Feasibility demonstration of imaging in vivo biodistribution of Yttrium-90 microspheres after radioembolization with a digital detector PET/CT system.

Objectives To assess the clinical feasibility of next generation digital PET detector technology for imaging Yttrium-90 internal pair production in vivo following radioembolization and compare to existing conventional photomultipler detector PET/CT technology.

Methods A next-generation, solid-state, digital PET/CT system (Vereos TF 64, Philips Healthcare) is being used to image patients following Yttrium-90 microsphere radioembolization and compare its image characteristics, by intra-individual comparison, with a conventional photomultiplier detector time-of-flight PET/CT (Gemini TF 64, Philips Healthcare). In addition, true coincident event rates corresponding to Yttrium-90’s internal pair production were normalized to the acquisition bed volume and total image volume for both PET/CT systems and compared.

Results When compared with conventional PET/CT, digital detection of Yttrium-90’s internal pair production also produced evaluable images for qualitatively and quantitatively assessing Yttrium-90 biodistribution throughout the liver. Furthermore, the normalized total true coincident event rate was higher for the digital PET/CT.

Conclusions The initial evidence demonstrates that ⁹⁰Y internal pair production can be readily imaged in vivo with digital detector technologies at least equivalent to conventional PET/CT. It appears feasible that reduced acquisition times may be possible without significant impact on subsequent quantification of Yttrium-90 activity.

Research Support This research was supported by the Ohio Third Frontier ODSA TECH 09-028 TECH 10-012 and TECH 13-060