X-ray production Flashcards by Melissa Trappen

On the cathode side of the x-ray tube, neg. charged electrons are boiled off of the thoriated tungsten filament wire in a process known as

Thermonic emmission

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They form what is called a

space charge or electron cloud

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electrons are herded together by the neg. charged

nickel focusing cup

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when the exposure switch is depressed, the anode begins to rotate as the _ is created

space charge

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The distance between any 2 successive points on a wave

wavelength

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the max. height of the wave

amplitude

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the # of waves that passes a particular point in a given time frame

frequency

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frequency and wavelength are _ proportional

inversely

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Photon energy and frequency are _ proportional

directly

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The three factors that affect x-ray emission are under who’s control

radiographer

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The three factors that affect x-ray are known as

prime factors

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What are the prime factors

mA, kV, S, and distance

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what is the measurement of the #’s of electrons crossing the tube per sec.

mAs

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what is the primary controlling factor for x-ray quantity

mAs

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more mAs = _ density on the image

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mAs is calculated my x

mA x s of exposure

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what is the primary controlling factor for x-ray quality

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Higher kV = _ penetrability

higher

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Higher penetrability = _ scatter and _ density on the film

higher, higher

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kV is a _controlling factor for density (quantity)

secondary

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The relationship of x-ray quantity to distance is described in the

inverse square law

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If distance is doubled from an x-ray source the pt would only receive _ the radiation

1/4

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Distance and radiation intensity are _ proportional

inversely

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what is the formula for inverse square law

I1 (D2)2
— = ———
I2 (D1)2

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Exposure Maintenance formula or DSL

mAs1 (D1)2 ------- = ------- mAs2 (D2)2

What formula states that if the radiation intensity decreases, the density on the image receptor decreases

Exposure maintenance formula or DSL

Intensity and density are _ proportional

directly

x-rays qualities

highly penetrating invisible rays form of electromagnetic radiation

x-rays are electrically

neutral

x-rays are not affected by either _ & _ fields

electric and magnetic

x-rays can be produced over a wide variety of

energies and wavelengths | polyenergetic and heterogeneous

x-rays release very small amounts of _ upon passing through matter

heat

x-rays travel in

straight lines

x-rays travel at the

speed of light

x-rays can _ matter

ionize

x-rays cause _ of certain crystals

fluorescence

x-rays cannot be _ by a lens

focused

x-rays affect

photographic film

x-rays produce _ and _ changes in matter through ionization and excitation

chemical and biological

x-ray produce

secondary and scatter radiation

x-ray beam after it exits the tube and before it enters the pt.

primary beam

x-rays that exit the pt to strike the image receptor

exit

weak x-ray photon interacts with the force field of an atom and is absorbed. The atom is put in an excited state and releases the energy in the form of a scattered x-ray that is traveling in a different direction than originally

coherent scatter

Coherent scatter is also called

classical or Thompson or Rayleigh

Coherent interacts w

entire atom

Coherent scatter is in what range

below diagnostic range

What has a net loss of e-

compton scatter

compton interacts with

outershell e-

Compton causes

radiographic fog and is responsible for may. of scatter during procedures

what has total absorption of k-shell

photoelectric effect creates

photoelectron

what creates the annihilation affect and is above the diagnostic range and interact w/the nuclear field

Pair Production

what interacts with the nucleus and is above the diagnostic range

Photodisintegration

what is the reduction in # of x-ray photons in the beam as it passes through matter due to scatter and absorption

Attenuation

attenuation is affected by 2 things

thickness of body pt | z# of the tissue the beam is striking

Attenuation is caused by

absorption (PE) | scatter (compton)

what are the 3 principal parts of an x-ray system

x-ray tube operating console high voltage generator

x-ray tube has a protective housing which reduces

amount of leakage radiation

the housing often contains

oil

the oil serves as both an insulator against _ and as a thermal cushion to

electric shock | dissipate heat

the tube is a vacuum tube made of either

glass or metal

vacuum tube is also known as

diodes

diode means what

has two ends one positive and one neg.

neg. end of tube is known as

cathode

positive end is known as

anode

the cathode contains

the filament | focusing cup

most tubes are _

dual focus

dual focus means

they have both large and small filament w?different levels of resolution

most tubes have rotating anodes why?

to dissipate heat

target has

have high z# excellent conductor of heat high melting point

target consists of

tungston

the target is supported by

molybdenim and graphite

an induction motor that is located outside of the glass housing

stator

the stator causes the rotor to

spin

there are slight changes in the voltage coming into the x-ray circuit from the wall outlet. This keeps the voltage coming in at a steady 220 volts

line compensator

what has a single coil and can at most either double the incoming voltage, thus cutting the incoming amperes in half or vice versa

autotransformer

this cuts off the current in order to stop the x-ray exposure

exposure timers

exposure timers are

electronic timers

step up transformer works by

mutual induction

step up transformer has more coils on the

secondary side vs the primary side

what reduces current to mA

step down transformer

step down transformer has more coils on the

primary side than on the secondary side

what only allow current to flow in one direction, thereby changing the incoming AC to DC

rectifiers

Single phase, the wavelength of the electricity rises and falls

120 times per second

single phase has _%voltage ripple

100

what is three lines of current run at the same time, keep the sine wave amplitude at its peak nearly all of the time

three phase power (3 phase 6 pulse fully rectified)

three phase power has _% voltage ripple

14%

what are 4 beam restricting devices

aperture diaphragm cones/cylinders collimators PBL

when an image receptor is placed in the bucky, a sensing device automatically sets the collimators to film size

PBL

X-ray production Flashcards

(89 cards)