@article {Lodge121P, author = {Martin Lodge and Arman Rahmim and Frank Bengel and Richard Wahl}, title = {Examining the effect of patient body size on 2D and 3D PET}, volume = {49}, number = {supplement 1}, pages = {121P--121P}, year = {2008}, publisher = {Society of Nuclear Medicine}, abstract = {482 Objectives: PET image quality deteriorates with increasing patient body mass due to a combination of greater image noise and reduced lesion contrast. For BGO systems, it has been shown that 3D acquisition is associated with a more significant deterioration than 2D. The objective of this study was to determine whether this was also the case for an LYSO scanner with improved 3D performance. Methods: The NEMA NU 2-2001 image quality phantom was used to assess 2D and 3D performance with and without an additional 10 kg of tissue-equivalent padding material. Paired images were acquired in each mode using an interleaved protocol (2D$\#$1/ 3D$\#$1/ 2D$\#$2/ 3D$\#$2) for both levels of attenuation, over a range of activity concentrations. All data were acquired on a GE Discovery RX: LYSO detectors, 425-650 keV, 6.5 ns, randoms from singles, 2D OSEM (2i, 21s, 5 mm post filter) and 3D OSEM (2i, 21s, 3 mm post filter). Image statistical quality (SNR) was measured for each acquisition mode and attenuation level by calculating both the mean and the difference between corresponding background pixels in the paired images. Results: Hot sphere recovery coefficients were significantly (p=0.002) greater for 3D compared to 2D with the standard phantom. With the padded phantom there was no significant difference (p=0.45) indicating matched contrast recovery between 2D and 3D. Image SNR in 3D divided by 2D was 1.59 {\textpm} 0.02 for the standard phantom and 1.71 {\textpm} 0.01 for the padded phantom indicating substantially lower noise in 3D for both phantom sizes. Conclusions: Although image noise deteriorated with increasing patient body mass, 3D acquisition did not lead to a greater noise deterioration than 2D for this LYSO scanner. Reduced contrast recovery in 3D for large patients was compensated by a slightly higher resolution reconstruction while still maintaining the noise advantage of 3D.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/49/supplement_1/121P.3}, eprint = {https://jnm.snmjournals.org/content}, journal = {Journal of Nuclear Medicine} }