Beam Characteristics

the x-ray beam can be described by its

quality and quantity

beam quality describes the

shape (energy) of the x-ray spectrum

the xrays coming out of the tube are not all

one energy

beam quantity describes

the number of xrays

beam quantity can be changed without

changing shape (i.e. changing mA)

a soft xray spectrum has more

low energy photons

a hard xray spectrum has more

high energy photons

the beam quality will inherently affect the

contrast in an image

a softer xray beam has a

lower average energy and will give you higher image contrast

a harder xray beam has penetration ability through

thick anatomy

the effect of beam filtration is to

decrease beam intensity and increase average beam energy

the main purpose of filtration is to

reduce unnecessary radiation exposure to the patient

very low energy photons are not going to be able to

penetrate the patient and therefore dont stand a chance of contributing to the image

very low energy photons are considered

wasted dose as they deposit energy in the patient but dont contribute to an image