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Background: Residual activity in dispensing syringes is a problem that has been sporadically reported with various radiopharmaceuticals. Studies with [99mTc]Tc-tetrofosmin are non-consistent so far. The aim was to quantify the residual activity of [99mTc]Tc-tetrofosmin in different syringes in a clinical setting and to assess its impact on the clinical imaging procedure. Methods: The residual activity of [99mTc]Tc-tetrofosmin was measured in 3 types of syringes: 3-part lubricated and non-lubricated syringes and 2-part syringe (n ≥ 30 for each syringe). The residual activity was located and quantified using a CzT SPECT camera and radio-counting then was correlated with different clinical parameters and processed by multiple linear regression analysis. Results: Residual activity was different in all syringe types but lubricated syringes showed significantly higher levels with a mean ± SD of 26.12 ± 10.21% (P <.001). For these syringes, the residual activity was mainly located on the lubricated body. They also have a positive and significant impact on the standardized counting duration of patients' acquisitions. Conclusion: Lubricated syringes with high residual activity should be avoided as they increase the risk of prolonging patient acquisition time and potentially increasing the risk of poor image quality. [ABSTRACT FROM AUTHOR]

Background: Refining the risk of malignancy in patients presenting with thyroid nodules with indeterminate cytology (IC) is a critical challenge. We investigated the performances of 18F-fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) to predict malignancy. Methods: Between May 2016 and March 2019, 107 patients presenting with a thyroid nodule ≥15 mm with IC and eligible for surgery were included in this prospective study. Head-and-neck PET/CT acquisitions were performed 20 and 60 minutes after injection of 1.5 MBq/kg of FCH. PET/CT acquisition was scored positive when maximal standardized uptake value in the IC nodule was higher than in the thyroid background. Pathology was the gold standard for diagnosis. Results: At pathology, 19 (18%) nodules were malignant, 87 were benign, and one was a noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Sensitivity, specificity, accuracy, positive-predictive value (PPV), and negative-predictive value (NPV) of FCH PET/CT in detecting cancer or NIFTP were 90%, 50%, 55%, 29%, and 96% at 20 minutes and 85%, 49%, 67%, 28%, and 94% at 60 minutes, respectively. Higher specificity (58% vs. 33%, p = 0.01) was observed in nononcocytic (n = 72) than in oncocytic IC nodules (n = 35). The pre-PET/CT probability of cancer or NIFTP in Bethesda III–IV nodules was 11% and the post-PET/CT probability was 19% in PET-positives and 0% in PET-negatives. In retrospective analysis, 42% of surgeries would have been unnecessary after PET/CT and 81% before (p < 0.001), resulting in a hypothetical 48% reduction (95% confidence interval [32–64]). Conclusions: FCH PET/CT offers high NPV to reliably exclude cancer in PET-negative IC nodules, but suffers from low PPV, particularly in those with oncocytic cytology. ClinicalTrials.gov identifier: NCT02784223. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to determine the potential diagnostic value of regional myocardial adrenergic I-metaiodobenzylguanidine (MIBG) single photon emission computed tomography (SPECT) imaging to identify patients with Lewy body diseases (LBD+). Methods: Sixty-four consecutive patients who underwent cardiac I-MIBG SPECT to differentiate LBD+, including Parkinson's disease (PD) and dementia with Lewy bodies (DLB), from patients without LBD (LBD−) were retrospectively reviewed. A neurologist expert in memory disorders determined the final clinical diagnosis by using international clinical diagnostic criteria. Planar [heart to mediastinum ratio (HMR)] and I-MIBG SPECT[(innervation defect score (IDS)] using the 17-segment left ventricular model (five-point scale) were obtained 4 h after the injection of I-MIBG on a low-energy high-resolution (LEHR) collimator. Receiver-operating characteristic (ROC) analysis was performed to determine the optimal HMR and IDS cut-off values to discriminate LBD+ from LBD−. Results: Of the 64 patients, 45 (70 %) were diagnosed LBD+ (DLB, n = 27; PD, n = 18) and 19 were diagnosed LBD− (5 other dementias, 14 other parkinsonisms). The HMR and IDS of LBD+ were significantly different from those of LBD− (1.30 ± 0.21 vs 1.65 ± 0.26, p < 0.001; 39 ± 28 vs 8 ± 16, p = 0.001). The optimal HMR and IDS cut-off values to discriminate LBD+ ( n = 45) from LBD− ( n = 19) were 1.47 and 6/68, providing a sensitivity and specificity of 82.2 and 84.2 % and 86.7 and 73.7 %, respectively. Conclusion: Regional myocardial adrenergic I-MIBG imaging SPECT has a potential diagnostic value to identify LBD+. [ABSTRACT FROM AUTHOR]

