Erdi A K, Erdi Y E, Yorke E D, Wessels B W
Precision Mathematics Inc, Columbia, MD 21045, USA.
Phys Med Biol. 1996 Oct;41(10):2009-26. doi: 10.1088/0031-9155/41/10/011.
To foster the success of clinical trials in radio-immunotherapy (RIT), one needs to determine (i) the quantity and spatial distribution of the administered radionuclide carrier in the patient over time, (ii) the absorbed dose in the tumour sites and critical organs based on this distribution and (iii) the volume of tumour mass(es) and normal organs from computerized tomography or magnetic resonance imaging and appropriately correlated with nuclear medicine imaging techniques (such as planar, single-photon emission computerized tomography or positron-emission tomography). Treatment planning for RIT has become an important tool in predicting the relative benefit of therapy based on individualized dosimetry as derived from diagnostic, pre-therapy administration of the radiolabelled antibody. This allows the investigator to pre-select those patients who have 'favorable' dosimetry characteristics (high time-averaged target: non-target ratios) so that the chances for treatment success may be more accurately quantified before placing the patient at risk for treatment-related organ toxicities. The future prospects for RIT treatment planning may yield a more accurate correlation of response and critical organ toxicity with computed absorbed dose, and the compilation of dose-volume histogram information for tumour(s) and normal organ(s) such that computing tumour control probabilities and normal tissue complication probabilities becomes possible for heterogeneous distributions of the radiolabelled antibody. Additionally, radiobiological consequences of depositing absorbed doses from exponentially decaying sources must be factored into the interpretation when trying to compute the effects of standard external beam isodose display patterns combined with those associated with RIT.
为促进放射免疫疗法（RIT）临床试验的成功，需要确定：（i）随着时间推移，患者体内所施用放射性核素载体的数量和空间分布；（ii）基于此分布，肿瘤部位和关键器官的吸收剂量；（iii）通过计算机断层扫描或磁共振成像确定肿瘤团块和正常器官的体积，并使其与核医学成像技术（如平面成像、单光子发射计算机断层扫描或正电子发射断层扫描）适当关联。RIT的治疗计划已成为一种重要工具，可根据放射性标记抗体诊断性、治疗前给药所得到的个体化剂量测定法来预测治疗的相对获益。这使研究者能够预先选择那些具有“有利”剂量测定特征（高时间平均靶标：非靶标比率）的患者，从而在使患者面临与治疗相关的器官毒性风险之前，更准确地量化治疗成功的机会。RIT治疗计划的未来前景可能会使反应与关键器官毒性和计算出的吸收剂量之间建立更准确的相关性，并汇总肿瘤和正常器官的剂量体积直方图信息，以便对于放射性标记抗体的异质分布能够计算肿瘤控制概率和正常组织并发症概率。此外，在试图计算标准外照射等剂量显示模式与RIT相关模式相结合的效应时，必须将指数衰减源沉积吸收剂量的放射生物学后果纳入解释之中。
