Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MRI > Basic MRI Safety > Flashcards

Basic MRI Safety Flashcards

1
Q

In what year was the first human scanned using MRI?

A

the mid 1977s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Even if the electrical
supply to the equipment is shut down, the magnetic field still is in force.

True or False

A

True, it is NEVER powered off.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Who is responsible for patients and workers not getting hurt once stepping into the MRI department?

A

the MRI technologist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the four types of magnetic classifications?

A

Diamagnetic
Paramagnetic
Superparamagnetic
and ferromagnetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is considered a diamagnetic substance?

A

A substance that has no net magnetic moment because they have no unapired orbital electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an example of a diagmagnetic object?

A

sheets of paper and plastic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a paramagnetic substance?

A

They have unpaired orbital electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens when a diamagnetic substance is exposed to a magnetic force?

A

they demonstrate NEGATIVE magnetic susceptibility (repelled by magnet)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens when a paramagnetic substance is exposed to MR

A

they have a SMALL positive magnetic susceptibility of less than one. They are SLIGHTLY attracted. therefore the magnetic field is greater.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an example of a paramagnetic material?

A

gadolinium based contrast and rare earth metals such as lanthanide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a superparamagnetic substance?

A

they have ferromagnetic (attracted to magnets) properties in bulk. They behave similar to paramagnetic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is an example of a superparamagnetic substance?

A

iron- containing contrast agent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a ferromagnetic substance

A

there is a positive magnetic susceptibility of greater than one. The word ferromagnetic literally means attracted to magnets.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When exposed to a magnetic field, what happens to a ferromagnetic substance?

A

it is permanently magnetized, even after the magnetic field is removed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are some examples of ferromagnetic objects?

A

oxygen tanks, stretchers, wheelchairs, IV poles, scissor, floor buffers, mops, mop buckets.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the preferred unit that we measure the magnetic force?

A

Tesla (T)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

A 1.5 T scanner has a static field of appx. 30,000 that of the earths magnetic field.

True or False

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What term is a form of measuring the magnetic field around MR equipment?

A

GAUSS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

1 Tesla equals how much gauss?

A

1 Tesla = 10,000 GAUSS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

When you see a 5-gauss line around the MRI scanner, what do you assume that means?

A

means the static field is higher than 5 GAUSS, which is potentially hazardous.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

If I have a 2 month old baby, can they be scanned? If so , how much static magnetic field strength can be used?

A

up to 8.0 Tesla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

If I have a one month old, how much static magnetic field strength can be used?

A

4.0 Tesla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is a 5 GAUSS warning?

A

means the strength is 5 GAUSS which can be hazardous. People with non-compatible implants should not enter that area.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a fringe field?

A

the invisible magnetic force that extends outside the magnet. It is 360 degree perimeter around the scanner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is active shielding?

A

it consists of tightly wound electromagnetic coils that alternate electrical current to restrict the magnetic field and reduce the fringe field exposures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is passive shielding?

A

Iron beams that were used during construction of the MRI room. It pulls the magnetic field into the scanner room which keeps the fringe field from extending outside of the room.

27
Q

Decreasing the fringe field reduces the risk to people with pacemakers and other metallic implants or things that might enter the magnetic field on accident

True or False

A

True

28
Q

What is an example of translational force?

A

an oxygen tank becoming projectile and being forced into the magnetic bore.

29
Q

What is an example of a rotational force?

A

something like a non-compliant pacemaker or ferromagnetic aneurysm clips experiencing torque bc of the magnetic field.

30
Q

Say I walk a patient into the MRI scanning room and they suddenly tell me “I forgot to tell you, i have an aneurysm clip”, what should your next step be

A

CAREFULLY BACK THE PATIENT UP without turning to minimize the risk of torque.

31
Q

Say I walk a patient into the MRI scanning room and they suddenly tell me “I forgot to tell you, i have an aneurysm clip”, what will happen if you or the patient panics and turns around to run out?

A

the spinning/turning motion can cause the implanted device to torque.

32
Q

The metal detectors that are located before you walk into the MRI room have a strength of how much GAUSS?

A

1,000

33
Q

What are three factors that affect the amount of RF Energy deposited into patient during MRI scan?

A

the body weight, the imaging pulse sequence, the repetition time (TR), the number of slices, and the amount of patient tissue scanned, and the type of MR imaging coil.

34
Q

The more RF pulses used, the more energy deposited into patient. What will this do the patients tissue temperature?

A

it will rise as well. All directly related.

35
Q

What is SAR stand for and what is it?

