Sgouros G, Chiu S, Pentlow K S, Brewster L J, Kalaigian H, Baldwin B, Daghighian F, Graham M C, Larson S M, Mohan R
Dept. of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.
J Nucl Med. 1993 Sep;34(9):1595-601.
Absorbed-dose calculations for radioimmunotherapy are generally based on tracer imaging studies of the labeled antibody. Such calculations yield estimates of the average dose to normal and target tissues assuming idealized geometries for both the radioactivity source volume and the target volume. This work describes a methodology that integrates functional information obtained from SPECT or PET with anatomical information from CT or MRI. These imaging modalities are used to define the actual shape and position of the radioactivity source volume relative to the patient's anatomy. This information is then used to calculate the spatially varying absorbed dose, depicted in "colorwash" superimposed on the anatomical imaging study. By accounting for individual uptake characteristics of a particular tumor and/or normal tissue volume and superimposing resulting absorbed-dose distribution over patient anatomy, this approach provides a patient-specific assessment of the target-to-surrounding normal tissue absorbed-dose ratio. Such information is particularly important in a treatment planning approach to radioimmunotherapy, wherein a therapeutic administration of antibody is preceded by a tracer imaging study to assess therapeutic benefit.
放射免疫疗法的吸收剂量计算通常基于标记抗体的示踪成像研究。此类计算得出正常组织和靶组织平均剂量的估计值，前提是假设放射性源体积和靶体积具有理想化的几何形状。本研究描述了一种将从单光子发射计算机断层扫描（SPECT）或正电子发射断层扫描（PET）获得的功能信息与计算机断层扫描（CT）或磁共振成像（MRI）的解剖信息相结合的方法。这些成像方式用于确定放射性源体积相对于患者解剖结构的实际形状和位置。然后利用该信息计算空间变化的吸收剂量，以“彩色渲染”的形式叠加在解剖成像研究上。通过考虑特定肿瘤和/或正常组织体积的个体摄取特征，并将所得吸收剂量分布叠加在患者解剖结构上，该方法提供了针对患者的靶组织与周围正常组织吸收剂量比的评估。此类信息在放射免疫疗法的治疗计划方法中尤为重要，其中在进行抗体治疗给药之前，需先进行示踪成像研究以评估治疗效果。
