ESTABLISHMENT AND CLINICAL APPLICATION OF PROLIFERATION ACTIVITY AND MALIGNANT GRADE EVALUATION WITH POSITRON EMISSION TOMOGRAPHY.

在过去的两年中，FLT-PET检查可用于23例，其中包括12例原发性脑肿瘤。患者在知情同意后，静脉注射FLT。40分钟后，通过20分钟发射扫描和3分钟透射扫描获得脑图像。在肿瘤上设置感兴趣区，测量摄取半定量值（SUV），并与组织学诊断进行比较，结合既往病例，探讨FLT-PET在评价原发性脑肿瘤恶性程度中的临床作用，现报道如下：1）FLT在脑肿瘤中的积聚反映了恶性程度，2）FLT在脑肿瘤中的积累与Ki-67的组织学表达相关，Ki-67是细胞增殖的标志物，和3）具有血脑屏障破坏的病变如良性肿瘤和肉芽肿显示FLT摄取的假性增加（佐贺T，et al. Clin Nucl Med，2006;31：774-80）。在4例接受FLT-PET检查的患者中，将治疗前后FLT-PET摄取的变化与患者的临床状态进行比较。在2例治疗后FLT摄取减少较低的病例中，观察到2例患者均出现早期复发。在2例FLT摄取减少率高的患者中，虽然在1例中观察到早期复发，但在另1例中观察到长期无复发生存。为了利用FLT-PET检测到的FLT的肿瘤内分布来制定放射治疗计划和确定最佳活检部位，尝试将FLT-PET图像与相应的CT或MRI图像融合。

For the past two years, FLT-PET examination could be performed for 23 cases, including 12 cases of primary brain tumors. Patients, who gave informed consent, were given intravenous injection of FLT. Image of the brain was obtained 40 minutes later by 20-min emission scan and 3-min transmission scan. Region of interest was set on the tumor and semi-quantitative value of uptake (SUV) was measured and compared with histological diagnosis.Including prior cases, the clinical role of FLT-PET in the evaluation of malignant grade of primary brain tumors was investigated and reported in the paper as follows; 1) accumulation of FLT in the brain tumor reflected the malignant grade, 2) accumulation of FLT in the brain tumor correlated with the histological expression of Ki-67 which is a marker of cell proliferation, and 3) lesions with blood-brain barrier disruptions such as benign tumors and granuloma showed falsely increased FLT uptakes (Saga T, et al. Clin Nucl Med, 2006;31:774-80).In order to evaluate whether pretreatment FLT uptake can predict the prognosis of brain tumor patients, clinical status of brain tumor patients were followed. However, no correlation was observed between FLT uptake and duration of recurrence-free survival.In four patients who received FLT-PET examinations before and after treatment, change of FLT-uptake was compared with the clinical status of the patient. In two cases in which reduction of FLT uptake after treatment was low, early recurrences were observed for both patients. In two patients in which reduction rate of FLT uptake was high, although early recurrence was observed in one case, long-term recurrence-free survival was observed in the remaining case.In order to utilize the observed intratumoral distribution of FLT detected by FLT-PET to radiation treatment planning and determination of optimal biopsy site, image fusion of FLT-PET images was tried with corresponding CT or MRI images.