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Flashcards in Hardware control Deck (30)
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1

High field scanners typically have field strengths greater than or equal to:

1.5 Tesla

2

Consistent room temperature of 65-75°F, humidity of 50-70%, and sufficient air flow in the MR scan room is recommended to

Make patients less vulnerable to the RF heating effects

3

In a cross sectional view of the MR magnet design, which coils are closest to the patient?

Radiofrequency coils

4

The liquid cryogens are cooled in a superconducting magnet at a temperature of

4° Kelvin

5

Which of the following is NOT a magnetic field associated with MR imaging?

Gravitational earth magnetic fields

6

The purpose of shimming the magnet is to

make the B0 field as homogenous as possible

7

The array processor is responsible for:

Reconstructing the images using the Fourier transform

8

: In order for energy to be efficiently transferred between a transmitter and receiver, the two must be at the same

Frequency

9

The _____ is located within an equipment room.

RF power amplifier

10

During a quench of the MR system, patients and employees should be evacuated from the scan room to avoid

A. Damage to tympanic membranes

  B. Frostbite

  C. Asphyxiation

D. All of the above

all of the above

11

Field strength at magnet isocenter is measured in units of:

Tesla

 

12

The unit of measurement of the magnetic field surrounding the periphery of the MR scanner is expressed as:

Gauss

13

The intensity limit for a static magnetic field in clinical use is limited by the Food and Drug Administration (FDA) to _____________?

4 Tesla

14

The patient image display with sequence parameter visualization is located in the

Scan control room

15

The local RF coil used to image a human brain is typically located/kept in the __________.

Magnet room

16

The CPU used to plot and adjust slices in an MR sequence is located:

Scan control room

17

Radiofrequency (RF) shielding can be achieved by lining the scanner room walls with

Copper

18

The location of the coils installed in the MRI scanner, from the inner point closest to the patient to the outer most edge, are

Radiofrequency coils, gradient coils, shim coils, main magnet

19

The liquid cryogens most often used to maintain field strength in a super conducting MR system are:

Helium

20

The coil construction in an MR system, from the innermost aspect to the outer:

Radiofrequency coils, gradient coils, shim coils, main magnet

21

Doubling the magnetic field strength will:

Yield an increase of double the SNR

22

: What type of magnet is used with most systems currently manufactured

Superconducting

23

: Image 78 is an example of what type of MR scanner?

Open magnet

24

Image 79 is an example of which MR system?

Superconducting magnet

25

The direction of the magnetic field in Image 79 is:

Horizontal

26

: Image 82 was acquired at what field strength?

1.5 Tesla

27

Passive shielding can be accomplished by lining the MR room with ___________.

Steel

28

Active shielding can be defined as:

Superconducting windings within the MR scanner, reducing the fringe magnetic field

29

_________ would be used to contain the RF in an MR magnet room.

Copper

30

___________ could be used to line the walls and/or floors of the MR magnet room to reduce the fringe field, and is defined as __________ shielding

Steel; passive