310 likes | 1.21k Views
Radiation safety and protection. Christos Aggelopoulos, DDS. Vilhelm Konrad Roentgen. December 22, 1895. Setting the tube…. Setting the tube…. Early medical radiology…. January 14, 1896, the first dental radiograph. Dr Edmund Kells. ALARA. A s L ow A s R easonably A chievable.
E N D
Radiation safety and protection Christos Aggelopoulos, DDS
ALARA As Low As Reasonably Achievable
Radiation protection measures… • For the patient • For the oral health proffesional
FILTRATION Removes unwanted, low energy X-rays 1.5 mm Al For 50-69 KVp 2.5 mm Al For 70 KVp and above
COLLIMATION Restricts the size and shape of the X-ray beam
COLLIMATION Field size from round cone is 3X that what is needed to expose a #2 film With RC the skin exposure is reduced by about 60% Compared to round collim.
COLLIMATION Beam diameter no greater than 7 cm at skin (Federal Regulation)
BEAM INDICATING DEVICES Long (12”-16”), open-shielded, lead-lined BIDs (cones) are recommended Rectangular cones are recommended over round cones
FILM HOLDING DEVICES Accurate aiming Eliminates patient holding film
FILM SPEED E speed film reduces patient exposure by 40%-50%
DIGITAL IMAGING Further exposure reduction Image enhancement
EXPOSURE CONTROL Use electronic timers only Mechanical timers not recommended
DARKROOM PROCEDURES Adequate safelighting and free of light leaks Time temperature processing
FILM MOUNTING AND VIEWING Use opaque mounts Mask viewbox
TAKE X-RAYS ONLY WHEN NEEDED • X-rays every 6 mo is not the rule • Apply FDA selection criteria for radiographic examinations • Take into account the welfare of the patient • Avoid routine radiographs
Radiation protection measures for the operator Occupational exposure: 50 mSv/yr Public exposure: 1-5 mSv/yr Maximum permissible dose (MPD): The maximum dose of radiation which will not be expected to cause any significant radiation effects in a lifetime
Radiation protection measures for the operator • Stand at least 6 feet away from the patient and 90o-130o to the primary beam • Stand behind a barrier • Never stand in the primary beam • Never hold films in the patient’s mouth • Never hold or stabilize the X-ray tubehead during the exposure
Radiation protection measures for the operator Quality assurance program: Proper staff training Monitoring of the X-ray machines Darkroom protocol Film badge service Office design: Primary and secondary barriers
DISCUSSION What to keep in mind…