Nathalie Prevot

Aerosol delivery during invasive mechanical ventilation is influenced by multiple factors, including nebulizer type and ventilatory settings. Current intensive care unit (ICU) guidelines generally discourage modifying these parameters due to limited and conflicting evidence. This study evaluated the effects of inspiratory flow and inspiratory-to-expiratory (I:E) ratio on pulmonary aerosol deposition according to nebulizer technology using a controlled preclinical model.Using a validated ex vivo porcine respiratory model under volume-controlled ventilation, we assessed the impact of inspiratory flow (35 vs. 60 L/min) and I:E ratio (1:2 vs. 1:3) on regional aerosol deposition. Experiments were performed with a vibrating mesh nebulizer (VMN) and a jet nebulizer (JN) placed 15 cm upstream of the Y-piece, with active heated humidification. Deposition was measured by planar scintigraphy with radiolabeled aerosol and a mass balance approach.VMN showed significantly higher delivery efficiency than JN in all conditions. With VMN, lower inspiratory flow increased pulmonary deposition (57% ± 8% vs. 45% ± 5%, p = 0.022), and a longer expiratory phase (I:E 1:3 vs. 1:2) further improved deposition (60% ± 9% vs. 45% ± 5%, p < 0.0001), with reduced losses in the inspiratory limb. In contrast, JN had low output and no significant variation across settings.Ventilatory parameters significantly influence aerosol deposition with VMN but not JN in mechanical ventilation. Combining lower inspiratory flow and longer expiratory time may optimize delivery with VMN. These findings support a device-specific approach and require clinical confirmation.

Aerosol delivery during invasive mechanical ventilation is influenced by multiple factors, including nebulizer type and ventilatory settings. Current intensive care unit (ICU) guidelines generally discourage modifying these parameters due to limited and conflicting evidence. This study evaluated the effects of inspiratory flow and inspiratory-to-expiratory (I:E) ratio on pulmonary aerosol deposition according to nebulizer technology using a controlled preclinical model.Using a validated ex vivo porcine respiratory model under volume-controlled ventilation, we assessed the impact of inspiratory flow (35 vs. 60 L/min) and I:E ratio (1:2 vs. 1:3) on regional aerosol deposition. Experiments were performed with a vibrating mesh nebulizer (VMN) and a jet nebulizer (JN) placed 15 cm upstream of the Y-piece, with active heated humidification. Deposition was measured by planar scintigraphy with radiolabeled aerosol and a mass balance approach.VMN showed significantly higher delivery efficiency than JN in all conditions. With VMN, lower inspiratory flow increased pulmonary deposition (57% ± 8% vs. 45% ± 5%, p = 0.022), and a longer expiratory phase (I:E 1:3 vs. 1:2) further improved deposition (60% ± 9% vs. 45% ± 5%, p < 0.0001), with reduced losses in the inspiratory limb. In contrast, JN had low output and no significant variation across settings.Ventilatory parameters significantly influence aerosol deposition with VMN but not JN in mechanical ventilation. Combining lower inspiratory flow and longer expiratory time may optimize delivery with VMN. These findings support a device-specific approach and require clinical confirmation.

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.

(1) Background: ¹⁸F-FDG PET/CT diagnostic accuracy for liver metastasis (LM) could be influenced by technical parameters, lesion size, and the patient’s covariates. This retrospective study aimed to evaluate these covariates’ impact on PET/CT sensitivity. (2) Methods: Consecutive patients with suspected LMs who underwent ¹⁸F-FDG PET/CT scans were included. PET/CT scans were interpreted visually. The reference standard integrated histopathological and imaging follow-up. Logistic regression modeling and average marginal predictions were used to calculate per-lesion diagnostic performance measures with cluster robust 95% confidence intervals and to assess the covariates’ impact on PET/CT sensitivity. (3) Results: We included 192 patients with 330 lesions. ¹⁸F-FDG PET/CT exhibited a per-lesion sensitivity, specificity, positive predictive value, and negative predictive value of 86%, 79%, 91%, and 69%, respectively. In multivariate analysis, TOF PET/CT exhibited a higher sensitivity than non-TOF PET/CT (91% vs. 78%, p = 0.02). Sensitivity was reduced for lesions < 10 mm compared to larger lesions (56% vs. 93%, p < 0.001). A 5 kg/m² increase in BMI led to an average 5% sensitivity reduction (p < 0.001). Age, sex, blood glucose level below 11 mmol/L, and liver density did not significantly impact sensitivity (p > 0.05). (4) Conclusions: ¹⁸F-FDG PET/CT sensitivity might be reduced with non-TOF PET, lesions < 10 mm, and higher BMI.

