collimation and filtration

what is the main purpose of filtration

decreases dose by absorbing low energy radiation

what are the 2 parts of total filtration

inherent and added

what materials make up filtration

aluminum and copper

what is minimum amount of filtration required if i have a room that uses 50 kv

.5

what is minimum amount of filtration required if my room uses 50-70kv

1.5

what is minimum amount of filtration required if my room uses 70-100

2.5

what filtration is recomended if room uses 50-70 kv

3

what filtration for rooms using greater than 100 kv

3

what measures beam quality

half value layer

what is half value layer

amount of absorber required to reduce initial beam intensity by half

where is added filtation added

in between source and patient

as i increase filtration what happens to overall receptor exposure

decrease

as i increase kvp what happens to overall receptor exposure

increase

as i increase filtration what happens to prevelance of scattter

increase

as i increase kvp what happens to scatter

increase

if beam is more penetrating does it interact with innermost or outermost shell

outer

as i increase filtration does penetrability/ quality go up or down

up

as i increase kvp does it increase or decrease quality

increase

as i increase kvp what happens to patient skin exposure

decrease

what is simplest type of beam restriction device

lead aperture

what does pbl stand for

positive beam limitation

what is positive beam limitation

autimatically collimated to detector size

if distance from focal spot is 12mm what is distance from light source to mirror

12mm

what is purpose of entrance shutter

remove stem radiation

what is off focus or stem radiation

creating in tube but its anywhere but the anode

what is a compensating filter

evens out uneven body parts

examples of compensating filter

wedge

as the tube ages what creates more inherent filtration (built into tube)

tube tanning

what is tube tanning

vaporization tungston

collimate from 14×17 to 8×10 does that increase or decrease scatter

decrease

does scatter increase or decrease when increase kvp

increase

what happens to compton interaction when increase kvp

slightly less

why is there more scatter when increase kvp

lots of PE is lost

what happens to scatter when increase volume of tissue

increase

what happens to scatter when something has a low A#

increases

where does brems happen

tube