Comparison of four 1-mL syringes for administering first-pass radionuclide angiography doses.

OBJECTIVE For optimal imaging in first-pass radionuclide angiography (FPRNA) studies, 1.11 GBq (30 mCi) 99mTc-sestamibi doses are drawn up in volumes of 0.1-0.3 mL. A single bolus injection of this small volume is important to obtain accurate time-activity curves. Because of the small volume and concentrated radioactivity, it is undesirable for study effectiveness and image quality to have a significant amount of residual activity remaining in the syringe after injection. The purpose of this study was to compare the amount of residual activity in 4 different 1-mL syringes. METHODS Each test syringe (n = 20) was filled with a volume (0.2 mL) of approximately 1.11 GBq (approximately 30 mCi) 99mTc-sestamibi. Initial activity was measured, and the dose was injected back into a vial only once, simulating bolus injection into a patient. The remaining activity was measured, followed by the calculation of percent residual activity. RESULTS The two 25-G x 5/8-in. permanent needles had a low percent of residual activity, as well as a much sturdier needle for injection. However, one of these syringes is more expensive. CONCLUSION The results of our comparison studies showed that the syringe with a 25-G x 5/8-in. permanent needle is ideal for FPRNA doses because of its sturdiness, low residual activity, and the quality of the bolus and resulting images.