Dealing with dry waste disposal issues associated with 177mLu impurities: a long-term challenge for nuclear medicine departments.

PURPOSE: A strategy for management of radioactive waste associated with 177Lu-dotatate (Lutathera®) treatments was established in our institution, based on predicted storage times of 3-5 years extrapolated from the results of a 2-year measurement study. The aim of this work was to validate this strategy by identifying contaminants and confirming disposal based on the clearance level twice-the-background was within expected time frames. METHODS: We conducted a prospective series of measurements of radioactive waste associated with the first 65 treatments administered. Sequential measurements of the first 45 vials used were performed on a dose calibrator to identify contaminants. Exposure rates in contact were monitored with a dose ratemeter on a 6-monthly basis for all waste stored: 46 empty vials, 19 vials partially used and 61 biohazard containers. RESULTS: Initial median activity of the first vials used was 118 MBq [4-4188 MBq]. For each vial, the decay curve of activity obtained was adjusted to a bi-exponential model. The major component, representing 99.7% of the activity, has a median half-life of 6.6 days [5.7-7.2 days] corresponding to 177Lu. The second, representing only 0.3% of the activity and having a median half-life of 152 days [104-205 days] corresponding to 177mLu, determines necessary storage times. Partially used vials can be disposed of after 5 years, other waste after 3 years. Compliance with the regulatory clearance level is achieved within expected time frames. CONCLUSION: Although only present as traces, 177mLu associated with the direct production route results in major radioactive waste disposal issues for hospitals. Availability of radiopharmaceuticals without impurities appears to be crucial for an expanding use of targeted radionuclide therapy.

Smartphone-based application and nurses' interventions for symptoms monitoring in patients treated with oral anticancer agents: A 1-year follow-up in a tertiary cancer center.

AIM: The increasing use of oral anticancer agents over the past years has necessitated changes in monitoring toxicities to ensure patients' adherence and tolerance at home. The aim of this study was to describe nurses' interventions and medical changes after alerts triggered by a web-based platform designed to support the management of oral anticancer agents-related toxicities. METHODS: This retrospective study included patients undergoing oral anticancer agents in a cancer center from September 2018 to September 2019 (excluding hormonal therapy). In this cancer center, the standard of care included symptoms' collections for 1 month thanks to a web platform based on patient-reported outcomes. Patients had to fill a weekly questionnaire (Q1 to Q4). The web-based platform triggered orange alerts when patients reported moderate symptoms and red alerts when severe toxicities were declared. The rate of orange and red alerts, the rate of patients with medical changes consecutively to an orange or a red alert, and the different types of nurses' interventions and medical changes were assessed. RESULTS: A total of 524 patients were extracted but the final number of 436 patients were included in this study and 1488 questionnaires were filled in. More than 90% of patients declared that they took their medication as prescribed. Up to 60% of patients recorded all grade symptoms, including 8% of patients who recorded Grades 3-4 symptoms during the month, mostly anorexia, fatigue, and diarrhea. The web platform system triggered 700 orange and 212 red alerts: 305/700 (44%) of orange alerts resulted in nurses' interventions, most frequently phone counseling (78%), and 65/212 (31%) of red alerts resulted in medical changes, most frequent treatment interruptions (48%). CONCLUSION: Implementing an e-health (electronic-health) system can be helpful for monitoring symptoms in patients under oral anticancer agents, enhancing that this organization should be a standard of care in every cancer centers.

[Factors influencing platelets labelling with indium-111 oxine]. / Facteurs influençant le marquage des plaquettes à l'oxinate d'indium-111.

Autologous indium-111 labelled platelets can be used for kinetic studies in patients with autoimmune thrombocytopenic purpura [AITP]. The objective of this study was to evaluate some biological and clinical factors influencing the labeling efficiency. METHODS: We studied incubation media (Plasma media [MP] or dry media [MS]), platelet concentration [NP], mean platelet volume [VPM], hemoglobin level and pathology associated with AITP. RESULTS: This was a retrospective study of 93 platelets labelling (43 in MS and 50 in MP), 38 primary AITP (41%) and 55 secondary AITP (59%). The labeling efficiency was 72% (78% in MS versus 53% in MP; p < 0.0001). The labeling efficiency was correlated with VPM (p = 0.0004), NP (p = 0.03), hemoglobin level (p = 0.037) and type of AITP (p = 0.0036). The incubation medium, hemoglobin level and type of the AITP have an independent predictive value on the labeling efficiency. CONCLUSION: These data confirm the influence of the incubation medium on the labeling efficiency and identify two other predictive criteria, hemoglobin level and type of AITP.

