Figure 4From: Performance assessment of a NaI(Tl) gamma counter for PET applications with methods for improved quantitative accuracy and greater standardizationSystem stability assessed by repeated measurements of a 68Ge/68Ga source over a 100-day period. The data were corrected for radioactive decay with the first measurement being taken as the reference time. The dashed line indicates the mean of the data which are shown normalized to an arbitrary value of 100.Back to article page