Kline J L, Noto R B, Glantz M
Department of Diagnostic Imaging, Brown University School of Medicine, Providence, RI 02906, USA.
AJNR Am J Neuroradiol. 1996 Oct;17(9):1681-6.
To differentiate radiation necrosis from tumor recurrence using single-photon emission CT (SPECT).
Forty-two thallium-201 SPECT scans were obtained in 33 adult patients. All patients had previously been treated with either conventional external-beam radiation therapy (XRT) (26 patients) or gamma knife radiosurgery (16 patients) and had subsequent contrast-enhanced MR examinations before nuclear medicine imaging. Patients were injected intravenously with 4 mCi of thallous chloride Tl 201 with rapid acquisition of SPECT scans thereafter. Findings on thallium-201 SPECT scans were categorized as either positive or negative on the basis of an abnormal focus of increased activity in the area of the known lesion. Evaluation of the accuracy of the thallium-201 SPECT scan was made by correlation with subsequent histologic or cytologic analysis (28 cases) or, in cases in which biopsy was not performed, by subsequent clinical course or MR findings (14 cases).
For all patients in this series, the sensitivity and specificity of thallium-201 SPECT scans in detecting tumor recurrence were 94% and 63%, respectively. The sensitivity and specificity for patients who had been treated with XRT were 95% and 60%, respectively. The sensitivity and specificity for patients who had been treated with gamma knife therapy were 92% and 67%, respectively. Tumor/scalp (T/S) ratios were calculated for all patients. High T/S ratios (> 2.0) had a positive predictive value for tumor recurrence of 92%. T/S ratios less than 0.5 had a negative predictive value for tumor recurrence of 83%.
Thallium-201 SPECT is a sensitive and accurate test to differentiate tumor recurrence from radiation necrosis in a population of patients with abnormal MR findings. This technique was equally efficacious in patients who had undergone gamma knife radiosurgery and in those who had received XRT.
利用单光子发射计算机断层扫描（SPECT）鉴别放射性坏死与肿瘤复发。
对33例成年患者进行了42次铊-201 SPECT扫描。所有患者此前均接受过传统外照射放疗（XRT）（26例）或伽玛刀放射外科治疗（16例），并在核医学成像前进行了后续的增强磁共振检查。患者静脉注射4毫居里氯化铊Tl 201，随后快速采集SPECT扫描图像。根据已知病变区域活动增加的异常焦点，将铊-201 SPECT扫描结果分为阳性或阴性。通过与后续组织学或细胞学分析（28例）进行相关性评估，或在未进行活检的病例中，通过后续临床病程或磁共振成像结果（14例），对铊-201 SPECT扫描的准确性进行评估。
在本系列所有患者中，铊-201 SPECT扫描检测肿瘤复发的敏感性和特异性分别为94%和63%。接受XRT治疗的患者的敏感性和特异性分别为95%和60%。接受伽玛刀治疗的患者的敏感性和特异性分别为92%和67%。计算了所有患者的肿瘤/头皮（T/S）比值。高T/S比值（>2.0）对肿瘤复发的阳性预测值为92%。T/S比值小于0.5对肿瘤复发的阴性预测值为83%。
铊-201 SPECT是一种敏感且准确的检测方法，可用于鉴别磁共振成像异常的患者群体中的肿瘤复发与放射性坏死。该技术在接受伽玛刀放射外科治疗的患者和接受XRT治疗的患者中同样有效。
