Image Noise Analysis of a Large Ring PET Scanner

Abstract

Image noise analysis of a large ring PET scanner "macro PET" performed using two different phantoms, namely a Jaszczak SPECT phantom and a uniform cylindrical phantom. In the present work, simple 2D filtered back projection was used to reconstruct all the images, and in almost all the cases a Hamming filter of cutoff frequency 0.4 and a 256 by 256 matrix with zoom factors from 1 to 4 were used in order to investigate the imaging capabilities of the new scanner and the influence of filter and cut-off frequency on the filtered back projected images. Results indicate that 11.1 mm cold rod in the Jaszczak phantom images can consistently be seen. The Coefficient of variation (CV) results for Hann and Hamming filters are very similar and increase approximately in linear fashion with higher cutoff frequency. The value of CV for the Parsen filter is lower than the value for Hann and Hamming filters. It concludes that all filters with low cut off-frequency (<0.6) would suppress image noise but decrease contrast.

Study of Image Contrast Recovery Coefficient (CRC) of a Large Ring PET Scanner

“…There is no significant difference between the images generated from three filters in case of lesion detection as expected. In our previous study [9], it was very hard to make conclusion to choose the better filter from the reconstructed images. But the image generated by the Hamming filter with cut-off frequency of 0.4 and 0.8 may be slightly better visible than the other images.…”