Dose evaluation of therapeutic radiolabeled bleomycin complexes based on biodistribution data in wild-type rats:Effect of radionuclides in absorbed dose of different organs

Bleomycins(BLMs), as tumor-seeking antibiotics, have been used for over 20 years in treatment of several types of cancers. Several radioisotopes are used in radiolabeling of BLMs for therapeutic and diagnostic purposes. An important points in developing new radiopharmaceuticals, especially therapeutic agents, is the absorbed dose delivered in critical organs. In this work, absorbed dose to organs after injection of ~(153)Sm-,~(177)Lu- and ~(166)Ho-labeled BLM was investigated by radiation dose assessment resource(RADAR) method based on biodistribution data in wild-type rats. The absorbed dose effect of the radionuclides was evaluated. The maximum absorbed dose for the complexes was observed in the kidneys, liver and lungs. For all the radiolabeled BLMs,bone and red marrow received considerable absorbed dose. Due to the high energy beta particles emitted by ~(166)Ho, higher absorbed dose is observed for ~(166)Ho-BLM in the most organs. The reported data can be useful for the determination of the maximum permissible injected activity of the radiolabeled BLMs in the treatment planning programs.     

与年龄有关的放射性核素在体内的代谢模型

本文扼要介绍了近几年发表的与年龄有关的核素在体内的代谢模型,它是制订不同年龄公众成员内照射剂量次级标准所必需的资料。胃肠道模型显示出,未成年人员胃肠道各段质量及内容物通过速率的不同均可影响难溶性物质对胃肠道本身的剂量,只有对1周岁以下婴儿才考虑月龄对核素经胃肠道吸收分数的影响。肺模型表明,微粒在呼吸系统各部位的沉积和廓清均与年龄有一定关系。对吸入~(222)Rn、~(220)Rn子体所致气管、支气管和肺部α剂量的估算表明,以6岁儿童为最高,约为成人的3倍。已报道了氚、碘-131、铯-137、放射性锶,镭和钚等核素与年龄有关的在体内器官的代谢模型。在慢性照射条件下,可用线性方程由同一元素在成人某器官的沉积分数和生物半排期求得给定年龄人员相应的数值。可获得此类数据的元素有21个。     

大鼠吸入~(239)PuO_2后肺巨噬细胞核吸收剂量的估算

本文利用大鼠吸入~(239)PuO_2后肺钚滞留函数,肺巨噬细胞的更新函数及有关的生物学资料,采用 Monte-Carlo 方法,估算了大鼠吸入~(239)PuO_2后肺和肺巨噬细胞核的平均吸收剂量。对于初始肺钚沉积量分别为8.7、6.7、2.7和3.0kBq,照射时间分别为2、7、13和28d 的4组实验动物,估算出肺平均吸收剂量(?)_P为0.69、1.7、1.2和2.6Gy,肺巨噬细胞陔的平均吸收剂量(?)_(PM)为0.95、2.21、1.71和3.23Gy。(?)_(PM)与(?)_P的比值的平均值为1.3。肺巨噬细胞核的受照剂量主要求自沉积于肺巨噬细胞内的钚,周围钚粒子的剂量贡献仅占1%左右。     

Na188ReO4、188Re-DTPA和188Re-MAG3的生物分布及排泄比较

为比较Na^188ReO4、^188Re-DTPA和^188Re-MAG3在冠状动脉再狭窄防治中的优劣,将这三种放射性药物注入到ICR小鼠和SD大鼠体内,观察其在小鼠体内的分布及在大鼠体内的排泄动力学.结果显示,^188Re-MAG3在小鼠体内的血液清除明显快于^188Re-DTPA和Na^188ReO4,并且在各主要组织脏器的吸收也明显低于^188Re-DTPA和Na^188ReO4.注射后2 h,77.28%的^188Re-MAG3经尿液排出体外,而此时^188Re-DTPA 和Na^188ReO4的尿液排出量不到注射剂量的50%.188Re-MAG3在动物体内的行为明显优于^188Re-DTPA和Na^188ReO4,更适于冠状动脉再狭窄的防治.     

