week 2 Shielding Flashcards
Aprons are made from
vinyl w/lead inside
minimum amount of lead in an apron is
.25mm
Fluoro is to check for what
lead cracks
shield gonads if they are w/in _ of the primary beam
4-5cm
what are the 3 types of shields
flat contact-lead blockers
shaped contact-cup shaped for males
shadow shields-in the path of the beam and cast a shadow over the part to be protected
what controls the size and shape of the x-ray field coming out of the tube (coning)
collimator
collimator controls the movement of the _ that block a portion of the x-ray beam
lead shutters
collimator can be either
manual and automatic
automatic is the
PBL
what is PBL
positive beam limitation-detects the size of the image receptor
what cuts down on patient dose and increases film quality by preventing fog
PBL
filtration is the use of attenuating material made of _ between the x-ray tube and the patient
aluminum
grids are made of
lead strips in between spacing material
where are grids placed
between the patient and the image receptor
why are grids used
to remove as may scattered photons exiting the patient before it reaches the film and creates fog on the cassette
reducing scatter creates an image with
better contrast
why does grids not help the patient dose
due to increased lead in the grid we have to use a higher technique to get through it. Grids create a higher ESE
THe higher the grid ratio (more lead strips)
the less scatter on the film but also less density
Radiation protection uses what concept
ALARA
what is a regulator agency that collects and distributes info regarding radiation awareness and safe practice to the public
NCRP
Radiation protection uses what law
inverse square law
personnel monitoring determines
estimated occupational exposure
what are the most common personnel monitoring
OSL
film badge
TLD
pocket dosimeter
rad. techs use what type of personnel monitor
OSL
