image production final

what is the leakage radiation limit

100mR per hour at 1 meter

part measuring at/or more than________require the use of a grid to offset the scatter

10cm

how do you find SOD

SID-OID

what is aec's main claim to fame

consistency and reproducity on a wide range of people. less likely to repeat image due to technique in accuracy. also less patient dose.

more absorption by the body means more_______?

contrast

window width controls ____what window level controls _____

contrast, receptor exposure/image brightness

purpose of exposure timer

controls or regulates length of exposure time

what is the function of the output phosper in the image intensfier

convert electrons sent from the photocathode into light photons

in a filament transformer when the number of turns decrease what happens to CURRENT

current increases proportionally.

subject density has a direct or indirect relationship with contrast

direct

MR value never shows its self on direct or indirect square law questions

direct ( if i value use inverse square law) REMBER BY THE LETTER I

motion has a direct or indirect relationship with shape distorion

direct ( motion may cause a body part to appear to be a slightly different shape)

what is the purpose of the electrostatic lens

direct for focus the path of electrons from the photocathode to the surface of the output phospher screen

Ei and lgm numbers have direct or indirect relationship with exposure

direct if you have a low ei or lgm number image was underexposed.

size distortion occurs because of what?

distance

size distortion can only be effected by what

distance, because distance effects magnification

how do you limit production of scatter radiation

drop kvp collimate use of compression? air gap

transformers operate on the principle of what type of induction

electromagnetic induction and require an alternating current to operate

what exposure timer is the most accurate

electronic

define latent image

electronic image of valence electrons stored in high energy traps and is made manifest by exposure to a very small beam from a high energy laser.

indirect converts x rays into light while direct converts x rays into _________

electrons

x ray tube diagram

electrons move from cathode to andoe

which are the two examples of shape distorion

elongation and foreshortening ALWAYS THE ANSWER

define isotropic

equal intensity in all directions ( x rays are produced isotropically)

what material makes up the phospher in the casete

europium activated barium flurohalide

how do you get a reciprocating or moving grid

exposure stoped at somepoint and lead strips exhibit a unfifrom appearnce across the iamge

true or false filtration is not a beam attenuator

false is a beam attenuator

with use of magnification in fluro patient dose decreases true or false

false!

true or false grids effect the production of scatter

false!! grids clean up scatter but do not produce it!

true or false kvp only effects quality and mas only effects quantity

false, kvp effects both quality and quantity while mas only effects quantity.

an image with high contrast has ________shades of grey

few (more black and white)

beam restriction can also be defined as what two terms

field size, collimation (be careful, an increase in field size moves "hands" outward as opposed to inward)

what is the main controlling factor of recorded detail

focal spot size

what is the caliper rule when using it for the variable kvp chart

for every centimeter in part thickness a 2 kvp adjustment is made.

distortion is what type of factor

geometric

focal spot size is what type of factor

geometric factor

factors that affect the degree of divergence of the x ray beam and the information recorded on the image receptor is termed what

geometric factors.

the more pixels sampled per minutes the greater or less sampling frequency

greater

what two wave forms have a 100 percent voltage ripple

half and full wave

what is does an uncrectified wave length look like

half of the wave is above the line and half is below the. an unrectified wave length can also be called the alternating current

once a wave length gets rectified the wave turns into a __________

half wave or pulse laplse because only half of the wave is showing itself.

the secondary circuit has what type of voltage

high

step up transfers is also know as high or low voltage transformer

high voltage or high tension

what does his stand for

hospital information system contain full patient inoformation

each pixel is given a numeric value called what

hounsfield

define subject density

how tightly compacted at the atomic level (moving from air to bone/thickness of a part

why does kvp and contrast have an inversely proportional relationship

if you increase kvp the amount of scatter reaching the IR will increase as well. ( scatter creates less contrast on the image)

what type of motor drives or power the anode during an exposrue

induction motor

magnification of the fluoroscopic image is a function of what component of the image intensfier

input phospher

what is the magnification factor in fluor

input phospher 1 divided by input phospehr 2

define quantum mottle (noise)

insufficient quantity of x rays to reach the IR (not enough x rays made it to the IR

what assist in cooling the x ray tube

insulating or dielectric oil (located outside glass envelope but inside protective housing

latent image is what image

invisible image

what are the two types of phototimers

ionization chamber and photomultiplier tube

what are the two main controlling factors of contrast

kvp and look up chart

a radiographic method to identify an image is ________while an electronic method to identify an image is _______

lead characteristics like r or l marker, annotation on computer after image is taken.

