Cerebral angiography provides valuable information for use in the clinical management of patients but can result in relatively high radiation doses to patients and staff due to the extended fluoroscopy time and number of images acquired during an examination. In this study, extremity doses to radiologists and scrub nurses working in a neuroradiological centre were monitored during a 3 month period using thermoluminescent dosemeters (TLDs). Electronic personal dosemeters were also used to monitor doses above the lead apron at chest height to the radiologists, radiographers and the scrub nurses. Patient doses were recorded using a dose-area product meter whilst patient thyroid dose was measured using TLDs. Two types of examination were studied: cerebral angiography and arterial embolization. It was deduced from the results of the study that the radiologist may expect to receive a mean dose above the lead apron at chest height of 11 microSv and 25 microSv per examination when performing cerebral angiography and arterial embolization, respectively. A radiologist mean hand dose of 19.3 microSv per examination was found, whilst the average eye dose for both radiologist and scrub nurse was 13.4 microSv per examination. The patient dosimetry results revealed a mean thyroid dose of 1.7 mSv and a dose-area product of 48.5 Gy cm2 for cerebral angiography. Average dose-area product for arterial embolization was 122.2 Gy cm2 along with a mean patient thyroid dose of 3.3 mSv. More detailed patient dosimetry was also performed using a Rando anthropomorphic phantom loaded with TLDs to measure organ doses and hence estimate effective dose. A typical four vessel angiogram was found to result in a patient effective dose of 3.6 mSv.
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...
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