If you have problems in seeing the GIF animation with your web browser, then save the images and view them with a program capable of showing animated GIFs.
These GIFs are made using Jasc Animation Shop 3.00 from a series of TIFF images produced from PET images using self-made program ecat2tif.
[18F]FDG uptake in the brain shown in fast-motion (100x)
[11C]flumazenil uptake in the brain shown in fast motion (100x)
[15O]O2 uptake in the thighs, with the right leg exercising. Fast motion (50x)