The magnitude of the flip angle depends on what two?

Duration of RF pulse, Amplitude of RF pulse

When does the nucleus gain energy?

When an external force has the same frequency

What does thermal equilibrium state?

A greater # of spins aligned in the same direction as B0 than against it.

measurement of the static magnetic field

When is the MR signal produced?

when coherent magnetization in the transverse plane cuts across the coil

recovery of longitudinal magnetization

What does an isotope have?

Same number of protons but different number of neutrons

What does phase refer to?

Position of magnetic moment on a path

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MRI Physics Week 1

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Questions 39

Answers

1
What is relaxation?
When the hydrogen loses its energy and returns to alignment with B0
When we apply the RF pulse to give hydrogen energy
What our hydrogen protons do when placed in a magnetic field
A slower speed of precessional frequency
2
What is an ion?
An atom with the same number of neutrons and electrons
An atom with the same number of protons and electrons
An atom that is electrically stable
An atom that is electrically unstable
3
The magnitude of the flip angle depends on what two?
Duration of RF pulse
Longitudinal plane
Amplitude of RF pulse
Parallel Spins
Transverse Plane
Antiparallel Spins
4
What is the Atomic number?
Sum of Protons and neutrons
Just the electrons
Just the neutrons
Just the protons
5
When does the nucleus gain energy?
When there is an odd number of protons in the nucleus
When an external force has the same frequency
When they are placed in the B0 field
When it is deemed an ion
6
How many types of motion are in an atom?
1
3
4
2
7
What is the most abundant atom in the body?
Nitrogen
Oxygen
Carbon
Hydrogen
8
A nuclei that has an even mass number...
Has an odd number of protons and neutrons
Has no net spin
Has a net spin
has an even number of electrons
9
What does alignment have? Pick 2
Ferromagnetism
Value
Paramagnetism
Direction
10
What two things cause a magnetic moment?
MR active nuclei
A spin
External magnetic field
Electricity
11
What type of hydrogen isotope do we focus on?
Deuterium
Tritium
Protium
12
What does FID stand for?
Frequency in decay
Flux Induction Delay
Free Induction Decay
Ferromagnetism is deadly
13
What does thermal equilibrium state?
There is an abundance of high energy spins
A greater # of spins aligned in the same direction as B0 than against it.
there is a small deficit in the spin up states
A lesser # of spins aligned in the same direction as B0 than against it.
14
What is the unit of precessional frequency?
Milliseconds
Megahertz
Microtesla
Hertz
15
A neutron has what kind of charge?
Negative
Not in a nucleus
No Charge
Positive
16
When the terms spin, nucleus or hydrogen nucleus are used we are referring to this particular isotope of hydrogen?
Deuterium
Carbon
Protium
Tritium
17
Where do we get net spin from?
Protons, electrons, and neutrons
Protons only
Neutrons and electrons
Electrons only
Protons and neutrons
Neutrons only
18
What is the other term for net spin?
Isotope
Angular momentum
Vector
Ions
19
What is the gyromagnetic ratio of hydrogen?
4.31 MHz
5.77 MHz
10.70 MHz
42.58MHz
20
What contains all the atom's mass?
Neutrons
Electron
Proton
Nucleus
21
In a 3T magnet which do we need?
Ferromagnetism
Less energy in RF pulse
More energy in RF pulse
An RF pulse at 42.58MHz
22
What is Tesla?
Oscillating magnetic field responsible for resonance
magnetic flux density
measurement of the static magnetic field
large magnetic field of the MR scanner
23
What are the other names for Parallel Alignment?
Spin Up
Low energy
Isotope
Vector
High energy
Spin Down
24
When is the MR signal produced?
when incoherent magnetization in the transverse plane cuts across the coil
At the same time as the RF pulse
when coherent magnetization in the transverse plane cuts across the coil
25
What is T1 recovery?
recovery of longitudinal magnetization
Ability to gain signal
decay of transverse magnetization
Energy given to spins in RF pulse
26
What is TE?
Energy Time
Echo Time
Excitation Time
Entry Time
27
Who do we give credit to for Classical Theory?
Max Planck
Albert Einstein
Paul Dirac
Sir Isaac Newton
28
Usually the number of electrons are the same number as which?
Protons
Neutrons
29
The B0 field is also termed what?
Transverse Plane
Transverse Magnetization
Longitudinal Magnetization
Logitudinal plane
30
What does an isotope have?
Same number of protons but different number of neutrons
Same number of protons with different numbers of electrons
Same number of protons and neutrons
Same number of protons and electrons
31
What are the three things needed for the laws of electromagnetic induction?
Hydrogen
Ions
Tritium
Charge
Motion
Magnetism
32
What are all things made of?
Protons
Atoms
Electrons
Molecules
33
What is the mass number?
Just the protons
Sum of protons and neutrons
Sum of protons and electrons
Sum of electrons and neutrons
34
What is TR?
Recovery Time
Relaxation Time
Release Time
Repetition Time
35
What does phase refer to?
The rate at which the magnetic moment speeds
If magnetic moments are incoherent
A Radian
Position of magnetic moment on a path
36
We will have a larger NMV in a 1.5T or a 3T scanner?
1.5T
3T
37
What is precession?
The excess of spin up spins
An additional spin or wobble
How fast we recover longitudinal magnetization
How fast we decay with transverse magnetization
38
What is the term used to describe when the RF pulse is applied?
Spin up
Larmor Equation
Excitation
Resonance
39
What is the timing measurement of precessional frequency?
1 Hz is one cycler per minute
1 Hz is one cycle per 10 milliseconds
1 Hz is one cycle per second
1 Hz is one cycle per millisecond

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