RQ E2
sharpness of image detail is best described as?
Spatial resolution.
The visibility of image detail is best measured by?
contrast resolution.
Why is it important to keep exposure time as short as possible?
minimize motion blur.
In reference to what occurs with Low kVP, what does LHS stand for?
LOW kVp, HIGH contrast, SHORT gray scale.
How does SID affect your beam quality.
Inverse square law: Distance increases, intensity decreases. Distance decreases, intensity increases. (inverse relationship).
If OID is increased, what happens to spatial resolution.?
it decreases (inverse relationship).
Long scale means we have______contrast. It is ideal in radiography of_________?
1.Low contrast
2. organs within chest and abdomen.
3. WIDE LATTITUDE
How does kVp affect image contrast?
Why would decreasing kVP increase the patients dose?
the mAS would be increased in order to maintain IRE.
When do you use a small focal spot?
1. fine detail
2. magnification
3. Limb radiography.
How does an increase in focal spot size affect spatial resolution?
it decreases (inverse relationship).
Short scale means we have_________contrast. It is ideal in radiography of_________?
1. high contrast
2. bones
What happens when kVp is increased?
1. more scatter
2. reduction in contrast
3. longer scale contrast.
If kVP is increased, how does this affect receptor exposure?
Increases RE. (Direct relationship).
When do you use a Large focal spot?
For thick/dense body parts.
If SID is increased, what happens to spatial resolution?
Increases (direct relationship).
As collimation increases, what is the effect on image contrast?
Increases (direct relationship).
In reference to what happens when kVp is increased, what does HLL stand for?
HIGH kVp, LOW contrast, LONG gray scale.
An increase in mAs has what affect on RE?
Increases RE (direct relationship).
Why would you use a Large focal spot versus a small focal spot?
1.large focal spot is used when short exposure time is priority, because it requires higher heat capacity.
What are some ways to improve spatial resolution?
small focal spot size, collimation.
What are the 4 exposure factors?
1. kvp
2. mA
3. time
4. SID
What occurs with Low kVp?
Less penetration.
If SID is increased, how does this impact RE?
it decreases RE (inverse relationship).
Why does an x-ray tube have two focal spot sizes?
small focal spot improves spatial resolution of high contrast anatomy.
Large focal spot useful when high intensity x-ray beam is needed for thick anatomy.