Objectives: In the context of a supply disruption of mebrofenin (Cholediam)-based kits for radiolabelling with technetium-99m [ 99m Tc], the medicine agencies allowed the importation of a back-up radiopharmaceutical diagnostic agent, etifenin (Techida), to ensure continuous management of patients with hepatobiliary disorders in nuclear medicine departments. There are still issues regarding the measurement of radiochemical purity (RCP) with these kits based on the European Pharmacopoeia and the Summary of Product Characteristics (SPC). This study aims to identify and to optimise, in a clinical context, the most suitable thin layer chromatography (TLC) method for the determination of the RCP in terms of speed of response and reliability for [ 99m Tc]Tc-mebrofenin and [ 99m Tc]Tc-etifenin., Methods: [ 99m Tc]Tc-etifenin (n=4) and [ 99m Tc]Tc-mebrofenin (n=5) were individually controlled using six different TLC methods and one high-performance liquid chromatography (HPLC) method for impurity identification ([ 99m Tc](TcO 2 ) n and Na[ 99m Tc]TcO 4 ), RCP (%) and duration of analysis (min). Two TLC methods were selected according to the recommendations of the Pharmacopoeia and SPC, two others were exactly the same but with a heating step, and the other two corresponded to a mix between the methods of the SPC and the Pharmacopoeia that were chosen to optimise RCP determination parameters., Results: Radio-HPLC analysis allowed effective separation of [ 99m Tc]Tc-etifenin and [ 99m Tc]Tc-mebrofenin with a retention time of 8.05±0.02 min and 8.94±0.07 min, respectively, from Na[ 99m Tc]TcO 4 (retention time 2.76±0.03 min). HPLC showed an absence of Na[ 99m Tc]TcO 4 for [ 99m Tc]Tc-mebrofenin and 0.2% for [ 99m Tc]Tc-etifenin. Among the TLC methods, we identified the most suitable method which ensures the most compliant RCP (98.3±0.9%) in a time of 31.5±1.1 min. Also, it allowed a time saving of 15 min compared with the methods proposed by the Pharmacopoeia and the SPCs., Conclusion: We propose a TLC method that accelerates quality control by an average of 15 min while guaranteeing a reliable RCP., Competing Interests: Competing interests: None declared., (© European Association of Hospital Pharmacists 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Technetium-99m mercapto-acetyl-triglycine ([ 99m Tc]Tc-MAG3) is a radiopharmaceutical diagnostic agent used in nuclear medicine intended for the exploration of nephrological and urological disorders. Patient safety and reliability of this imaging procedure especially depend on the radiochemical purity (RCP) of the [ 99m Tc]Tc-MAG3 preparation. Recently, the Summary of Product Characteristics (SPC) of NephroMAG, a kit dedicated to [ 99m Tc]Tc-MAG3 preparation, proposed a two-strip thin layer chromatography (TLC) based quality control (QC) method. Also, Straub et al recently proposed another TLC based QC method. We sought to evaluate the transferability of these QC methods in our hospital radiopharmacy and compared them to our currently employed TLC method and radio-HPLC (high-pressure liquid chromatography) to select the most appropriate in the context of hospital radiopharmacy., Methods: Ten consecutive [ 99m Tc]Tc-MAG3 preparations were controlled using: HPLC combined with a radiodetector (radio-HPLC), a single strip TLC method (method 1) in current use in our centre, a two-strip TLC method described in the SPC (method SPC) and a two-strip TLC method (method 2) described by Straub et al . Quantitative results for the four tested QC methods were measured and compared in terms of RCP (%), sodium pertechnetate ([ 99m Tc]TcO 4 - ) (%) and duration of analysis (min)., Results: RCP was significantly different between method SPC and radio-HPLC (p<0.001) and method 2 (p<0.001). Also, the percentage of [ 99m Tc]TcO 4 - was statistically different between the radio-HPLC and the method SPC (p<0.001), but not with the method 1 and method 2 group (p>0.05). The duration of analysis (min) was significantly different between the four QC procedures (p<0.001) with method 2 and method SPC being the quickest., Conclusions: Our study showed it is possible to transfer and select a quick and reliable QC method for the preparation of NephroMAG kits in our centre. We therefore advise the widespread use of the method from Straub et al in hospital radiopharmacies., Competing Interests: Competing interests: None declared., (© European Association of Hospital Pharmacists 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Refining the risk of malignancy in patients presenting with thyroid nodules with indeterminate cytology (IC) is a critical challenge. We investigated the performances of 18 F-fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) to predict malignancy. Methods: Between May 2016 and March 2019, 107 patients presenting with a thyroid nodule ≥15 mm with IC and eligible for surgery were included in this prospective study. Head-and-neck PET/CT acquisitions were performed 20 and 60 minutes after injection of 1.5 MBq/kg of FCH. PET/CT acquisition was scored positive when maximal standardized uptake value in the IC nodule was higher than in the thyroid background. Pathology was the gold standard for diagnosis. Results: At pathology, 19 (18%) nodules were malignant, 87 were benign, and one was a noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Sensitivity, specificity, accuracy, positive-predictive value (PPV), and negative-predictive value (NPV) of FCH PET/CT in detecting cancer or NIFTP were 90%, 50%, 55%, 29%, and 96% at 20 minutes and 85%, 49%, 67%, 28%, and 94% at 60 minutes, respectively. Higher specificity (58% vs. 33%, p  = 0.01) was observed in nononcocytic ( n  = 72) than in oncocytic IC nodules ( n  = 35). The pre-PET/CT probability of cancer or NIFTP in Bethesda III-IV nodules was 11% and the post-PET/CT probability was 19% in PET-positives and 0% in PET-negatives. In retrospective analysis, 42% of surgeries would have been unnecessary after PET/CT and 81% before ( p  < 0.001), resulting in a hypothetical 48% reduction (95% confidence interval [32-64]). Conclusions: FCH PET/CT offers high NPV to reliably exclude cancer in PET-negative IC nodules, but suffers from low PPV, particularly in those with oncocytic cytology. ClinicalTrials.gov identifier: NCT02784223.