Method and system for determining surrounding radiation dose rate of nuclear medicine subject

The embodiment of the invention discloses a method and system for determining the surrounding radiation dose rate of a nuclear medicine subject. The method comprises the steps of acquiring human body model parameters of the subject and a gray value of a target image, wherein the target image comprises a PET/CT image or a PET image of the subject; determining the space-time distribution of the surrounding radiation dose rate of the subject according to the human body model parameters and the gray value of the subject by using a surrounding radiation dose rate space-time distribution prediction model, wherein the surrounding radiation dose rate space-time distribution prediction model is determined according to the gray level radioactivity specific activity relation and the human body model, and the gray level radioactivity specific activity relation comprises the relation between the gray level and the radioactivity specific activity of the corresponding human body structure unit. According to the embodiment o