final Flashcards
When measuring a body part of varying thickness the caliper should be placed
along the path of the central ray.
The electrical component that temporarily stores a charge is known as
a capacitor.
The maximum exposure that a back-up timer may legally deliver is
600 MAS.
An ionization chamber consists of
two sheets of metal between which is found air.
When using AEC the technologist surrenders control of
S (time)
In using ionizing chamber AEC devices electrons are sent to a
capacitor.
Selecting the wronged bucky when using AEC will result in
a long exposure time, the need to repeat the image, unnecessary exposure to the patient.
The recommended back- up timer for an exposure expected to be 50 MAS should be
75 MAS (150%)
With a fixed KVP technique chart variation for a patient size is
based upon +/- 20% MAS per cm.
When using AEC, collimating the selected ion chamber out of the exposure field will result in
overexposure of the image.
An increase in film screen speed when using AEC will result in
increase in image density.
When using AEC having a low mA setting will result in
a longer exposure time.
With a variable KVP technique chart variation for patient size is based upon
+/- 2 KV per cm.
It is recommended that the AEC back-up timer be set at
150% the expected MAS.
The cells of an ionization chamber AEC device are found between
patient and image receptor.
When using AEC, decreasing collimation (larger field size) will result in
underexposure of the image.
The technologist
does not need to adjust the AEC density control settings for all patients.
AEC is designed to
compensate for variations of patient thickness and pathology.
A tech can select
multiple photochambers per x-ray exposure.
The technologist has to be extra careful
with positioning when using AEC.
Ionization chamber type AEC devices
are the most common type seen today.
when using the small cassette the technologist should
select only the center chamber.
Changes in KVP result in
changes in image contrast.
Refining a technique chart is a
a never-ending task.
Goal of AEC-
to obtain the same density and quality image with every exposure regardless of patient size and pathology.
Undercutting when using AEC- means
collimating too much therefore not having full selected AEC cell in collimation field.
Anatomically programmed radiography-
radiography where the control console allows you to select for your patients build (sthenic, hypersthenic, asthenic, etc.) and it makes the appropriate technique adjustments for you.
Anthropomorphic phantom-
phantom meant to mimic a human body so that you can get a technique chart started without having to expose humans.
The function of the reducing agents in developer solution is
to change silver ions into black metallic silver.
The device that measures film density is known as
the densitometer.
The sequence of order through an automatic processor is
developer, fixer, washer, dryer.
The addition of an electron to a positively charged silver ion results in
black metallic silver.
Removal of unreduced silver halide crystals happens in the
fixer.
As radiographic film speed decreases film detail
increases.
As radiographic film detail increases film contrast
is not affected.
Developer solution giving up electrons results in
its oxidation.
The addition of an electron to a positively charged silver ion results in
its reduction.
The minimum change in density for the human eye to see is
30%.
The margin for technique error is known as
latitude.
The portion of the sensitometric curve representing minimum optical density is known as
base +fog.
A sensitometric curve will tell you all of the properties of the film in question
except spectral sensitivity
The device that delivers a precise exposure to the film for sensitometry is known as
the sensitometer.
The portion of the sensitometric curve representing maximum optical density is known as
D-max.
The range of grays that a film is capable of recording is
demonstrated by the straight line portion.
As the amount of reduction in a film’s emulsion increases the effect on the film is
increased density.
The latent image is made manifest in
the developer.
The image held in the chemical code within a film’s emulsion is known as
the latent image.
The rate at which sensitometry must be performed is
daily.
As radiographic film contrast increases film latitude
decreases.
The number of density steps in a sensitometric scale is
21.
The acceptable range of variation in sensitometric speed and contrast measurements is
+/- .15 OD
Developer solution is sensitive to
everything.
As radiographic film speed increases film latitude
does nothing because speed and latitude are not related.
An aluminum step wedge used for sensitometric testing is known as
a penetrometer.
Speed and detail are related.
Speed and detail are related.
Latitude and contrast are related.
Latitude and contrast are related
Sensitometry- the amount of light absorbed by a film.
the amount of light absorbed by a film.
Base + Fog-
the whitest a film can get. It is the dyed base plus any environmental energy the film has received.
Film latitude-
the margin for technique error for a given film.
Film speed-
how fast a film can develop an image based on size of crystals.
Larger silver halide crystals make for a faster film speed whereas smaller crystals make for slower film speed.
Larger silver halide crystals make for a faster film speed whereas smaller crystals make for slower film speed.
The smallest component of a radiographic digital image is known as a pixel.
a pixel.
Measuring the distance from the center of a pixel to the center of an adjacent pixel is known as pixel pitch.
pixel pitch.
The laser found in CR imaging processor is helium-neon.
helium-neon.
The exposure indicator for Agfa brand CR imaging products is LGM
LGM
The wavelength of the red laser light used in a CR processor is approximately 600 nm.
approximately 600 nm.
The weakening of a stored latent image within a CR imaging plate is known as
fading
In a CR system, stored electron energy is trapped in the
F centers.
The color of visible light emitted by photostimulated luminescence in a CR system is
purple-blue.
The number of grays that an individual pixel is capable of demonstrating is known as
bit depth.
In a CR system, visible light emitted by the imaging plate is collected and channeled by the
light gate/fiber optics.
The mathematical formula used to process the digital image is known as
algorithm.
With CR digital imaging a “perfect” exposure indicator measures radiation to the IP at a dose of
1 mR.
Measuring the distance from one side of a pixel to the other side is known as
pixel size.
Within a radiographic CR cassette is found an
imaging plate.
The phosphor material found within a CR imaging plate is
europium barium fluorohalide.
The capture element of CR digital imaging is
europium barium fluorohalide.
The process of translating an analog image to a binary code is known as
digitizing.
The coupling element of CR digital imaging is the
light gate/ fiber optics.
The crossed rows and columns that form the framework of a digital image are known as
matrix.
The amount of radiation received by the CR imaging plate is measured and expressed as
exposure indicator.
CR plates are erased and made ready for re-use by
exposure to high intensity visible light.
All of the following terms are synonymous with digital image contrast ability
pixel depth, dynamic range and bit range.
The exposure indicator for Fuji brand CR imaging products is
s number.
Information expressed in variable physical quantities is known as
analog.
In a CR system, the latent image is held within the
photostimulable phosphor.
The 3-D pieces of digital information obtained by CT scan are known as
voxels.
Computers see, store, and transfer information in a language that is known as
binary code.
Information expressed in variable numeric quantities is known as
digital.
The number of pixels per given area is known as
pixel density.
The component in a CR system that converts visible light energy into electrical energy is the
photomultiplier tube.
The input phosphor of an image intensifier is composed of
cesium iodide.
The minimum source to skin distance for a mobile fluoroscopy machine is
12 inches.
KVPxMAxTimexRectification Factor is the
formula for calculating heat units.
The anode of an image intensifier is shaped like a
donut.
The voltage that accelerates electrons from cathode to anode in an image intensifier is
approximately 25-30 KV
The exposure timer used in fluoroscopy must alarm at time increments of
every 5 mins.
