MDCB Board Prep Exam Questions
With 100% Verified Answers
The line focus principle is used in diagnostic x-ray tube design in
order to:
A. make the apparent anode smaller than the actual anode angle
B. make the apparent focal spot size smaller than the actual focal
spot size
C. make the apparent focal spot size larger than the actual focal
spot size
D. make the apparent anode angle smaller than the actual anode
angle -
correct answer ✅B. make the apparent focal spot size smaller than
the actual focal spot size
The apparent focal spot size equals the actual focal spot size x the
sin of the anode angle. This allows a larger portion of the anode to
be irradiated because the heat is more evenly dispersed, while
keeping the spatial resolution in the image as good as possible.
Insufficient vacuum inside the x-ray tube can lead to___________.
A. reducing image contrast
B. increased patient dose
C. tube arcing
,MDCB Board Prep Exam Questions
With 100% Verified Answers
D. need to increase tube voltage -
correct answer ✅C. tube arcing (no useful beam is produced when
the tube is arcing.
The output of an x-ray tube is approximately proportional to:
A. square of tube current at a given kVp
B. square of filament current at a given kVp
C. thickness of xray target
D. square of tube voltage at a given tube current -
correct answer ✅D. square of tube voltage at a given tube current
Output (kVp)^2 (mAs)
Standards defining the minimum necessary amount of inherent
filtration to be used in x-ray tubes are intended to ____________.
A. increase image contrast
B. reduce patient skin dose
C. increase x-ray tube life
D. allow reduced tube voltage -
correct answer ✅B. reduce patient skin dose
, MDCB Board Prep Exam Questions
With 100% Verified Answers
Filtration hardens the beam, increasing the portion of the beam
that penetrates the patient and contributes to the image. Increased
filtration reduces the image contrast.
The surface dose rate of Sr-90 eye applicator was 4.5 cGy/ second
on May 25. If a patient is to be treated 1 year later, what is the
treatment time if 500cGy is prescribed? (half life of Sr-90 is 28
years). -
correct answer ✅114 sec
When 10 mCi of I-125 (half life =60 days) and 25 mCi of Pd-103 (half
life = 17 years) have equal activities? -
correct answer ✅43.17 days
A 10 MeV photon undergoes a Compton interaction, and the
scattered photon is emitted perpendicular to the direction of the
incident photon. What is the approximate energy of the scattered
photon?
A. 0.51 MeV
B. 1.02 MeV
C. 1.25 MeV
With 100% Verified Answers
The line focus principle is used in diagnostic x-ray tube design in
order to:
A. make the apparent anode smaller than the actual anode angle
B. make the apparent focal spot size smaller than the actual focal
spot size
C. make the apparent focal spot size larger than the actual focal
spot size
D. make the apparent anode angle smaller than the actual anode
angle -
correct answer ✅B. make the apparent focal spot size smaller than
the actual focal spot size
The apparent focal spot size equals the actual focal spot size x the
sin of the anode angle. This allows a larger portion of the anode to
be irradiated because the heat is more evenly dispersed, while
keeping the spatial resolution in the image as good as possible.
Insufficient vacuum inside the x-ray tube can lead to___________.
A. reducing image contrast
B. increased patient dose
C. tube arcing
,MDCB Board Prep Exam Questions
With 100% Verified Answers
D. need to increase tube voltage -
correct answer ✅C. tube arcing (no useful beam is produced when
the tube is arcing.
The output of an x-ray tube is approximately proportional to:
A. square of tube current at a given kVp
B. square of filament current at a given kVp
C. thickness of xray target
D. square of tube voltage at a given tube current -
correct answer ✅D. square of tube voltage at a given tube current
Output (kVp)^2 (mAs)
Standards defining the minimum necessary amount of inherent
filtration to be used in x-ray tubes are intended to ____________.
A. increase image contrast
B. reduce patient skin dose
C. increase x-ray tube life
D. allow reduced tube voltage -
correct answer ✅B. reduce patient skin dose
, MDCB Board Prep Exam Questions
With 100% Verified Answers
Filtration hardens the beam, increasing the portion of the beam
that penetrates the patient and contributes to the image. Increased
filtration reduces the image contrast.
The surface dose rate of Sr-90 eye applicator was 4.5 cGy/ second
on May 25. If a patient is to be treated 1 year later, what is the
treatment time if 500cGy is prescribed? (half life of Sr-90 is 28
years). -
correct answer ✅114 sec
When 10 mCi of I-125 (half life =60 days) and 25 mCi of Pd-103 (half
life = 17 years) have equal activities? -
correct answer ✅43.17 days
A 10 MeV photon undergoes a Compton interaction, and the
scattered photon is emitted perpendicular to the direction of the
incident photon. What is the approximate energy of the scattered
photon?
A. 0.51 MeV
B. 1.02 MeV
C. 1.25 MeV
