Assessing the absolute quantitative accuracy of Positron Emission Tomography for Cu-64 using traceable calibrated...

Using uniform cylindrical phantoms containing calibrated solutions of ¹⁸F and ⁶⁴Cu, we evaluated for the first time the accuracy with which the activity concentration of ⁶⁴Cu can be quantified on an absolute basis using Positron Emission Tomography (with X-ray Computed Tomography, PET-CT). The scanner was first calibrated for ¹⁸F using the manufacturer's calibration protocol and a phantom with an activity concentration value traceable to the U.S. National standard. By using a similarly calibrated ¹⁸F solution phantom, we were able to determine a correction factor that can be applied to the ⁶⁴Cu imaging data that gave a result that is consistent with 100% recovery with a combined standard uncertainty of 2%. We also demonstrate how a calibrated, solid phantom containing ⁶⁸Ge as a long-lived ¹⁸F surrogate can be used to monitor and transfer the correction factor to other studies.