This work aims to investigate bronchodilator delivery with the use of different vaping drug delivery systems (VDDS) by determining the dose equivalence delivered in relation to different references: a clinical jet nebulizer, a pMDI (pressurized metered dose inhaler) and a DPI (dry powder inhaler). Three different bronchodilators were used (terbutaline, salbutamol hemisulfate, ipratropium bromide). The e-liquids contained the active pharmaceutical ingredient (API) in powder form. Two different VDDS were tested (JUUL and a GS AIR 2 atomizer paired with a variable lithium-ion battery (i-stick TC 40 W), 1.5 ohm resistance, and 15 W power). Samples were collected using a glass twin impinger (GTI). High-performance liquid chromatography (HPLC) was used to quantify the drugs. A next-generation impactor (NGI) was used to measure the particle size distribution. Terbutaline emerged as the optimal API for bronchodilator delivery in both VDDS devices. It achieved the delivery of a respirable dose of 20.05 ± 4.2 µg/puff for GS AIR 2 and 2.98 ± 0.52 µg/puff for JUUL. With these delivered doses, it is possible to achieve a dose equivalence similar to that of a jet nebulizer and DPI, all while maintaining a reasonable duration, particularly with the GS AIR 2. This study is the first to provide evidence that vaping bronchodilators work only with appropriate formulation, vaping technology, and specific drugs, depending on their thermal degradation properties.

This study aims to evaluate the impact of the nasal delivery technique and nebulizing technologies (using different frequencies of oscillating airflow) for acoustic aerosol targeting of maxillary sinuses. Sodium fluoride (chemical used as a marker), tobramycin (drug used as a marker) and ^99mTc-DTPA (radiolabel aerosol) were used to assess the intrasinus aerosol deposition on a nasal cast. Two commercial medical devices (PARI SINUS nebulizer and NL11SN ATOMISOR nebulizer) and various nasal delivery techniques (one or two nostrils connected to the aerosol inlet, the patient with the soft palate closed or open during the acoustic administration of the drug, the presence or not of flow resistance in the nostril opposite to the one allowing the aerosol to be administered) were evaluated. The closed soft palate condition showed a significant increase in drug deposition even though no significant difference in the rest of the nasal fossae was noticed. Our results clearly demonstrated a higher intrasinus aerosol deposition (by a factor 2–3; respectively 0.03 ± 0.007% vs. 0.003 ± 0.0002% in the right maxillary sinus and 0.027 ± 0.006% vs. 0.013 ± 0.004% in the left maxillary sinus) using the acoustic airflow generated by the PARI SINUS compared to the NL11SN ATOMISOR. The results clearly demonstrated that the optimal conditions for aerosol deposition in the maxillary sinuses were obtained with a closed soft palate. Thus, the choice of the nebulizing technology (and mainly the frequency of the pulsating aerosol generated) and also the recommendation of the best nasal delivery technique are key factors to improve intrasinus aerosol deposition.

Study objective: The aim of this study was to evaluate the performance of indocyanine green (ICG) compared to that of the gold standard 99mtechnetium (99mTc-nanocolloids) in detecting sentinel lymph nodes (SLN) in early vulvar cancer. Material and Methods: A single-center retrospective cohort study comparing SLN detection by 99mTc-nanocolloids and ICG was performed in patients presenting early vulvar cancer (T1/2), with clinically negative nodes. All SLN showing a radioactive and/or fluorescent signal were resected. The primary endpoints were the sensitivity, positive predictive value (PPV) and false negative (FN) rate of ICG in detecting SLN compared to 99mTc-nanocolloids. Results: Thirty patients were included and 99 SLN were identified in 43 groins. Compared to 99mTc-nanocolloids, ICG had a sensitivity of 80.8% (95% CI [72.6; 88.6%]), a PPV of 96.2% (95% CI [91.8; 100%]) and a FN rate of 19.1% in detecting SLN. Seventeen (17.1%) infiltrated (positive) SLN were identified out of the 99 SLN detected. Compared to 99mTc-nanocolloids, ICG showed a sensitivity of 82.3% (95% CI [73.1; 91.5%]), a PPV of 100% and a FN rate of 17.6% (3/17) in detecting infiltrated SLN. Conclusion: Despite its many advantages, ICG cannot be used as the sole tracer for the detection of SLN in early vulvar cancer and should be employed in conjunction with 99mTc-nanocolloids.

(1) Background: As outcome of patients with metastatic melanoma treated with anti-PD1 immunotherapy can vary in success, predictors are needed. We aimed to predict at the patients’ levels, overall survival (OS) and progression-free survival (PFS) after one year of immunotherapy, based on their pre-treatment 18F-FDG PET; (2) Methods: Fifty-six metastatic melanoma patients—without prior systemic treatment—were retrospectively included. Forty-five 18F-FDG PET-based radiomic features were computed and the top five features associated with the patient’s outcome were selected. The analyzed machine learning classifiers were random forest (RF), neural network, naive Bayes, logistic regression and support vector machine. The receiver operating characteristic curve was used to compare model performances, which were validated by cross-validation; (3) Results: The RF model obtained the best performance after validation to predict OS and PFS and presented AUC, sensitivities and specificities (IC95%) of 0.87 ± 0.1, 0.79 ± 0.11 and 0.95 ± 0.06 for OS and 0.9 ± 0.07, 0.88 ± 0.09 and 0.91 ± 0.08 for PFS, respectively. (4) Conclusion: A RF classifier, based on pretreatment 18F-FDG PET radiomic features may be useful for predicting the survival status for melanoma patients, after one year of a first line systemic treatment by immunotherapy.