MRI/ Nuc Med test reveiw

Which types of implants may pose a problem during scanning?

Intracranial aneurysm clips, auditory implants, electromechanical implants

What could result from scanning a pt with a cardia pacemaker?

They can malfunction if exposed to strong magnetic fields.

Who are likely candidates for sedation cases?

People with anxiety, confused, claustrophobic

What procedures would be acceptable in checking for ferrous qualities of accessory devices in MRI?

X-ray, CT scan, hand-held magnet

What factors are responsible for including a physiologic response to induced voltage?

PT size, orientation, frequency of stimulus, gradient field

Following the injection of contrast, what types of pts are most likely to have serious reactions?

Asthmatic and pts with low kidney function

Gadolinium is what strength of magnet?

Paramagnetic

What special precautions are required with sedation cases in MRI?

Making sure they are not allergic, and always be monitored by nurse or tech

What allows the excretion of gadolinium from the kidneys?

Chelating agents

If not for this bounding agent, where would gadolinium be deposited?

Liver or bone marrow

For what pts id gadolinium contraindicated?

Stage 4-5 renal disease

One tesla equals ________gauss

10,000

What cryogen is typically used in MRI systems to keep the magnet cool?

Helium

What way is known as the most efficient at demagnetizing a superconducting MRI magnet?

Quenching

What is meant by “shimming” of the magnet

The magnetic field is balanced

What does the Larmor frequency tell us?

Magnetic field strength

There are _______ coil windings within the magnet itself

3

MRI imaging quality is _________,__________ as a function of time

Contrast/spatial resolution, signal noise

What categories is motion divided into

Periodic and aperiodic

How aperiodic motion is effectively reduced?

Gating technology

What is currently the highest magnetic strength approved by the FDA?

3.0 T

What are the similarities between CT and MTR

Cross-sectional images

What happens to signal to noise as magnetic strength increase?

It increase

What part of the MRI process that is responsible for sending the signal and acting as a type of antenna?

Gradient coils

What is the purpose of multi-channeled coils?

To get higher signal to noise ratio provided by the smaller coils.

A strong signal that is sent from the MRI unit is represented by a _______ color tone

White

What anatomy benefits most from the use of a 3T magnet?

Neurological

What line defines the limit beyond which ferromagnetic objects are strictly prohibited?

Gauss line

What present of pts are unable to have a traditional MRI done as a result of claustrophobia?

10%

MRI zone 1

Waiting area, accessible to the public

MRI zone 2

Changing area

MRI zone 3

Tech area, personnel only

MRI Zone 4

MRI machine

A chemical compound in which one or more atoms have been replaced by a radioisotope defines?

Radioactive layer

Preparation areas in nuclear med must have?

Isolated ventilation and protective lead or glass shield

What is the purpose of the wipe test?

To make sure no radioactive material leaks into the general public

What is a Geiger-miller detector used for in Nuclear med?

Measures radioactivity

What are the active elements utilized in monitoring devices in nuc med?

Lithium fluoride TDL and Aluminum oxide OSL

PET scanning is known as a ________ process

annihilation

Why are pts who have sensitivity to noise susceptible to pain in MRI?

The coils vibrate loud

What are the symbols for half life?

T 1/2

Biological Half life?

TB