RAD210 Midterm Questions With Complete Solutions

RAD210 Midterm Questions With Complete Solutions


Federal law requires that the exposure should terminate at?
600 mAs w/ kVp above 50
Density controls allow for changes of what percentage?
~25-30% incements
AEC should not be used with which conditions?
- Additive pathologies
- Surgical prosthesis
- Positive contrast
What are some causes of overexposure when using AEC? (5)
- (+) density control
- AEC malfunction
- Incorrect detector selected
- Metal prosthesis
- external artifacts
What are some causes of underexposure when using AEC? (5)
- Backup timer too short
- (-) density control
- Lack of collimation
- Incorrect detector selected
- Detector not completely covered by tissue of interest
When a manual technique recommended over AEC? (4)

,- Distal extremities
- x-table projections
- Mobile trauma
- Metal artifacts
What is APR?
Automatically programmed radiography
Focal spot size spatial resolution (LIMITS & TEST TOOLS)
+/- 50%, star test, slit camera
Collimation (LIMITS & TEST TOOLS)
+/- 2%, metal markers
kVp (LIMITS & TEST TOOLS)
+/- 5%, kVpmeter
Exposure time (LIMITS & TEST TOOLS)
+/- 5% times > 10 ms, exposure meter, spinning top
Exposure reproducibility (LIMITS & TEST TOOLS)
+/- 20% times < 10 ms, dosimeter
Exposure linearity (LIMITS & TEST TOOLS)
+/- 10%, dosimeter
AEC (LIMITS & TEST TOOLS)
+/- 10%, exposure meter
Filtration/HVL
>/- 2.5 m Al

, What change in kVp is needed to affect OD?
3%
What is a typical fluoro ESD rate?
2R/min/mA or 20Gy/min/mA
What is the fluoro stationary SSD?
38cm or 15"
What is the mobile fluoro SSD?
30cm
OR
12"
What is the exposure rate limit for fluoro?
100mGy/min
OR
10R/min
What is the exposure rate limit for interventional fluoro?
200 mGy/min
OR
20R/min
What is meant by ghosting or image lag?
Indicates inadequate erasure
What are the 2 type of viewing monitors?
- Primary (used for diagnosis)
- Secondary (used for simple viewing)