Alazraki N
Crit Rev Diagn Imaging. 1980;13(3):249-67.
The current enthusiasm for gallium (Ga) citrate as a tumor imaging agent reflects the need of clinical medicine for a good tumor imaging agent. To date, Ga-67 is probably the best tumor imaging agent available for clinical use. Initially, Ga-67 was investigated for its bone scanning potential. In this process, in 1969, Edwards and Hayes accidentally found that Ga-67 concentrated in soft tissue tumors, mainly lymphomas, in patients. Later studies reported the clinical experience with Ga-67 concentration in many different tumor types. Great variation was noted in the ability of different tumors to concentrate Ga-67. However, Ga-67 was most consistently and reliably taken up in lung tumors, with sensitivities of Ga imaging positivity in lung cancer ranging from 85 to 95%. Within the lung cancer group, squamous cell carcinoma consistently has been much more reliably positive than adenocarcinoma or alveolar cell carcinoma. Subsequent studies on Ga-67 led to the recognition of its preferential concentration in inflammatory lesions and abscess. These reports resulted in the clinical application of Ga-67 imaging as a diagnostic tool in the evaluation of patients with suspected abscesses. Mechanisms of Ga localization in tumor and inflammatory lesions are not currently well understood. Electron microscopic studies have revealed some information regarding the intracellular localization of Ga, but the mechanism by which it is taken up by the cell remains unproven, although several explanations have been suggested. The biodistribution of Ga-67 is responsible for the great difficulty experienced in interpreting Ga images of the abdomen, mainly because of the normal of the normal excretion in the bowel. Clinical studies have shown that the Ga scan can be used in the workup of patients with lung cancer as a sensitive tool in excluding the presence of mediastinal metastases. In some institutions, a negative Ga mediastinal scan in the presence of positive Ga uptake in the presumed primary tumor in patients with lung cancers has been used in lieu of a staging mediastinoscopy. Data regarding the thresholds of various factors which determine visibility of a lung tumor by Ga-67 imaging have been described in some detail. The factors include lesion size, depth in tissue, gallium concentration in tumor relative to background, type of film and instrumentation used, and count rates obtained. The data suggest the need for very high radiopharmaceutical concentrations in small tumors relative to background activity for identification of the tumor on an image.
目前对枸橼酸镓（Ga）作为肿瘤显像剂的热情反映了临床医学对优质肿瘤显像剂的需求。迄今为止，Ga - 67可能是临床可用的最佳肿瘤显像剂。最初，人们研究Ga - 67的骨扫描潜力。在此过程中，1969年，爱德华兹和海斯意外发现Ga - 67在患者的软组织肿瘤（主要是淋巴瘤）中浓聚。后来的研究报告了Ga - 67在许多不同肿瘤类型中的临床浓聚经验。不同肿瘤浓聚Ga - 67的能力差异很大。然而，Ga - 67在肺肿瘤中浓聚最为一致且可靠，肺癌中Ga显像阳性的敏感性为85%至95%。在肺癌组中，鳞状细胞癌一直比腺癌或肺泡细胞癌更可靠地呈阳性。随后对Ga - 67的研究导致人们认识到它在炎性病变和脓肿中优先浓聚。这些报告促使Ga - 67显像在评估疑似脓肿患者时作为一种诊断工具得到临床应用。目前对Ga在肿瘤和炎性病变中的定位机制了解尚不清楚。电子显微镜研究揭示了一些关于Ga细胞内定位的信息，但尽管有人提出了几种解释，其被细胞摄取的机制仍未得到证实。Ga - 67的生物分布导致解读腹部Ga图像时遇到很大困难，主要是因为肠道正常排泄。临床研究表明，Ga扫描可作为一种敏感工具用于肺癌患者的检查，以排除纵隔转移的存在。在一些机构中，肺癌患者假定的原发肿瘤Ga摄取阳性而纵隔Ga扫描阴性时，已被用于替代分期纵隔镜检查。关于通过Ga - 67显像确定肺肿瘤可见性的各种因素阈值的数据已被详细描述。这些因素包括病变大小、组织深度、肿瘤中镓浓度相对于背景的情况、所用胶片和仪器的类型以及获得的计数率。数据表明，对于小肿瘤，相对于背景活性，需要非常高的放射性药物浓度才能在图像上识别肿瘤。
