Chemotherapy and radiotherapy are the three major treatments for tumors, which sounds like the rush of biohazard, as a layman of medical knowledge, you may be full of curiosity. Is there much radiation in the hospital? Doctor, I’ve had 3 CTs in the last 6 months, will I get cancer? In fact, chemotherapy is just an infusion, and radiotherapy is just “baking electricity”. Chemotherapy is the abbreviation of chemical drug treatment, the essence of chemotherapy is just drug treatment, to be frank, you have a tumor, give you some medicine, all can be collectively called chemotherapy. However, when patients use the term chemotherapy, the concept of chemotherapy is ambiguous, as if chemotherapy refers to those very toxic drugs, chemotherapy is bound to vomit, chemotherapy will lose hair, no treatment is okay, once chemotherapy, it will die faster. Most of the drugs used in chemotherapy are cytotoxic drugs, this is true, because chemotherapy drugs to poison is the tumor cells, modern pharmaceutical technology makes the majority of drugs into the body will be selective, the impact on normal cells is very small, so the majority of patients can better tolerate chemotherapy. Chemotherapy is designed to shrink tumors and destroy potential metastatic lesions. Chemotherapy can prolong the life of patients, and many tumors can be cured by chemotherapy alone. The pathological complete remission rate is said to be the probability that the tumor is completely eliminated by chemotherapy. Chinese herbal medicine, proprietary Chinese medicine, targeted drugs, endocrine drugs, immune drugs, etc. are often used as anti-tumor drugs, but the current scope of chemotherapy drugs does not cover these drugs, and chemotherapy drugs refer to cytotoxic “chemical” drugs. In contrast to chemotherapy, there should also be physical therapy. Radiation therapy is a broad form of physical therapy, that is, radiation therapy, in which radiation is used. When cells are ionized by radiation, DNA is damaged, which causes different degrees of apoptosis and damage, and apoptosis of tumor cells is certainly the most desirable result. However, some of the cells only undergo non-lethal damage, and the body responds to the damage: repair. If there is damage, there is repair. When radiation irradiates tumor cells, it will inevitably irradiate normal cells as well. Because tumor cells are actively proliferating, most of them are in mitotic phase M, while normal cells in the body are more stable, most of them are in synthetic phase G. A lot of in vitro experiments show that cells in phase M are more sensitive to radiation, in other words, most tumor cells in phase M are more vulnerable to radiation damage, while normal cells in phase G are not sensitive to radiation and are not easily damaged, which is the basic reason why radiation can treat tumors. This is the basic principle of radiation being able to treat tumors. The radiation hurts the tumors, but not so much the normal cells. We are often concerned about children, men and women preparing for pregnancy, pregnant women should not receive X-ray examinations, to stay away from radiation, indeed, because our gonads are too fragile to radiation, the limit of tolerance dose is only a few Gy, some data show that 0.15Gy dose may lead to temporary testicular sterility (male friends must be careful). So how much radiation dose will you receive from a chest X-ray and a CT scan? Chest X-ray once about – 1.1mSv; Chest X-ray once dose – 0.2mSv; CT of the head – 2mSv; CT of the chest – -8mSv; abdominal CT – 10mSv; pelvic CT – 10mSv; dose for a 20-hour airplane ride – 0.1 mSv; subway security passengers may receive a dose of <0.01mSv per year. Here are two different units of dose, roughly speaking, Gy is 1000 orders of magnitude higher than mSv. Looking at the data, I am often correct in saying that a single chest CT is equivalent to doing dozens of chest films. For those patients with cancer, if you are going to receive radiation therapy, you will generally have to tolerate tens of Gy, which is equivalent to 10,000 CT exams. So we won't be upset because we had a few more CT exams. If cancer patients can tolerate radiotherapy, what's the harm of having more CTs? Hint: This is to allay the concern of patients who need to have CT repeatedly because of the evaluation of their disease but refuse to have the test for fear of excessive radiation dose. There is no increased risk of cancer as long as the test is performed in compliance.