The imaging of neuroendocrine tumors using single photon emission computed tomography/computed tomography.

There have been several advances in technology over the past decade with the advent of hybrid imaging having a large impact on nuclear medicine, first with PET/CT and then more recently with SPECT/CT. Initial SPECT/CT systems used low dose but very low quality CT and except for attenuation correction offered no great advantage over reviewing SPECT and CT images side by side. More recently hybrid machines have become available and a series of studies have shown improved accuracy compared to SPECT alone with resulting changes in patient management. This has been true not only with somatostatin analogue imaging but also for demonstrating amine uptake using MIBG. Whilst PET/CT may be seen as the ideal, this may be less accessible due to the high cost and limited availability. In this case hybrid SPECT/CT offers hope for providing high quality and accurate imaging of neuroendocrine tumors.

Sentinel node studies in truncal melanoma: does an increased number of draining basins correlate with an increased risk of lymph metastasis?

OBJECTIVES: To assess whether an association exists between drainage to multiple basins and lymphatic metastasis in patients with truncal melanoma. METHODS: We retrospectively reviewed 227 patients with primary malignant melanoma between January 2006 and December 2009. All patients received an intradermal injection of (99m)Tc-nanocolloid and lymphoscintigraphy followed by sentinel node biopsy. Pre-staging histology with Breslow thickness from excision biopsy was also obtained. RESULTS: 82/227 (36%) patients with primary truncal melanoma were identified. Nodal histology was positive for metastatic disease in 27/82 (32.9%) patients. Of these 27, 15 had 1 basin of drainage, 7 had 2 basins of drainage and 5 had 3 basins of drainage. Of the 55 node-negative patients, 35 had 1 basin, 18 had 2 basins and 2 had 3 basins of drainage. We found no significant correlation with sentinel node positivity and those that had ≥2 drainage basins. Breslow thickness was available in 65/82(79.2%) patients. Sentinel node biopsy was positive in 6/28 patients who had <1.5 mm thickness, 8/14 who had a 1.5-3.9 mm thickness and 9/23 who had ≥4 mm thickness. There was a significant correlation between Breslow thickness of ≥4 mm and nodal positivity (P = 0.03). CONCLUSION: This study demonstrates no association between multiple drainage basins and sentinel node histology. Sentinel lymph node status did correlate with Breslow thickness.