Radiation Protection in Medical Radiography
Wendy Wiredu
XRA 230
A. PERSONNEL PROTECTION * Primary X-Ray Beam * Emerges directly from the x-ray tube collimator. * It moves without deflection (toward a wall, door, viewing window, etc). * Primary radiation is also known as direct radiation.
* Secondary Radiation (aka Scatter radiation & Leakage Radiaiton) * Scatter Radiation – results whenever a diagnostic x-ray beam passes through matter. * Compton interactions between the x-ray photons and the electrons of the atoms within attenuating object deflect x-ray photons from their initial trajectories. * X-ray photons emerge from the object in all direction. * Leakage Radiation – radiation generated in the x-ray tube that does not exit from the collimator opening but rather penetrates through the protective tube housing and to some degree through the sides of the collimator. * Leakage radiation is always present in some amount.
* Patient as a Source * During diagnostic examination the patient becomes a source of scattered radiation. * At a 900angle to the primary x-ray beam, at a distance of 1m (3.3 ft), the scattered x-ray intensity is generally approximately 11000 of the intensity of the primary x-ray beam. * Use of any devices and appropriate technique can lessens the amount of scattered radiation and significantly reduce occupational exposure. * Automatic collimation, or positive beam limitation device (PBL), restrict the size of radiographic beam so that its margin do not extend beyond the image receptor. B. Basic Method of Protection * Time * The amount of exposure is directly proportional to the duration of exposure. * As the length of exposure time increases, the radiation dose received increases in direct proportion. * During fluoroscopy, reduced exposure time will decrease both the patient and personnel exposure. * Fluoroscopic x-ray units are equipped with 5
XRA 230
A. PERSONNEL PROTECTION * Primary X-Ray Beam * Emerges directly from the x-ray tube collimator. * It moves without deflection (toward a wall, door, viewing window, etc). * Primary radiation is also known as direct radiation.
* Secondary Radiation (aka Scatter radiation & Leakage Radiaiton) * Scatter Radiation – results whenever a diagnostic x-ray beam passes through matter. * Compton interactions between the x-ray photons and the electrons of the atoms within attenuating object deflect x-ray photons from their initial trajectories. * X-ray photons emerge from the object in all direction. * Leakage Radiation – radiation generated in the x-ray tube that does not exit from the collimator opening but rather penetrates through the protective tube housing and to some degree through the sides of the collimator. * Leakage radiation is always present in some amount.
* Patient as a Source * During diagnostic examination the patient becomes a source of scattered radiation. * At a 900angle to the primary x-ray beam, at a distance of 1m (3.3 ft), the scattered x-ray intensity is generally approximately 11000 of the intensity of the primary x-ray beam. * Use of any devices and appropriate technique can lessens the amount of scattered radiation and significantly reduce occupational exposure. * Automatic collimation, or positive beam limitation device (PBL), restrict the size of radiographic beam so that its margin do not extend beyond the image receptor. B. Basic Method of Protection * Time * The amount of exposure is directly proportional to the duration of exposure. * As the length of exposure time increases, the radiation dose received increases in direct proportion. * During fluoroscopy, reduced exposure time will decrease both the patient and personnel exposure. * Fluoroscopic x-ray units are equipped with 5