Marquis Harry, Schmidtlein C Ross, de Nijs Robin, Mínguez Gabiña Pablo, Gustafsson Johan, Kayal Gunjan, Ocampo Ramos Juan C, Carter Lukas M, Bailey Dale L, Kesner Adam L
Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York;
Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
J Nucl Med. 2025 Mar 3;66(3):457-465. doi: 10.2967/jnumed.124.268520.
Accurate quantification in emission tomography is essential for internal radiopharmaceutical therapy dosimetry. Mean activity concentration measurements in objects with diameters less than 10 times the full width at half maximum of the imaging system's spatial resolution are significantly affected (>10%) by the partial-volume effect. This study develops a framework for PET and SPECT spatial resolution characterization and proposes 2 MIRD recovery coefficient models-a geometric mean approximation (RECOVER-GM) and an empirical model (RECOVER-EM)-that provide shape-specific partial-volume correction (PVC). The models were validated using simulations and phantom experiments, with a comparative PVC test on ellipsoidal phantoms demonstrating that the RECOVER models significantly reduced error in activity quantification by factors of approximately 1.3-5.7 compared with conventional sphere-based corrections. The proposed recovery coefficient models and PVC methodology provide a robust framework for improved region-based PVC, including corrections for nonspherical tumor volumes. This work is part of the ongoing MIRDsoft.org project that aims to enhance accessibility to advanced dosimetry tools for improved disease characterization, treatment planning, and radiopharmaceutical therapy dosimetry.
发射断层扫描中的准确量化对于体内放射性药物治疗剂量测定至关重要。在直径小于成像系统空间分辨率半高宽10倍的物体中，平均活度浓度测量会受到部分容积效应的显著影响（>10%）。本研究建立了一个用于PET和SPECT空间分辨率表征的框架，并提出了2种MIRD恢复系数模型——几何平均近似法（RECOVER-GM）和经验模型（RECOVER-EM），它们可提供特定形状的部分容积校正（PVC）。这些模型通过模拟和体模实验进行了验证，在椭球体模上进行的对比PVC测试表明，与传统的基于球体的校正相比，RECOVER模型将活度量化误差显著降低了约1.3至5.7倍。所提出的恢复系数模型和PVC方法为改进基于区域的PVC提供了一个强大的框架，包括对非球形肿瘤体积的校正。这项工作是正在进行的MIRDsoft.org项目的一部分，该项目旨在提高先进剂量测定工具的可及性，以改善疾病表征、治疗规划和放射性药物治疗剂量测定。
