Viala J, Vanel D, Meingan P, Lartigau E, Carde P, Renschler M
Department of Radiology, Institut Gustave-Roussy, Villejuif, France.
Radiology. 1999 Sep;212(3):755-9. doi: 10.1148/radiology.212.3.r99se10755.
To evaluate magnetic resonance (MR) imaging results after administration of gadolinium texaphyrin, a tumor-selective radiation sensitizer that is detectable at MR imaging, and to determine an appropriate intravenous dose of gadolinium texaphyrin for repeated injections during radiation therapy, the dose-limiting toxicity of reiterated doses of gadolinium texaphyrin, the maximal tolerated dose, the biolocalization of gadolinium texaphyrin (as assessed at MR examinations), and the response to treatment.
Ten daily intravenous injections of gadolinium texaphyrin, each followed by whole-brain radiation therapy (total of 10 fractions, 30 Gy), were administered to patients with brain metastases in a multicenter study. At the study institution, 11 patients underwent MR imaging before and after the first injection, after the 10th injection, and 8 weeks after entry into the study.
MR imaging revealed selective drug uptake in metastases, without enhancement of normal brain tissue. In 10 patients, tumor uptake was higher after the 10th injection than after the first injection, which indicated accumulation of gadolinium texaphyrin in metastases. One lesion was visible only after the 10th injection and not at the pretherapeutic MR examination with injection of conventional gadolinium-based contrast material. Response to treatment was defined as a reduction in the size of the metastases between the preinjection MR study and the last MR study; seven patients achieved partial remission with tumor regression exceeding 50% of the initial size, and four achieved a minor response with less than 50% tumor regression.
These preliminary results indicate that gadolinium texaphyrin is tumor selective and that brain metastases can be depicted at MR imaging long after the administration of gadolinium texaphyrin.
评估钆克沙卟啉（一种在磁共振成像中可检测到的肿瘤选择性放射增敏剂）给药后的磁共振（MR）成像结果，确定在放射治疗期间重复注射钆克沙卟啉的合适静脉剂量、钆克沙卟啉重复剂量的剂量限制性毒性、最大耐受剂量、钆克沙卟啉的生物定位（通过MR检查评估）以及治疗反应。
在一项多中心研究中，对脑转移瘤患者进行了10次钆克沙卟啉的每日静脉注射，每次注射后进行全脑放射治疗（共10次分割，30 Gy）。在研究机构，11名患者在首次注射前和后、第10次注射后以及进入研究8周后接受了MR成像检查。
MR成像显示转移瘤中有选择性的药物摄取，正常脑组织无强化。10名患者中，第10次注射后肿瘤摄取高于首次注射后，这表明钆克沙卟啉在转移瘤中蓄积。1个病灶仅在第10次注射后可见，在注射传统钆基对比剂的治疗前MR检查中未见。治疗反应定义为注射前MR研究与最后一次MR研究之间转移瘤大小的缩小；7名患者实现部分缓解，肿瘤消退超过初始大小的50%，4名患者实现轻微反应，肿瘤消退小于50%。
这些初步结果表明钆克沙卟啉具有肿瘤选择性，并且在钆克沙卟啉给药后很长时间，脑转移瘤在MR成像中仍可显示。
