Willkomm P, Bender H, Bangard M, Decker P, Grünwald F, Biersack H J
Department of Nuclear Medicine, University of Bonn, Germany.
J Nucl Med. 2000 Oct;41(10):1657-63.
The aim of this study was to compare FDG PET with a new monoclonal antibody-based imaging agent that comprises an anti-carcinoembryonic antigen (CEA) monoclonal antibody Fab' fragment directly labeled with 99mTc.
Twenty-eight patients who were previously treated for colorectal carcinoma and in whom recurrence was suspected were examined with FDG PET and immunoscintigraphy. The most common indications were an elevation of serum CEA (13 patients), suggestive lesions documented by CT (9 patients), sonography (4 patients), and severe constipation (2 patients). Planar imaging and SPECT were performed 4-6 h after intravenous injection of the new imaging agent. Whole-body PET was performed 45-60 min after intravenous injection of FDG. The findings were confirmed by conventional diagnostic modalities, surgery, and histology.
Histology confirmed local tumor recurrence in 9 of 28 patients. Clinical follow-up or CT confirmed the presence of liver metastases in 9 patients and lymph node involvement, lung metastases, and bone metastases in 2 patients each. The new agent correctly detected 8 of 9 local recurrences, whereas FDG PET was able to detect all 9 cases and in 1 case was false-positive. Liver metastases were confirmed in 9 patients by FDG PET but in only 1 patient by the new agent. Two cases with lymph node metastases and 2 cases with lung metastases were correctly identified by FDG PET, but none were detected by the new agent. Finally, bone metastases were identified in 1 patient by FDG PET but not with the new agent, whereas bone marrow infiltration (n = 1) was diagnosed by both imaging modalities.
These results indicate that FDG PET and 99mTc-labeled anti-CEA Fab' are suitable for the diagnosis of local recurrence of colorectal carcinoma but that FDG PET is clearly superior in the detection of distant metastases (liver, bone, and lung) and lymph node involvement.
本研究的目的是比较氟代脱氧葡萄糖正电子发射断层显像（FDG PET）与一种基于单克隆抗体的新型显像剂，该显像剂包含直接用99m锝标记的抗癌胚抗原（CEA）单克隆抗体Fab′片段。
对28例既往接受过结直肠癌治疗且怀疑复发的患者进行了FDG PET和免疫闪烁显像检查。最常见的指征是血清CEA升高（13例）、CT发现可疑病变（9例）、超声检查发现可疑病变（4例）以及严重便秘（2例）。静脉注射新型显像剂4 - 6小时后进行平面显像和单光子发射计算机断层显像（SPECT）。静脉注射FDG 45 - 60分钟后进行全身PET检查。通过传统诊断方法、手术及组织学检查对结果进行确认。
组织学检查证实28例患者中有9例存在局部肿瘤复发。临床随访或CT检查证实9例患者有肝转移，2例患者有淋巴结受累、肺转移和骨转移。新型显像剂正确检测出9例局部复发中的8例，而FDG PET能够检测出所有9例，且有1例假阳性。FDG PET证实9例患者有肝转移，而新型显像剂仅证实1例。FDG PET正确识别出2例淋巴结转移和2例肺转移患者，但新型显像剂均未检测到。最后，FDG PET发现1例骨转移患者，新型显像剂未发现，而两种显像方法均诊断出1例骨髓浸润。
这些结果表明，FDG PET和99m锝标记的抗CEA Fab′适用于结直肠癌局部复发的诊断，但在检测远处转移（肝、骨和肺）及淋巴结受累方面，FDG PET明显更具优势。
