title: Assessment of 99mTc-succimer residual activity using inert nonreactive syringes.
abstract: It has been widely reported that (99m)Tc-succimer adsorbs to plastic syringes significantly (up to 50%), often resulting in a lower administered dose than intended or inaccurate dosing. This adsorption rate is especially problematic in the pediatric population. To improve (99m)Tc-succimer dosing, we compared the adsorption of (99m)Tc-succimer with 2 types of syringes: silicone-coated syringes with nonlatex rubber on the plunger and inert nonreactive syringes with no silicone coating and no rubber on the plunger.
  
  
  METHODS
  (99m)Tc-succimer kits were compounded according to the manufacturer's instructions. (99m)Tc-succimer doses (37-185 MBq) were drawn into 3-mL (silicone-coated or inert nonreactive) syringes in a 1-mL volume. Thirty min, 1 h, 2 h, and 4 h later, the syringes were assayed in a dose calibrator and assayed again after being emptied and rinsed with saline. In addition, we examined the data collected from 129 (99m)Tc-succimer doses administered in a pediatric department, in which 52 were dispensed in silicone-coated syringes and 77 were dispensed in inert nonreactive syringes. The doses were assayed immediately before and after injection. The syringes were flushed with normal saline.
  
  
  RESULTS
  The labeling efficiency of the (99m)Tc-succimer kits was more than 95%. Residual activity left in the inert nonreactive syringes was 0.73% (SD, ±0.18%), which was significantly lower than the activity left in the silicone-coated syringes, 20.9% (SD, ±5.6%; P < 0.0001). The extent of adsorption did not change significantly between 30 min and 4 h of incubation. The clinical data showed that the residual activity was 30.6% (SD, ±12.5%) from doses dispensed in silicone-coated syringes and 6.38% (SD, ±2.95%) from doses dispensed in inert nonreactive syringes (P < 0.001).
  
  
  CONCLUSIONS
  The inert nonreactive syringes had significantly less residual of (99m)Tc-succimer than silicone-based syringes, making it possible to accurately administer calculated doses of (99m)Tc-succimer to pediatric patients.
authors.affiliation: University of Oklahoma College of Pharmacy, Oklahoma City, Oklahoma wendy-galbraith@ouhsc.edu.
authors.forename: Wendy
authors.initials: W
authors.lastname: Galbraith
authors.affiliation: University of Oklahoma College of Pharmacy, Oklahoma City, Oklahoma.
authors.forename: Xinlian
authors.initials: X
authors.lastname: Chen
authors.affiliation: OU Medical Center Children's Hospital, Oklahoma City, Oklahoma; and.
authors.forename: Katie
authors.initials: K
authors.lastname: Talley
authors.affiliation: College of Allied Health Department of Medical Imaging and Radiation Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
authors.forename: Vesper
authors.initials: V
authors.lastname: Grantham
mesh_terms: D000327:Adsorption; D002648:Child; D006801:Humans; D011854:Radiochemistry; D012408:Rubber / Q000737:chemistry; D012828:Silicones / Q000737:chemistry; D013594:Syringes; D019783:Technetium Tc 99m Dimercaptosuccinic Acid / Q000737:chemistry*; D013997:Time Factors
chemical_list: D012828:Silicones; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D012408:Rubber
keywords: 99mTc-dimercaptosuccinic acid; administered activity; radiopharmaceutical; succimer; syringe residual