1.
A patient has an abdominal CT scan. The scan range is 30 cm. If the scan is repeated with a scan range of 40 cm. The dose will:
A) Decrease
B) Remain the same
C) Increase
Answer:
B) Remain the same
dose is in units of energy/kg so presumably the extra 10 cm of exposed tissue had the same "dose"
2.
A patient has an abdominal CT scan. The scan range is 30 cm. If the scan is repeated with a scan range of 40 cm. The equivalent dose will:
A) Decrease
B) Remain the same
C) Increase
Answer:
B) Remain the same
3.
A patient has an abdominal CT scan. The scan range is 30 cm. If the scan is repeated with a scan range of 40 cm. The effective dose will:
A) Decrease
B) Remain the same
C) Increase
Answer:
C) Increase
4.
When a signal drops in intensity by a factor of 100 the loss in dB would be:
A) 1
B) 2
C) 10
D) 100
Answer:
B) 2
dB is a logarithmic scale, 2 dB or 102 is a factor of 100
5.
Which of the following is one of the fundamental units in the SI system?
A) sievert
B) rayl
C) joule
D) second
Answer:
D) second (the others are derived units)
6.
In Hounsfield units, the number zero denotes
A) Air
B) Fat
C) Water
D) Bone
Answer:
C) Water
7.
As an ultrasound beam penetrates into a patient the pressures created by the beam are reduced. These are measured in
A) joules
B) watts
C) grays
D) pascals
Answer:
D) pascals
8.
The ultrasound energy deposited in the patient is best measured in:
A) joules
B) watts
C) grays
D) pascals
Answer:
A) joules
9.
During an MR scan there is a concern about the amount of energy that is being delivered to the tissue. The rate the energy is being delivered is measured in:
A) watts
B) joules
C) grays
D) sieverts
Answer:
A) watts
10.
What is the appropriate unit for measuring the amount of visible light falling on a surface?
A) joule
B) watt
C) lux
D) candela
Answer:
C) lux
11.
The unit used to measure dose is the
A) joule
B) gray
C) sievert
D) Roentgen
Answer:B) gray
12.
The unit used to measure equivalent dose is the
A) joule
B) gray
C) sievert
D) roentgen
Answer:
C) sievert
13.
The unit used to measure effective dose is the
A) joule
B) gray
C) sievert
D) Roentgen
Answer:
C) sievert
14.
Pressure in ultrasound is measured in
A) pascals
B) watts
C) joules
D) rayls
Answer:
A) pascals
15.
Even though it is not a SI unit energy is frequently measured in
A) joules
B) gray
C) keV
D) Lamberts
Answer:
C) keV