Marcelo Araujo Queiroz MD, Presenter: Nothing to Disclose

Gaspar Delso PhD, Abstract Co-Author: Employee, General Electric Company

Patrick Veit-Haibach MD, Abstract Co-Author: Research Grant, Bayer AG Resaarch Grant, F. Hoffmann-La Roche Ltd Research Grant, General Electric Company

Gustav K. Von Schulthess MD, PhD, Abstract Co-Author: Research Grant, General Electric Company

Scott David Wollenweber, Abstract Co-Author: Nothing to Disclose

To optimize injected dose of FDG in a Time-of-Flight (TOF) PET/MR, based on cross-evaluation of patient-based NECR measurements by means of the NECR curves.

A total of 71 consecutive patients were evaluated in this retrospective study. PET/CT imaging was performed on a PET/CT-MR setup including a time-of-flight Discovery D 690 PET/CT (TOF-PET/CT) and a time-of-flight Discovery 750w 3T MR (TOF-PET/MRI). An optimal NECR for diagnostic purposes was defined in clinical patients (NECRP). Subsequent optimal activity concentration at the acquisition time ([A]0) and target NECR (NECRT) were obtained. These data were used to predict the FDG dose requirement of a new TOF-PET/MR system.

The obtained values for NECRP, [A]0 and NECRT were 114.6Kcps, 4.0KBq/mL and 45Kcps, respectively. Evaluating the NECRT together with the phantom curve of a TOF-PET/MR device, the optimal activity concentration was found to be approximately 1.3KBq/mL, which represents 35% of the activity concentration required by the TOF-PET/CT.

The new TOF-PET/MR device requires significantly less activity to generate PET images with good-to-excellent image quality, due to improvements in detector geometry and embedded detector technologies. For the new TOF-PET/MR system, a reduction of approximately 65% of FDG-dose might maximally be achieved while maintaining the same clinical image quality.

Patients will need less FDG dose on the new TOF-PET/MR, decreasing the radiation exposure without loss of image quality.

Queiroz, M, Delso, G, Veit-Haibach, P, Von Schulthess, G, Wollenweber, S, Dose Optimization in TOF-PET/MR Compared to TOF-PET/CT.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045763.html