1. RAD 354 Chapt. 8 X-ray emission
X-ray output in AIR is measured in ROENTGENS and refers to x-ray QUANTITY
1 R = X C/kg

2. 4 Factors affect the QUANTITY of RADIATION: mAs, kVp, distance & filtration
mAs – DIRECTLY proportional to the x-ray quantity
kVp – x-ray quantity varies proportional to the SQUARE of the RATIO of the kVp
Distance – Inverse square law
Filtration – Absorbs/Attenuates the LOW energy LONG wavelength photons – INCREASES average hardness of the beam

3. X-ray QUALITY = Penetrability
INCREASED hardness = INCREASED penetration and DECREASED wavelength
Measured via HALF VALUE LAYER (HVL = BEST measure of x-ray QUALITY)
Penetrometer/step wedge
Filtration – used to harden the beam and absorb the “useless, long wave photons”
Inherent (.5 mm al) Added = 2 mm al (70-80 kVp)

4. “Special” Filters Trough – for CXR’s
“Bow Tie” – for some generations of CT
Wedge – for use with an AP foot, etc.
Conic – for digital fluoro
Don’t reduce patient dose, but improve the image