1 Flashcards
to double the density of a film using mAs you would increase it by:
100%
a reciprocating grid is THICKER than a
stationary grid
when converting from a grid with a low ratio to a grid with a high ratio, what do you need to do to maintain good film quality?
increase mAs
what grid type is recommended for spinal radiography in the usual chiropractic office?
focused grid
what effect does using a high kV technique have?
produces more scatter
the preferred focused grid range for spinal radiography is
40” to 72”
if a film has an overall darkened gray appearance but visible structures the probable cause of the PROBLEM would be:
exposure of the film to scatter
the term “optimal kV” refers to the:
lowest possible mAs w/ acceptable contrast on the film
***how many lines per inch are recommended for a stationary grid?
100-103 (?)
diminished penetration at the periphery of a grid is termed:
grid cut-off
if a film is said to be “burned out” what would it look like?
too dark
the main reason why a “fixed kV technique is preferred”
contrast is consistent
remnant radiation refers to (2)
- scattered rays that leave the pt and reach the grid
- primary rays that leave the pt and reach the grid
a ____ grid would produce the LEAST amount of grid lines
moving
exceeding the optimal kV range while maintaining good density will yield a film that has:
long scale contrast
as a gen rule, if youre going to xray an elderly pt you should do what to your established radiographic technique?
decrease it
**using what would increase pt exposure
a 10:1 stationary grid
if you took a lateral cervical with 66 kV at 100 mA for 1/10th of a sec at 72” FFD and it was too light but you could see the structures, what would the best solution be
increase kV by 15% (to make 66 in optimal range)
about how much increase in mAs is required when going from a non grid technique to using a technique with a 12:1 grid
5x
if you took a 14x17” lateral lumbar film and saw that the L5-S1 area was too LIGHT what would be the best thing to do?
take a spot 8x10” lateral, increase mAs by 60%
only add kV if 8x10 is STILL too light
if you saw a blood vessel on end (axially) on a chest film it would probably look like which of the four natural body (subject) densities
water
if you saw 2 structures each w/ paralleling tracks of calcification overlying the articular pillars diverging at the superior and closer at the inferior, what would you be looking at?
part of thyroid cartilage
if you took an AP lumbar on a thin pt using 85 kV at 100mA w/ the exposure time of 1/2 a sec and the film demonstrated all of the structures but was too light what would you do to get a better film
increase mAs by doubling it
an elderly, overweight, retired exotic dancer injured her back after a fall. you first take an AP lumbar using 90kV with 100 mAs for 1 sec at 40” SID. the film is very gray and you need to retake it. what should you do?
use 200 mA and decrease kV 15%
you take a lateral cervical film at 65 kV and 10 mAs w/o a grid, and its light but you can see the structures. what is the best thing to do for the retake?
increase kV by 15%
if you took four Ap lumbar films, which would have the lowest contrast? 95 kV and 6.25 mAs 106 kV and 3.75 mAs 58 kV and 60 mAs 85 kV and 8.0 mAs
the second
you decided not to use a grid for an AP lumbar film and adjusted the radiographic technique to maintain a good density what would be the outcome?
film would be very gray
to double the density of a film with kVp, you should apply which rule?
15%
if you compared 2 radiographs of the CS, one taken at 40” the other at 72” with the appropriate change in the rad technique, what would you find?
72” film the image would be smaller and clearer
what could be a problem if your xray tube was laterally shifted from the center of the film?
shape distortion
primary purpose of a grid
reduce scatter radiation to the film
