Comparison of (90)Y activity measurements in nuclear medicine in Germany

In 2014, PTB and the company Eckert & Ziegler organized a national comparison exercise to determine the activity of a (90)Y solution. One aim of the comparison was to assess the measurement capability of hospitals and medical practices in Germany. P6-type vials were filled with aliquots of a radioactive (90)Y solution and then sent to 19 participants who were asked to measure the activity in the ampoules as well as in their own standard geometry using syringes. Most of the submitted results have a deviation of less than ±10% from the PTB reference activity when measured in the P6-type vials. The spread is somewhat larger when measured in a syringe geometry. The comparison revealed that some participants have difficulties in applying decay corrections and only a few participants were capable of estimating realistic measurement uncertainties.