Impact of contouring methods on pre-treatment and post-treatment dosimetry for the prediction of tumor control and survival in HCC patients treated with selective internal radiation therapy.

INTRODUCTION: The aim of this study was to evaluate the impact of the contouring methods on dose metrics and their predictive value on tumor control and survival, in both situations of pre-treatment and post-treatment dosimetry, for patients with advanced HCC treated with SIRT. METHODS: Forty-eight patients who underwent SIRT between 2012 and 2020 were retrospectively included in this study. Target volumes were delineated using two methods: MRI-based contours manually drawn by a radiologist and then registered on SPECT/CT and PET/CT via deformable registration (Pre-CMRI and Post-CMRI), 99mTc-MAA-SPECT and 90Y-microspheres-PET 10% threshold contouring (Pre-CSPECT and Post-CPET). The mean absorbed dose (Dm) and the minimal absorbed dose delivered to 70% of the tumor volume (D70) were evaluated with both contouring methods; the tumor-to-normal liver uptake ratio (TNR) was evaluated with MRI-based contours only. Tumor response was assessed using the mRECIST criteria on the follow-up MRIs. RESULTS: No significant differences were found for Dm and TNR between pre- and post-treatment. TNR evaluated with radiologic contours (Pre-CMRI and Post-CMRI) were predictive of tumor control at 6 months on pre- and post-treatment dosimetry (OR 5.9 and 7.1, respectively; p = 0.02 and 0.01). All dose metrics determined with both methods were predictive of overall survival (OS) on pre-treatment dosimetry, but only Dm with MRI-based contours was predictive of OS on post-treatment images with a median of 23 months for patients with a supramedian Dm versus 14 months for the others (p = 0.04). CONCLUSION: In advanced HCC treated with SIRT, Dm and TNR determined with radiologic contours were predictive of tumor control and OS. This study shows that a rigorous clinical workflow (radiologic contours + registration on scintigraphic images) is feasible and should be prospectively considered for improving therapeutic strategy.

[Effect of obesity, age and gender on glomerular filtration rate measured in normal adults]. / Influence de l'obésité, de l'âge et du sexe sur le débit de filtration glomérulaire mesuré chez l'adulte normal.

The aims of this study were to assess the dependence of glomerular filtration rate (GFR) on age and gender and to produce reference data for the interpretation of 51Cr-EDTA GFR measurements in adults. METHODS: This was a retrospective study of 120 live kidney donors (75 females, 45 males). GFR was evaluated from 51Cr-EDTA plasma clearance using blood samples taken at 3, 4 and 5 hours. The slope-intercept GFR was corrected for body surface area using the Dubois & Dubois and for the fast exponential using the Brochner-Mortensen equation. Scatter plot of DFG against age in live kidney donors was plotted and the 98% range limits have been defined. RESULTS: The median GFR obtained for kidney donors was 88 mL/min/1.73 m2 [68-130]. No significant difference with gender was found. 51Cr-EDTA clearance was strongly correlated with patient age (r = - 0.62, P < 0,0001). GFR decreased by approximately 8 mL/min/1.73 m2 per decade. Based on these results, a nomogram for GFR is presented. CONCLUSION: The interpretation of GFR requires age-adjusted normal values. These standards need not be adjusted to the patient's sex or BMI.

[Effect of 99mTc elution in vivo from red cells on red cell volumes measured using autologous 99mTc-labeled red cells: comparison with 51Cr method]. / Effet de l'élution in vivo du technétium sur les volumes globulaires mesurés à l'aide d'hématies autologues marquées au 99mTc : comparaison avec la technique au 51Cr.

The purpose of this work was to compare the measured red-cell volume (RCV) using sodium pertechnétate [RCV-99mTc] compared to the reference technique using sodium radiochromate [RCV-51Cr] and to assess the influence of technetium-99 elution on the RCV-99mTc value. Ten patients had simultaneous measurements of RCV-99mTc and RCV-51Cr. Elution of Tc-99m from red blood cells was 2.9% and led to an average overestimation of RCV-99mTc of 3.7%. The introduction of individual tracer elution rates in the RCV-99mTc calculation corrects this overestimation.