T/F For the x-ray light field and x-ray field to correspond accurately, the x-ray tube focal spot and the light bulb must be exactly the same distance from teh center of the mirror.
TRUE
NCRP guidelines for x-ray tube housing leakage
less than 100 mR/hr 1 meter from tube
Where should the focal spot location be indicated? (NCRP)
outside of tube housing
High ratio grids with low kV
BAD, discouraged because of unnecessary exposure required
NCRP guideline for manual collimation must be within _____ of the SID.
2%
NCRP
national council on radiation protection and measurements
Minimum response/reaction time
length of the shortest exposure possible with a particular AEC
Cone/cylinder -used for relatively small field size (paranasal sinuses)
circular, lead-lined, slide into place in the tube head or onto the collimator housing Straight-prox and dist diameters identical Flare-dist diameter greater than prox diameter -limited use, more efficient bcs beam restriction is closer to anatomy