Identification of factors affecting the retention of 99mTc-DMSA in syringes among the paediatric population in Sri Lanka

Background: ^99mTc-DMSA is a common paediatric renal scintigraphystudy, where radiopharmaceutical is introduced intravenously usingdisposable syringes. Radiopharmaceuticals can be retained on disposablesyringes, causing under-dosing, and impacting imaging quality inpaediatric patients. The study aimed to specify the factors affecting onretention of ^99mTc-DMSA in disposable syringes. Furthermore, theinfluence of the medical staff, patient positioning, and the ascendancy ofthe MON.TEK ^99mMo/^99mTc generator were investigated.
Methods: A study of 212 paediatric patients undergoing ^99mTc-DMSA renalscintigraphy was conducted using CAPINTEC-CRC-15R and CAPINTEC-CRC/15 BETA radiation dose calibrators. The ^99mTc-Pertechnetate waseluted with a MON.TEK ^99mMo/^99mTc generator and the radio-pharmaceutical volume were recorded. Six types of 1ml/1cc disposablesyringes (Types 1-6) and one 1ml insulin syringe (Type 7) were used. Pre-and post-doses of these syringes were measured.he administered activityvalue was considered to develop DRL.
Results: Results showed a significant moderate, positive correlationbetween retention dose and dilution (radiopharmaceutical volume). Therewas no correlation between retention dose and pre-dose or patient weight.No significant difference in retention was found based on patient genderor position. Significant differences in retention dose were observed amongsyringe types, injection sites, labeling personnel, and administeringpersonnel.
Conclusion: Retention of ^99mTc-DMSA varies by syringe type, withType-1 syringes showing the highest retention and Type-7 the lowest,making Type-7 the most suitable. Retention is influenced byradiopharmaceutical dilution, labeling, injecting personnel, and injectionsite, while pre-dose, patient gender, weight, positioning, and decay timehave no significant effect. This highlights the importance of syringeselection and standardizing procedures to minimize retention, improvedosing accuracy, and enhance imaging quality.