67Ga-SPECT/CT with a hybrid system in the clinical management of lymphoma

Abstract. Purpose: The purpose of this study was to investigate the added value of co-registered fusion imaging using a hybrid system in patients with lymphoma. Methods: Twenty-four lymphoma patients underwent 67Ga- SPECT/CT using a hybrid tomograph consisting of a dual-head, variable-angle gamma camera and a low-dose X-ray tube. Results were compared with those of SPECT alone. Results: Forty-five lesions were identified by SPECT alone, while 49 were detected by SPECT/CT. Forty out of the 45 lesions observed on SPECT were confirmed as lymphoma,but five were due to other causes (thoracic aorta blood pool activity, sialoadenitis in the submandibular gland, bowel activity, rib fracture and bone marrow activation due to radiotherapy). SPECT/CT identified nine more neoplastic lesions compared with SPECT alone: four areas of radiopharmaceutical accumulation were observed in para-aortic lymph nodes, three in the spleen, one in the liver and one in para-iliac lymph nodes. In five cases, SPECT/CT provided additional anatomical information over SPECT alone. In four patients, four large areas of 67Ga uptake (one mediastinal, two supraclavicular and one para-aortic) were better characterised; in one subject uptake was localised in the seventh thoracic vertebra only by SPECT/CT. Hybrid imaging provided additional data in 13 patients (54.2%), thus inducing oncologists to reconsider the therapeutic approach in eight subjects (33.2%): unnecessary treatment was avoided in four (16.6%) while therapy was altered in another four (16.6%). Conclusion: SPECT/CT hybrid system is able to provide information not obtained by SPECT alone. It allows the anatomical localisation of lymphoma and physiological radiopharmaceutical uptake, facilitates the diagnosis of tumours located in the abdomen (subdiaphragmatic lesions) and provides information that may cause a change in therapeutic strategy.