Imaging and quantifying radioactive contamination with gamma cameras in Nuclear Medicine departments

Nuclear medicine departments are equipped with gamma cameras with NaI scintillation detectors that are optimized to detect photons with energies ranging from around 20 keV to 400 keV. The cameras have lead collimators to narrow down the direction of the incoming photons and they allow for the creation of images with spatial resolutions ranging from around 0.6 cm to 1.5 cm. In addition, when these cameras are properly calibrated, the counts collected can be used to estimate the amount of activity that is being imaged.

Several years ago, we started to use these gamma cameras to image and quantify radioactive contamination on staff who have been accidentally contaminated during the course of their clinical work. This has proven to be a very useful technique, as it can help to locate the body areas that are contaminated, the extent of the contamination, and the amounts of activity involved. The information collected has helped to guide the management of these incidents. In this talk, I will review the use of gamma cameras to image and quantify radioactive contamination on persons. I will review the imaging and calibration parameters that have been used and show examples of contamination incidents where imaging has been performed. I will also discuss some of the advantages and disadvantages we have encountered with this technique.