Part D: Instrumentation Flashcards
1
Q
- Magnetic fields associated with MR imaging systems include the:
- Static magnetic field (B₀)
- RF (radiofrequency) field (B₁)
- Gradient field
- Gantry field
a. 1 only
b. 1 and 2 only
c. 1, 2, and 3 only
d. 1, 2, 3 and 4
A
c. 1, 2, and 3 only
2
Q
- The MR system component that produces the B₀ field is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
a. Main magnet
3
Q
- The MR system component that produces the B₁ field is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
b. Radiofrequency system
4
Q
- There are various types of magnets that can be used for MR images: These include:
- Permanent magnet
- Resistive magnet
- Hybrid magnet
- Superconducting magnet
a. 1 only
b. 1 and 2 only
c. 1, 2 and 3 only
d. 1, 2, 3 and 4
A
d. 1, 2, 3 and 4
5
Q
- The MR system component that provides a means for alignment (magnetisation of proton spins) is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
a. Main magnet
6
Q
- The MR system component that provides a means for excitation is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
b. Radiofrequency system
7
Q
- The MR system component that provides a means for spatial encoding is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
c. Gradient system
8
Q
- The liquids cryogen(s) commonly used to maintain the magnet coil at superconducting temperature is (are):
a. Helium
b. Hydrogen
c. Nitrogen
d. a and c
A
a. Helium
9
Q
- Some systems use only one cryogen. In such systems, the cryogen is:
a. Nitrogen
b. Hydrogen
c. Helium
d. Oxygen
A
c. Helium
10
Q
- Faraday’s law of induction states that if a loop of wire is moved through a magnetic field, _______ will be created in the wire.
a. A magnetic wave
b. A voltage
c. Torque
d. Resonance
A
b. A voltage
11
Q
- The equation associated with Faraday’s law of induction is:
a. W/kg
b. ω0= B₀γ
c. ∆B/ ∆T= ∆V
d. Ppm
A
c. ∆B/ ∆T= ∆V
12
Q
- According to Faraday’s law of induction, the amount of current produced in a loop of wire moving through a magnetic field is proportional to the:
a. Length of the wire
b. Strength of the magnetic field
c. Spin density of the wire
d. Time it takes for the magnetic field to reach full potential
A
b. Strength of the magnetic field
13
Q
- In a typical superconducting (cylindrical bore) magnet, the direction of the magnetic field is:
a. Vertical
b. Horizontal
c. Around the flux lines
d. Hard to measure
A
b. Horizontal
14
Q
- The direction of the magnetic field in a typical permanent magnet is:
a. Vertical
b. Horizontal
c. Around the flux lines
d. Hard to measure
A
a. Vertical
15
Q
- To maintain the magnetic fields of a resistive magnet, which of the following should be applied to the magnet coils?
a. Water
b. Heat
c. Current
d. Cooling
A
c. Current
16
Q
- Magnetic field strength is measured in units of Tesla (T) and Gauss (G) whereby 1T equals:
a. 1 G
b. 1 000 G
c. 10 000 G
d. 100 000 G
A
c. 10 000 G