Detecting strontium-89 removable contamination using a sodium iodide well counter.
Monitoring for 89Sr removable contamination is required for incoming DOT-labeled packages and work areas containing radioactivity. However, few nuclear medicine departments are equipped for liquid scintillation counting, which is the preferred method for detecting beta emitters. We investigated using a sodium iodide well counter to detect 89Sr through its bremsstrahlung photon production.


METHODS
We used a manufacturer's 89Sr-chloride solution of known concentration and tested various parameters: type of tube, access of tube contents to air, volume of sample, type of wipe material and counting geometry. Liquid scintillation samples also were obtained.


RESULTS
Initial counting efficiencies were 0.10-0.14 cpm/dpm for small volume (10-microliter) samples. The various parameters tested had either positive or negative effects on the system's efficiency to detect 89Sr. One set of samples, counted over time, demonstrated a calculated mean half-life of 50.8 days, which is similar to the 89Sr reported half-life of 50.5 days. Liquid scintillation samples demonstrated efficiencies of almost 1.0 cpm/dpm and a calculated mean half-life of 50.8 days, both as expected.


CONCLUSIONS
This study demonstrates that 89Sr removable contamination can be detected sensitively using a sodium iodide well counter, but special considerations must be made when determining the system's counting efficiency.
Hackett
M T
MT
Radiation Safety Office, Department of Veterans Affairs Medical Center, Lexington, Kentucky 40511-1093, USA.
Coupal
J J
JJ
Perdikaris
N
N
D000396:Air Pollutants, Radioactive; D006801:Humans; D009684:Nuclear Medicine Department, Hospital; D011835:Radiation Protection; D012588:Scintillation Counting / Q000379:methods; D012974:Sodium Iodide; D013326:Strontium Radioisotopes
D000396:Air Pollutants, Radioactive; D013326:Strontium Radioisotopes; D012974:Sodium Iodide