Ch 3 Review of Equipment Operation and Quality Control

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In many cases, digital fluoroscopy eliminates what?

Postprocedure "overhead" films

A photostimulable phosphor is the active component of what piece of quipment?

Computed radiography imaging plate

In computed radiography, the image must be turned into digital form by what device?

Analog-to-digital converter

A mathematical formula used to recontruct the image in digital imaging is called:

An algorithm

Picture elements in a digital image are called:

Pixels

A digital image is composed of rows and columns known as a:

Matrix

Direct digital radiography differs from computed radiography in what way?

The use of fixed detectors that communicate directly with the computer

Window width in computed radiography and digital radiography controls what image property?

Contrast

A graphic display that is constructed to show the radiographer the distribution of pixel values is called:

A histogram

The law stating that the oouter shell of an atom can contain no more than eight electrons is called:

Octet Rule

Examples of particulate radiation are:

Helium nuclei and beta particles

Electromagnetic radiation travels:

In waves along a straight path

Electromagnetic raiation travels in bundles of energy called:

photons

X-rays travel at what speed?

The speed of light, 186,000 miles per second

Waves of radiation are called:

Sine waves

Wavelength is defined as the distance from:

Peak to peak of the wave

Frequency is defined as:

The number of waves passing a point per unit time

The speed of w-rays is based on:

The fact that they are a form of electromagnetic radiation

Wavelength and frequency are:

Inversely proportional to each other

The x-ray beam will change as it travels through th patient by a process called:

Attenuation

The intensity of radiation is inversely proportional to the square of the distance between the source of radiation and the person receiving it . This descibes:

Inverse square law

As radiation strkes matter:

The energy is transferred to the atoms according to the law of conservation of energy

Which of the statements are true regarding electrostatic charges?

1) Electrostatics is the study of electirc chares at rest
4) Electrostatic charges concentrate on a conductor in the area of greatest curvature

Which of the statements are false regarding Equipment Operation?

4) The volt is the unit of electric curretn
6) The ampere is the unit of electromotive force
9) Ohm's law is calculated unsing the quation VI=R

Electromagnetic induction is the process of causing an electric current to flow in a conductor:

When it is placed in the magnetic field of another conductor

The two types of electromagnetic induction are:

Self-induction and mutual induction

Self-induction is used in the operation of what device?

Autotransformer

The strength of the magnetic fields in a transformer is increased by:

Coiling the vires and letting their magnetic fields overlap

Electricity is supplied to the imaging department by a:

Generator

The electricity provided to the radiology department is:

60 Hz Ac

The electricity provided to the radioglody department operates at:

120 pulses per second

High-frequency power:

Has almost no ripple

The primary advantage of three-phase power is that:

Voltage never drops to zero

A variable transformer that is used to select kVp for the x-ray circuit is the:

Autotransformer

A transformer that has more turns in the secondary than in the prmary coild is called a:

Step-up transformer

The transformer used to boost voltage to kilo-voltage levels is called a(n):

Step-up transformer

Voltage coming to the x-ray machine is kept constant through the use of a(n):

Line voltage compensator

A step-down transformer:

Steps down voltage

Where does thermionic emission occur?

Cathode

What device is prereading?

kVp meter

What device reduces voltage and provides current to produce an electron cloud or space charge at the filament?

Step-down transformer

What device is electronic, with increments as low as 0.001 second?

Timer

What changes AC to DC?

Rectifier

What is surrounded by a negatively charged focuing cup?

Filament

What is composed of solid-state, silicon-based diodes?

Rectifier

What regulates the duration of x-ray production?

Timer

What is located in the x-ray circuit between the high-voltage tranformer and the x-ray tube?

Rectifier

What measures tube current?

mA meter

What device spines at 3300 to 10,000 rpm?

Anode

What device uses maximum heat storage ability of the tube to deliver mAs?

Falling load generator

What is the source of bremsstrahlung and characteristic rays?

Anode

What device increases voltage approximately 500 times?

Step-up transformer

What is the most commonly used AEC?

Ionization Chamber

What device always delivers the shortest exposure time possible?

Falling load generator

What device is turned by a rotor?

Anode

Which of the following is located between the patient and the image receptor?

