Evaluation of Patients with Head and Neck Cancer by Means of 99mTc-Glucarate

Abstract

Preliminary findings have suggested that 99m Tc-glucarate has tumor-seeking properties. The purpose of this study was to explore the potential of this tracer to evaluate malignant head and neck tumors by means of SPECT/CT software fusion imaging. Methods: Eleven male patients with advanced head and neck carcinoma were included in the study: 9 with locally advanced disease and 2 with clinical suspicion of local relapse. Scanning started 3-6 h after the injection of 1,110 MBq of 99m Tc-glucarate. Planar and SPECT images of the head, neck, and thorax were acquired. Three-dimensional images were also coregistered with CT. Results: We found 99m Tc-glucarate uptake in all suspected lesions. SPECT/CT fusion imaging was helpful in all cases for topographically localizing the tracer foci. Conclusion: 99m Tcglucarate can be considered a potential tracer for the evaluation of patients with head and neck tumors. Al though 18 F-FDG PET has set a new standard for the evaluation of cancer patients (1), the development of new 99m Tc-based SPECT radiopharmaceuticals may become an attractive alternative because of its lower cost and better availability. Glucarate is a 6-carbon dicarboxylic acid, a product of the metabolism of D-glucuronic acid that can be labeled with 99m Tc (2). 99m Tc-glucarate has been described as an agent avid for acute cerebral injury and myocardial infarction (3-7) and as a possible tumor tracer (8-13). The mechanism involved in uptake of 99m Tcglucarate by necrotic cells may be related to binding of the tracer to histones in the cells (14-16). Besides, because of the similarity of 99m Tc-glucarate to fructose, 99m Tcglucarate enters the cell by this metabolically active sugar transport system (8). Furthermore, Ballinger et al. (17) reported that 99m Tc-glucarate showed a 2-to 3-fold enhanced accumulation in hypoxic cells relative to aerobic cells in an in vitro system of cultured ovary fibroblasts.Malignant tumors arising in the head and neck constitute a diagnostically challenging pathology representing about 3% of all newly diagnosed cases of cancer in humans (18). The purpose of this study was to explore the potential of 99m Tc-glucarate to evaluate malignant head and neck tumors by means of SPECT. Additionally, SPECT/CT software fusion was performed to increase diagnostic precision. MATERIALS AND METHODSEleven male patients with advanced head and neck squamous cell carcinoma were included in the study: 9 patients with locally advanced disease enrolled before surgery and 2 patients with clinical suspicion of postsurgical local relapse (Table 1). Imaging was performed at the Clinical Hospital of the University of Uruguay after ethical clearance had been obtained. Before undergoing scintigraphy, all patients had pathologic confirmation of their primary tumors, as well as corresponding conventional imaging examinations. Once written informed consent had been obtained, imaging started 3-6 h after the injection of 1,110 MBq of 99m Tc-glucarate, with a 10-min planar image of the head, neck, and thorax bein...

99m Tc glucarate as a potential radiopharmaceutical agent for assessment of tumor viability: From bench to the bed side

“…Gambini et al . [17] have demonstrated its tumor-seeking properties in a preliminary study. They found avid tracer concentration in head and neck tumors with good tumor to background ratio and concluded that glucarate could be a potential radiotracer for the evaluation of these malignancies.…”