposition method. Conclusion: The choice of dosimetry method or software had a small contribution to the overall variability of dose estimates.
摘要：
基于图像的剂量测定引导的放射性药物治疗具有通过限制对风险器官的毒性并最大化治疗效果来个性化治疗的潜力。核医学和分子成像协会的177Lu剂量测定挑战包括5项任务，评估剂量测定工作流程的变异性。第五个任务调查了与最后一步相关的可变性，剂量转换，本研究所基于的剂量测定工作流程。方法：由2名医学物理学家使用不同的软件评估参考变异性，方法,以及挑战中提供的输入分割格式和时间点的所有可能组合。计算了参与者提交的全球吸收剂量值的一般描述性统计，变异性是用四分位数离散系数测量的。结果：对于肝脏，其中包括高摄取的病变，变异高达36%。基线分析显示，肝脏吸收剂量结果的变异性为29％，数据集包括和排除的病变进行分组，这表明正常肝脏病变治疗方式的变化是变异性的重要来源。对于其他器官和病变，变异性在7%以内，独立于使用的软件，除了局部沉积方法。结论：剂量测定方法或软件的选择对剂量估计的总体变异性有很小的贡献。
