Ionizing radiation is a recognized carcinogen. X-rays are ionizing, meaning they have the ability to interact with electrons, causing the atoms to have an electrical charge. The area of a cellular structure that is interacted with can have a significant impact on a cells ability to function. If the x-rays simply interact with water molecules within the cell, no damage may be evident. However, if the x-rays interact with protein molecules, DNA, RNA, or enzymes, the cell can be greatly affected. When this happens, the cell can either repair itself, survive in a damaged state, or die. So what can happen?
Law of Bergonie and Tribondeau
Two scientists established a law which states the radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation. In normal people speak, this means immature or rapidly dividing cells are much more sensitive to radiation than mature cells or those that do not reproduce rapidly. This is true for ALL types of cells. Examples of various cells and tissues and their radiosensitivity are:
Radiosensitive
White blood cells - Due to white blood cells short life spans, lymphocytes live for about a day, they are constantly needing to be replenished. High reproduction rates mean high radiosensitivities. This is why cancer patients undergoing radiation therapy are so susceptible to infections.
Epithelial tissues - These are tissues that line the intestines, respiratory tract, blood and lymphatic vessels. Epithelial tissues are constantly being regenerated, which results in high radiosensitivity.
Reproductive cells
Rapidly dividing cells - Any cells which are rapidly dividing will be sensitive to radiation. A fetus in its first trimester will be more susceptible than one in its second trimester, which in turn is more susceptible than one in its third trimester. This can be carried all the way through life. An infant is more susceptible to radiation than a teenager. A teenager is more susceptible than an adult. A young adult is more susceptible than a geriatric patient.
Somewhat radiosensitive
Red blood cells - Since red blood cells can live, on average, about 4 months, they are not generated as quickly as white blood cells. Red blood cells can be classified as radiosensitive, but are not nearly as sensitive as white blood cells.
Radioresistant - Cells that do not rapidly divide are said to be resistant. These include:
Muscle tissue
Nervous tissue