Chapter 1- Basic Principles Flashcards

1
Q

There are two different views of MRI and they are :

A

Quantum theory and classical

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2
Q

The classical theory focuses more on how the universe works “mechanically”

A

True

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3
Q

The quantum theory focuses more on the different energy levels of protons and neutrals and electrons

True or False?

A

True

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4
Q

An atom is organized into “____” which are two or more atoms arranged together?

A

a molecule

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5
Q

In humans, the most abundant atom is hydrogen.

True or False

A

True

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6
Q

An atom consists of a central nucleus and orbiting ___

A

electrons

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7
Q

Protons and neutrons are subcategories of

A

nucleons

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8
Q

the sum of the protons in a nucleus is called

A

anomic number

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9
Q

The sum of the protons and neutrons in a nucleus is called the

A

mass number or atomic weight

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10
Q

When an atom has less neutrons than protons this is called an

A

isotope

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11
Q

Electrons are particles that spin around the nucleus

True or False

A

True

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12
Q

Protons have a ____ electrical charge

positive, negative or none

A

positive

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13
Q

Neutrons have a ____ electrical charge

positive, negative or none

A

No net charge

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14
Q

Electrons have a ____ electrical charge

positive, negative or none

A

negative

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15
Q

An atom is considered electrically stable if the number of electrons ____ the number of protons?

equals, is less, is more

A

equals

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16
Q

How can we alter the balance of an electrically stable atom?

A

apply energy to knock out the electrons from the atom. This will produce electrical instability.

This is called an ION

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17
Q

the process of knocking out electrons is called

A

ionization

18
Q

What are the three types of motion in an atom?

A

Electrons spinning in their own axis

electrons orbiting the nucleus

the nucleus spinning on its own axis.

19
Q

If an atom has an even atomic and mass number, (6 protons 6neutrons mass 12), will it have a spin?

A

no

if they have an even number , half the nucleons spin one direction and the other half another direction which cancels itself out??

20
Q

How is angular momentum caused?

A

in nuclei with an odd number of protons, odd number of neutrons, the spin directions are not equal and opposite so it will have a net spin.

21
Q

What is the large magnetic field of the MRI scanner called?

22
Q

What is the magnetic field measured in ?

23
Q

The influence of B 0 prouces an additional spin or wobble of the magnetic moment of hydrogen around b0.

24
Q

What is another name for precessional frequency?

A

Larmor Frequency

25
What does RF stand for?
radiofrequency
26
How would you explain "phase"
it refers to the position of magnetic moments on their precessional path at any moment in time.
27
The magnetic moment travels thru 360 degrees during one rotation. True or False
True
28
What is the difference in out of phase and in phase?
In phase means the magnetic moment of hydrogen are at the SAME place on the precessional path at the moment in time Out of phase means the magnetic moments of hydrogen are at DIFFERENT places on the precessional path.
29
Out of phase is also called ____
incoherent
30
in phase is also called
coherent.
31
Resonance is also called "reverb"
True
32
Resonance is achieved by transmitting an RF pulse called a ____
RF excitation pulse
33
Excitation means "energy giving"
True
34
A RF exciation pulse ____ energy to hydrogen nucleu and causes a net ___ to the number of high energy spin down nuclei Takes energy/ gives energy net increase or net decrease.
it gives energy to cause a net increase
35
The process at which hydrogen loses its energy is called
relaxation
36
Explain what TR is
TR is the time from the application of one RF excitation pulse for each slice.
37
TR is measured in seconds True or False
FALSE Tr is measured in milliseconds
38
TR determines the amount of longitudinal relaxation that occurs between the end of 1 RF pulse to the next. True or False
True
39
Explain what TE is
The time from the application of the RF pulse to the peak of signal induced in the receiver coil.
40
TE is measured in milliseconds. True or False
True
41
TE determins how much decay of transverse magnetization occurs.
True
42
TE controls the amount of T2 relaxation.
True