Rubin R H, Fischman A J
Center for Experimental Pharmacology and Therapeutics, Harvard-MIT, Division of Health Sciences and Technology, Massachusetts General Hospital, Boston.
Semin Nucl Med. 1994 Apr;24(2):169-79. doi: 10.1016/s0001-2998(05)80230-2.
The serendipitous discovery that radiolabeled nonspecific immunoglobulin G (IgG) accumulates at a site of focal inflammation has led to the development of a new radiopharmaceutical for inflammation scanning, 111In-IgG. This reagent has been extensively studied in humans with focal infection and has been shown to be both safe and effective. It has been especially useful in the evaluation of patients with possible abdominal and skeletal infection, with the ability to perform serial scans being an important attribute in terms of determining "proof of cure." Preliminary data suggest that this approach may be particularly useful in immuno-compromised patients and may find a role in the quantitative assessment of patients with such noninfectious inflammatory processes as rheumatoid arthritis and inflammatory bowel disease. A new method of labeling IgG with technetium, via the hydrazino nicotinamide derivative, holds promise in terms of substituting this more practical radionuclide for indium. However, caution must be directed against total substitution, because such processes as suspected vascular or skeletal prosthesis infection may require the longer half-life of 111In for satisfactory diagnosis. When one compares the results obtained with radiolabeled IgG against the ideal specifications for a radiopharmaceutical to be used for inflammation imaging, most of the requirements are met. The major weakness of this approach is that even with the technetium-labeled reagent, a minimum of 6 to 12 hours is necessary for a scan to become positive, which is not acceptable in the evaluation of acutely evolving processes. Development of other radiopharmaceuticals for this purpose remains to be accomplished.
放射性标记的非特异性免疫球蛋白G（IgG）在局灶性炎症部位聚集这一意外发现，促成了一种用于炎症扫描的新型放射性药物——铟-111标记的IgG（111In-IgG）的研发。这种试剂已在患有局灶性感染的人体中进行了广泛研究，结果表明它既安全又有效。它在评估可能患有腹部和骨骼感染的患者时特别有用，能够进行系列扫描这一特性在确定“治愈证据”方面是一个重要优势。初步数据表明，这种方法在免疫功能低下的患者中可能特别有用，并且可能在定量评估患有类风湿性关节炎和炎症性肠病等非感染性炎症过程的患者中发挥作用。一种通过肼基烟酰胺衍生物用锝标记IgG的新方法，有望用这种更实用的放射性核素替代铟。然而，必须谨慎避免完全替代，因为对于疑似血管或骨骼假体感染等情况，可能需要铟-111较长的半衰期才能做出满意的诊断。当将放射性标记IgG获得的结果与用于炎症成像的放射性药物的理想规格进行比较时，大部分要求都能满足。这种方法的主要缺点是，即使使用锝标记的试剂，扫描至少需要6至12小时才能呈阳性，这在评估急性进展过程时是不可接受的。为此目的开发其他放射性药物仍有待完成。
