Many malignant tumors may metastasize when they reach a certain stage of disease. Malignant tumors can metastasize to various organs and systems in the body, such as brain, liver, lung, kidney, etc. When tumors metastasize to bones, resulting in the growth of bone tumor lesions, it is called bone metastasis cancer. According to research, the incidence of bone metastasis of certain malignant tumors is very high, for example, the incidence of bone metastasis of breast cancer, prostate cancer and lung cancer is as high as 50~85%, and other cancers such as nasopharyngeal cancer, bladder cancer, kidney cancer, cervical cancer, pancreatic cancer, etc. may occur. Bone metastases often cause severe pain, fracture, bone marrow failure, difficulty in walking and nerve compression symptoms. Bone pain is the most prominent symptom in many patients, which is the result of tumor invasion of the periosteum, which is rich in innervation, and can also be caused by thinning of bone tissue due to mechanical compression of the tumor and tumor spreading from bone to nerve tissue. Irritation of nerve endings by chemicals released from the destruction of bone tissue is also an important cause of bone pain. Due to this severe bone pain, patients suffer from severe pain and their quality of life is severely reduced. The treatment goals for bone metastatic cancer are two: one is to stop pain; the other is to eliminate and reduce lesions. Only by eliminating and reducing the lesions can we fundamentally achieve the goal of pain relief. At present, the commonly used treatment methods include surgery, external radiotherapy, chemotherapy and the application of various pain relieving agents. These treatments have their clinical value for patients with different sites and clinical stages, but all of them have certain limitations and disadvantages. For example, surgery and external radiotherapy are often powerless against extensive bone metastases; chemotherapy has heavy systemic toxic side effects; and some pain relievers are addictive. At present, medical experts at home and abroad are studying and searching for new and effective treatment methods. Radionuclide therapy is one of the important results of such research. The two main methods include 89Sr treatment and 153Sm-EDTMP treatment. The indications for radionuclide therapy are: 1. Clear diagnosis of bone metastatic cancer, especially those with extensive bone metastases. 2.Radionuclide bone imaging shows obvious uptake of radioactivity in bone metastases, so bone imaging is a necessary preparation before treatment. 3.Severe bone pain caused by bone metastasis, chemotherapy and external radiotherapy are ineffective, some patients have bone metastasis but no pain, radionuclide therapy can prevent the pain. 4. Those with leukocytes > 3.5×109/L and platelets > 80×109/L. 89Sr (89 strontium) for bone metastases 89Sr is a pure beta-emitting radionuclide, which was used in 1942 for the treatment of bone metastases and is an early bone treatment drug. Strontium is in the same group as calcium in the periodic table, and its metabolism is similar to that of calcium, mainly concentrated in the skeletal system but less in other tissues and organs of the body. After 89Sr enters the body through intravenous injection, 90% of it is concentrated in the skeletal system and only 10% is excreted by the kidney. 89Sr concentration in bone metastases is 2~25 times of normal bone, which has very good analgesic effect on the pain caused by bone cancer. The half-life of 89Sr is relatively long, reaching 50.5 days, and it is taken up by bone soon after injection. The biological half-life in metastases is >50 days, while that in normal bone is 14 days. The long residence time of 89Sr in metastases is probably due to the recirculation of 89Sr released from normal bone. Ninety days after injection, the retention of 89Sr in the metastases can still reach 20%~88%, which can maintain a long-lasting drug effect. Therefore, 89Sr treatment is given once every three months. Regular follow-up review of bone imaging in some patients showed that the abnormal concentrated shadow continued to shrink, fade, or even disappear with the prolongation of time after 89Sr sedation, and clinical symptoms also improved significantly. 89Sr can also reduce the level of alkaline phosphatase and prostaglandin (PEG), which is conducive to reducing osteolysis, repairing bone, achieving pain relief and lowering blood calcium. The main therapeutic effect of 89Sr is analgesia to improve the quality of life of patients and reduce pain. It has been reported that 79%-92% of prostate cancer and breast cancer patients with 89Sr treatment have reduced pain and improved quality of life. Most scholars now believe that 89Sr is most effective for bone metastases caused by these two types of cancer, with an overall effective rate of 80% to 90% and complete disappearance of pain in 10% to 18% of patients. 89Sr has also been used for the treatment of painful bone metastases caused by lung cancer, kidney cancer, nasopharyngeal carcinoma and other cancers. Another purpose of 89Sr treatment is to make bone metastases shrink or disappear in order to relieve the disease and prolong the life of the patient. Its b-rays can kill tumor cells, thus in addition to analgesia, 89Sr can also have a therapeutic effect on bone metastases. Currently, some scholars use 89Sr for the treatment of bone metastases without pain in order to prevent and delay the occurrence of bone pain. 153Sm (153Sm)-EDTMP for bone metastases The Department of Nuclear Medicine of related hospitals is the first one in China to develop a successful drug for bone tumor guided internal radiotherapy, 153Sm-EDTMP (ethylenediamine tetramethyldiphosphonic acid), commonly known as a biological missile for treating bone tumors, which is also known as radionuclide therapy for bone cancer. The drug has a high affinity for bone, especially bone tumor site after intravenous injection, and the drug concentration in bone is 4000 times greater than that in muscle, and the drug concentration in lesioned bone is 18~32 times greater than that in normal bone, therefore, the b-rays released by radionuclide 153Sm can be used to inhibit the growth of tumor cells, stop the development of lesions, and then cause tumor cell degeneration and death, so as to achieve both pain relief and elimination and reduction of lesions. The purpose of the treatment is to eliminate and reduce the number of lesions while relieving pain. The advantages of 153Sm-EDTMP treatment are: 1. Simple treatment method: only one intravenous injection is needed for one course of treatment, and the treatment can be repeated in half a month to one month depending on the situation, and there is generally no serious discomfort. 2. Good pain relief effect: According to the data of our hospital, the total effective rate of 153Sm for bone cancer pain relief is 93% according to the internationally recognized classification of cancer pain and WHO cancer efficacy standards. Generally, bone pain disappears or is significantly reduced 2~7 days after injection, and can be maintained for 1~6 months and up to 1 year. 3. It has the effect of eliminating and shrinking bone metastasis cancer: according to our statistics, its elimination and shrinking rate is about 30%. 4. No obvious damage to important organs; because 153Sm is basically completely cleared from blood 1 hour after injection, except for more than 50% reaching bones and lesion sites to play a therapeutic role, the rest is rapidly excreted from urine, so it will not cause damage to other organs and tissues. 5. No serious myelosuppressive effect: According to the data of our hospital, 153Sm treatment before receiving no other treatment or only receive radiotherapy, there is no significant difference in blood picture before and after treatment, a few patients have platelet and white blood cell reduction, but generally can be recovered in a short time. Because of the above advantages, domestic and foreign experts believe that the success of this treatment method has created a new way of treating bone tumors with radionuclide, which is another fruitful achievement of the peaceful use of nuclear technology for the benefit of mankind. Therefore, it won the First Prize of Sichuan Provincial Science and Technology Progress in 1995. It has also been exchanged in many academic conferences at home and abroad, and has won wide acclaim and praise. It must be pointed out that any malignant tumor is not a local disease, but a systemic one. The complexity and systemic nature of malignant tumor determines the multidisciplinary nature of treatment. Besides surgery, radiotherapy and chemotherapy, there are also immunotherapy, endocrine therapy, Chinese medicine, fever therapy, laser therapy, interventional therapy, etc. Each of these methods has its own indications, advantages and disadvantages, and if radionuclide therapy is scientifically arranged and integrated with other treatment methods, it will definitely achieve better efficacy.