Ionization chamber

The filament is kept warm by:

A standby current from the time the x-ray machine is turned on

Activating the rotor will:

Reduce tube life

When making an exposure, the radiographer should:

Activate the rotor and exposure switch in one continuous motion

The process of thermionic emission causes:

Electrons to boil off the filament

The electron stream passes from cathode to anode because of ______ passing through the x-ray tube.

Current

Heat is produced in the x-ray tube as:

Electrons interact with the target material

Most of the energy conversion in the x-ray tube produces:

heat

X-rays are produced as incident electrons interact with target atoms by a process called:

Brensstrahlung

X-rays are produced as incident electrons interact with inner shell electrons in target atoms by a process called:

Characteristic

What percentage of energy in the x-ray tube is converted to x-rays?

1 %

What are properties of x-rays?

2) Affect film emulsion
3) scatter and produced secondary radiation
4) Invisible
7) Travel in bundles called photons
8) Ionize matter and gases
10) cause phosphors to fluoresce

The x-ray beam is:

Hetergeneous or polyenergetic, consisting of many different energies (wavelengths)

The x-ray emission spectrum consists of:

Discrete spectrum (produced by characteristic rays) and continuous spectrum (produced by brems rays)

The primary purpose of filtration is:

Radiation protection

The amount of material needed to reduce the intensity of the beam by 1/10 is called:

Tenth-value layer

What statements are true regarding filtration?

Total filtration (not less that 2.5-mm aluminum equivalent) = inherent filtration (glass envelope, tube housing, oil) + added filtration (aluminum)

Calculating heat untties for three-phase, twelve-pulse quipment requires the use of ____ as a constant; calculating heat units for single-phase equipment requires the use of _____ as a constant; calculating heat units for three-phase, six-pulse equipment requires the use of _____ as a constant.

1.41, 1, 1.35 because average photon energy is different with each type of equipment

Which of the following charts may be consulted to determine the safety of a single x-ray exposure?

Tube rating chart

Which of the following charts may be consulted to determine the safety of a series of x-ray exposure?

Anode cooling curve

The portion of the image intensifire tube that converts elctron energy to visible light is the :

Output phoshor

The portion fo theII tube that converts visible light to an electronic image is the:

Photocathode

The input phosphor of the image-intensifier tube converts:

xray evergy to visible light

Total brightness gain achieved using an image intensifier equals:

flux gain times minification gain

Single-phase, full-wave rectification produces:

Pulsating direct current with 120 pulses per sec and 100%

Three-phase, six-pulse full-wave rectification produces:

DC with 13% ripple

Three-phase, twelve-pulse full-wave rectification produces:

DC with 4% ripple

The increase in average photon evergy when using three-phase, six-pulse equipment compared with single-phase equipment is:

35%

The increase in average photon energy when using three-phase, 12-ulse quipment compared with single-phase equipment is:

41%

Programs that deal with the safe and reliable operation of equipment and those that adress all aspects of the delivery of radiology services are called, respectively:

Quality control and qulity assurace

Eamples of dedicated x-ray equipment include:

mammo, tomo. mobile units

The collimator must be accurate to a level of :

2% of SID

kVp must be accurate to within:

4

Exposure linearity must be accurate to within:

10%

Exposure reproducibility must be accurate to within:

5%

When a spinning top test is performed on single-phase equipment , a radiograph exhibting four dots would indicate:

An accurate timer, if set on 1/30 second

When a spinning top test is performed on three-phase equipment, a timer setting of 1/60 sencond should indicate the following on the resultant radiograph:

a 6-degree arc

The test that measures the accuracy of adjacent mA stations is :

Exposure Linearity

The test that measures the accuracy of successive exposures is:

Exposure Reproducibility

Effective focal-spot size may be measured using the followin tools

slit camera, star test pattern, pinholde camera

Resolution of the television system by be measured ising the following tools

resolution test pattern

Automatic exposure controls may be tseted using:

Phantoms

The amount of mA used for fluoroscopy is:

3 to 5

Marks on the focal track of the anode resulting from bombardment of electrons are called:

Pitting

Effective quality control and quality assureance programs are requiresd for accreditation by:

The Joint Commission

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