CORRECT DETAILED ANSWERS WITH RATIONALES
(VERIFIED ANSWERS) |AGRADE
How far away must the operator stand from the xray tube if not covered with lead? -
ANSWER: 3 meters
90% of man made radiation to the population is related to? - ANSWER: Medical
Radiography and Dental
For each peak xray voltage, what lead equivalent is required?
100kV or less (o-100)
Between 101kV-149kV
150kV or greater (150+) - ANSWER: 0-100kV = 0.25mm of lead
Greater than 100kV but less then 150kV = 0.35mm of lead
150kV or greater = 0.50mm of lead
What protective equipment is required during interventional procedures - ANSWER:
Full wrap around protective gowns of 0.50mm pb in the front panels and 0.25mm pb
in the back panels
Thyroid shields with an equivalent of 0.50mm of pb
Lead drapes/curtains mounted to II of 0.25mm of pb at 100kv
What lead equivalent must protective gloves/ gauntlets possess? - ANSWER: 0.25mm
of pb
What lead equivalent must ceiling mounted lead screens and moveable shields
provide? - ANSWER: 0.50mm of pb
What are the annual radiation dose limits for radiation workers? - ANSWER: Whole
body= 20mSv
Lens of eye= 150mSv
Skin = 500mSv
Hands = 150mSv
All other organs = 500mSv
For pregnant women an effective dose of 4 mSv must be applied for the remainder
of the pregnancy from all sources
What are the annual radiation dose limits to members of the public? - ANSWER:
Whole body = 1mSv
,Lens of the eye= 15mSv
Skin = 50mSv
Hands = 50mSv
All other organs = 50mSv
*these also apply for students*
What are primary protective barriers? Give examples - ANSWER: Primary barriers
provide shielding from the direct xray beam. Such as, the walls and floor where the
tube can be directed
-The wall behind the wall bucky
-Floor under the table
What are secondary barriers and give examples - ANSWER: Provide shielding against
both leakage and scattered radiation. Walls that the primary beam is not directed
towards and the ceiling are secondary barriers.
The control booth is also a secondary barrier, the primary beam should never be
directed towards it.
What should the focal spot to skin distance be for:
-Mobile equipment
-Stationary equipment
-Radioscopic equipment - ANSWER: Must not be less than:
-Mobile: 30cm
-Stationary: 38cm
-Radioscopic: 20cm (designed for special procedures that would be impossible at
30cm or 38cm)
What are the maximum air kerma rates for radioscopic equipment:
-with automatic intensity control
-without AIC - ANSWER: Not equipped with AIC: 50mGy/min
With AIC: 100mGy/min
The air kerma rate must not exceed ___ from scattered radiation of radioscopic
equipment - ANSWER: 2 mGy/h
HVL of Aluminum for given tube voltages? (70kV-150kV) - ANSWER: 70: 2.5mm
80: 2.9mm
90: 3.2mm
100: 3.6mm
110: 3.9mm
, 120: 4.3mm
130: 4.7mm
140: 5.0mm
150: 5.4mm
How frequently should IP's and cassettes be cleaned and inspected? - ANSWER:
Cleaned: monthly
Visual inspection: Weekly
What are daily QC tests for CR/DR/Fluoro/CT equipment - ANSWER: -Warm up (all)
-Meter operation (all)
-Equipment condition (all)
-System movements (fluoro)
-Visual assessment of electronic display devices (all)
What are weekly QC tests for CR/DR/Fluoro/CT equipment - ANSWER: - Visual
inspection of cleanliness of system (all)
-Laser film printer operation (all)
-CT # accuracy
-CT noise
-CT uniformity
What are monthly QC tests for CR/DR/Fluoro/CT equipment - ANSWER: -Cassette,
screen, IP plate cleaning (CR)
-Retake analysis (CR/DR)
-Electronic display device performance (all)
-Laser film printer operation (all)
-CT slice thickness
-CT # calibration
-CT # linearity
What should the monthly retake analysis be below? - ANSWER: 5%
What are quarterly QC tests for CR/DR/Fluoro/CT - ANSWER: -Collimator operation
(CR/DR/Fluoro)
-Interlocks (all) (on doors to prevent exposure if door is open)
-Compression devices (Fluoro)
-Table angling/motion (Fluoro)
-Fluoro protection devices (lead drapes = .25mm of pb)
-CT patient support movement
-CT spatial resolution
-CT low contrast detectability
What are the annual QC tests for CR/DR/Fluoro/CT - ANSWER: -Accuracy of loading
factors (CR/DR/fluoro)
-Output reproducibility
-Output linearity