Detecting strontium-89 removable contamination using a sodium iodide well counter

Area of Science:

• Nuclear medicine
• Radiological monitoring
• Radiation detection

Background:

• Monitoring for Strontium-89 (89Sr) removable contamination is crucial for radioactive materials.
• Liquid scintillation counting is the preferred method but not widely available in nuclear medicine departments.
• Alternative detection methods for beta emitters like 89Sr are needed.

Purpose of the Study:

• To investigate the use of a sodium iodide well counter for detecting 89Sr contamination.
• To evaluate the feasibility of using bremsstrahlung photon production for 89Sr detection.
• To compare the performance of a sodium iodide well counter with liquid scintillation counting.

Main Methods:

• Tested 89Sr-chloride solutions of known concentration.
• Evaluated parameters including sample volume, tube type, air access, wipe material, and counting geometry.
• Obtained liquid scintillation samples for comparison.

Main Results:

• Initial counting efficiencies for the well counter were 0.10-0.14 cpm/dpm for small samples.
• Various tested parameters affected the system's detection efficiency.
• Calculated half-life of 50.8 days closely matched the known 50.5-day half-life of 89Sr.
• Liquid scintillation samples showed expected efficiencies (approx. 1.0 cpm/dpm) and half-life.

Conclusions:

• Sodium iodide well counters can sensitively detect 89Sr removable contamination.
• Special considerations are necessary for determining counting efficiency with this method.
• This offers a viable alternative for departments without liquid scintillation capabilities.