Ann Marie Alessi, BS, CNMT, NCT, RT(N), Product Sales Manager, Nuclear Medicine, Biodex Medical Systems, Inc.
A series of data obtained by counting a single radioactive sample repeatedly will always demonstrate variation. To determine if the variation is due to the natural randomness of radioactive decay or is due to inconsistency in instrument performance, a chi-square (x2) test is performed.
The chi-square test allows you to determine how close a series of counts would come to a true Poisson distribution (bell curve) and provides a measure of the precision of the counting instrument’s performance. >>