The compressed files save a lot of space, but they are not suitable for real-time rendering and display. So we still need 15 gigabytes to store the whole data set. After downloading, converting and checking some slices, we found that we can crop the image to smaller size and save some space. This is caused by some error operations by NLM and can not be recovered. So we just leave those files blank.
Some Images are bad.
We believe it is also caused by the problems in the NLM data collection. Some images are shifted and not aligned with the adjacent image. I already spend some time to determine the actual offset and made some corrections. In order to fix the body, they apply semi-transparent blue gelatin to surround the body and make the image full of blue color outside the body. We have written some programs to eliminate it.