Identification of Factors Affecting the Retention of 99mTc-DMSA in Syringes Among the Paediatric Population in Sri Lanka

Abstract

Background: 99mTc-DMSA is a common paediatric renal scintigraphy study, where radiopharmaceutical is introduced intravenously using disposable syringes. Radiopharmaceuticals can be retained on disposable syringes, causing under-dosing, and impacting imaging quality in paediatric patients. The study aimed to specify the factors affecting on retention of 99mTc-DMSA in disposable syringes. Furthermore, the influence of the medical staff, patient positioning, and the ascendancy of the MON.TEK 99mMo/99mTc generator were investigated.

Methods: A study of 212 paediatric patients undergoing99mTc-DMSA renal scintigraphy was conducted using CAPINTEC-CRC-15R and CAPINTEC CRC/15 BETA radiation dose calibrators. The99mTc-Pertechnetate was eluted with a MON.TEK 99mMo/99mTc generator and the radio pharmaceutical volume were recorded. Six types of 1ml/1cc disposable syringes (Types 1-6) and one 1ml insulin syringe (Type 7) were used. Pre and post-doses of these syringes were measured.he administered activity value was considered to develop DRL. Conflicts of Interest: None Funding: None. Ethics Approval: The approval for the research proposal for this study was obtained from the Ethical Review Committee (ERC) of the Faculty of Medicine, General Sir John Kotelawala Defence University. Permission for data collection and the continuation of the study was obtained from the Institutional Review Boards of Lady Ridgeway Hospital for Children, Borella, and Lanka Hospital, Narahenpita, Sri Lanka.

Results: Results showed a significant moderate, positive correlation between retention dose and dilution (radiopharmaceutical volume). There was no correlation between retention dose and pre-dose or patient weight. No significant difference in retention was found based on patient gender or position. Significant differences in retention dose were observed among syringe types, injection sites, labeling personnel, and administering personnel.

Conclusion: Retention of 99mTc-DMSA varies by syringe type, with Type-1 syringes showing the highest retention and Type-7 the lowest, making Type-7 the most suitable. Retention is influenced by radiopharmaceutical dilution, labeling, injecting personnel, and injection site, while pre-dose, patient gender, weight, positioning, and decay time have no significant effect. This highlights the importance of syringe selection and standardizing procedures to minimize retention, improve dosing accuracy, and enhance imaging quality.