1 R (roentgen) is defined as quantity of x ray producing a charge of 2.58 × 10 –4 C (coulombs) per kilogram air.
Radiation exposure is a measure of the concentration of free electrons produced in air by the x rays. Radiation Measurement (Exposure and Equivalent Dose) It is important for physicians performing these procedures to know the accumulated radiation dose of patients during the procedures, and to make efforts to minimize the radiation exposure to patients in order to avoid occurrence of radiation injuries.
Serious radiation-induced skin injuries resulting from fluoroscopically guided interventional procedures have recently been reported 1- 4. In many cases, longer periods of radiation exposure are required than the exposure times associated with diagnostic procedures. A combination of the improvement of digital subtraction angiography (DSA) and the introduction of new devices including microcatheters and fine guidewires as well as coils and embolic materials facilitates the interventional treatment. After the beginning of the 1990s, fluoroscopically guided interventional procedures have been increasingly used to treat various neurovascular diseases. In the recent clinical settings, serious radiation injuries do not occur in routine diagnostic procedures. All radiological procedures need to satisfy these principles. In its Publication 26 and 60 the ICRP issued its basic recommendations for the principles of radiation protection as follows: 1) justification, “no practice involving exposure shall be adopted unless its introduction produces a net benefit”, 2) optimization, “all radiation exposures should be kept as low as reasonably achievable (ALARA), economic and social factors being taken into account”, and 3) limitation, “the dose equivalent to individuals shall not exceed recommended dose limits for the appropriated circumstances”. International Commission on Radiological Protection (ICRP) provides recommendations on all aspects on radiation protection. We have accumulated experience and knowledge of the x rays and radiation injuries through numerous clinical cases and unfortunate events. The mysterious rays gave a light on many patients, but the rays produced many victims in the period, in which diagnostic as well as therapeutic radiology has made a rapid progress. More than one hundred years have passed from the discovery of x rays by Wilhelm C.