the more magnification the less or more recorded detail

less( think of when you zoom to close in on an object, the image appears to big and is misrepresented)

how is a digital image created in indirect capture?

light from the scintillator strikes the ccd and is converted into an electronic signal. the signal is sent to an analog to digital converter where it becomes a data and forms the digital image

define edge enhancement

limiting the number of pixels in a neighborhood of the matrix. the smaller the neighborhood the greater the enhancement ( outlines an image)

how is spatial resolution masured

line paris per mm

what does lan stand for

local area network local sharing

the greater the sampling frequency the shorter or longer it takes to process a plate

longer, more information is being collected

what is the main controlling factor of contrast in the DIGITAL WORLD

look up table

the filament heating circuit has what type of voltage

low

image noise or quantum mottle is controlled by what three factors

low mas, high kvp and fast IR, probably dont need to know fast ir

the primary circuit has what type of voltage circuit

low voltage circuit

the filament transformer is also know has the _____voltage transformer

low voltage or step down

high absorption happens where there is_______kvp and low absorption happens when there is ______ kvp

low,high

what two transformers use mutual induction

step up and step down transformer

define self induction

the changing magnetic field that is created by inducing an opposing voltage in a single coil of wire

define value of interest VOI

the digital data set of information that is arranged into a histogram distribution

what are the two components that make up the cathode

the filament wires and focusing cup

define sampleing frequency

the number of pixels sampled per millimeter as the laser scans each line of the imaging plate (used when a cassete is placed into the reader)

define receptor exposure

the overall amount of x rays to reach the IR

how is a current created in a filament transformer

the power formula kick is as the number of turns decreases. voltage will decrease and current will increase proportionally which is responsible for sending the proper current to the filament wire to set electrons up for thermionic emission.

define quantization

the process of mapping a large set of input values into a smaller set

before the x ray current hits the tube it is run through a device called what

the rectificer

which anode angle gives greater spatial resolution

the smaller angle (usually 5 degree)

define minimum response time

the time it takes for a system to respond and send the signal to terminate the exposure MRT

when do you know a wave length has been rectifeid?

when the wave doesn't drop below the line anymore.

how do you et moire pattern in a grid

when two linear grids are paled on top of each other but lead lines are not aligned at right angles. wave like apperence.

define actual focal spot size

where electrons ACTUALLY strike the target

what does wan stand for

wide area network cross state sharing

what is the thinnest part of the glass envelope which reduces inherent filtration

window

the primary x ray beam comes from what part of the tube

window (all other radiation that does not come from the window is considered leakage.

what is the purpose of a ccd

with the help of scintillator material produce light for indirect capture.

what is the sequence of processing a flim on a cassette

x rays go through anatomy of interest and go on cassette. disruption of valence electrons occurs. cassette is put through reader where laser reads the disruption of electrons. at that point that signal goes from analog to digital signal through the AEC. last laser washes cassette clean.

does the oil contribute to filtration

yes

does the use of filtration create a more homogeneous beam

yes because now all they electrons in the beam are alike since the low energy electrons have been filtered out.

how do you get an upside down grid

you placed grid upside down. strips appear noraml in the middle but complet cutt off on both edges

what material is the output phosper made of

zinc cadmium sulfide.

bright lights control______While low light controls_____

cones, rods

a grid has a direct or indirect relationship with contrast

direct

additive pathology has a direct or indirect relationship with contrast

direct

angulation of the tube or part has a direct or indirect relationship with shape

direct

beam restriction has a direct or indirect relationship with contrast

direct

destructive pathology has a direct or indirect relationship with image exposure

direct

direct or indirect capture gives better spatial resolution

direct

flat panel (DEL) has a direct or indirect relationship with spatial resolution

direct

what is the main controlling factor of receptor exposrue

MAS

kvp has a direct or indirect relationship with image exposure

direct

mas has a direct or indirect relationship with receptor exposure

direct

matrix size has a direct or indirect relationship with spatial resolution

direct

number of turns and voltage always has a direct or indiect relationship

direct

the cr needs to be within what percent of the indicator

0.5

name the four beam restricter devices

1. aperture diaphragm

what are 4 factors of post processing

1. brightness-intesnity of light that represents each pixel on the monitor 2.contrast-differences in brightness 3.region of interest ROI-boundares of an object on an image 4. electronic collimation/masking-can cause small detail loss and it is accomplished by suppressing frequencies of lesser importance.

