Magnetic Resonance Imaging

Superconductive magnets are limited to _ T in clinical MRI by the FDA.

• 4

How is Beam Modification used?

This magnet can be used in horizontal or vertical field system, and have strengths up to 0.3 T, and can be turned off.

• Resistive

Require the use of solenoid coils due to the orientation of the B0, more effiecient than linear coil, and can be combine with other coils electronically to improve signal uniformity through a region of interest.

• Quadrature
• Vertical
• Helmholtz pair
• Phased array

Main controlling factor of contrast?

• MA
• KVp
• MAs
• None of the above

Attenuation is a process by which the primary beam is reduced in energy as it passes through the patient (Absorbed)

• True
• False

Decreasing the KVp by 15% will?

• Halve

What is beam quality?

Allow for increased area of coverage without the reduction in SNR, have multiple coils and receivers.

• Quadrature
• Vertical
• Helmholtz pair
• Phase array

The true border of an object as seen on a radiograph?

• Border
• Edge
• Umbra
• True border

What is a Grid Ratio?

• Ratio of the height of the lead strips and the distance between them
• 15% rule
• 1 block
• None of the above

How does Filtration remove patient exposure?

• Removes Low energy non diagnostic photons
• Removes exposure
• Double their exposure

When a patient comes for an exam who has had a nuclear medicine study within 48 hours you should:

• Wear a lead apron while performing examination.
• Refuse to proceed with examination.
• Ask patient to return in 72 hours.
• Maintain a safe distance from patient when possible.
• Both a) and d)

What is under the direct control of the radiographer to produce quality radiographs?

• Knowledge
• Practice
• Skill
• Technique

What is size distortion most affected by?

If the KVp is increased what kind of image do you get?

• Lighter image
• Darker image
• No image

MRSA stands for:

• More Resistant Sickness Area
• Methicillin Resistant Staphylococcus Aureus
• Nothing, it's just a made up acronym.

What do Beam Modification result in?

10000 gauss = _ Tesla

• 5000T
• 1 T
• 15000T
• None

When does Attenuation vary?

Heartbeat & Peristalsis CAN be controlled by the patient

• True
• False

What DIRECTLY controls the energy/penetrating ability of the primary beam?

• MAs
• KVp
• Force

The chemicals for processing must be at proper?

If 256 frequency samples are collected and the readout or sampling period is 8 ms, the receiver bandwidth would be

• 16 Khz

What will happen if you lower KVp?

• Contrast will go down
• Contrast will go up
• Remains the same
• Nothing

The receiver bandwidth is determined by the number of

• Phase steps in the martrix
• Frequency samples in the matrix

How can object unsharpness be lessened? Correct use of:

THE FID CAN BE ALTERED BY

• FOURIER TRANSFORM

How often should work surfaces be disinfected?

• Once per shift
• Once per day
• Once per week
• Right before accreditation

What happens if you increase KVp?

• Contrast will go down
• Contrast will go up
• Remains the same
• None of the above

The __ Shift person is to check each room for safe working conditions each morning.

• A

What can under or over development in the chemical processing do?

If you lower you KVp, what happens to your image?

• Nothing
• Darker
• Lighter

What is the basis for radiographic contrast that attenuate the primary beam to differing degrees?

• KVp
• MAs
• Differential Attenuation
• Absorption

WHEN IS THE SLICE SELECTION GRADIENT APPLIED

• DURING THE ECHO
• DURING THE 90 DEGREE RF PULSE
• AFTER THE 180 DEGREE RF PULSE
• DURING THE 90 AND 180 DEGREE RF PULSE

This gradient coil varies the intensity of the magnetic field in the head to foot direction

• X
• Y
• Z

What specialty department uses Film/Screen Combinations?

• MRI
• Angiography
• Mammography
• CT

How can voluntary motion be controlled?

To result in equivalent mAs values, mA & time must change in the opposite direction by the same factor; If you raise one you have to lower the other

• True
• False

The receiver gandwidth represents the range of frequencies sampled during the

• Phase gradient
• Slice selection gradient
• Frequency encoding gradient
• Gradient coils

Contrast is need to view the visibility of detail.

• True
• False

Changing the mAs will have an effect on the beam

• True
• False

For Infection Control and Prevention those working with patients should wear nothing below the:

• Wrists
• Waist
• Elbows

A narrow bandwidth allows for _slices

• Thicker
• Thinner

These coils utilize additional loops and circiutry to improve the efficiency with which the MR signal is induced in the coil, and increase SNR approximately 40% over the coil of the same size.

• Quadrature
• Vertical
• Helmholtz pair
• Phased array

This gradient coil varies the intensity of the magnetic field in the right to left direction

• X
• Y
• Z

What is a major infulence on the size and sharpness of an image?

• OID
• KVp
• SID
• Holding still

Code ________ indicates Fire.

• red

What happens when scatter radiation reaches the IR, what will it do?

• Cause a fogging effect (Grey Effect)
• White effect
• Does not show up
• A normal image

When may employees who do not get immunized during the Immunization Program, but decide to get immunized when an outbreak occurs, return to work?

