Anatomically Programmed Radiography and Techniques Flashcards
What is the purpose of APR? What factors does it show you on the monitor?
-Purpose is to standardize everything (Is a default) to get the same results
-Focal spot size, kVp, mAs, mA, AEC, bucky, filtration, SID, grid/no grid, sec. comes up when we select a procedure
Can we change APR?
Yes, they come preset by a certain vendor with certain techniques-however we can change them
What factors are standardized with an APR in AEC?
- kVp,
- back up time,
- detector,
- density selectors
What sometimes happens to back up time when you increase density selectors?
Back up time increases
When using AEC, what 3 factors do we need to be aware of after we take our exposure? Why?
- Be aware of the anticipated mAs for the exposure
- Know your final technique
- Appropriate EI ranges for each exposure
-Why: Because we are responsible for the total amount of radiation the patient receives
Why do we need single variable technique charts?
-Standardization and consistency of techniques and procedures
What does having translucency between overlying structures mean/
The ability to see structures through structures. i.e.; seeing patella over knee
What is the main determining factor for contrast?
Algorithm (we don’t adjust this)
How can we prove that the algorithm exists?
Can prove that different algorithms exist by taking exposures using different APR’s with the same body part
What are the 2 benefits of single variable technique charts?
a. Best standardization
b. Least errors
What is the one factor that is not standardized in fixed technqiues with a single variable chart?
Time/mAs
Define optimum kVp
It is a certian kVp picked that is able to penetrate a range of different thickness (body size) to provide optimum contrast (can penetrate small, med. large)
What 3 factors should we know when we select an mA?
- Fss
- Approximate exposure time
- Heat on the anode
What is the variable on our single variable technique charts? What other factor does this change as the body part size changes?
-Time is typically our variable
-As patient/part size changes:
○ time changes
○ mAs changes
What are the requirements for single variable technique charts in order to get consistant results?
- QC Program
- Constant input
- No one changes the tech chart unless everyone agrees
- Periodic evaluation
- Everyone must follow them
What principle does using a technqiue by proportionality follow?
Principle of equivalent total technique
What does Equivalent total technique mean?
The total amount of radiation for an exposure and gives us something to work off of to figure out other techniques
What positions have the same total technique (using mA and s with reciprocity)
- AP Lsp
- AP ABD
- AP Pelvis
- Townes skull
With an oblique torso, what total mAs would you use if you were given the mAs for an AP torso?
2x the amount for AP
With an Lateral torso, what total mAs would you use if you were given the mAs for an AP torso?
4x the amount for AP
What projections have the same SID, and therefore the same techniques?
- All c-sp (13cm)
- AP shoulder
- Lat skull
- AP/PA Knee
What is the four cm rule?
-For every 4cm of thickness change, Double mAs (approximately)
-Only applies to the same body parts with different projections
What is the rule for using an optimum kVp?
kVp should never < optimum for the body part (will always be a little bit higher to penetrate thickness)
What are five factors to keep in mind when using techniques by proportionality?
- Bucky factors
- Inverse sq law
- Generators
- 4cm rule of thumb
- 15% rule
As we go from single phase to high frequency, what happens to mAs, # of photons, peak E, and average E?
mAs-can decrease
Number of photons-Increases
Peak E-no change
Average energy-increases
What kVp do you use for the shoulder? What detector do you use?
75-85 and center
What kVp do you use for the ankle?
60-75
What kVp do you use for a knee? what detectors?
70-85
Center
What kVp do you use for an Abdomen SC? What detector?
100-125 and all 3 detectors
What kVp do you use for an Abdomen DC? What detectors?
80-90, all 3
What kVp do you use for a hip/pelvis? What detector?
80-85
Center