what are the two sub sections of dr

1. direct capture 2. indrect capture

the filament circuit contains what three structures

1. focal spot selector 2.ma selector 3. step down transformer EVERYTHING ELSE IS PRIMARY CIRCUIT

what three factors effect the production of scatter radiation

1. high kvp 2. large thick part? 3. large field size

what are the 6 types of exposure timers

1. mechanical 2. synchronous 3.electronic 4.mas 5.impulse 6.aec

what makes an image legal

1. name/medical record number 2. date performed 3. institution name 4.right or left marker patient age and DOB is optional

the secondary circuit contains what three structures

1. rectificer 2.ma meter 3. tube

image receptor exposure and contrast are inversely proportional except for in what two times?

1. screen and image receptor speed. 2. beam filtration

what are the 6 types of compensator filters

1. wedge- mounted on collimator 2. supertech/trough- mounted on collimator 3. bboomerang- placed on patient 4.ferlic swimmers-collimator 5. ferlic shoulder- patient and collimator 6.supertech/full lenght-collimator

sampling frequency has a direct or indirect relationship with spatial resolution

direct

the aec backup timer should be set to ________% of the anticipated manual exposure time.

150

which of the following SNRs give greates spatial resolution 2,1 4,1 8,1 16,1

16:1 (more signal greater resoltuion) or lower ratio more noise greater ratio less noise

on a pa projection of the chest what two ionization chambers will be selected

2 outer chambers

image plates that have been unexposed for longer than how many hours should be erases

24-48 hours

what wavelength has a 4 percent voltage ripple

3 phase 12 pulse.

what wavelength has a 13 percent voltage ripple

3 phase six pulse

indrect capture is a ____step process while direct is a ____step process

3, 2

what is the angle capacity of the anode?

5-15 degree angle

at what angle in a transformer is the greatest emf produced

90

define attenuation

Attenuation is the reduction in intensity of an x-ray beam as it passes through an object due to the absorption and scattering of photons. (clean up scatter)

who own image

INSTITUTION OWNS THEM, NOT TECH OR PATINET

sid has a direct or indirect relationship with recorded detail

direct

is spatial resolution related to exposure amount

NO!

what has a greater effect on magnification SID or OID

OID

what is a hysterogram

a graph of exposure information

define look up table

a histogram of the luminance values derived during image acquisition. each pixel is changed to a new gray value where the resultant image will have the appropriate brightness and contrast. a there is a lut for every body part.

define spatial resolution

ability of the system to record adjacent small structures equipment related

define windowing

ability to alter the receptor exposure and contrast of a digital image following processing. (post minipulation)

if image exposure decrease the more photons will be _________?

absorbed by the body

what current must the x ray tube always be supplied with

ac or alternating current for the process of induction

what focal spot size is larger actual or effective

actual

how do you calculate total resistance in a series circuit?

add the the respective resistance together if the three resistances are 1, 4, 5. total resistance is 10

list from least to greatest attenuation factors

air, fat, muscle, bone,

what ionization chamber would you use for apelvis

all three

rectifiers creates wave from and change the current for ______to_______

alternating current to direct current.

direct capture uses what materials

amorphous selenium

define radiographic receptor exposure

amount of blackness of an area of a radiograph

analog signals or electric pulses are converted to digital signals via what

analog to digial converter

what does apr stand for

anatomically programed radiographY( NOT THE SAME AS AEC ( when you select hand and the control panel is set to 50@ 2)

name four factors that effect shape distortion

angulation of the tube,part,image receptor and motion

define focal spot size

area of anode surface which receives electrons ( smaller the focal spot the better!)

define umbra

area of sharpness

what is the purpose of a compensating filter

at attenuate varying amoounts of the x ray beam baseson filter type and exam being performed. produces an EVEN receptor exposure of anatomical structures.

what is the source for kvp not relating to contrast

autotransformer

what transformer uses self induction

autotransformer

define contrast resolution

better visibility of detail

short scale contrast is ________while long scale contrast is _______

black and white, many shades of gray

define penumbra

blurring around the edges or geometric unsharpness

how does the fluro image become magnified

by reducing the size of the area of the input phospher focused to the output phospher screen

inverse square law is used for ________while direct square law is used for _________.

