| Image compression has been proved a useful tool in medical image management and telemedcine, by which storage room and transmission time would be saved. Image compression is usually fulfilled in two modes. One is lossless or reversible compression, by which images can be restored to their original after decompression. The other mode of image compression is lossy or irreversible compression, in which some data is purposely removed, and the compressed images can not be restored to their original. Lossy image compression provides higher compression ratio and thus would be more useful when used in the right way. JPEG2000 is a recent international standard of image compression, which is based on the descrete wavelet transform instead of discrete cosine transform like JPEG. Features and advantages of JPEG2000 include multiresolution capability, high compression rate, perceptual quality coding, and superior lossy and lossless compression in a single code stream, as well as image zooming, panning, and tiling capabilities. As JPEG2000 support was added to the DICOM standard recently, more medical usage of JPEG2000 is expected.Nuclear medicine image is called functional image because it reveals the function of organs and tissues in the human body. However, nuclear medicine images have lower resolution power and higher noise level compared with other medical image modalities. To study the usefulness of JPEG2000 compression of nuclear medicine image, research work was carried out in this article as following. To have a good beginning, two elementary works were accomplished. The first is to optimizing the pixel size measurement protocol, which turned out to produce a gain of precision from 7.07 ± 6.35mm to 3.01 ±0.00mm, and a reduce of relative error from >100% to < 1%. The second is the establishment of golden standard for image diagnostic quality assessment. The golden standard is an image set, composed of 30 normal images and 30 images with a 1-cm diameter cold or hot, artificial lesion...
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