正常成年男子肝脏中元素含量的中子活化分析

在我国4个不同膳食类型地区河北、山西、江西和四川,采集21例正常成年男子尸体（意外死亡）的肝脏样品,用中子活化分析方法测定了8种人体必需微量元素的含量。结果表明：肝脏中8种元素的含量由高到低依次为铁、锌、铜、锰、钼、硒、铬、钴,且个体差异大;某些元素的含量地区差异明显,山西样品的Co含量、四川样品的Cr含量和河北样品的Fe含量分别是其它3个地区的1.7~2.0倍、2.5~5.2倍和1.5~2.4倍;与国际辐射防护委员会（ICRP）参考人的最新估算值相比,铬含量明显偏高,铁、铜和钼含量也稍高。作为质量控制,还对3种标准物质中8种元素的含量进行了测定,分析结果与标准值吻合。     

Biological distribution of 131I-labeled anti-nucleus antigen monoclonal antibody chTNT in patients with pulmonary metastases from differentiated thyroid carcinoma

This work is to study the in vivo biological distribution of 131I-labeled mouse/human chimeric monoclonal antibody (131I-chTNT) in patients with pulmonary metastases from differentiated thyroid carcinoma.Ten patients with differentiated thyroid carcinoma were injected intravenously with a single dose of 131I-chTNT (5 MBq.kg-1 body weight).Radioactivity of blood and urine samples was measured at different time points.The in vivo stability and the metabolic status of 131I-chTNT were detected with supersaturated trichloroacetic acid.Continuous imaging was performed to outline the region of interest (ROD and estimate the intake level on the whole body,major organs and tumor lesions at different time points.The serum time-radioactivity curve of 131I-ehTNT accorded with the two-compartment model after a single intravenous injection:T1/2(h)=65.28±14.83,AUC0-t(MBq.h.mL-1)=8.93±1.32,AUC0-∞(MBq-h-mL-1)=10.58±2.19,and CL(mL.min-1.kg-1)=1635±359.The time-radioactivity percentage curve of 131I-chTNT urine excretion accorded with the one-compartment model after a single intravenous injection:T1/2(h)=99±10,and accumulative (31±9) % radioactivity of the injected dose was excreted in urine in one week.The percentages of serum 131I-ehTNT in radioactive components at 24,48 and 72 h were over 95% and it was still (88±7)% at 168 h.As for chemical composition of radioactive substances in urine,radioactivity in urine samples originated from free 131I by 100%.Radioactivity of 131I-chTNT after intravenous administration was mainly concentrated in the lung and liver,least in the brain.Radioactivity of tumor tissues reached the maximum at 24 h and the tumor/normal tissue (T/N) ratio reached the maximum (1.28～3.83) during 3～7 d.The characteristics of in vivo biological distribution of 131I-chTNT in patients with pulmonary metastases from differentiated thyroid carcinoma are favorable for its therapeutic application for the metastasis tumors.     

99mTc-TRODAT-1内照射辐射吸收剂量的计算

为估测^99mTc-TRODAT-1在全身靶器官的内照射辐吸收剂量及生物学分布，对3例帕金森病患者（PD）、2例原发性震颤（ET）患者静脉注射^99mTc-TRODAT-1后，用双探头SPECT采集24h内系列全身前、后位图像；利用ROI技术获各时相全身各脏器的摄取放射性活度，采用Microcal Origin5.0应用程序中的非线性拟合方法得到全脏器的时间－放射性曲线，通过各种源器官的累积活度计算出放射性核素的滞留时间，然后由美国MIRDOSE3．1应用程序得到各靶器官的内照射辐照吸收剂量，另外，注药后3h离断层显像，实验结果显示，^99mTc-TRODAT-1全身各脏器内照射辐射吸收剂量均较小，脑断层显像，纹状体影像清晰。^99mTc-TRODAT-1人体应用安全，是一种优良的多巴胺转运体（DAT）显像剂。