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

两年来，可行FLT-PET检查23例，其中原发性脑肿瘤12例。给予知情同意的患者静脉注射FLT。40分钟后通过20分钟发射扫描和3分钟透射扫描获得大脑图像。在肿瘤上设置感兴趣区域，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，对FLT-PET在评价原发性脑肿瘤恶性分级中的临床作用进行了探讨，现报告如下：1) FLT在脑肿瘤中的积累反映了恶性程度，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，3)良性肿瘤和肉芽肿等血脑屏障破坏的病变显示FLT摄取错误增加（Saga T, et al.）。临床核医学杂志，2006;31:774-80)。为了评价预处理FLT摄取是否能预测脑肿瘤患者的预后，我们对脑肿瘤患者的临床状况进行了随访。然而，没有观察到FLT摄取与无复发生存时间之间的相关性。4例患者在治疗前后接受FLT-PET检查，比较患者的flt摄取变化与临床状况。在两例治疗后FLT摄取减少较低的病例中，两例患者均观察到早期复发。在两例FLT摄取降低率高的患者中，尽管在一例中观察到早期复发，但在其余病例中观察到长期无复发生存。为了利用FLT- pet检测到的肿瘤内FLT分布情况来制定放射治疗计划和确定最佳活检部位，我们尝试将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.