calculate for change ,maintaining a constant exposure by compensating

what determines how much you vary the kvp on a variable kvp chart

caliper,

is penumbra greater on the cathode or anode side of tube

cathode

__________is negative and ______is positve

cathode, andoe

what cell should be used for ap projection of hip

center

what ionization chamber will be used on a lateral chest

center chamber

what material is the input phosphor made of

cesium iodine

ccd stands for what

charged couple device

x- x rays interact with input phosepr and get converte to light. l-light interacts wtih the photocathode and get converted to electrons e-electrons run through anode and interact with output phospher and get converted back into light. L-light goes through ace and analog Digital converter get broadcast on the monitor m- monitor

chasing the flow of the image intensfier

which recording system device gives the greatest patient dose

cine fluoroscopic device.

grid clean up definiton

cleanup of scatter raditon

cr stands for what, dr stands for what

computed radiogrpahy, digital radiography

a decrease in mas will do what to image exposure

decrease

an increase in kvp will do what to contrast

decrease contrast. (less shades of grey more black and white)

a decrease in kvp will do what to image exposure

decrease image exposure

filtration increases or decreases skin dose

decreases because it absorbs low energy x rays

minification formula

diameter of the input phosphor squared divided by the diameter of the output phosphor squared.

for both thorax and abdomen where do you place the cathode over

diaphram (upper abdomen) (lower thorax and tspine)

how do you exchange images through different modalities

dicom

define contrast

difference in adjacent areas

what is subject contrast

difference in different organs

define radiographic contrast

differences in densities on adjacent areas on a radiograph

what does dicom stand for

digital imaging and communication in medicine

define rescaling

digital processing technique that is used to modify and under or overexposed image.

OID has a direct or indirect relationship with size distortion

direct

explain the 15 percent rule

if you increases or decrease kvp by 15 percent you have to double or cut receptor exposure in half. DO NOT TOUCH MAS, YOU ARE CHANGING EXPOSURE BY CHANGING KVP (remember kvp can effect mas but not vice versa)

high kvp means more penetrating x rays through the body parts creating what type of image

image with more shades of grey/less contrast

where is the electrostatic lens located

in the image intensfier along the ful lenth of the tube

what is the greatest disadvantage when using aec?

inaccurate or improper positioning.

an increase in mas will do what to image exposure

increase

as field of view increases you will get an in increase or decrease in pixel size

increase

if more x rays get absorbed contrast will increase or decrease

increase ( more x rays getting absorbed means a better photographic picture)

does a increase in atomic number increase or decrease attenuation

increase because an increase in atomic number means atoms are more closely packed and can attenuate or absorb more x rays.

a decrease in kvp will do what to to contrast

increase contrast ( more shades of grey)

an increase in kvp will do what to image exposure

increase image exposrue

define anode heel effect

increase in beam intensity toward the cathode end of the beam and a decrease on anode end of beam (hint fat cat fattest or thickest part goes under cathode because there is more intensity. or compensate with a wedge.

how do you minimize quantum mottle

increase mas, drop kvp

if you increase image receptor size does the matrix increase or decrease

increase, now there are more rows and columns

as number of turns in a transformer increases voltage increases or decreases

increases

sampling frequency increase or decreases spatial resoluton

increases

decreasing pixel size increase or decreases spatial resolution

increases spatial resolution (m&ms) also increases visibility of small structures and recorded detail

OID has a direct or indirect relationship with recorded detail

indirect

SID has a direct or indirect relationship with receptor exposure

indirect

a grid has a direct or indirect relationship with image exposure

indirect

additive pathology has a direct or indirect relationship with receptor exposure?

indirect

angulation of the tube or part has a direct or indirect relationship with recorded detail

indirect

beam filtration has a direct or indirect relationship with contrast

indirect

beam filtration has a direct or indirect relationship with image exposure

indirect

beam restriction has a direct or indirect relationship with receptor exposure

indirect

destructive pathology has a direct or indirect relationship with contrast

indirect

focal spot size has a direct or indirect relationship with recorded detail

indirect

kvp has a direct or indirect relationship with contrast

indirect

motion has a direct or indirect relationship with recorded detail

indirect

subject density has an direct or indirect relationship with image exposure

indirect

psp plate size has a direct or indirect relationship with spatial resolution

indirect ( think of the same amount of peanut butter being spread over an 8 by 10 plate and a 14 by 17 plate. you get more coverage (or in this case spatial resolution the the smaller plate)

field of view has a direct or indirect relationship with spatial resolution

indirect ( larger the field of view the larger the pixel size)

pixel size has a direct or indirect relationship with spatial resolution

indirect ( think of a jar of m&ms in a jar compared to a jar full or golf balls) the golf balls are greater in size and dont pack together as nicely as the m&ms )

sid has a direct or indirect relationship with size distortion?

