Systematic Assessment of the Adsorption of 99mTc-Radiopharmaceuticals onto Plastic Syringes

Assessment of Residual [99mTc]Tc-Tetrofosmin Activity in Routine Nuclear Medicine Practice at Hospital Kuala Lumpur

Myocardial perfusion imaging using the radiopharmaceutical [99mTc]Tc-tetrofosmin plays a crucial role in diagnosing cardiac conditions. However, variations in the residual activity of [99mTc]Tc-tetrofosmin in plastic syringes after administration may impact imaging quality and patient safety. This study aimed to evaluate the residual activity of [99mTc]Tc-tetrofosmin in plastic syringes after administration during routine nuclear medicine procedures at Hospital Kuala Lumpur, assessing compliance with department protocols and variability among different syringe brands. Methods: A single-center prospective observational study was conducted using stratified quota sampling, encompassing 396 samples across 3 syringe brands (SJ, BD, and Ciringe). Residual activity was measured immediately after administration, and statistical analysis was performed to compare brands and assess compliance with the department dosage protocol range of 333-555 MBq. Results: All injected activities aligned with the department protocol dose, with a mean effective activity of 451.23 ± 30.73 MBq and a mean residual activity of 12.63% ± 4.73%. However, variability in residual activity was observed among syringe brands. BD exhibited the highest mean residual activity (16.45%), significantly differing from SJ (9.95%) and Ciringe (11.50%) (P < 0.001). Conclusion: Rigorous syringe selection is crucial in myocardial perfusion imaging procedures to minimize residual activity and ensure compliance with dosimetry standards, emphasizing the importance of integrating pharmacy practices into nuclear medicine protocols. Standardized protocols and quality assurance measures are essential to optimize imaging outcomes and prioritize patient safety. These findings highlight the importance of ongoing monitoring and interdisciplinary collaboration to navigate residual activity management effectively in routine nuclear medicine practice.

Container-content interactions with radiopharmaceuticals: Seeing is believing

This perspective article addresses the critical issue of container-content interactions in the administration of intravenous medications, with a focus on radiopharmaceuticals used in nuclear medicine. Medication administration errors pose a significant challenge to patient safety. The "five rights" framework-ensuring the right patient, drug, time, dose, and route-serves as a cornerstone for safe drug administration. In the context of radiopharmaceuticals, notable for their use in nuclear medicine, adherence to these principles is paramount due to their unique properties and role in diagnostic and therapeutic procedures. The article explores the impact of container materials, particularly in syringes, on radiopharmaceutical stability and administration accuracy. It delves into the complexities of sorption phenomena, highlighting studies demonstrating its occurrence and potential consequences, including variations in administered doses and compromised diagnostic or therapeutic outcomes. Noteworthy factors influencing sorption include the type of radiopharmaceutical, container composition, molecular properties, and dilution. Findings revealing residual activity in syringes and identifying specific components, such as lubricants, silicon gaskets, and plungers, contributing to adsorption are presented. Migration of metal contaminants from container to content is discussed, emphasizing the potential impact on radiochemical yield and stability. There is a need for comprehensive studies to characterize drug-container interactions and poses crucial questions about the true benefit patients derive from prescribed activities. It challenges current practices, suggesting a need for tailored activity levels, container validation protocols, and rigorous testing of hospital preparations. Ultimately, this perspective paper calls for a deeper understanding of these interactions, urging regulatory consideration and standardization to ensure optimal drug administration and patient outcomes.

Unusual Focal Lung Uptake without CT Abnormality on a Bone Scan: What Might It Mean?

A 48-year-old woman was referred for a bone scan as an assessment of bone metastasis from breast cancer. Surprisingly, two hot spots of lung uptake were present in the left lung without any abnormality on CT slices. No history of pulmonary disease was observed. An optimized CT scan with fine slices performed the same day was strictly normal (without any micronodule). A lung ventilation/perfusion scintigraphy showed no significant perfusion defect. A follow-up bone scan performed eight months later was normal and without any lung uptake. After exclusion of the main etiologies described in the literature, such as amylosis, sarcoidosis, abscess, or hypercalcemia, radiotracer microembolism seems to be the most likely hypothesis in this patient.