Technetium-99m eluate quality affects in vitro red blood cell labeling of healthy human volunteers blood: An university teaching hospital experience

Purpose of the present study is to report and disseminate an initial experience gained with the ⁹⁹mTechnitium sodium pertechnetate eluate; obtained after second elution of the ⁹⁹Moly-^99mTc column generator within 3-4 h on the same day; influences the labeling efficiency of ^99mTc labeled RBC while performing by in vitro method in the hospital pharmacy laboratory. Eluate from ⁹⁹Moly- ^99mTc column generator was used consisting radioactive concentration of 50 μCi in 1 ml of normal young healthy human volunteers (n = 27, male =14 and female =13) has not consumed any interfering synthetic chemicals/drugs blood collected in the heparinised syringe after taking informed consent duly approved by Institutional Ethics committee. SnCl₂.2H₂O used as reducing agent for ^99mTc of 2 μg/ml of concentration with mixing, incubating 20-30 min, separating packed red cells, washing with 0.9% saline and then counted in the calibrated Gamma ray Spectrophotometer. Percentage labeling efficiency of ^99mTc-RBC was calculated. Statistical variation Mean ± SD was calculated. Labeling efficiency by in vitro method of RBC collected from human volunteers blood with the ^99mTc was showing poor percentage of 56.5 ± 3.8 as compared to the expected standard percentage binding of ≥90%. Result analysis reflecting that ^99mTc0₄ − eluate used for RBC labeling may be containing more ground Technetium (⁹⁹Tc (ground)) that means ratio of ^99mTc to ⁹⁹Tc (g) may be very low, which has interfered with the ^99mTc (Gamma emitter 140 keV). Limitation of the study is that ⁹⁹Tc (g) in the eluate from the column generator has to be quantified with the suitable and feasible method at different intervals to provide more evidence. Study concludes that ^99mTco4 − eluted for the red blood cell labeling should be fresh and should not be used if the generator has been eluted earlier within 3-4 h. (author)