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131I-labeled metaiodobenzylguanidine (MIBG) is an established treatment modality for neuroendocrine tumors. Because of low tumor doses, it has a predominantly palliative character. Our approach was to investigate whether intraarterial application of 131I-MIBG has the potential to enhance tumor uptake.Seventeen patients with primary or metastasized neuroendocrine tumors received intraarterial treatment with 131I-MIBG, and 12 of these patients also had intravenous treatment. Every patient underwent intravenous 131I-MIBG whole-body scanning before therapy. For quantification, a tumor-to-whole-body ratio was calculated from the diagnostic and 24-h posttreatment scans.Compared with the intravenous application, intraarterial 131I-MIBG treatment provided an up to 4-fold higher tumor uptake. Mean uptake was enhanced by 69%, but this varied widely between patients. We did not observe any immediate complications from catheterization. Carcinoid-related side effects were noted in 7 of 17 patients and were not different from those seen with intravenous application.Intraarterial treatment with 131I-MIBG is a safe alternative to intravenous application and provides a 69% higher mean tumor uptake. We propose to attempt intraarterial MIBG treatment in every patient to assess its potential benefit.

(18)F-FDG PET is an important diagnostic tool for detecting myocardial viability in patients with coronary artery disease. In combination with perfusion scanning, (18)F-FDG PET allows differentiation between reversibly and irreversibly damaged myocardium and selection of patients likely to benefit from revascularization. Viability PET is usually performed in two-dimensional (2D) mode. Taking into account the rising number of three-dimensional (3D)-only scanners, a validation of 3D acquisition is required.Twenty-one patients with coronary artery disease referred for (18)F-FDG PET underwent an imaging protocol of nongated 2D (2D-NG) and gated 2D (2D-G) acquisitions for 15 min each, followed by 3D gated acquisitions for 10 min (3D-10) and 5 min (3D-5), using an ECAT Exact HR+ scanner. Results were analyzed using a 20-segment polar map in terms of activity concentration (Bq/mL), viability (50% uptake threshold), regional activity distribution, visual assessment of viability based on a 3-point rating scale, and left ventricular ejection fraction.Activity concentration measured in each segment with 2D-G, 3D-10, and 3D-5 showed a good linear correlation with 2D-NG. Quantitative viability assessment with 3D-5 gave a sensitivity of 84% and a specificity of 98%, compared with 2D-NG. No differences in regional activity distribution and visual viability assessment were found between the various protocols. Left ventricular ejection fractions obtained with 3D-10 and 3D-5 showed a good linear correlation with those measured with 2D-G.An ECG-gated 3D imaging protocol gave results comparable to those of 2D acquisition with regard to absolute and regional myocardial activity distribution, left ventricular function, and visual viability assessment. Sensitivity for viability assessment with a 50% uptake threshold was significantly less with 3D, but specificity was maintained. This protocol delivers a clinical performance nearly equivalent to that of 2D acquisition.