Objective: PET imaging is possible with copper (Cu) isotopes, 60Cu, 61Cu, 62Cu and 64Cu. Although 62Cu- and 64Cu-labeled radiotracers are often used for preclinical and clinical PET studies, we do not know which radiotracers have better image quality for tumor imaging. In this study, we compare image quality between 62Cu and 64Cu imaging with a different acquisition mode and reconstruction algorithm using a whole-body phantom for tumor imaging. Methods: In a National Electrical Manufacturers Association (NEMA) 2001 whole-body phantom, the concentration of 62Cu-ATSM and 64Cu-ATSM was, respectively, approximately 2.7 and 1.8MBq/mL in all the spheres and approximately 0.9 and 0.6MBq/mL in the background. After adjustment for true coincidence events between 62Cu and 64Cu, two-dimensional (2D) and three-dimensional (3D) PET scan data were acquired for 10min. The data were reconstructed using filtered back projection (FBP) and the ordered subset expectation maximization (OSEM) algorithm. Image quality of 62Cu and 64Cu was compared using recovery coefficient (RC), sphere-to-background ratio (SBR) and coefficient of variation (%COV). Results: There were little significant differences between 62Cu and 64Cu imaging, visually. Recovery coefficients of 64Cu images were higher than those of 62Cu images. The RC of 64Cu images with 3D acquisition mode and OSEM was the highest in all experiments. No SBR values were significantly different from the true value of 3.0 in 37mm sphere diameters, but 3D acquisition and OSE-Myielded slight overestimations compared with 2D acquisition and FBP, the gold standard for quantification in PET studies. Percentage COV values of 64Cu with OSEM were significantly lower than those of 62Cu. Conclusions: Copper-64 radiotracers provide higher image quality than 62Cu-radiotracers in whole-body tumor imaging only when the 3D acquisition mode and OSEM algorithm are applied. However, the quantitative values for smaller tumors may be slightly overestimated.
|Number of pages||5|
|Journal||Hellenic Journal of Nuclear Medicine|
|Publication status||Published - 01-06-2015|
All Science Journal Classification (ASJC) codes
- Radiology Nuclear Medicine and imaging