Ohnishi H, Koizumi K, Uchiyama G, Yamaguchi M, Okada J, Ogata H, Toyama K, Monzawa S, Oba H, Araki T
Department of Radiology, Narita Red Cross Hospital.
Nihon Igaku Hoshasen Gakkai Zasshi. 1994 Dec 25;54(14):1388-98.
Thallium-201 (201Tl) SPECT was performed 48 times in 26 patients to clarify its usefulness in the evaluation of malignancy and viability of brain tumors. The early counts ratio (ER) and delayed counts ratio (DR) of a lesion compared with normal brain were obtained 10-15 minutes and 3 hours, respectively, after intravenous administration of 185 MBq of 201Tl chloride. Untreated high grade malignant tumors and recurrent tumors did not always show high ER and DR, and they were widely distributed. High grade malignant tumors that showed low ER and DR were not well enhanced on CT or MRI. In low grade malignant tumors, such as pituitary adenoma which was well enhanced on CT, ER and DR were as high as in high grade malignant tumor. Whether a tumor recurred within three months after radiotherapy or not was retrospectively predicted at accuracy rates of 93.8% and 87.5% with cut-off points of 4.0 for ER and 3.5 for DR. Cerebral radiation necrosis showed ring-like increased uptake of 201Tl in proportion to the progress of necrosis and intensity of enhancement on MRI. In conclusion 201Tl SPECT is considered to be less useful for lesions that are well enhanced on CT, because they show high uptake of 201Tl regardless of their malignancy and viability. On the other hand, in tumors that are not well enhanced on CT. 201Tl shows good accumulation in viable and high grade malignant lesions. 201Tl SPECT should be performed in such cases.
对26例患者进行了48次铊-201（201Tl）单光子发射计算机断层扫描（SPECT），以明确其在评估脑肿瘤的恶性程度和存活情况方面的作用。静脉注射185兆贝可氯化201Tl后，分别于10 - 15分钟和3小时获得病变与正常脑相比的早期计数比值（ER）和延迟计数比值（DR）。未经治疗的高级别恶性肿瘤和复发性肿瘤并不总是表现出高ER和DR，且它们的分布范围较广。ER和DR较低的高级别恶性肿瘤在CT或磁共振成像（MRI）上强化不佳。在低级别恶性肿瘤中，如在CT上强化良好的垂体腺瘤，ER和DR与高级别恶性肿瘤一样高。以ER为4.0、DR为3.5为截断点，回顾性预测放疗后三个月内肿瘤是否复发，准确率分别为93.8%和87.5%。脑放射性坏死表现为201Tl摄取呈环状增加，与坏死进展和MRI上的强化强度成比例。总之，对于在CT上强化良好的病变，201Tl SPECT被认为作用较小，因为无论其恶性程度和存活情况如何，它们都表现出高201Tl摄取。另一方面，在CT上强化不佳的肿瘤中，201Tl在存活的高级别恶性病变中积聚良好。在这种情况下应进行201Tl SPECT检查。
