Radiopharmaceutical therapy is growing rapidly. However, yet to be addressed is the implementation of methods to plan treatments for circulating tumor cells, disseminated tumor cells, and micrometastases. Given the capacity of radiopharmaceuticals to specifically target and kill single cells and multicellular clusters, a quality not available in chemotherapy and external-beam radiation therapy, it is important to develop dosimetry and bioeffect modeling tools that can inform radiopharmaceutical design and predict their effect on microscopic disease. This pamphlet describes a new version of MIRDcell, a software tool that was initially released by the MIRD committee several years ago. Methods: Version 3 (V3) of MIRDcell uses a combination of analytic and Monte Carlo methods to conduct dosimetry and bioeffect modeling for radiolabeled cells within planar colonies and multicellular clusters. A worked example is provided to assist users to learn old and new features of MIRDcell and test its capacity to recapitulate published responses of tumor cell spheroids to radiopharmaceutical treatments. Prominent capabilities of the new version include radially dependent activity distributions, user-imported activity distributions, cold regions within the cluster, complex bioeffect modeling that accounts for radiation type and subcellular distribution, and a rich table of output data for subsequent analysis. Results: MIRDcell V3 effectively reproduces experimental responses of multicellular spheroids to uniform and nonuniform distributions of therapeutic radiopharmaceuticals. Conclusion: MIRDcell is a versatile software tool that can be used for educational purposes and design of radiopharmaceutical therapies.

放射性药物治疗正在迅速发展。然而，尚待解决的是循环肿瘤细胞、播散性肿瘤细胞和微转移的治疗计划方法的实施。鉴于放射性药物具有特异性靶向和杀死单细胞和多细胞簇的能力，这是化学疗法和外束放射治疗所不具备的，因此开发剂量测定和生物效应建模工具非常重要，这些工具可以为放射性药物设计提供信息并预测其对微观的影响。疾病。本小册子介绍了 MIRDcell 的新版本，这是一种软件工具，最初由 MIRD 委员会几年前发布。方法： MIRDcell 版本 3 (V3) 使用分析方法和蒙特卡罗方法相结合，对平面集落和多细胞簇内的放射性标记细胞进行剂量测定和生物效应建模。提供了一个可行的示例，帮助用户了解 MIRDcell 的新旧功能，并测试其概括已发表的肿瘤细胞球体对放射性药物治疗的反应的能力。新版本的突出功能包括径向相关的活动分布、用户导入的活动分布、簇内的冷区域、考虑辐射类型和亚细胞分布的复杂生物效应建模，以及用于后续分析的丰富的输出数据表。结果： MIRDcell V3 有效地再现了多细胞球体对均匀和不均匀分布的治疗性放射性药物的实验反应。结论： MIRDcell 是一种多功能软件工具，可用于教育目的和放射性药物疗法的设计。