We aimed to assess the additional value of SPECT/CT over planar lymphoscintigraphy (PI) in sentinel node (SN) detection in malignancies with different lymphatic drainage such as breast cancer, melanoma, and pelvic tumors. Methods: From 2010 to 2013, 1,508 patients were recruited in a multicenter study: 1,182 breast cancer, 262 melanoma, and 64 pelvic malignancies (prostate, cervix, penis, vulva). PI was followed by SPECT/CT 1-3 h after injection of 99m Tccolloid particles. Surgery was performed the same or next day. Results: Significantly more SNs were detected by SPECT/CT for breast cancer (2,165 vs. 1,892), melanoma (602 vs. 532), and pelvic cancer (195 vs. 138), all P , 0.001. The drainage basin mismatch between PI and SPECT/CT was 16.5% for breast cancer, 11.1% for melanoma, and 51.6% for pelvic cancers. Surgical adjustment was 17% for breast cancer, 37% for melanoma, and 65.6% for pelvic cancer. Conclusion: SPECT/CT detected more SNs and changed the drainage territory, leading to surgical adjustments in a considerable number of patients in all malignancies studied but especially in the pelvic cancer group because of this group's deep lymphatic drainage. We recommend SPECT/CT in all breast cancer patients with no SN visualized on PI, all patients with melanoma of the head and neck or trunk, all patients with pelvic malignancies, and those breast cancer and melanoma patients with unexpected drainage on PI. The status of regional lymph nodes is a major prognostic factor in many malignant tumors. Sentinel lymph node (SN) biopsy in patients with clinically node-negative tumors is a validated technique for accurate staging of nodal disease in breast cancer (1,2) and melanoma (3,4) and is being used with promising results in other solid tumors including pelvic malignancies (5,6). The use of SN mapping in an increasing list of tumors shows a variety of lymphatic drainage basins containing the SN (7). SNs are the lymph nodes draining the primary tumor and therefore the most likely to contain tumor cells spreading to the drainage basin (8). Assuming an orderly progression of lymph flow, the tumor status of the SN predicts the status of the regional draining basin (1). Selective SN biopsy enables the detection of metastatic and occult micrometastatic nodal involvement by thorough histopathologic examination in the intraoperative setting, sparing patients a systematic regional lymphadenectomy when the node is negative.Planar lymphoscintigraphy (PI) after local injection of radiocolloid is well suited for the mapping of regional lymph nodes, but occasionally no SNs are visualized, for instance, in obese patients or when SNs are located too close to the injection site. In addition, the anatomic information provided by planar scintigraphy is limited and the exact SN location is difficult to define in deeply located nodes (9,10). Unexpected basin drainage sites and unpredictable pathways also hinder interpretation of planar images. Because of its superior contrast, resolution, and display of exact anatomic landmarks, SPECT...

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BackgroundLow iodine diet (LID) is recommended in patients with differentiated thyroid cancer before radioiodine administration. Patients with increased thyroglobulin (Tg) level, but negative 131I whole body scan present diagnostic and therapeutic dilemma. This study was designed to evaluate the benefit of a two-week LID in patients with elevated serum Tg levels and negative 131I whole body scans.Patients and methods.For the impact assessment of two-week LID on radioiodine tissue avidity, radioiodine scans before and after LID were compared. Sixteen patients with serum Tg > 2 μg/L, negative Tg-antibodies, and negative radioiodine scans underwent two-week LID before the 131I administration. Fourteen patients underwent diagnostic scanning and two patients received radioiodine therapy. Iodine concentration in the morning urine specimens were measured in each patient, a day before and 15th day after starting LID.ResultsFollowing self-managed LID, patients were able to significantly reduce their iodine body content by 50% (range 28–65%, p<0,001). 13 patients (82%) accomplished mild iodine deficiency (50-99 μg/L) and one patient (6%) achieved targeted moderate iodine deficient state (<50 μg/L). All diagnostic post-LID scans were negative. Both post-therapy 131I scans showed radioiodine accumulation outside of normal 131I distribution (neck region and diffuse hepatic uptake). This study demonstrated that two-week LID is effective way to decrease total body iodine content, although without a visible effect on post-LID diagnostic 131I scans.ConclusionsA more stringent dietary protocol and longer iodine restriction period are probably needed to achieve targeted moderate iodine deficiency in patients preparing for 131I administration. This might result in higher radioiodine avidity of thyroid remnant/metastases.

F-DOPA PET/CT is a clinically useful modality in MTC whenever the calcitonin level is increased. There is a clear trend toward more positive scans with the higher calcitonin values, but patients with moderately elevated calcitonin values should also be taken into consideration for molecular imaging with F-DOPA PET/CT as the tumor burden in these patients is probably low, enabling further therapy to be individualized and consequently more efficient.

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