[Objective and quantitative study on the effect of lossy JPEG2000 compression of nuclear medicine image].

To objectively and quantitatively study the effect of JPEG2000 lossy compression of nuclear medicine image, line source images of various noise levels, actual quadrant-bar phantom images and simulated quadrant-bar phantom images of various noise levels were compressed using a JPEG2000 plug-in at 10 : 1 to 50 : 1 with a 10 : 1 step. Modulation transfer function (MTF), full width at half-maximum (FWHM) and the peak to total count ratio (PTCR) of line spread function of the simulated line source images were analyzed quantitatively. Image quality of the quadrant-bar phantom images was visually evaluated according to quality control procedures and the result was used to verify the quantitative analysis. It was observed that PTCR decreased as compression ratio increased and the higher the noise level, the faster PTCR decreased, which was in accordance with the increase of the width of the smallest bars that can be visually resolved in the actual quadrant-bar phantom images and simulated quadrant-bar phantom images. On the other hand, no significant change of MTF and FWHM was observed as compression ratio increased. It was concluded that PTCR may serve as an objectively quantitative metrics of image quality assessment.