Intestinal radiculopathy presents with small bowel crisis in about 1 week. Acute radiation sickness (acuteradiationdisease) is a systemic disease caused by exposure of the body to a large dose (1Gy) of ionizing radiation in a short period of time. External and internal irradiation may occur acute radiation sickness, but external irradiation is the main. External irradiation caused acute radiation sickness rays gamma; line, neutrons and X-rays. I. nuclear war 101kt below the nuclear explosion of exposed and shielded personnel, 101kt above the explosion of shielded personnel, in the heavily contaminated area through and stayed too long personnel, by early nuclear radiation or radioactive contamination of external irradiation, is the main factor in the occurrence of a large number of acute radiation sickness casualties. Second, usually 1, nuclear radiation accidents The world now has more than 430 nuclear power plants in operation, the new nuclear power plants are still increasing, from the fifties to date there have been several accidents. One of the biggest was the Chernobyl nuclear power plant accident in 1986, in which more than 200 cases of acute radiation sickness occurred and 29 people died. Various types of radiation sources are being used more and more extensively in various fields of production and medical care, and hundreds of radiation accidents of various types have occurred as a result of improper use or storage. Since the 1960s, China has also had a number of accidents involving radiation sources, with many casualties. 2, medical accidents Radionuclides and radiation devices for medical applications, there may also be medical accidents. For example, there have been accidents in foreign countries in which excessive radionuclides were mistakenly used to treat patients, resulting in acute radiation deaths from internal irradiation, and there have also been accidents in which patients were exposed to excessive irradiation due to the failure of radiation devices. 3, therapeutic irradiation treatment needs to give patients a large dose of irradiation, can cause therapeutic acute radiation sickness. Such as bone marrow transplantation before the commonly used large-dose (6Gy) whole-body irradiation or whole-body lymph node irradiation, as a pretreatment before bone marrow transplantation. Hematopoietic injury is characteristic of bone marrow radiculopathy and it occurs throughout the course of the disease. Reduced cell division index, dilated and congested blood sinusoids are seen in the bone marrow immediately after a few hours of irradiation. This is followed by bone marrow cell necrosis, hematopoietic cell reduction, blood sinus seepage and rupture, and hemorrhage. Hematopoiesis of the erythroid lineage precedes that of the granulomatous lineage, initially with a decrease in naïve cells, and later with a decrease in mature cells. The degree of bone marrow changes is related to the irradiation dose, irradiation dose is small, blood cells only slightly reduced, bleeding is not obvious. If the irradiation dose is large, the hematopoietic cells are severely deficient, or even completely disappeared. Only adipocytes, reticulocytes and plasma cells remain, lymphocytes can be relatively increased, others such as tissue basophils, osteoclasts, osteoblasts are also increased, and there is severe hemorrhage, presenting the phenomenon of severe suppression of bone marrow. After the destruction of bone marrow, if enough hematopoietic stem cells are retained, hematopoiesis can be rebuilt. The recovery of bone marrow hematopoiesis can be started in the third week after irradiation, and the obvious regeneration can be recovered in 4~5 weeks after irradiation. Hematopoiesis often does not recover on its own if the irradiation dose is high. The change rule of lymphocytes (mainly spleen and lymph nodes) is similar to that of bone marrow, and is also dominated by inhibition of cell division, cell necrosis, reduction and hemorrhage, which develops faster than bone marrow and recovers earlier than bone marrow, but it takes a longer time for complete recovery. With the development of hematopoietic organ lesions, the clinical process of myeloid radiculopathy has obvious stages, which can be divided into the initial stage, false healing stage, extreme stage and recovery stage. Particularly pronounced are the moderate and severe stages.