Wang S J, Lin W Y, Chen M N, Chi C S, Chen J T, Ho W L, Hsieh B T, Shen L H, Tsai Z T, Ting G, Mirzadeh S, Knapp F F
Department of Nuclear Medicine, Veterans General Hospital-Taichung, Taiwan.
J Nucl Med. 1998 Oct;39(10):1752-7.
Intratumoral injection of 90Y microspheres is a potential alternative in the treatment of primary liver tumor. However, complicated preparation and lack of a gamma ray for imaging are the disadvantages of 90Y. In this study, we used 188Re, a generator-produced radioisotope with 155-keV gamma ray emission, to label microspheres. After intratumoral injection of 188Re microspheres into rats with hepatoma, biodistributions and survival times were analyzed.
Twelve male rats with hepatoma were killed at 1, 24 and 48 hr (4 rats at each time point) after intratumoral injection of approximately 7.4 MBq 188Re microspheres. Samples of various organs were obtained and used to calculate the tissue concentrations. In addition, 30 male rats bearing hepatoma were divided into two groups (15 rats in each group) to evaluate survival time. Group 1 received intratumoral injection of 37 MBq 188Re microspheres, whereas Group 2 served as the control group and received an intratumoral injection of 0.1 ml normal saline only. Survival time was calculated from the day of injection to 2 mo after treatment.
Radioactivity in the tumor was very high throughout. Biological half-time was 170.8 hr. Radioactivity in the lung was 1.78% injected dose (i.d.)/g at 1 hr but declined rapidly over time. The concentration in the urine was approximately 6.14% i.d./ml after the first hour and rapidly declined thereafter. The concentrations of radioactivity in other organs, such as normal liver, muscle, spleen, bone, testis and whole blood, were quite low throughout the study. Twelve of 15 (80%) of rats survived over 60 days after intratumoral injection of 188Re microspheres, whereas only 4 of 15 (26.7%) survived more than 60 days after injection of normal saline only. The difference between the groups was significant (p < 0.05).
Rhenium-188 offers cost-effectiveness, on-site availability, short half-life, energetic beta particle, emission of gamma photons for imaging, easy preparation, easy clinical administration and apparent lack of radiation leakage from the treated tumor. Direct intratumoral injection of 188Re microspheres is extremely attractive as a clinical therapeutic alternative in hepatoma patients.
瘤内注射90Y微球是治疗原发性肝癌的一种潜在替代方法。然而，90Y存在制备复杂且缺乏用于成像的γ射线的缺点。在本研究中，我们使用188Re（一种由发生器产生的放射性同位素，发射155keV的γ射线）来标记微球。将188Re微球瘤内注射到肝癌大鼠体内后，分析其生物分布和生存时间。
12只雄性肝癌大鼠在瘤内注射约7.4MBq的188Re微球后1、24和48小时（每个时间点4只大鼠）处死。获取各种器官的样本并用于计算组织浓度。此外，将30只荷瘤雄性大鼠分为两组（每组15只）以评估生存时间。第1组接受瘤内注射37MBq的188Re微球，而第2组作为对照组，仅接受瘤内注射0.1ml生理盐水。从注射日计算至治疗后2个月的生存时间。
肿瘤内的放射性始终很高。生物半衰期为170.8小时。肺内放射性在1小时时为1.78%注射剂量（i.d.）/克，但随时间迅速下降。尿液中的浓度在第1小时后约为6.14%i.d./毫升，此后迅速下降。在整个研究过程中，其他器官如正常肝脏、肌肉、脾脏、骨骼、睾丸和全血中的放射性浓度相当低。15只大鼠中有12只（80%）在瘤内注射188Re微球后存活超过60天，而仅注射生理盐水的15只大鼠中只有4只（26.7%）存活超过60天。两组之间的差异具有统计学意义（p<0.05）。
铼-188具有成本效益、现场可用性、半衰期短、高能β粒子、发射用于成像的γ光子、制备容易、临床给药简便以及治疗肿瘤明显无辐射泄漏等优点。直接瘤内注射188Re微球作为肝癌患者的临床治疗替代方法极具吸引力。
