Occupational internal monitoring in nuclear medicine service of Sainte-Anne military hospital: previous considerations and results.

The Nuclear Medicine Department of Sainte-Anne military hospital in Toulon uses 99mTc, 123I and 18F unsealed sources to provide therapeutic and diagnostic care. For a few years, only ambient air and surface monitoring were performed to check the absence of internal contamination risk for workers. To verify this risk assessment hypothesis, confirmatory monitoring programme including in vivo and in vitro measurements was performed by the French defence radiation protection service (SPRA, Clamart). Here, due to the short half-life of targeted radionuclides, the analytical sensitivity was determined with estimations of minimal detectable activities and derived recording levels. It was shown that sensitivity was sufficient to detect an internal contamination leading to an effective dose of 0.1 mSv for few days post intake. At the same time, around 20 whole-body countings were performed. Results were below minimal detectable activity and were confirmed by 24-hours urine analysis. So, actual working conditions do not lead to measurable internal contamination for nuclear medicine staff.

Internal Jugular Vein Tumor Thrombus: A Tricky Question for the Thyroid Surgeon.

Internal jugular vein tumor thrombus is an extremely rare condition in thyroid carcinoma, but it does exist. Correlated with greater aggressiveness with a higher incidence of distant metastases at diagnosis and a higher recurrence rate, this important prognostic element should be systematically investigated by ultrasound operators in all patients presenting with thyroid carcinoma. The patient's follow-up must be careful. This can be a trap that surgeons must look for in their preoperative checklist. We report the case of a 58-year-old woman with an IJV thrombus associated with multiple bone metastases. She underwent successful surgical treatment, and postoperative pathology showed a poorly differentiated follicular carcinoma of the thyroid and a tumor thrombus in the internal jugular vein.

Rationale Efficacy and Safety Evidence of Lenvatinib and Pembrolizumab Association in Anaplastic Thyroid Carcinoma.

Anaplastic thyroid carcinoma (ATC) are highly aggressive malignant tumors with poor overall prognosis despite multimodal therapy. As ATC are extremely rare, no randomized controlled study has been published for metastatic disease. Thyrosine kinase inhibitors, especially lenvatinib and immune checkpoint inhibitors such as pembrolizumab, are emerging drugs for ATC. Few studies have reported the efficacity of pembrolizumab and lenvatinib association, resulting in its frequent off-label use. In this review, we discuss rationale efficacy and safety evidence for the association of lenvatinib and pembrolizumab in ATC. First, we discuss preclinical rationale for pembrolizumab monotherapy, lenvatinib monotherapy and synergistic action of pembrolizumab and lenvatinib in the metastatic setting. We also discuss clinical evidence for immunotherapy and pembrolizumab in ATC through the analysis of studies evaluating immunotherapy, lenvatinib and pembrolizumab lenvatinib association in ATC. In addition, we discuss the safety of this association and potential predictive biomarkers of efficiency.

RECOMMENDATIONS FOR MONITORING AND INTERNAL DOSIMETRY FOR NUCLEAR MEDICINE STAFF EXPOSED TO RADIOPHARMACEUTICALS 223Ra DICHLORIDE.

223Ra is a radiopharmaceutical used as unsealed source in nuclear medicine. In the case of staff inhalation contamination of 223Ra, methods to estimate the committed effective dose should be chosen with care. Three methods are available: whole-body measurement and gamma spectrometry for urine or faeces samples. Considering the analytical performances and uncertainties of these three methods, we propose recommendations for special dose assessment. As a first choice, due to its rapidity and its non-invasiveness, an in vivo analysis (with HPGe detector) is the most appropriate method. However, after 24 h, whole-body counting is not sensitive enough to detect a minimum effective dose of 1 mSv. Sufficient sensitivity can only be reached up to 8 days after contamination by true 24 h faeces samples analyses. Thus, despite its main drawbacks, this method appears to be more appropriate than urine to estimate the committed effective dose in addition to whole-body counting.

A Method to Improve the Semiquantification of 18F-FDG Uptake: Reliability of the Estimated Lean Body Mass Using the Conventional, Low-Dose CT from PET/CT.

UNLABELLED: The standardized uptake lean body mass (SUL), calculated using lean body mass (LBM), is essential for the semiquantification of (18)F-FDG uptake using PET coupled with CT to avoid a bias linked to the adipose mass. It allows the evaluation of a response to therapy according PERCIST 1.0. The aim of this study was to evaluate the reliability of a method for the estimation of the LBM using the data of the low-dose CT from PET/CT acquired over standard acquisition fields (from skull base to ischia, from vertex to ischia, from skull base to mid thigh, from vertex to mid thigh). METHODS: We wrote an automated program that determined the LBM from a CT with limited fields of acquisition and applied this method in a large (184 patients) and heterogeneous population. Its results were compared with the measurement of LBM from whole-body CT (reference standard) and the results of 5 predictive equations described in the literature. RESULTS: The results of LBM measurement evaluated with this technique were much closer to the reference standard than those obtained by the mathematic formulas. The intraclass correlations (ICC) of this technique compared with the reference standard were excellent (the best ICC being obtained for the largest acquisition field, from vertex to mid thigh: ICC, 0.994; 95% confidence interval [95% CI], 0.992-0.995; P < 0.0001), much better than the ICC obtained with the mathematic formulas (the best ICC for a mathematic formula was 0.841; 95% CI, 0.714-0.903; P < 0.0001). Moreover, the analysis with the Bland-Altman plot showed that the differences in mean lean masses between the studied technique and the reference standard was the smallest for the proposed technique (for the largest acquisition field, mean difference 0.2 kg with the narrowest 95% CI [-1.8 to 2.2 kg]). CONCLUSION: This technique could be easily implemented on computers used in practice to allow a more reliable assessment of the SUL in clinical practice notably for the therapeutic evaluations after PERCIST 1.0.

18F-FDG PET/CT imaging of Sister Mary Joseph's nodule.

An 82-year-old woman was followed up for an uterine cervical adenocarcinoma treated by surgery. A whole-body fluorodeoxyglucose positron emission tomography study revealed a pathologic fluorodeoxyglucose uptake located in the umbilicus associated to peritoneal carcinomatosis. Biopsy of the umbilical nodule demonstrated an umbilical metastasis from the uterine adenocarcinoma, the so-called "Sister Mary Joseph's nodule."