Gerald Bonardel

The organization of nuclear medicine facilities, particularly those dedicated to PET, must balance quality of care and radiation protection in accordance with the ALARA principle. The evolution of PET technologies and the integration of AI improve sensitivity and allow large reductions in injected activities. In this context, the traditional practice of individual isolation room after radiopharmaceutical (RPM) injection is being questioned, since exposure levels in shared waiting rooms remain very low. This multicenter study evaluated the dosimetric consequences of using shared waiting rooms. Measurements carried out in three French departments show that the additional dose to patients is negligible (<1%) and that the increase in daily dose to technologists remains low (≈ 2.3 µSv/day), well below regulatory thresholds. No degradation in the diagnostic quality of images was observed. The use of shared waiting rooms therefore appears to comply with French regulations (ASN Guide No. 32) and provides a significant organizational benefit, enabling better patient flow management without compromising radiation protection or quality of care. The results of this study could be taken into account by the ICRP in the context of the planned revision of the radiation protection system by 2030.

Purpose: This study aimed to explore metabolic tumor volume (MTV) as assessed by 18F-fluorodeoxyglucose positron emission tomography–computed tomography (18F-FDG–PET/CT) and understand its biological meaning in patients with non–small cell lung cancer (NSCLC) exposed to immune checkpoint blockers (ICB). Experimental Design: In this study, patients with advanced NSCLC and a positive PET scan within 42 days of first-line treatment were enrolled in 11 institutions across four countries. Total MTV (tMTV) was analyzed, with a 42% maximum standardized uptake value threshold. Survival was analyzed according to high tMTV (≥median). Plasma proteomic profile, whole exome, transcriptome, and other analyses were performed on monocentric cohorts to explore its biological correlates. Results: Of the 518 patients included, 167 received ICBs, 257 had chemotherapy plus ICBs, and 94 had chemotherapy. Median tMTV was 99 cm3. Median overall survival (OS) for patients with high tMTV treated with ICBs was 11.4 vs. 29.6 months (P < 0.0012) for those with low tMTV. In patients who received chemotherapy–ICB, tMTV did not correlate with OS (P = 0.099). In patients with programmed death-ligand 1 (PD-L1) ≥1% and high tMTV, chemotherapy–ICB combination was associated with longer OS compared with ICBs alone (20 vs. 11.4 months; P = 0.026), while no survival differences were observed in the low tMTV group. High tMTV correlated (and its detrimental effect seems to be driven) with a specific proteomic profile and increase in genomic instability. Conclusions: Our analysis indicates high tMTV is linked to an increase in systemic inflammation, specific cytokines production, and chromosomal instability. tMTV may serve as one of the biomarkers to select the best upfront strategy in patients with PD-L1–positive advanced NSCLC.

Background: We aimed to assess the clinical utility of a previously published score combining the total metabolic tumor volume (TMTV) on baseline FDG-PET/CT and pretreatment derived from the neutrophils to lymphocytes ratio (dNLR) for prognostication in NSCLC patients undergoing first-line immunotherapy (IT). Methods: In this multicenter retrospective study, 63 advanced NSCLC patients with a PD-L1 tumor proportion score (TPS) ≥50%, who underwent FDG-PET/CT before first-line IT, treated from January 2017 to September 2019, were enrolled. Associations between this score and the progression-free survival (PFS), overall survival (OS), disease control rate (DCR), and overall response rate (ORR) were evaluated. Results: The median (m) PFS and mOS were 7.7 (95% CI 4.9–10.6) and 12.1 (8.6–15.6) months, respectively, and DCR and ORR were 65% and 58%, respectively. mOS was 17.9 months (14.6 not reached) for the good group versus 13.8 (95%CI 8.4–18.9) and 6.6 (CI 2.0–11.2) months for the intermediate and poor groups, respectively. mPFS was 15.1 (95%CI 12.1–20.0) months for the good group versus 5.2 (1.9–8.5) and 1.9 (95%CI 1.3–2.5) months for the intermediate and poor groups, respectively. The poor prognosis group was associated with DCR and ORR (p < 0.05). Conclusions: The metabolic score combining TMTV on the baseline FDG-PET/CT scan and pretreatment dNLR was associated with the survival and response in a cohort of advanced NSCLC patients with ≥50% PD-L1 receiving frontline IT.