Magnetic Resonance Imaging

How can object unsharpness be lessened? Correct use of:

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

• X
• Y
• Z

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

• Quadrature
• Vertical
• Helmholtz pair
• Phase array

What are Grids?

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

How can voluntary motion be controlled?

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

THE OUTER LINES OF K SPACE HOLD

• EDGE DETAIL

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

• MAs
• KVp
• Force

When does Attenuation vary?

What are (6) characteristics of x-rays?

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

• Nothing
• Darker
• Lighter

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

• True
• False

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

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

• True
• False

Less radiation makes an image?

• Lighter
• Darker
• Invisible
• Nothing changes

What does the Remnant beam do?

• produces the image

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

• A

How can involuntry motion be controlled?

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

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

• Knowledge
• Practice
• Skill
• Technique

Motion is NOT the most common cause of radiographic unsharpness

• True
• False

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

• Superconducting

Contrast is need to view the visibility of detail.

• True
• False

How is Beam Modification used?

Changing the mAs will have an effect on the beam

• True
• False

SLICE THICKNESS IS DETERMINED BY THESE 2 THINGS

• AMPLITUDE OF THE GRADIENT
• BANDWIDTH OF THE RF PULSE

A difference of attenuation causes a formation of the image?

• True
• False

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

THE FID CAN BE ALTERED BY

• FOURIER TRANSFORM

What controls beam quality?

• MAs
• KVp
• Seconds
• Radiographer

10000 gauss = _ Tesla

• 5000T
• 1 T
• 15000T
• None

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

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

What is size distortion most affected by?

More radiaiton makes an image

• Lighter
• Invisible
• Nothing changes
• Darker

WHEN DOES PHASE ENCODING TAKE PLACE

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

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

• FREE INDUCTION DECAY

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

• KVp
• MAs
• Scatter Radiation
• Absorption

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

• True
• False

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

• Lighter image
• Darker image
• No image

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

• Passive
• Active

MRSA stands for:

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

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

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

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

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

• 4

The visible difference between adjacent radiographic densities?

• Density
• Contrast
• KVp
• MAs

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

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

• Cones
• Collimators
• Cylinders
• Grids

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

• KVp
• MAs
• Differential Attenuation
• Absorption

TO EVALUATE IMAGES WITH T2* CONTRAST _ IMAGES ARE REQUIRED

• GRADIENT ECHO

What areas are contrast used in?

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

• True
• False

The receiver bandwidth is determined by the number of

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

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

Code ________ indicates Fire.

• red

What specialty department uses Film/Screen Combinations?

• MRI
• Angiography
• Mammography
• CT

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

• Passive
• Active

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

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)

Staff should notify their supervisor of all safety concerns.

• True
• False

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

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

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

• Speed up
• Slow down
• Constant speed
• Stop

Raising the KVp by 15% will?

• Double

What does KVp control?

What happens if you increase KVp?

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

What are some exposure factors? (aka Technique)

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

Permanent magnets have field strengths of

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

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

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

• True
• False

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.

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

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

• IMAGE DETAIL, IMAGE CONTRAST

What is the source of x-rays?

• Cathode
• Anode
• Target
• Rotating anode

What does KVp do?

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

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

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

A narrow bandwidth allows for _slices

• Thicker
• Thinner

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)

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

What is a latent image?

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

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

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

• Border
• Edge
• Umbra
• True border

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

What is beam quality?

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

• T2*

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

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

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

• Reistive
• Permanent
• Superconducting
• Selenoid

What are types of Beam Limitations?

Major components of Fluoroscopic Image?

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 often should work surfaces be disinfected?

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

How is the best image obtained?

The gyromagnetic ratio of h+ in 1 T is

• 42.6 MHz

Fuzzy border of an object on a radiograph?

• True border
• Soft Edge
• Umbra
• Penumbra

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.

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

With a smaller OID there is better recorded detail.

• True
• False

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 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

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

• OID
• KVp
• SID
• Holding still

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

• Solenoid horitzontal

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

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.

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

• True
• False

Wires are aligned side by side to create magnet field

• Permanent magnet
• Resistive magnet
• Selenoid magnet
• Superconducting

Main controlling factor of contrast?

• MA
• KVp
• MAs
• None of the above

The degree of blackening an image?

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

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)

Decreasing the KVp by 15% will?

• Halve

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

What are other words used for Recorded Detail?

Gadilinium is an example of a _ substance

• Diamagnetic
• Paramagnetic
• Superparamagnetic
• Ferromagnetic

Heartbeat & Peristalsis CAN be controlled by the patient

• True
• False

What are the major types of image receptors?

How does distance affect density?

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

If the KVp has more energy what does it have?

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

The receiver gandwidth represents the range of frequencies sampled during the

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

What do Beam Modification result in?

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

The chemicals for processing must be at proper?

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

RF SHIELDING IS KNOWN AS A

• FARADAY CAGE

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

• X
• Y
• Z

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

• FOURIER TRANSFORM
• FID
• SPIN DENSITY
• CHEMICAL SHIFT

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

• Wrists
• Waist
• Elbows

How does Filtration remove patient exposure?

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

What does KVp INDIRECTLY control? (15% rule)

• Quality
• Quantity
• Penetrating ability
• Peak