Langes imaging production

what percentage of the total energy used to produce x-rays is actually converted to xrays

0.2%

when the xray tube filament is heated this is termed

thermoionic emissions

heating the x-ray tube filament to incandescence functions to provide a source of

electrons

organize the following electromagnetic radiations in order of longest wavelength to shortest wavelent (visible light, xrays and microwaves)

microwaves, visible light, xrays

what electromagnetic radiation is most likely to be considered ionizing (visible light, xrays and microwaves)

xrays

which characteristic xrays of tungstens are the only xrays that are useful for diagnostic purposes

K shell xrays

what kind of xrays are emitted when an outer shell electron fills an inner shell vacancy

characteristic xrays

what type of xrays are produced when a high speed electron is decelerated by the nuclear field of the target atom nucleus

bremsstrahlung xrays

how are xray energy and xray wavelength related

inversely

what serves to accelerate the electrons toward the anode

the application of high voltage

which device functions to direct the electrons toward the anodes focal spot

the focusing cup

rapid decelertion of electrons at the anode results in

production of xrays

what is the electrical charge of the anode

postiive

although all electromagnetic radiations travel at the same velocity, in which ways do they differ

wavelength and frequency

what are the two types of xradiations that are produced at the anode through every conversion processes

brems and characteristic

which of the two xray producton processes predominates

brems

how are wavelength and frequency related

they are inversely related

what term is used to describe the breaking apart of electrically natural atoms by high-energy electromagnetic radiation

ionization

what term is used to describe the number of cycles per second

frequency

the distance between two consecutive crests is termed

wavelength

the xray beam emerging from the xray tube, before striking anything, is referred to as the ___

primary beam

the xray beam emerging from the part and striking the image receptor is referred to as the _____

remnany beam

how is a shorter wavelength photon associated with frequency, energy and ionizing potiental

higher

structures that absorb xray photons are termed____

radiopaque

what exposure factor regulated xray beam quantitiy

mA

what exposure factor regulated xray beam quality

kV

what exposure factor regualted xray photons wavelength and beam penetration

kV

what is defined as the reduction in intensity resulting from scattering and absorption processes

attenutation

how is the intensity of electromagnetic radiation related to distance

inversely related

xrays have a/an ____ effect on all matter

penetrating

xrays have a/an ___ effect on living tissue

physiological

how can the energy of an xray beam be described as

polyenergic

what is the electrical charge of an xray beam

electrically natural

what kind of effect do xrays have on air

ionizing

what part of xray equipment is used for the selection of exam parameters

the operating console

in a general purpose xray room, the fluoroscopy tube will usually be located

under the xray table

What does D represent

filament cup

What material is E usually made of

copper

What does H represent

stator

At what letter is the source of electrons

D

for what three reasons is tungsten the target material of choice

high atomic number, high melting point, high thermal conductivity

what device functions to rotate the anode

the induction motor

how do the actual and effective focal spots differ in size

the effective focal spot is smaller then the actual focal spot

to what does the line focus principle refer

the relationship between the actual and effective focal spots

the stator and the rotor are the two parts of which device

the induction motor

of what material is the anode stem usually made, and what is it purpose

copper, to conduct heat away from the face of the anode

list two reasons why xray tubes are surrounded with oil

to conduct heat away from the anode, and for insulation

what is the heat unit formula

HU = mA x time x kV

what is used to determine the maximum safe exposures for a particular xray tube

tube rating chart

the xray tube may accurately be described as a/an

diode

list the three fundamental parts of the typical diagnostic xray tube

anode, cathode, vacuum glass envelope

a double focus xray tube is one that has

two focal spots with two filaments

the xray tube filament is made of what material

tungsten

the body of the anode is made of ___ and its focal track is made of ____

molybdenum, tungsten

what is most damaging to the xray tube

heat

what is the device that automatically terminates the exposure once the IR has received the required radiation intensity/exposure

AEC

the type of AEC located behind the IR is the

photomultiplier

the type of AEC most often used, which is placed between the patient and IR is the ____

ionization chamber type

when using AEC, the electronic timer acts as the ____ and should be set to 1.5 times the expected exposure time. this is done to protect the ___ and the ____

backup timer, patient, xray tube

what type of AEC used a fluorescent screen to terminate the exposure

photomultiplier type

in order to produce predictable and accurate results, AEC’s require precise ___ and ____

positioning, centering of CR

list three types of beam restrictors

cones, collimators, aperature diaphragms

why are the uppermost collimator shutters placed as close as possible to the xray tube port window

to reduce the amount of off-focus radiation exiting the xray tube

what are the two most important functions of beam restriction

to reduce patient dose and improve image contrast

xray photons produced when projectile electrons interact with structure other than the focal spot are termed____

off focus radiation

what are the two devices that function to reduce the amount of scattered radiation reaching the IR

beam restrictors and grids

in what two ways can we reduce the production of scattered radiation

use of beam restriction and appropriate level kV

what is the name of the electrical device that operates on a principle of mutual indication and functions to change the magnitude of voltage and current

a transformer

what type of current is required to operate a transformer

alternating current

a step-up transformer has a ___ number of turns in the secondary coil then in the primary coil

greater

how does a step up transformer change voltage and amperage

voltage is increased, and amperage is decreased proportionally

step up and step down transformer operate on what principle

mutual induction

what type of transformer has a turn ratio greater than 1

a step up transformer

in a step up transformer, the secondary current is ___ the primary current

less then

what type of transformer has one coil and varies both the current and voltage

an autotransformer

what type of transformer is the high voltage transformer

a step up transformer

what type of transformer is the filament transformer

a step down transformer

the high voltage side of the typical Xray circuit contains which three principal parts

the high voltage transformer, filament transformer, rectifiers

the process of converting alternating current to unidirectional pulsating current/direct current is called

retificiation

electronic devices found in xray circuit that allow current to flow in only one direction are called

rectifiers

on what type of current does the xray tube most efficiently operate

unidirectional

most solid state diode rectifiers are made of what semiconductor material

silicon

xray equipment operated by three phase 12-pulse power produces what percentage voltage ripple

4% ripple

what type of electrical power utilizes three simultaneous voltage waveforms out of step with each other by 120 degrees

three phase power

what type of voltage generators uses inverter circuits to convert dc into a series of square pulses

high frequency

xray equipment operated by single-phase power produces what percentage voltage ripple

100%

how much kV reduction can be expected using three phase equipment compared to single phase equipment

10 kV

how are xray quantity and quality affected when changing from half wave to full wave rectification

quantity doubles and quality is unchanged

what is the name of the electronic vacuum tube that functions to amplify the fluoro image, thereby reducing patient dose

image intensifier

fluoroscopic xray photons exiting the patient first encounter which part of the image intensifier

input phosphor

what component of the image intensifier emits electrons

the photocathode

how does the image on the image intensifiers output phosphor compare with the image on its input phosphor

the image on the output phosphor in minified, brighter and inverted

of what material is the image intensider input phosphor usually made

cesium iodide

what is emitted by the photocathose when it is struck by light photons amitted by the input phosphor

electrons

what component of the image intensifier assists in directing electrons towards the output phosphor

electrostatic focusing lenses

what is the minification gain equation

(input screen diameter/output screen diameter)²

minification gain x flux gain =

total brightness gain

how is fluorscopic magnification mode related to spatial resolution, contrast resolution, and patient dose

improves spatial resolution, improves contrast resolution, higher patient dose

the reduction in brightness around the periphery of the fluoro image is termed

vignetting

what two kinds of devices may be used to convert the fluoro output phosphor image into an electronic signal

a TV camera or a CCD