click below
click below
Normal Size Small Size show me how
RT Exposure - Part I
Review items for midterm and final exam. Covers Bushong chapters 1, 2,3 &9
Question | Answer |
---|---|
The SI unit for the Roengen | Gy in air |
The unit of occupational exposure | rem or Seivert |
divide by this to convert mR to R | 1,000 |
The radiation quantity received by the patient | rad or radiation absorbed dose |
When an atom loses or gain an electron | ionization |
If you double your distance from the radiation source the amount of exposure | 1/4th the original amount |
When doubling the distance from the radiation source you need to __ mAs to maintain density | 4 times the original mAs |
As the kVp increases this happens to x-ray energy or speed or penetrating ability | they increase |
As kVp increases the frequency is ____________ | shortened |
As kVp increases the wavelength ___________ | decreases |
Direct or Indirect relationship between mAs and x-ray quantity | direct |
relationship between kVp and distance | direct by kVp squared |
As filtration increases x-ray quantity _______ and why? | decreases because filtration absorbs low energy x-rays |
kVp stands for; | kilovoltage peak |
The "square law" is used to calculate | changes required for mAs if the distance changes |
Higher or lower energy x-rays are more capable of penetrating patient tissue | higher |
Higher quality x-rays are also known as ______ penetrating | More |
The reduction in x-ray intensity that results from absorption and scattering | attenuation |
Thickness of absorbing material to reduce x-ray intensity to half its original value | HVL or half value layer |
Increase in HVL increases or decreases x-ray beam quality | increases |
As filtration increases the x-ray quantity increases or decreases | decreases |
The glass or metal enclosure of x-ray tube is called __________ filtration | inherent |
The amount of inherent filtration is usually this amount | 0.5 mm Al equivalent |
True or False - As the x-ray tube ages inherent filtration increases due to this | vaporization of tungsten target and filament of x-ray tube deposited on window inside |
With the addition of filtration more low energy x-rays are ______________ | attenuated |
The amount of added filtration | 2.0 mm Al equivalent |
In diagnostic range the required amount of total filtration | 2.5 mm Al equivalent |
This type of filter is used to achieve an image with uniform density when body part varies in thickness | compensating filter |
A trough, "bow-tie", wedge or conic are types of this | compensating filter |
The number of HVL's needed to reduce x-ray beam intensity to less than 6% of original amount | 5 ( key is less than not equal to) |