RT Journal Article
SR Electronic
T1 Evaluation of the Stability of <sup>99m</sup>Tc-ECD and Stabilized <sup>99m</sup>Tc-HMPAO Stored in Syringes
JF Journal of Nuclear Medicine Technology
JO J. Nucl. Med. Technol.
FD Society of Nuclear Medicine
SP 197
OP 200
VO 29
IS 4
A1 Koslowsky, Ingrid L.
A1 Brake, Stephanie E.
A1 Bitner, Sandra J.
YR 2001
UL http://tech.snmjournals.org/content/29/4/197.abstract
AB Objective:To determine and compare the stability of 99mTc-ECD and stabilized 99mTc-HMPAO when stored in syringes over an 8-h period. Methods:99mTc-ECD and stabilized 99mTc-HMPAO were prepared according to the manufacturers’ protocols, with the following exception: eluate less than 60 min old was used to prepare 99mTc-HMPAO rather than the recommended 30 min. Once prepared, 185 MBq (5 mCi) of both products were drawn into 5-mL syringes and allowed to sit at room temperature. At 2, 4, 6, and 8 h after preparation, the radiochemical purity (RCP) of the contents of the syringes was determined and compared to the RCP of the products in vials. Retention of activity of each product in syringes was also evaluated by measuring activity remaining in each syringe (and filter, in the case of 99mTc-HMPAO) after expressing its contents. Results:The RCP of stabilized 99mTc-HMPAO stored in syringes decreased from a mean of 87.7% at 2 h to 74.0% at 8 h after preparation. In contrast, 99mTc-ECD retained an RCP of greater than 94% throughout the time tested. The impurity that appeared to increase over time with 99mTc-HMPAO was found to be sodium pertechnetate. Total retention of activity remaining in the syringe and filter ranged from 11.6% at 2 h to 9.5% at 8 h for 99mTc-HMPAO; the syringe itself retained less than 5% of the total activity at all time periods. 99mTc-ECD exhibited 6.2% to 11.3% retention of activity in the syringe. The sorption of sodium pertechnetate to the syringe for the same time period was less than 1%. Conclusions:99mTc-ECD is a more stable product than stabilized 99mTc-HMPAO in a syringe. Both products demonstrate retention of radioactivity in the syringe. Some of this retention may denote sorption of the products to plastic.