With the rapid development of nuclear medicine, isotopes play an increasingly important role in disease diagnosis and clinical treatment. Its research field has penetrated into genes, nucleic acids, proteins, and studied the process of disease occurrence, development, outcome and evolution, etc. Developing and establishing isotope production reactors with high productivity and good safety is expected to break through the bottleneck of nuclear medicine, so as to achieve the purpose of exploring pathogenesis and correctly diagnosing diseases.

Radioimmunoassay

Using radioimmunoassay to analyze the bioactive substances in patients' body fluids in vitro can quickly and effectively diagnose diseases in vitro. It is an in vitro microanalysis method of radioisotopes, which uses competitive inhibition reaction between labeled isotopes and unlabeled antigens and antibodies. It is also called the competitive saturation analysis method. The radioisotopes commonly used to label antigens are 3H, 125I, 131I, and so on. Radioimmunoassay is used in endocrinology to determine insulin, growth hormone, parathyroid hormone, angiotensin, catalytic hormone, luteinizing hormone, follicle-stimulating hormone, prostaglandins, etc., in order to identify, diagnose, study the physiological and pharmacological effects of hormones, and study the binding mechanism between hormones and receptors. It is widely used in the classification and determination of hepatitis B antigen subtypes in epidemiology. Immunoglobulin G, immunoglobulin E, anti-deoxyribonucleic acid antibody, thyroglobulin antibody, rheumatoid factor, complement and anti-food antigen antibody were measured in clinical immunology. In oncology aspect, it is used to determine carcinoembryonic antigen, plasminogen, folic acid, vitamin B12, fibrinogen and fibrin degradation products. In pharmacology aspect, morphine, chlorpromazine, phenytoin, gentamicin, digoxin, theophylline, etc. can be measured, which is a quick and simple method to detect drug poisoning and drug metabolism.

Internal drug therapy

Medical isotopes, as radiopharmaceuticals, are mainly used for the diagnosis and treatment of diseases. They use the specific enrichment and distribution of radiopharmaceuticals in tissues (including implantation intervention) or the targeted specificity of carriers (monoclonal antibodies, polypeptides, etc.) to bind to diseased parts, and relies on the biological effects produced by radioactive nuclide emission particles (α, β, secondary electrons and Auger electrons, etc.) carried by them to achieve the purpose of treating or destroying diseased tissues. For example, 131I radiopharmaceuticals are widely used in the diagnosis and treatment of thyroid cancer, hyperthyroidism, hypothyroidism and kidney diseases. Na131I treatment of differentiated thyroid cancer has become the first choice or classic treatment for postoperative follow-up treatment of such patients.

External irradiation therapy

At present, radiation therapy is one of the three effective methods for cancer treatment. Ionizing radiation has the ability to kill cancer cells. Cells in rapid division are extremely sensitive to radiation. Radiation therapy can control the growth of cancer cells or kill cancer cells, and try to avoid harming normal cells. More than 70% of cancer patients are treated with radiation, and many radiation therapies can also be used to relieve pain. For example, 153Sm and 186Re are used to relieve bone pain caused by cancer. Radiotherapy can be divided into long-distance irradiation, intracavity reloading short-range irradiation, interstitial short-range irradiation and internal interventional irradiation.

Imaging agent

Imaging can show the shape, size and uptake degree of the lesion; at the same time, with the help of CT scanning, the lesion site and its relationship with surrounding tissues can be accurately located. According to the results of Single-Photon Emission Computed Tomography (SPECT) /CT, the treatment plan and dosage of radiopharmaceuticals can be adjusted to improve the treatment effect and the prognosis of patients. The difference between nuclear medicine imaging technology and other imaging technologies such as CT and B-ultrasound is that the former depends on the blood flow, cell function, cell number, metabolic activity and excretion and drainage of organs or tissues, and is a functional metabolic imaging; The latter mainly shows the anatomical morphological changes of organs or tissues, which is a kind of anatomical imaging. There are more than 100 kinds of radioisotope labeled radiopharmaceuticals, and many of them can be made into medicine boxes for supply. The labeling is simple and easy to use, which promotes the development of SPECT imaging diagnosis application in modern nuclear medicine. For example, 99mTc imaging agent has been widely used for imaging the morphology and function of various human organs such as heart, brain, kidney, bone, lung and thyroid.