Nuclear medicine, also known as atomic (nuclear) medicine, is a science that studies the medical applications and theoretical basis of isotopes and nuclear radiation, an emerging discipline that combines nuclear technology and medicine, and an important aspect of mankind’s peaceful use of atomic energy. The mission of nuclear medicine is to diagnose, treat and study diseases with nuclear technology. Nuclear medicine diagnostic techniques include organ imaging, functional assays and in vitro radioimmunoassays. When performing organ imaging and/or functional assays, the physician, depending on the purpose of the examination, gives the patient an oral or intravenous injection of a radioactive tracer that enters the body and participates in the circulation and metabolism of specific organs and tissues in the body, and continuously emits radiation. In this way, we can track and investigate with various special detection instruments outside the body, and show the morphology and function of the patient’s internal organs in the form of numbers, images, curves or photographs. Nuclear medicine imaging methods are simple, sensitive, specific, non-invasive, safe (the radiation dose to the patient is lower than the dose received in a single X-ray), easily reproducible, accurate and reliable, and reflect the function and metabolism of the organs, and are therefore increasingly used in clinical and basic research. Nuclear medicine instruments The instruments used in nuclear medicine imaging are mainly γ camera and ECT. γ camera is an important diagnostic equipment of modern nuclear medicine, γ camera can simultaneously record the rays of various parts of the organ, in order to quickly form a frame of the static plane image of the organ, and at the same time, because of its fast imaging speed, can also be used to obtain continuous photos reflecting the changes in the distribution of radioactivity in the organ, after data processing, can observe the dynamic organ After data processing, the dynamic functions of organs and their changes can be observed, so the γ camera is both a visualizer and a functional instrument. ECT includes SPECT and PET What we usually call ECT refers to single photon emission computed tomography, i.e., SPECT, which is actually a γ camera with a probe that can rotate 360° around a certain organ of the patient and acquire a frame every certain angle (3° or 6°) during the rotation, and then automatically processed by the electronic computer to superimpose the images and reconstruct them as cross-sectional, cross-sectional and functional images of the organ. SPECT also has the function of general γ-camera, which can perform planar and dynamic (functional) imaging of organs. The basic principle of PET is to use ultra-short half-life isotopes, such as 18F, 13N, 150, 11C, etc., produced by a gas pedal as tracers into the human body to participate in the physiological and biochemical metabolic processes in the body. These ultra-short half-life isotopes are the main elements of the human body, the use of their emission of positrons combined with the body’s negative electrons to release a pair of gamma photons, detected by the probe’s crystal, to obtain high-resolution, high-definition in vivo tomographic images to show the human brain, heart, other organs and tumor tissue physiology and pathology of the function and metabolic situation. The development of PET and its successful clinical application is one of the major signs of contemporary high-tech medical diagnostic technology. cardiovascular system, and oncology. However, PET is expensive, requires a small medical cyclotron, and has high daily management costs, making it difficult to be widely used. In clinical applications, PET is a very sensitive and specific tool for diagnosing heart disease; PET has a unique role in diagnosing and observing the efficacy of tumors, epilepsy, dementia, Parkinson’s disease, depression, cerebrovascular diseases and neurodegenerative diseases; PET plays a unique role in diagnosing and guiding the treatment of tumors, with specific applications including: differentiation of benign and malignant The specific applications are: differentiation of benign and malignant; assessment of malignancy; clinical staging; search for primary and metastatic foci, evaluation of efficacy and determination of recurrence.