MDCB BOARD PREP
(TESTS + DOSEGRID +
OTHERS) 2024
QUESTIONS WITH
100% COMPLETE
ANSWERS!!
Evatee 9/5/24 MDCB
,MDCB BOARD PREP (TESTS + DOSEGRID +
OTHERS) 2024 QUESTIONS WITH 100%
COMPLETE 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
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
D. need to increase tube voltage 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 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 Answer - B. reduce patient skin dose
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). 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? 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
(TESTS + DOSEGRID +
OTHERS) 2024
QUESTIONS WITH
100% COMPLETE
ANSWERS!!
Evatee 9/5/24 MDCB
,MDCB BOARD PREP (TESTS + DOSEGRID +
OTHERS) 2024 QUESTIONS WITH 100%
COMPLETE 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
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
D. need to increase tube voltage 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 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 Answer - B. reduce patient skin dose
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). 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? 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