• Immediately after the immunization
• One week after immunization
• 14 days after immunization
• Immediately after the immunization providing they take the appropriate anti-viral medication for 14 days.
• Both c) and d)

When and how often should you be fit tested for an N-95 mask?

• Annually in January
• Never
• When you think of it
• When your supervisor tells you to
• Every six months, January and July
• Annually in your birth month

The main purpose of the gradient subsystem is to

• _Select the slice plane
• _Select the imaging plance
• Spatially encode the MR signal
• All of the above

When is a sharps container considered full?

• When it's too heavy to lift.
• When the fill line is reached.
• When you can't possibly fit anything more into it.
• When your supervisor tells you.

Fuzzy border of an object on a radiograph?

• True border
• Soft Edge
• Umbra
• Penumbra

A Film/Screen Combinations are cassettes with intensifying screens that emit a specific color of light and the x-ray film that is sensitive to that same color of light

• True
• False

Staff should wear their identification badges:

• When working with patients
• At all times in the hospital
• Unless they don't like their picture
• When going to the OR, ER or ICU

The gyromagnetic ratio of h+ in 1 T is

• 42.6 MHz

Which of the following constitute and infection control hazard? (check all that apply)

The slice location is determined by the

• Phase gradient
• Transmit frequency of the rf coil
• Receiver frequency of the rf pulse
• Transmit frequency of the rf pul

When performing examination on patient who is on "droplet precautions", what precautions should be taken?

• Gown & gloves only, mask not required.
• Gown only, gloves if you have an open wound.
• Gown, gloves and N-95 fit mask.
• Gown, gloves and surgical grade mask with visor.

If you are with a patient in Room 3 and you hear Code Red paged over head, you should: (check all that apply)

What does KVp control?

The majority of superconducting magnets are __ in design and exhibit a (horizontal or vertical) magnetiic field.

• Solenoid horitzontal

Magnets that utilize direct current applied to a coil of wire, and are submerged in liquid helium or cryogen to cool the wires.

• Superconducting

THE SIGNAL INDUCED IN A RECEIVER COIL IMMEDIATELY FOLLOWING AN RF EXCITATION PULSE IS KNOWN AS THE

• FREE INDUCTION DECAY

This type magnetic shielding uses metal, usually steel, in the scan room walls to contain the fringe field

• Passive
• Active

TO EVALUATE IMAGES WITH T2* CONTRAST _ IMAGES ARE REQUIRED

• GRADIENT ECHO

Major components of Fluoroscopic Image?

What are Grids?

• Device to remove or absorb scatter radiation as possible
• Props patient up
• None of the above

If the KVp has more energy what does it have?

• More penetrating force
• Less penetrating force
• Same penetrating force
• No penetrating force

What areas are contrast used in?

What is the source of x-rays?

• Cathode
• Anode
• Target
• Rotating anode

More radiaiton makes an image

• Lighter
• Invisible
• Nothing changes
• Darker

What are types of Beam Limitations?

What does KVp do?

• Low energy level
• Controls penetrating ability
• Controls time
• None of the above

THE OUTER LINES OF K SPACE HOLD

• EDGE DETAIL

This type of magnetic shielding uses other magnets and their associated magnetic field to confine the field of the main magnet

• Passive
• Active

How is the best image obtained?

Magnets made of blocks or slabs or naturally occurring ferrous material.

• Reistive
• Permanent
• Superconducting
• Selenoid

The visible difference between adjacent radiographic densities?

• Density
• Contrast
• KVp
• MAs

A difference of attenuation causes a formation of the image?

• True
• False

The degree of blackening an image?

• Density (mAs)
• Contrast
• SID
• Scatter radiation

Changing either mA or S will cause a change in the degree of blackening?

• True
• False

What are (6) characteristics of x-rays?

WHEN DOES PHASE ENCODING TAKE PLACE

• DURING THE FID
• , AFTER THE SLICE SELECTION AND BEFORE THE READOUT

Substances that exhibit a slight increase in the magnetic field when placed in an externally applied magnetic field. They have low and positive susceptibility.

• Diamagnetic
• Paramagnetic
• Superpapmagnetic
• Ferromagnetic

What results with a fast film speed (Less Radiation) ?

• Repeats
• Recorded Detail
• Unsharpness of Detail
• None of the above

What does KVp INDIRECTLY control? (15% rule)

• Quality
• Quantity
• Penetrating ability
• Peak

THE DIFFERENCE IN PRECESSIONAL FREQUENCY OF THE HYDROGEN IN FAT AND WATER IS KNOWN AS

• FOURIER TRANSFORM
• FID
• SPIN DENSITY
• CHEMICAL SHIFT

IF A THICKER SLICE IS DESIRED

• A LOWER AMPLITUDE OF THE Y GRADIENT IS SELECTED
• A HIGHER AMPLITUDE OF THE Z GRADIENT IS SELECTED
• A HIGHER AMPLITUDE OF THE X GRADIENT IS SELECTED
• A LOWER AMPLITUDE OF THE Z GRADIENT IS SELECTED

These substances exhibit positive suseptibility , are stronger than paramagnetic substances, but are weaker than ferromagnetic substances, and are used as T2 contrast agents

• Diamagnetic
• Paramagnetic
• Superparamagnetic
• Ferromagnetic

Less radiation makes an image?