A

specific absorption rate

has to do with the amount of RF energy absorbed by the body.

36
Q

What is SAR measured in?

A

WATTS PER KILOGRAM (W/KG)

37
Q

How does the MRI machine create “heat” to make an image?

A

The RF coils produce an oscillating electromagnetic field. These RF pulses are transmitted to patient and excites tissues to produce a signal.

38
Q

Sudden increases in body temperature can cause serious complications with patients with what type of conditions?

A

Diabetes, high blood pressure, certain cardiac conditions, or any other conditions that affect the ability to perspire.

39
Q

What are MR-approved ECG leads made of?

A

Silver and silver chloride to avoid burns

40
Q

What are examples of things that can experience excessive heating during MR Scanning?

A 
Pacemakers and ICDS,
Neurostimulation systems
halo vests
damaged ECG leads
Pulse oximeters
41
Q

MR Techs should screen patients for jewelry, body piercing, tattoo, and permanent wake up, regular eye make-up.

A

True

42
Q

When would it be important to removed eye make up >

A

If we are imaging the orbits/ if we are scanning that area because it can cause burns. Some make ups contain metallic flakes and that can create a void artifact in the orbital area.

43
Q

Why is body piercings subject to cause a burn?

A

because it is made up of stainless steel which is not attracted to magnets but can potentially heat up.

44
Q

When patients have tattoos or body piericings, it is important to tell them to hit the “help” button and tell us if they feel any irritation or anything unusual in those areas.

A

True

45
Q

The gradient field can potentially stimulate peripheral nerves in patient and the loud noises can lead to hearing loss if they don’t use earplugs.

A

True

46
Q

What is the loud noises from the machine caused from?

A

Caused from the gradient coils being turned on and off and can damage a patient’s hearing.

47
Q

How many times is a an MR patient screened before entering the MR scanner?

A

3

48
Q

Are intracranial vascular clips a contraindication for MRI scanning?

A

yes!!! absolutely. It can cause the clip to torque which would tear the vessels. They also are subject to thermal heating. If they are made of titanium they are safe.

49
Q

If a patient has a pacemaker, can they have an MRI?

A

yes. technically its a contraindication but if they deem the benefit outweighs the risk, then a doctor, cardiologist and other ppl need to be present in case of emergency complications.

50
Q

Ferrous foreign bodies in a patient’s eyes can cause permanent blindness if exposed to high field magnets.

True or False?

A

true

51
Q

What kind of questions should we ask to make sure a patient doesnt have metal in their eyes?

A

Have you had eye surgery?

Have you had any metal fragments in your eyes?

Have you ever worked with metal or been hit in the eye with metal?

52
Q

What are cryogen gases used for in MRI?

A

it is used to cool superconducting magnet system. If these are released, its called quenching.

53
Q

If someone is exposed to a cryogen gas release, what symptom can that cause?

A

frost bite or asphyxiation.

54
Q

What does MR conditional 1 entail?

A

device is acceptable for the patient or individual in the MR environment—device is weakly ferromagnetic only

55
Q

What does MR conditional 2 entail?

A

weakly ferromagnetic coils, filters, stents, clips, cardiac occluders, or other implants typically in 6 weeks tissue is healed around the implant

56
Q

Conditional 3?

A

some transdermal patches with metallic foil can heat up during scan—have to take off before scanning

57
Q

What does conditional 4 entail?

A

halo vest or cervical fixation device may have ferromagnetic component parts—magnetic field interactions have not been determined (no report of patient injury with these devices at the static magnetic strength used for MRI safety testing

58
Q

Conditional 5?

A

device is acceptable in the MRI setting if specific guidelines are followed (specific information on this website ( www.mrisafety.com ) and contact the manufacturer for further information

59
Q

What is conditional 6 entail?

A

this device/implant was determined to be MRI conditional according to the terminology specified in the America Society for Testing and Materials (ASTM) International Designation: F2503

60
Q

Conditional 7?

A

– this device is not intended for use during the operation of an MR system for an MR procedure

61
Q

What is considered an MRI conditional 8?

A

this information pertains to an implant/device that has MRI labeling at 1.5 Tesla and 3 Tesla—device/implant may be safe at 1.0 Tesla but unsafe at 3.0 Tesla

62
Q

What do we do if a patient codes in our room?

A

We need to get the patient out of our scan room to prevent hazards from happening to patient, scanner or ppl involve.d

63
Q

If a patient insists that we scan a pregnant lady, what is our next step?

A

Do a creatinine for GFR.

MRI (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions