Quantitative impact of the first COVID-19 lockdown on nuclear medicine in France: the CORALINE study.

PURPOSE: The coronavirus disease 2019 (COVID-19) pandemic reshaped the usual risk: benefit equilibrium that became a trade-off between the infection exposure risk for the patient (and for staff) and the risk associated with delaying or cancelling the nuclear medicine examination. This study aimed at quantifying the impact of the first COVID-19 lockdown in France on nuclear medicine examination volume together with volume of examination cancellation and non-attendance. METHODS: We retrospectively assessed the volume of planned examinations from 1 month before to 1 month after the first lockdown in French high-volume nuclear medicine departments (NMD) sharing the same information management system including both university hospitals, UH (n = 7), and cancer centres, CC (n = 2). RESULTS: The study enrolled 31,628 consecutive patients referred for a nuclear medicine examination performed or not (NMEP or NMEnP). The total volume of NMEP significantly dropped by 43.4% between the 4 weeks before and after the starting of the lockdown. The comparison of the percentage of NMEP and NMEnP between UH and CC is significantly different (p < 0.001). The percentage of NMEP during the study was 67.9% in UH vs 84.7% in CC. Percentages of NMEnP in UH and CC were due respectively to cancellation by the patient (14.9 vs 7.4%), cancellation by the NMD (9.5 vs 3.4%), cancellation by the referring physician (5.1 vs 4.4%) and non-attender patients (2.7 vs 0.2%). CONCLUSION: The study underlines the public health issue caused by COVID-19 above the pandemic itself and should be useful in preparing for potential resource utilisation and staffing requirements.

Selective internal radiation therapy of hepatic tumors: Morphologic and functional imaging for voxel-based computer-aided dosimetry.

INTRODUCTION: Selective Internal Radiation Therapy (SIRT) is used for the treatment of hepatic tumors. The aim of this retrospective study was to compare two dosimetric approaches based on 99mTc-MAA SPECT/CT and 90Y PET/CT, using Simplicit90Y™ versus the supplier suggested method of activity calculation. MATERIAL AND METHODS: A total of 19 patients underwent 21 SIRT after baseline angiography and 99mTc-MAA SPECT/CT, followed by 90Y PET/CT. Overlap between 99mTc-MAA and 90Y-microspheres was quantified with different thresholds isocontours. The perfused volume and tumor absorbed dose were estimated using Simplicit90Y™ based on SPECT/CT and PET/CT, then compared with the supplier suggested method. These data were related to overall survival to evaluate their prognostic impact. RESULTS: The overlap between PET/CT and SPECT/CT was dependent on thresholds, decreasing with an increasing threshold. The overlap between the 99mTc-MAA and 90Y-microspheres biodistributions versus the tumor distribution on morphological imaging was suboptimal, in particular for small tumor volume. The tumor absorbed dose estimated after 90Y PET/CT was not different from tumor absorbed dose estimated after SPECT/CT. The Perfused lobe absorbed dose was significantly lower while the volume of the perfused lobe was significantly higher when estimated by Simplicit90Y™ compared to the supplier suggested conventional approach. A statistical parameter based on overlap between tumor and 90Y-microspheres distribution as well as tumoral dosimetry was significantly related to the overall survival. CONCLUSION: Post-treatment imaging remains paramount to estimate the irradiation dosimetry, due to an imperfect overlap. The perfused volume could be estimated from functional imaging, given its impact on dosimetry. Finally, survival seems related to tumoral overlap and dosimetry.

In Cellulo Evaluation of the Therapeutic Potential of NHC Platinum Compounds in Metastatic Cutaneous Melanoma.

We describe here the evaluation of the cytotoxic efficacy of two platinum (II) complexes bearing an N-heterocyclic carbene (NHC) ligand, a pyridine ligand and bromide or iodide ligands on a panel of human metastatic cutaneous melanoma cell lines representing different genetic subsets including BRAF-inhibitor-resistant cell lines, namely A375, SK-MEL-28, MeWo, HMCB, A375-R, SK-MEL-5-R and 501MEL-R. Cisplatin and dacarbazine were also studied for comparison purposes. Remarkably, the iodine-labelled Pt-NHC complex strongly inhibited proliferation of all tested melanoma cells after 1-h exposure, likely due to its rapid uptake by melanoma cells. The mechanism of this inhibitory activity involves the formation of DNA double-strand breaks and apoptosis. Considering the intrinsic chemoresistance of metastatic melanoma cells of current systemic treatments, these findings are promising and could give research opportunities in the future to improve the prognosis of patients suffering from unresectable metastatic melanoma that are not eligible or that do not respond to the most effective drugs available to date, namely BRAF inhibitors and the anti-PD-1 monoclonal antibody (mAb).