• Lighter
• Darker
• Invisible
• Nothing changes

THE MIDDLE LINES OF K SPACE CONTAIN OVER 90% OF THE

• IMAGE DETAIL, IMAGE CONTRAST

Film/Screen Combinations are also used to produce a particular scale of contrast

• True
• False

A higher ratio of lead strips will give a better clan up of scatter ratio

• True
• False

Permanent magnets have field strengths of

• 0.5 - 1 T
• 0.06 -0.35T
• 1-3 T
• Up to 10 T

THE DIFFERENCE IN PRECESSIONAL FREQUENCY, DUE TO THE CHEMICAL/MOLECULAR ENVIRONMENT, IS KNOWN AS

• T2*

THE CHEMICAL SHIFT BETWEEN FAT AND WATER AT 1.5 T IS __, OR H + WATER WILL PRECESS THIS MUCH FASTER THAN THE H+ IN FAT

• 224HZ

Gadilinium is an example of a _ substance

• Diamagnetic
• Paramagnetic
• Superparamagnetic
• Ferromagnetic

With a smaller OID there is better recorded detail.

• True
• False

THE ONLY WAY THE SPATIAL RESOLUTION CAN INCREASED IS TO

• INCREASE THE FOV
• DECREASE THE PHASE ENCODINGS OF THE MATRIX
• INCREASE THE VOXEL VOLUME
• REDUCE THE VOXEL VOLUME

Step 1 for needle poke, cut or bite includes which of the following: (check all that apply)

Motion is NOT the most common cause of radiographic unsharpness

• True
• False

What are the major types of image receptors?

These substances exhibit positive suseptibility, but when placed in an external magnetic field they will remain magnetized when external magnetic field is removed

• Diamagnetic
• Paramagnetic
• Superparamagnetic
• Ferromagnetic

What are some exposure factors? (aka Technique)

Daisy arrives for work in x-ray in open, mesh-type sandals. What does her supervisor direct her to do prior to starting duty?

• Change into her crocs
• Put socks on in her sandals
• Wear blue OR shoe covers over her sandals
• Change into approved duty shoes

Staff should notify their supervisor of all safety concerns.

• True
• False

RF SHIELDING IS KNOWN AS A

• FARADAY CAGE

What is responsible for the production of densities of the radiograph?

• KVp
• MAs
• Scatter Radiation
• Absorption

Wires are aligned side by side to create magnet field

• Permanent magnet
• Resistive magnet
• Selenoid magnet
• Superconducting

If you have been poked by a used needle you should:

• Put a bandage over the wound and watch for reaction.
• Follow Blood & Body Fluid Exposures Protocol.

What do the stream of electrons need to do in order to produce an x-ray?

• Speed up
• Slow down
• Constant speed
• Stop

Where is the x-ray safety manual located? (choose most correct)

• Supervisor's office.
• On line.
• Red binder in tech area.
• On line under JOH&S
• Both c) and d)

What are other words used for Recorded Detail?

System Speed is an arbitrary number given to a specific system. Average speed = 100

• True
• False

These substances exhibit a very slight negative or repelling effect when placed in externally applied magnetic field. They have low and negative susceptibility.

• Diamagnetic
• Paramagnetic
• Superparamagnetic
• Ferromagnetic

Static Images are Spot Films cassettes that are exposed by the remnant beam

• True
• False

What is needed to cause the e-stream to accelerate at an extremely high speed from the cathode to the anode?

• MAs
• KVp (high Voltage)
• Electric
• Light

A way to express the gradient performance referring to the acceleration of the gradient magnetic field to its maximum amplitude, expressed in units of T/m/s.

• Rise time
• Coil configuration
• Slew rate

THE PHASE ENCODING GRADIENT REPRESENTS

• THE AMOUNT OF TIMES THE ECHO IS SAMPLED
• THE LINE IN K SPACE ON WHICH THE DATA WILL BE PLOTTED DURING THE READOUT PERIOD
• THE AMOUNT OF RESOLUTION IN THE IMAGE

What is a latent image?

• Unprocessed, invisible image
• Light image
• Dark image
• Unsteady Image

What consists of many lead strips separated by a radiolucent material placed between the patient and the IR?

• Cones
• Collimators
• Cylinders
• Grids

How can involuntry motion be controlled?

• Shorten exposure time
• Repeat
• Do nothing to the exposure time
• None of the above

What are the steps taken to turn "Latnet Images" into visible images?

What does the Remnant beam do?

• produces the image

Raising the KVp by 15% will?

• Double

SLICE THICKNESS IS DETERMINED BY THESE 2 THINGS

• AMPLITUDE OF THE GRADIENT
• BANDWIDTH OF THE RF PULSE

How does distance affect density?

• 15% Rule
• Inverse Square Law
• Stay the same
• Has no affect

What controls beam quality?

• MAs
• KVp
• Seconds
• Radiographer