CH26 Density_Image Receptor Expose Flashcards
What is the controlling factor for Density?
mAs
mAs Formula
Quantity X Length of Exposure
Denisty influencing Factor
kVp
What does contrast media do?
It affects density, Barium is a substance used it appears white (Radiopaque)
Pathology
Study of disease or something not normal.
Additive Pathology causes:
An increase in technique
Destructive Pathology causes:
a decrease in technique
Types of additve pathologies
CHF, Pulmonary edema, Osteopetrosis, Pagets
Types of Destructive pathologies
Osteoporosis, emphysema
What does a grid do?
Increases contrast but decreases density.
Using a grid will require what of technique?
Increase of technique
As mAs increases what happens to Density? And what kind of relationship is this?
Increases, this is a direct or linear relatinship
Reciprocity
using different mA or time to achieve the same or similar density (mAs).
Kiliovotage Controls?
Quality of beam, Force (EMF), Penetrating power, (Potential Difference)
Increasing kV does what to densities?
Increases, therefore decreasing contrast
15% Rule
Applies to changing kV by 15% in order to double or half Density.
When should the 15% rule be used?
When a contast change is desireable, not when only density change is wanted.
Increasing kV by 15% will
Increase density by 2.
Decreasing kV by 15% will
decrease kV to 1/2
The 15% rule is most accurate within what range?
60-100 kV
