肿瘤注射90Y治疗的临界点与注射剂量的关系

目的 :探讨肿瘤间质注射 90Yβ核素治疗中的临界点及由此确定注射剂量的方法。方法 :依据建立的肿瘤间质注射 β核素治疗过程中的数学模型 ,由计算机模拟实验肿瘤中心注入 0 5mL的 90Y核素治疗时 ,肿瘤组织中形成的吸收剂量、克隆源性细胞生存率的时空分布和肿瘤控制概率(tumorcontrolprobability ,TCP) ,观察不同大小的肿瘤在不同活度的核素治疗时所能达到的临界点状态。结果 :1)肿瘤越小、注射剂量越大 ,则临界点时间越长 ;临界点时平均细胞生存率的对数值随注射剂量的变化呈线性 -二次关系。 2 )给出了临界点TCP达到 0 99时所需的注射剂量与肿瘤半径的定量关系式。结论 :临界点的TCP可以作为疗效的短期预测指标 ,并可由此确定临床所需的核素注射剂量。

Critical point during 90Y nuclide tumor therapy and radiopharmaceutical dose

OBJECTIVE:To investigate the critical time point and the radiopharmaceutical doses for different size tumors during 90 Y nuclide therapy.METHODS:The process of curing tumor with 0.5 mL 90 Y nuclide solution injected into tumor center was simulated with the computer program based on the mathematical model we had built.The tumor therapeutic efficiencies at the critical time (at which the death rate of the tumor cells was equal to their multiplication rate) for different radiopharmaceutical dose and tumor size were evaluated.RESULTS:1)The larger the radiopharmaceutical dose and the smaller the tumor size,the longer the critical time.The logarithm value of clonogenic cells survival fraction at critical time varied with the radioactivity in quadratic polynomial mode.2)The relationship of the 90 Y radioactivity required when TCP reached to 0.99 at critical time to the tumor radius was fit to a quantitative express.CONCLUSIONS:The TCP at the critical time could represent the therapeutic efficiency.According to it the radiopharmaceutical dose could be determined in clinic.