Ch. 10-11 mAs, Exposure And Density/ Receptor Flashcards
As mAs increases, density _______
Increases
If mA increases or s increases, mAs will ________
Increase
mAs
Represents how many X-rays will be produced and for how long, controls density and receptor exposure, controls the total number of X-rays that leave the tube (quantity)
As mA increases, current __________, temperature _________, and space charge _________.
Increases, increases, increases
True or False: The amount of mA is directly related to the patient.
True
mA controls the quantity of…..
Electrons flowing in the circuit and photons in the X-ray beam
Higher mA sends more _________ from the cathode to the anode.
Electrons
What’s is exposure time?
The duration of the X-ray
What is phototiming?
Cells that can sense what mAs to use
If milliseconds equals 40 what is seconds?
.04
200 mA x .1 sec =
20 mAs
mAs
A measure of the total quantity of electricity which flowed through the circuit during the exposure and therefore indicates the total number of X-rays used in the exposure
True or false? As long as the product remains the same either the exposure time (s) or mA can be changed to achieve the required radio graphic exposures?
True
mAs controls the _______ & _________ exposure.
Receptor and patient
Film density
The blacks of an xray
Window leveling
Describes the digital processing that produces change in density or brightness
Desintometer
A device that measure the density of a radiograph
An increase in mA, s, and mAs _________ image density and receptors exposure.
Increases (and vice versa)
What is the rule of thumb when making adjustments in technique?
Make adjustments in increments of doubles or halves.
A minimum of _____% will cause a visible shift in density.
30%
The density produced on the film will be ________ proportional to the exposure received by the film.
Directly
Failure of the reciprocity law usually means that what happened?
The exposure time was too short and the mA was too high or vice versa.
The overall radiographic density and receptors exposure of an image will be __________ proportional to the mAs used.
Directly
mAs formula
mAs = mA x s
mA formula
mA = mAs \ s
s formula
s = mAs / mA
Direct square law or maintenance exposure law
The direct relationship between the distance of the xray source from the image receptor and the amount of radiation which will strike image receptor.
As distance (SID) increases density decreases. What law explains this?
The direct square law
The direct square law explains that if you decrease SID density will ________.
Increase
Inverse square law or indirect law
This is the inverse relationship between distance and intensity.
What law explains that if you decrease distance you will increase intensity?
The inverse square law or indirect law
Direct square law
Used to maintain density for a change in distance.
Formula : (mAs1/ mAs2) = (Distance squared 1/ distance squared 2)
Cross multiply
Use a shorter or longer exposure time and why?
Use the shortest exposure time possible. With a higher mA and a shorter exposure time it will give you better detail and less chance of motion.
