Basic Considerations of
Radiation Safety and Barrier Protection

Understanding Radiology Radiology is the use of ionizing radiation for medical diagnosis, particularly the use of x-rays in medical radiography or fluoroscopy. In general, the term "radiology" refers to medical imaging techniques that employ advanced computers and other complex equipment enabling doctors to see inside a patient's body. At present, it is estimated that 30-50% of critical decisions in medical approaches are affected by x-ray examination.1 Using the x-ray as a diagnostic tool requires appropriate and accurate knowledge about its advantages, as well the negative biological effects that can occur when x-rays are used improperly or without approved protection measures. Warnings regarding the excessive use of these radiations and instructions proposed for safe application of these technologies are based on the recommendations of the National Council on Radiation Protection and Measurements (NCRP) and the International Commission on Radiological Protection (ICRP).2,3 X-RAY PROPERTIES X-rays, invisible electromagnetic radiation, pass through the body without creating a sensation. As x-rays pass through matter, there is enough energy to remove electrons from atoms. This creates ionized atoms and free radicals (atoms with an unpaired electron in the outer shell), which in turn can produce harmful biological effects. In clinical settings, a current passing through a negatively charged, electrically heated filament called a cathode generates x-rays. This produces electrons that are accelerated via high voltage (kilovolt peak: kVp) through an x-ray tube toward the positive electrode (the anode). Energy attained by the electrons is converted to x-radiation as a result of the electron-anode interaction. RADIATION SOURCES Primary radiation is a type of radiation used for medical diagnosis or treatment; it is referred to as "the useful beam." Secondary radiation is made up of leakage radiation, which comes from the x-ray tube housing assembly. Another source of secondary radiation is called scatter radiation. Scatter radiation results when the useful beam intercepts an object so that some x-rays pass through while others are dispersed or reflected. During medical procedures, the patient is the primary scattering object. The degree of scatter increases with increasing tissue density.

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