RTBC Radiation Protection and Devices
Exam UPDATED QUESTIONS AND
CORRECT ANSWERS
The primary purpose of the ALARA principle in diagnostic imaging is to - CORRECT
ANSWER Reduce radiation dose to occupational workers
A radiation worker received a radiation dose of 5 mGy while participating in a fluoroscopy
procedure for 10 minutes. What radiation dose would have been received by the worker if
they reduced their time in the radiation field to only 5 minutes? - CORRECT
ANSWER 2.5 mGy
- The radiation dose would have been 2.5 mGy. Radiation dose is directly proportional to
time in the radiation field. The time was reduced by half, so the radiation dose is also reduced
by half.
Which cardinal rule of radiation protection is mathematically defined by the inverse square
law? - CORRECT ANSWER distance
In order to reduce a technologist's occupational dose during a portable radiograph of the
chest, the technologist should - CORRECT ANSWER Stand several feet away from the
patient during the exposure
During a surgical procedure using 3 minutes of fluoroscopy time, a radiographer receives an
effective dose of 1 millisievert (mSv). What effective dose would be experience by the
radiographer if the fluoroscopy time is doubled? - CORRECT ANSWER 2 mSv
A radiographer is exposed to a dose rate of 10 mSv per hour while standing 3 ft from the
patient during c-arm procedures. What is the approximate dose rate if the radiographer stands
4 ft from the patient? - CORRECT ANSWER 5.6 mSv/hr
Use inverse square law
, A radiologist receives an equivalent dose of 100 microsieverts while standing 25 cm from a
patient during a fluoroscopy procedure. Estimate the equivalent dose if the radiologist and 10
cm from the patient. - CORRECT ANSWER 625 microsieverts
Which 3 properties of lead make it a valuable material for radiation shielding devices? -
CORRECT ANSWER High atomic number
High mass density
High attenuation
Which of the following materials requires the smallest half-value layer (HVL) to effectively
attenuate the xray beam? - CORRECT ANSWER Lead
How does radiation dose change if a technologist increases their distance from a radiation
source by a factor of 2? - CORRECT ANSWER Dose decreases by a factor of 2
squared
A half value layer (HVL) is the thickness of material required to reduce which of the
following by half? - CORRECT ANSWER x-ray beam intensity
A shielding device constructed with a thickness equivalent to 1 HVL will reduce the quantity
of radiation to: - CORRECT ANSWER 50% of the original quantity
A shielding device constructed with a thickness equivalent to 2 half-value layers (HVL) will
reduce the quantity of radiation to - CORRECT ANSWER 25% of the original quantity
If the half-value layer of shielding material is equal to 2mm, how much radiaiton will
transmit through 6mm of this material? - CORRECT ANSWER 12.5% of the original
quantity
What lead thickness equivalence is required for protective lead aprons designated for general
radiography, surgery and fluoroscopy? - CORRECT ANSWER 0.50 mm lead (Pb)
Exam UPDATED QUESTIONS AND
CORRECT ANSWERS
The primary purpose of the ALARA principle in diagnostic imaging is to - CORRECT
ANSWER Reduce radiation dose to occupational workers
A radiation worker received a radiation dose of 5 mGy while participating in a fluoroscopy
procedure for 10 minutes. What radiation dose would have been received by the worker if
they reduced their time in the radiation field to only 5 minutes? - CORRECT
ANSWER 2.5 mGy
- The radiation dose would have been 2.5 mGy. Radiation dose is directly proportional to
time in the radiation field. The time was reduced by half, so the radiation dose is also reduced
by half.
Which cardinal rule of radiation protection is mathematically defined by the inverse square
law? - CORRECT ANSWER distance
In order to reduce a technologist's occupational dose during a portable radiograph of the
chest, the technologist should - CORRECT ANSWER Stand several feet away from the
patient during the exposure
During a surgical procedure using 3 minutes of fluoroscopy time, a radiographer receives an
effective dose of 1 millisievert (mSv). What effective dose would be experience by the
radiographer if the fluoroscopy time is doubled? - CORRECT ANSWER 2 mSv
A radiographer is exposed to a dose rate of 10 mSv per hour while standing 3 ft from the
patient during c-arm procedures. What is the approximate dose rate if the radiographer stands
4 ft from the patient? - CORRECT ANSWER 5.6 mSv/hr
Use inverse square law
, A radiologist receives an equivalent dose of 100 microsieverts while standing 25 cm from a
patient during a fluoroscopy procedure. Estimate the equivalent dose if the radiologist and 10
cm from the patient. - CORRECT ANSWER 625 microsieverts
Which 3 properties of lead make it a valuable material for radiation shielding devices? -
CORRECT ANSWER High atomic number
High mass density
High attenuation
Which of the following materials requires the smallest half-value layer (HVL) to effectively
attenuate the xray beam? - CORRECT ANSWER Lead
How does radiation dose change if a technologist increases their distance from a radiation
source by a factor of 2? - CORRECT ANSWER Dose decreases by a factor of 2
squared
A half value layer (HVL) is the thickness of material required to reduce which of the
following by half? - CORRECT ANSWER x-ray beam intensity
A shielding device constructed with a thickness equivalent to 1 HVL will reduce the quantity
of radiation to: - CORRECT ANSWER 50% of the original quantity
A shielding device constructed with a thickness equivalent to 2 half-value layers (HVL) will
reduce the quantity of radiation to - CORRECT ANSWER 25% of the original quantity
If the half-value layer of shielding material is equal to 2mm, how much radiaiton will
transmit through 6mm of this material? - CORRECT ANSWER 12.5% of the original
quantity
What lead thickness equivalence is required for protective lead aprons designated for general
radiography, surgery and fluoroscopy? - CORRECT ANSWER 0.50 mm lead (Pb)
