Comparison of 2D and 3D performance for FDG PET with different acquisition times in oncological patients

Collecting positron emission tomography data in three-dimensional (3D) mode may potentially allow reduction of the tracer dose and/or the acquisition time without compromising image quality thereby making the procedure more patient-friendly and cost effective. The objective of our study was to compare VUE Point iterative reconstruction algorithm in positron emission tomography data obtained in 3D and two-dimensional (2D) mode in routine clinical diagnostic setting in oncological patients.

Standard whole-body imaging (33 patients) was followed by rescanning of the target region in 2D and 3D mode. The ListMode data were histogrammed to 4, 3 and 2 min frames. Visual and semiquantitative analyses were performed. Effects of tumour volume and body mass index on tissue visualisation were evaluated.

Visual image quality in 3D mode was superior to 2D. Maximum and mean standardised uptake values of tumours did not differ between 2D and 3D. Mean background standardised uptake values were significantly lower in 3D compared with 2D. 3D tumour to background ratios were higher than 2D in small lesions and obese patients (body mass index > or = 30) with all acquisition times.

The new reconstruction method produces images of similar or better quality with 3D compared with 2D mode. The difference is pronounced in small lesions and in obese patients. According to our study, 3D is the preferred acquisition mode for routine whole-body evaluation of oncological patients.