Iionisierender to radiation (radiation exposure and contamination) is one of high-energy electromagnetic waves (X-rays, gamma rays) particles (alpha particles, beta particles, neutrons) Ionizing radiation emitted from the radioactive elements and devices such as X-ray and radiation therapy apparatus. Most diagnostic tests that use ionizing radiation (eg. As X-ray, CT, scintigraphy), patients expose relatively low doses of radiation, which are generally regarded as safe. However, any ionizing radiation is potentially harmful, and there is no threshold below which no adverse effect occurs, so that every effort must be made to minimize the radiation exposure. There are several ways to measure the radiation exposure: The energy dose is the absorbed amount of radiation per unit mass. It is expressed in the special unit of Gray (Gy) and Milli Gray (mGy). Previously, the conventional unit, the absorbed dose of radiation ( “radiation-absorbed dose” = rad) 1 mGy = 0.1 was rad. The organ dose is the absorbed dose multiplied by a radiation weighting factor depending on the type of radiation, the tissue effects taken into account (for. Example, X-rays, gamma rays, electrons). It is expressed in sievert (Sv) and millisieverts (mSv). Previously, the unit “roentgen equivalents in man” (rem) for customary (1 mSv = 0.1 rem). For x-rays, including CT, the radiation weighting factor is 1. The effective dose is a measure of the risk of cancer. It depends on the organ dose depending on the sensitivity that is exposed to the radiation of the tissue (eg. B. gonads are particularly susceptible). It is expressed in Sv and mSv and. The effective dose is higher among young people. Medical imaging only provides a source of exposure to ionizing radiation is (see table: Typical radiation doses *). Another source is the environmental background levels (by cosmic rays and natural isotopes), the v. a. may be at altitudes of importance; Air traffic leads to increased exposure to environmental radiation, as follows: From a single flight from coast to coast: 0.01 to 0.03 mSv from the average annual exposure to background radiation in the United States: About 3 mSv of the annual exposure in large heights (e.g., Denver, Colorado.): Possibly> 10 mSv Typical radiation doses * Imaging method average effective radiation dose (mSv) X, thorax (postero-anterior view) 0.02 X-ray, thorax (2 Overviews: postero-anterior and lateral) x 0.1, lumbar spine in 2 planes x 1.5, x-ray 0.001-0.01 limb, abdomen 0.7 0.4 barium enema CT mammography 8, head 2 CT, the body (breast, abdomen or pelvis) 6-8 coronary angiography Coronary angiography 7 m it interventions 15 Lungenperfusionsscan 2.0 PET scan (without full body CT) 7 bone scan 6.3 Liver investigation 2.1-3.1 technetium Sestimibi heart scan from 9.4 to 12.8 * doses may vary. Data from Mettler FA, Huda W, Yoshizumi TT, Mahesh M: Effective doses in radiology and diagnostic nuclear medicine: A catalog. Radiology 248: 254-263, 2008. The radiation can be harmful if the total accumulated dose for a person is high, or if multiple CT scans are performed because CZ scans require a high dose. Radiation is also a concern in certain high-risk situations, as in the following: pregnancy childhood Early Childhood Young adulthood for women who need a mammogram in the US, the CT makes> 15% of all imaging tests, but causes about 70% of total radiation in diagnostic imaging. Multidetector CT devices that are most used in the US, provide about 40-70% more radiation per scan as a single older single-detector CT scanners. But recent advances (eg. As automatic exposure control, iterative reconstruction algorithms, third generation CT detectors) appear to be the radiation doses used for CT scans to probably significantly reduce. The American College of Radiology has initiated programs-Image Gently respond (for children) and Image Wisely (for adults) -to the concerns about the rise in exposure to ionizing radiation, which is used in medical imaging. These programs provide resources and information on the minimization of radiation exposure for radiologists, medical physicists, the other party in imaging procedures and patient. Radiation and cancer, the estimated cancer risk from radiation exposure in diagnostic imaging was extrapolated (survivors of the atomic bombings in Hiroshima and Nagasaki z. B.) from studies in people with very high doses of radiation. This bill suggests a small but real risk of cancer when radiation doses in the tens of mGy number (as in CT) are used. Pulmonary CT angiography, which is routinely performed to detect a pulmonary embolism, sends about as much radiation to the breast such as 10 to 25 mammograms in two planes. The risk is higher in young patients, because you live longer, allowing more time for the cancers is to develop. Stronger cell growth (and thus susceptibility to DNA damage) occurs in young people. With a 1-year-old child who is subjected to a CT of the abdomen, increases the lifetime risk of developing cancer by 0.18%. If an elderly patient of this study is subjected to the risk is lower. The risk also depends on the irradiated tissue. Lymphoid tissue, bone marrow, blood, as well as testes, ovaries and intestine are classified as very radiosensitv; in adults the central nervous system and the musculoskeletal system are relatively resistant to radiation. Precautions in pregnancy risks of radiation depend on dose nature of the investigation Untersuchtem area The fetus can be exposed to much less radiation than the mother; exposure to X-rays on the fetus during the X-ray imaging are the following: d head cervical extremities breast (mammography), when the uterus is shielded The extent of exposure of the uterus is dependent on the gestational age and the uterine size. The effects of radiation depend on the age of the pregnancy product (time since conception). Recommendations Diagnostic imaging with ionizing radiation, especially CT should be performed only when absolutely necessary. Alternatives should be considered. For example, in young children, minor head trauma can often be diagnosed based on clinical findings and appendicitis by sonography. However necessary investigations should not be withheld, even if the dose is high (eg. B in CT scans) when the benefit outweighs the potential risk. Tips and risks While imaging studies in which radiation is used to shield the uterus for all women of childbearing age as possible from because radiation risks are highest in the early (often unrecognized) pregnancy. Before diagnostic tests are performed in women of child-bearing age, a pregnancy should be considered, because the risks of radiation exposure are highest during the early, often unrecognized pregnancy during the first trimester. The uterus should be shielded in such women, if possible.