A comparison of 111In-octreotide and 67Ga scintigraphy in malignant lymphoma

We compared 111In-octreotide and 67Ga scintigraphy for staging malignant lymphoma. In 11 patients, planar imaging was performed 4 and 24 h after the injection of 111In-octreotide and 48 and 72 h after the administration of 67Ga. Radiological and clinical data were used as the 'gold standard', resulting in the identification of 26 lesions. Twenty-three (88%) of these lesions were detected by 67Ga and 18 (69%) by 111In scintigraphy. All 14 supra-diaphragmatic lesions were detected by 67Ga and 13 by 111In. In the intra-abdominal areas, only two of eight known localizations were identified by 111In scintigraphy, whereas 67Ga uptake was seen in six of them. In the inguinal regions, both tracers detected three of four lesions. Of the eight lesions of low-grade malignancy, seven were visualized by 67Ga and five by 111In-octreotide imaging. For the intermediate and high-grade lymphomas, 67Ga showed a similar detection rate (16/18 lesions), whereas 111In was only able to detect 13 lesions. We conclude that 111In-octreotide provides less information than 67Ga scintigraphy and conventional staging modalities. The best results for both tracers were observed above the diaphragm. The 67Ga results were more reliable for the detection of infra-diaphragmatic lesions.