This fifth edition was prompted by the need to provide up-to-date information to keep pace with the perpetual growth and improvement in the instrumentation and techniques employed in nuclear medicine since the last edition published in 2012. All chapters are updated, removing irrelevant information and adding the latest updates to the field. Two chapters on artificial intelligence have been added, one on the general concepts of AI and another on the application to nuclear medicine. Like previous editions, the book is intended for radiology and nuclear medicine residents to prepare for the American Board of Nuclear Medicine, American Board of Radiology, and American Board of Science in Nuclear Medicine examinations, all of which require a strong physics background. Additionally, the book serves as a textbook on nuclear medicine physics for nuclear medicine technologists taking the Nuclear Medicine Technology Certification Board examination.