This Fourth Edition reflects the significant recent progress that has occurred in functional brain imaging, particularly the increased use of PET/SPECT, the use of SPECT and PET in movement disorders and dementia, and advances in radiopharmaceutical development and instrumentation. Chapter topics include PET physics and instrumentation, PET radiopharmaceuticals, SPECT radiopharmaceuticals, and technical factors. The entire book has been thoroughly revised to reflect an appropriate balance between SPECT and PET applications. Highlights of this edition include a new chapter on neuroreceptor imaging and kinetic modeling, a new chapter on brain imaging in movement disorders, and significant updates on SPECT radiopharmaceuticals.