Ch 20, 22-24 Flashcards
Image on film after exposure but before processing
Latent
Image put into developer
Manifest/visible
Takes latent image and makes it manifest
Developer
The step in film processing; silver is deposited at the latent image sites and an image becomes visible
Developing
The process of removing undeveloped silver halides to make the image permanent for viewing
Fixing
Rinse of chemicals
Washer
The process of using water to remove as much of the fixer and developer solutions as possible
Washing
Blow on either side of film to dry it off
Dryer
The process of film developing in which hot air is forced over both sides of the film as it exits the processor
Drying
Able to give off light; the ability of a material to emit light in response to excitation
Luminescence
Instantaneous emission, preferred; the ability of a material to emit light instantaneously in responses to excitation within one nanosecond
Fluorescence
Delayed emission, bad; the ability of a material to delay emission of light in response to excitation
Occurs when light is emitted for a period longer than necessary
Screens would continue to emit light and end up with an picture with two images on it
Phosphorescence
Not enough x-rays/lack of exposure/mAs; a lack of sufficient incoming data to process an image (noise)
Increase mAs to fix this
Insufficient amount of x-rays interacting with imaging plate fixed by increasing exposure (increase mAs or kV)
Grainy image, takes away from detail
Can be caused by person setting technical factors
Quantum mottle
Chemical used in film developing in the fixer solution to maintain an acidic pH to enhance the functioning of the clearing agent
Activator
The effect on a film when unexposed silver halides are reduced
Chemical fog
A part of the automatic processing system designed to stabilize temperatures, agitate solutions, mix the chemistry and filter the solution
Circulation system
Primary agent of the fixer
Clearing agent
Twice the time necessary for the milky appearance of the film to disappear
Clearing time
Final stage of film processing that removes the excess water, cools and dries the film and seals the film for viewing and storage
Dryer system
Specially designed crossover network to begin the film traveling from the feed tray down into the developer section
Entrance roller
Chemical used in film processing that controls the swelling of the gelatin to prevent scratches and abrasions to the emulsion during processing; in a fixer solution, must function in an acidic environment
Hardener
Chemical used in film processing to help decrease the oxidation of the reducing agents when they are combined with air; also used in fixer solution to aid in removal of silver from the emulsion
Preservative
Chemical used in film processing that provides electrons to the silver ions attached to the sensitivity specks of the silver halide crystals
Reducing agent
Replaces chemicals that are depleted through the chemical reactions of processing, oxidation and evaporation
Replenishment system
Chemical used in film processing added to the developer to restrict the reducing action to those crystals with sensitivity speck gates
Restrainer
Chemicals used in developing film suspended in water
Solvent
When two reducing agents are combined, forming a PQ developer, their reducing ability is the sum of their independent abilities
Superadditivity
Part of the automatic processing unit that maintains all three solutions at compatible temperatures
Temperature control system
Part of the automatic processing system designed to move a film through the developer, fixer, wash and dryer sections of the processor
Transport system
Delayed phosphorescent emission
Afterglow/screen lag
Material film is made from
Usually polyester, tough, stable, rigid and uniformly lucent
Usually contains a blue tint
Base
Ability of the phosphor to emit as much light per x-ray photon interaction as possible, related to the screen speed
Conversion efficiency
Most accurate factor that measures the speed or sensitivity of an intensifying screen; measurement of the amplification of the image that occurs due to the screen’s ability to convert x-ray photons to light
Intensification factor
Device used to amplify the incoming x-ray beam and reduce patient radiation dose
Intensifying screen
When the incident x-ray photons match the K-shell binding energy of the phosphor, there is an increase in characteristic production within the screen
K-shell absorption edge
Measurement of recorded detail, sharpness and resolution; the minimum size and space between objects that can be visualized on the final image
Line pairs per millimeter (lp/mm)
Measurement of recorded detail, sharpness and resolution; measures the resolving ability of a film/screen combination
Modulation transfer function
Layer of material used in an intensifying screen that is capable of absorbing the energy of an incident x-ray photon and then emitting light photons
Phosphor layer
Layer of material used in an intensifying screen applied to the top of the phosphor layer to protect it from abrasions and stains, usually thick plastic
Protective coat
Layer of material used in an intensifying screen to reflect light toward the film
Reflective layer
The most useful rating of intensifying screens expressed with par-screens and film being arbitrarily assigned a relative speed number of 100 as a control point
Relative speed
An indication of the precise wavelength of light emitted by the phosphor
Spectral emission
Measures the ability of a film/screen system to accurately measure the boundaries of an image
Line spread function (LSF)
Platforms that are used for medical purposes, such as patient care, and for biological applications and activities related to health care, including both preclinical research (studying disease or treatments in cells and animals) and clinical research (ex: testing new drugs on patients or analyzing health-care statistics)
Biomedical informatics (BMI)
Standard format for communicating imaging files around the world
Must protect patients’ healthcare data
Digital imaging and communication in medicine (DICOM)
An electronic version of an individual patient’s collection of medical documents
Electronic health-care (or health) record (EHR)
All patient medical documentation stored in electronic format
Electronic medical record (EMR)
Images that are visualized on film
Laser printers and dry processors
Print them out onto film
Hard copy
The electronic database used in the hospital to store, generate and retrieve information on patients
Hospital information system (HIS)
A body of ideas, devices and processes related to handling multiple types of information
Informatics
Computer system that can manage images in an electronic form
Picture archiving and communication system (PACS)
Database of images and patient records specific to imaging department
Radiology information system (RIS)
Images visualized on monitors, either flat panel technology or older cathode ray tubes
Flat screen computer monitors, many advantages
Soft copy
Binary digits
Bit
8-bit word
Byte
Type or indirect digital radiography; the radiographer must usually move the detector, that is most often housed in a cassette, between image acquisition and display
Photostimulable imaging plates (PSP, IP) and filmless cassette
Computed radiography (CR)
Measure of the sensitivity and accuracy by which the image receptor converts the incoming data to the output viewing device
How effective IR is at detecting x-rays and sending it on
1 = 100% or no loss of information
Most IRs 30-70% accurate (0.3-0.7)
Detective quantum efficiency (DQE)
Indicator as to whether the detector response of a specified image Kind agrees with Ktgt
Deviation index (DI)
Flat-panel detectors
Imaging systems that replace traditional film with a reusable detector
Manufactured in table/wall bucky or cassette
Digital radiography (DR)
Conversion of incoming x-ray photons to an electronic signal without scintillation
Use amorphous selenium and thin film transistor (TFT)
Direct conversion
Increase in contrast due to high-pass filtering
Edge enhancement (sharpening)
Descriptive term used for the plates used in both direct and indirect DR digital systems
Flat panel detector
The number of shades of gray; ranges from 8 bits to 32 bits which equals a range of 1-4 bytes of storage that would be required per pixel in the image matrix
12 produces 2^12 gray levels
Represents 4096 different shades of gray
Grayscale bit depth
Amplifies or deletes all but the high frequencies
Uses a Fourier transform algorithm to convert the image into the spatial frequency domain
High-pass filtering