RT 203 LEC MIDTERMS

density

amount of overall blackness produced on the image after processing

density

a radiograph must have sufficient _______ to visualize the anatomic structure of interest

mAs

main controlling factor of density

mAs

controls the current, no. of electrons, and responsible for patient dose

direct

relationship of mAs and px dose

direct

relationship of mAs and density

focal film distance (ffd)

the distance measured from the focal spot to the recording medium (x-ray film)

focal film distance (ffd)

in most diagnostic x-ray, the _______ is standardized for all procedures

sid

focal film distance is also called as _______

40 to 42 inches

standard ffd for general radiography

70 inches

standard ffd of the thoracic cavity

inverse

relationship of density and distance

inverse

relationship of mAs and distance

kilovoltage peak (kVp)

the force applied to accelerate (push) the electrons from the cathode to the anode at the time of exposure

kilovoltage peak (kVp)

if it was appropriate to select one factor, _______ would be the most significant factor in the production of x-ray and radiographs.

quality

kvp has a significant effect on the ________ of the photons in the x-ray beam

energy

the ______ of the x-ray beam is determined by the kvp made at the control panel

direct

relationship of kVp and density

15 % kVp rule

an increase in 15% in the kVp will approximately double the intensity, therefore the mAs must be decreased by a factor of 2

divided by 2

if kVp + 15%, mAs is ______

multiplied by 2

if kVp - 15%, mAs is ________

(in pathology) destructive processes

___________ of the skeleton may be demonstrated by increased density readings

decrease in radiation absorption

bone tissue that has been destroyed by a disease process results in __________; it is demonstrated by an area of increased density

increased

exposure factors must be ________ for diseases that cause an increase in tissue density

decreased

exposure factors must be _______ for destructive diseases such as emphysema or osteoporosis

direct

relationship of activity of the solution and density

hyperactive

when the activity of the solution is __________, it will create more density in the film

decreased

processing time must be _______ to avoid overdeveloping the film

direct

relationship of processing time and density

intensifying screens

are cardboard or plastic base structures that are usually found as pairs inside the cassette

intensifying screens

converts x-rays into light rays that is used in image production; also intensifies the actions of the x-ray

decreased

slow intensifying screen = _______ density

increased

fast intensifying screen = _______ density

CAWO4 / Calcium Tungstate

a chelate natural tungstate, low speed (300-400), thomas edison

barium lead sulphite

used mostly in high kVp factors, 300-400 speed level

zinc sulfide

used mostly in low kVp factors

rare earth screens

high speed screens ranging from 900-1000

examples of rare earth screens

gadolinium oxysulfide, lanthanum oxysulfide, yttrium tantalate

film emulsion

active layer of the film; heart of the x-ray film

film emulsion

site of latent image production

light and radiation

film emulsion is activated by ______________ to create image

sensitive

film emulsion is ________ to both light and radiation

heel effect

the intensity of the beam is less on the anode side of the beam

focal spot area

x-rays originate from the _______ and travel in all directions

useful beam

the _______ consists of those photons exiting from the focal spot area and traveling through the tube port or window

heel

the lowermost portion of anode

less thick

parts that are ______ must be facing the anode part of the tube as it has lesser intensity; prevents overexposure

inverse

relationship of mAs and sid

decrease

when you move your x-ray tube away from your subject, the intensity of mAs will __________

inverse square law

radiation intensity will vary inversely with the square of the distance from the source

4

as the square of the distance increases, the beam intensity will decrease by a factor of ______

definition

describes the clarity and sharpness of the image

motion

biggest enemy in the production of a good radiograph

blurred

motion results to _______ image that is useless to the radiographer and the radiologist

voluntary

expression of thought through action

involuntary

uncontrolled movement

focal spot

the only part or area on the focal track of the target that is actually hit by the electrons during exposure

small focal spot

used when better spatial resolution is required; ranges from 0.1 to 1mm

large focal spot

used when large body parts are imaged and in techniques that produce high heat are required; ranges from 0.3 to 2mm

distortion

misrepresentation of size and/or shape of the part under study

size distortion

magnification of the part; image becomes larger than its original size

oid/ofd

main controlling factor of size distortion

shape distortion

part under study appears elongated or foreshortened

direct exposure film

designed specifically for use without intensifying screens

direct exposure film

recommended for use with low-risk or low-exposure examinations of thin body parts

thicker

direct exposure film has ______ emulsion due to an increase of SHC

less sensitive

direct exposure film is ________ to light, this means that the fluorescent light from the IS would be less effective

increased

__________ exposure factor is required with the use of direct exposure film

complete contact

to achieve maximum image sharpness, the film and screen must be in _________ across the entire surface of the film

wire mesh screen

film screen contact can be tested using a commercially produced ____________ enclosed in plastic

target-object-film alignment

refers to the correct alignment of your x-ray tube or position of the patient

image distortion

if your object/x-ray tube is misaligned, it will cause ____________

penumbra

unsharpness; thin blurred area around the umbra

umbra

true object recorded on the film

increases

increase in magnification __________ the size of penumbra

inverse

relationship of large focal spot size and recorded detail

direct

relationship of small focal spot size and recorded detail

direct

relationship of oid and magnification

inverse

relationship of sid and magnification

film speed

degree of sensitivity of film to x-ray and light

screen speed

degree of sensitivity to x-ray photons and capability to produce light photon

film screen contact

the space between the cassette and film

motion blur

biggest enemy in the production of radiograph; must be eliminated during exposure

image blur

blurry or fuzzy appearance of the detail due to poor film screen contact

foreshortening

object appears shorter than its actual size

elongation

refers to image that is stretched and appears larger than the actual size

elongated

a cephalad image appears _________

foreshortened

a caudal image appears ___________