[Impact of Residual Radioactivity Rate of Tc-macro Aggregated Albumin (MAA) in Syringes and Administration Routes with a Focus on Pediatric Nuclear Medicine Examinations].

PURPOSE

The purpose of this study was to evaluate the residual radioactivity in the syringe and route of administration of a low fluid volume Tc-macro aggregated albumin (MAA) intended for pediatric nuclear medicine examinations.

METHOD

We evaluated the residual characteristics, as the effect of elapsed time from drawing up of radiopharmaceuticals to plastic syringe to administration, and the effect of volume of TcO solution to be labeled, the effect of rinsed times of plastic syringe, effect of dose of calculated by consensus guidelines for pediatric nuclear medicine and residual location in injection sets with Tc-MAA. Residual radioactivity was measured using planar images obtained by the gamma camera.

RESULTS

Residual radioactivity rate of Tc-MAA, Tc-MAG, I-IMP showed 41.3±1.6%, 14.4±0.6%, 14.6±2.0%, respectively. Tc-MAA clearly showed a higher residual rate. Residual radioactivity rate increased with the extension of the elapsed time, and reached a high value of 41.3% in 30 minutes. Residual radioactivity rate was dependent on the different volume of TcO to be labeled (4.0 ml and 8.0 ml). Residual radioactivity rate did not change when the number of rinsed was more than one. Residual rate was around 40% at all doses of calculated by consensus guidelines for pediatric nuclear medicine.

CONCLUSION

Tc-MAA showed the highest residual radioactivity rate among radiopharmaceuticals used in pediatric nuclear medicine examinations. The factor that most affected the residual radioactivity rate of Tc-MAA was the elapsed time from draw up to the plastic syringe to administration.