Koral K F, Zasadny K R, Swailem F M, Buchbinder S F, Francis I R, Kaminski M S, Wahl R L
Department of Internal Medicine, University of Michigan, Ann Arbor 48109.
Eur J Nucl Med. 1991;18(6):432-5. doi: 10.1007/BF02258433.
The dosimetry for two, similarly sized tumours in a lymphoma patient being treated with non-bone marrow ablative, monoclonal antibody therapy is reported. The 45-year-old man was infused with 2.48 GBq (67 mCi) of 131I-labelled MB-1. Prior to therapy, a time series of diagnostic conjugate-view images and a radionuclide transmission scan were obtained and processed to obtain time-activity curves. Starting 2 days after the therapeutic infusion of radioactivity, a second conjugate-view time series was obtained. At that time, a quantitative single-photon emission tomography (SPET) acquisition was also carried out. Pre- and post-therapy X-ray computed tomography scans demonstrated a percentage reduction in volume for the right tumour which was 3.8 times that for the left tumour. In contrast, diagnostic conjugate views by themselves estimated the absorbed dose to be the same for the two tumours. Addition of therapy conjugate-view data increased the right-over-left ratio but only to 1.22. Normalizing either time-activity series by the intra-therapy SPET results increased the ratio to greater than 1.5. We assume here that a differential dose is correct according to the differential tumour shirnkage. One can further assume that the largest ratio corresponds most certainly to the most accurate dosimetric method. Other assumptions are possible. While additional study is essential, data from this patient suggest that the preferred dosimetric method is intra-therapy SPET normalization of either time series.
报告了一名接受非骨髓清除性单克隆抗体治疗的淋巴瘤患者体内两个大小相似肿瘤的剂量测定情况。该45岁男性接受了2.48GBq（67mCi）的131I标记的MB - 1注入。治疗前，获取并处理了一系列诊断性共轭视图图像和放射性核素传输扫描，以获得时间 - 活度曲线。在治疗性注入放射性物质2天后开始，获取了第二个共轭视图时间序列。此时，还进行了定量单光子发射断层扫描（SPET）采集。治疗前后的X射线计算机断层扫描显示，右侧肿瘤的体积减少百分比是左侧肿瘤的3.8倍。相比之下，仅通过诊断性共轭视图估计两个肿瘤的吸收剂量相同。加入治疗共轭视图数据后，左右比值增加，但仅为1.22。根据治疗期间的SPET结果对任一时间 - 活度序列进行归一化处理后，该比值增加到大于1.5。我们在此假设，根据肿瘤缩小差异，不同的剂量是正确的。人们可以进一步假设，最大的比值最肯定地对应最准确的剂量测定方法。其他假设也是可能的。虽然进一步的研究至关重要，但该患者的数据表明，首选的剂量测定方法是对任一序列进行治疗期间SPET归一化。
