kVp Flashcards
KeV
Unit used to measure the amount of X-ray photon energy in diagnostic range
The lowest energy valve will be controlled by _________
Filtration
The highest peak energy valve will be _______
90 KeV
The average energy of the beam is _____
30 KeV
When kVp increases, beam quality _______ and energy _______
Increases; increases
High kVp results in less ________ and more _________
Absorption ; transmission
No amount of ________ will ever compensate for insufficient amount of kVp.
mAs
Contrast
Gives visibility of detail
When kVp increases, contrast _______ , resulting in a ________ scale contrast, and a _______ dynamic range
Decreases ; long ; wide
When kVp decreases, contrast _______, resulting in a _________ scale contrast, and a ________ dynamic range
Increases; short ; narrow
Increased kVp resulting in what colors?
Grays, lower contrast
Decreasing kVp will result in more of what colors?
Black and whites, higher contrast
When an image is overexposed kVp was probably too _______ resulting in a _______ image
High ; black
When an image is underexposed kVp was probably too _______ resulting in a _______ image
Low ; white
eV
Unit used to measure X-ray photon energy
Optimum kVp
The maximum kVp level that will produce images with the appropriate contrast that are consistently within acceptable limits, will generally produce less contrast and less patient dose
A decrease in kVp will ________ density
Decrease
An increase in kVp will _________ density
Increase
15% Rule
A 15% change in kVp will result in a change in density by a factor of 2 or 50%
15% Rule : maintaining radiographic density
If kVp is increased by 15% the mAs must be cut in half to maintain density
If kVp is decreased by 15% the mAs must be doubles to maintain density
Long scale contrast
More shades of gray, low contrast, wide exposure latitude, wide dynamic range, high kVp, short wavelength, increased penetration, decreased patient dose,
Short scale contrast
Lower kVp, high contrast, image more black and white, less penetration, higher patient dose, narrow exposure latitude, narrow dynamic range, long wavelength
Other factors that influence kVp?
Filtration, beam restriction, grids, image receptor, processing
kVp controls what?
Contrast and density