indirect (think of the heart being done at 72 to decrease magnification)

which dr system converts x ray photons into light

indirect capture

define mutual induction

inducing a current through a secondary coil by varying the current through the primary coil

if you increase OID what happens to magnification

magnification goes up and recorded detail decreases

what has the greatest effect on quantum mottle

mas

variable kvp chart always used the same kvp or mas

mas, kvp varies by

number or rows X number of columns is term what (number of squares aligned in rows and columns, the greater the amount of the squares the greater the matrix)

matrix size ( this shows a large matrix with with small pixels. )

what is the brightness gain formula

minification gain multiplied by flux gain

distortion is __________of an image

misrepresentation

the focusing cup is made up of what material

molybdenum or nickel

more rows and more columns/matrix size gives you more or less pixels

more pixels

why does an increase in kvp decrease contrast

more scatter radiation reaches the IR

an image with low contrast has _____shades of grey

more shades of grey

when using aec device how do you change the rate of exposure?

new equipment select the large or small person on control panel old days before new technology - adjust density control ANSWER IS ADJUST DENSITY CONTROL

does SID have an effect on shape distorion

no because you are not angling the tube.

SID has a direct or indirect relationship with contrast

no relationship

angulation of the tube or part has a direct or indirect relationship with size

no relationship

focal spot size has a direct or indirect relationship with size distortion

no relationship

mas has a direct or indirect relationship with contrast

no relationship

motion has a direct or indirect relationshp with size distortion

no relationship

focal spot size has a direct or indirect relationship with shape distoriton

no relationship, focal spot size only has a relationship with recorded detail

does OID have any effect on shape distoriton

no, because you are not angling the tube.

does a fixed kvp chart means you always use 50 for a hand

no, it means 50 is a good starting point and can be appropriately adjusted according to part thickness and pathology. GENERALLY SPEAKING MAS CHANGES KVP STAYS THE SAME FOR THE MOST PART

a decrease in mas will do what to contrast

nothing

an increase in mas will do what to contrast

nothing

how do you get lateral off centering of a grid

off centering central ray. lead strips will appear more frequently on one side of the image.

autotransformers use self induction meaning they have how many wires

one

what is another term for degree of blackness

opacity

what is the magnification factor

or image size over object size, depends on what information is in question

what ionization chamber would you use for wings of pelvis

outer two cells

caliper is a device used to measure what

part thickness

what is the purpose of using a back up timer when using aec device

patient safety in case of malfunction, terminate exposure in case aec exposure fails. not the primary means of terminating aec exposure.

what is aec or automatic exposure control

photo timer, can only be used in upright and table buckey not table top. terminates X-ray exposures when a reference level is reached

bright light is also knows as _______while low light is also knows as________

photopic,scotopic

define pacs

pictures archival and communication systems

loss or resolution around the outside or pheripheal of an image is called what

pin cushion effect or vignetting

the filament transformer has more primary or secondary turns

primary

step up transformer has two coils left is ______right is _______

primary, secondary

define aquisistion

process of acquirring and reconstructing an image on a digital system

where does the cathode go over when x raying extremities

proximal jonint

what is the active material used in the cr cassette

psp photostimuable phospher plate.

the glass envelope in composed of what type of glass

pyrex glass which is heat resistant and has a high melting point

kvp controls______while mas controls _____

quality, quantity

define leakage radiation

radiation emitted through the metal protective housing

what does ris stand for

radiology information system contains radiology information only

define dynamic range.

range of acceptability in techniques. you dont need to be as precise with you techniques in digital imaging because dynamic range is included

define signal to noise ratio

ratio between signal or meaningful information and noise or background info

density is also referred to as what

receptor exposure

what are the two photographic factors

receptor exposure and contrast

degree of sharpness is termed what

recorded detail/spatial resolution

wht does a beam restriction device do

reduce pateint does

define line focus principle

reduction in the size of the focus directed toward the image receptor versus the size of the actual area on the surface of the anode bombarded with electrons.

