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

We compared In-111-octreotide and Ga-67 scintigraphy for staging malignant lymphoma. In 11 patients, planar imaging was performed 4 and 24 h after the injection of In-111-octreotide and 48 and 72 h after the administration of Ga-67. 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 Ga-67 and 18 (69%) by In-111 scintigraphy. All 14 supra-diaphragmatic lesions were detected by Ga-67 and 13 by In-111. In the intraabdominal areas, only two of eight known localizations were identified by In-111 scintigraphy, whereas Ga-67 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 Ga-67 and five by In-111-octreotide imaging. For the intermediate and high-grade lymphomas, Ga-67 showed a similar detection rate (16/18 lesions), whereas In-111 was only able to detect 13 lesions. We conclude that In-111-octreotide provides less information than Ga-67 scintigraphy and conventional staging modalities. The best results for both tracers were observed above the diaphragm. The Ga-67 results were more reliable for the detection of infradiaphragmatic lesions.