define shuttering

removes or replaces background information

a low s number means you under or over exposed an image

s stands for sensitivity and has an indirect relationship with exposure so that image was over exposed.

what is the only component that sits outside the glass or metal enclosure of the x ray tube.

sator

what materials are used in the indrect sub section of dr

scintillator, cesium iodide, or gadolinium oxysulfide ( indirect is a three step system therefore there are three materials)

in a step up transformer there are always more primary or secondary turns

secondary

in a turns ratio the number on the right is _______while the number on the left is _______

secondary, primary

what are the two different types of circuits

series and parallel

what is the simplest type of transformer and what is the most effeicent

simplest most efficient shell

what are two types of distortion

size(magnification) and shape(elongation/foreshortening)

increasing sampling frequency causes the laser over a smaller or shorter distacne

smaller

what is the difference between spatial resolution and contrast resolution

spatial resolution is the ability to distinguish between adjacent small structures while contrast resolution is better visibly in general .(or able to make an image lighter or darker for better visibility)

what is the reciprocity law

states that receptor exposure on a radiograph is proportional only to the total number imparted to the radiograph image receptor ( mas 1 = mas 2 ) ( it doesnt matter what combination of ma and time you use as long as it equals the same mas you will get the same result) example: 100ma x 1 sec =100 mas is the same as 200ma x .5 sec=100 mas

what two componets make up the induction motor

stator and rotor

what is the function of the input phosper of the image intensfier

to convert incoming x ray photons into light

what is the function of the photocathode in the image intensfier

to convert light photons from the input phospher into free electrons.

what is the function of an image intensfier

to convert x ray beam into visible light( increase brightness) used in fluro

what is the parallel circuit rule regarding total resistance

total resistance will be less than the least resister and be about half of that least resister.

cr and dr are both conisdered forms of digital imaging true or falase

true

filtration hardens beams and removes soft x rays true or false

true

if more x rays get absorbed in the patient and dont hit the ir then contrast will increase true or false

true

if more x rays go through the patient and reach the IR receptor exposure will increase true or false

true

true or false grids are attenuators

true

true or false digital world gives greater exposure latitued and provides better contrast

true because you can post minipulate

true or false image receptor exposure and contrast are inversely proportional

true, as image exposure increase contrast decreases. the number of different shades of grey decrease so a more black and white image is achieved.

true or false kvp and contrast have an inversely proportional relationship

true, as you increase kvp you get more black and white/less shades of gray

true or false if you increase mas you will increase receptor exposure

true, mas and receptor exposure are directly proportional ( if you double mas you will double receptor exposure.

true or false the smaller the angle the greater the spatial resolution

true, the smaller the angle the smaller the focal spot which means greater resolution

what is the disadvantage of using a small focal spot

tube damage, pitting, cracking, filament burning CANNOT WITH STAND HEAT. large can withstand the heat but with less spatial resoluton

the filament wires are made of what material

tungsten

anode target surface is made up of what material while the neck and the base of the target are made up of what material

tungston, copper/molybdenum

step up and step down use mutual induction meaning they have how many wires or coils

two

grid cut off definition

unintended absorption of the remant beam

is there a tool you can use to limit thickness part

use of compression

how do you get grid cuttoff

using a grid outside of the established focal spot range will exhibit uniform cutoff along the lateral edges.

define voltage ripple

variation in peak wave form

manifest image is what image

visible

electromotive force (EMF) or potential difference is the same thing as what

voltage

how is the secondary coil induced in a step up transformer (mutual induction)

voltage and current are sent to primary coil, and by virtue of position a flow is induced in the secondary coil

volume of tissue imaged is given a value called volume element or_______?

voxel

if you have a wet cast what do you do to kvp? dry cast fiberglass cast

wet cast increase kvp the most 8-10 increase dry cast inceease kvp the second most 5-7 increase fiberglass cast increase kvp the least 3-4 increase a wet cast creates more thickness due to adding water. when you have a thicker cast you need more kvp to get through the cast. also more attenuation takes place on a thicker cast creating a higher contrast image

define effective focal spot size (also called useful or projected)

what gets projected down onto the patient

when does the reciprocity law fail to exist

when exposure times are less than 10 miliseconds or longer than 5 seconds

where and when does voltage become kilivoltage

when it gets to the step up transformer