IMAGE PRODUCTION AND EVALUATION – VOCABULARY FLASHCARDS

Vocabulary flashcards covering key concepts, terms, and equipment related to image production and evaluation in radiography, drawn from the provided lecture notes.

Darkroom

A light-tight space used for handling radiographic film to prevent exposure to white light and ionizing radiation.

OSHA

Occupational Safety and Health Administration; sets safety standards for radiography, including protective gear and fumes.

Darkroom disease

Hypersensitivity reaction to fumes encountered in the darkroom.

Latent image

The invisible image formed on a film after exposure, revealed during development.

Latensification

Increase in film sensitivity after exposure to white light or ionizing radiation.

Exposed film

Film that has been exposed and is more susceptible to further exposure than unexposed film.

Processing room

Room where radiographic film processing (development, fixing, washing) occurs; important for proximity to exposure room and ventilation.

Automatic processor (Totally Inside)

All processing equipment located inside the darkroom; easy film retrieval but may increase heat, noise, and humidity.

Automatic processor (Bulk Inside)

Most components inside the darkroom with the drop tray outside; easier retrieval and reduced heat/noise.

Automatic processor (Bulk Outside)

Only feed tray inside; used when space is limited.

Passbox

Pass-through device that allows film transfer without entering the darkroom; often interlocked with alarms.

Film cassette

Container that holds film; designed to maintain light-tight integrity during exposure and transport.

Transfer cabinet

Enclosure used to move films between rooms without exposing them to light.

Illumination

Light used for maintenance, cleaning, and safe handling of films in the darkroom.

Safelight

Low-intensity light used in the darkroom to prevent fogging of films; typically amber/or red tones.

Amber filter

Filter used with safelights to block red/blue wavelengths, protecting blue-sensitive film.

WRATTEN 6B filter

A safelight filter that blocks certain wavelengths to protect blue-sensitive film.

GBX 2 filter

A safelight filter used to protect orthochromatic film by filtering specific wavelengths.

Panchromatic film

Film sensitive to the entire visible spectrum; requires safelight considerations.

Orthochromatic film

Film sensitive mainly to green/blue light; less sensitive to red end of spectrum.

Direct exposure/non-screen film

Thicker emulsion film used for direct exposure; offers less parallax but higher patient dose.

Screen film

Film exposed via light from an Intensifying Screen; thinner emulsion and lower patient dose.

Densitometer

Instrument that measures film optical density (OD) to quantify exposure and development.

Sensitometer

Device to create known optical step exposures for sensitometry testing.

Penetrometer

Aluminum step wedge used as an alternative to a sensitometer for densitometry.

Hurter and Driffield (H&D) curve

Characteristic curve describing film density versus exposure to assess speed and contrast.

Base density

Intrinsic density of film base before processing.

Base plus fog (B+F)

Baseline density including inherent fog present before development.

Dmin

Minimum radiographic density on the H&D curve (toe of the curve).

Dmax

Maximum radiographic density on the H&D curve (shoulder of the curve).

Toe

Initial portion of the H&D curve where density rises slowly with exposure.

Shoulder

High-exposure portion of the H&D curve where density increases at a slower rate.

Straight-line portion

Mid-range linear part of the H&D curve indicating gamma (contrast).

Film speed

The sensitivity of film to exposure; higher speed means less exposure needed for a given density.

Film contrast

Difference in optical density between adjacent image densities; influenced by emulsion and exposure.

Exposure latitude

Range of exposures that produce a useful radiographic density on the film.

Intensifying screen

Screen that converts X-ray energy into visible light to expose the film, reducing patient dose.

Phosphor

Material in the screen that emits light when stimulated by X-rays.

Calcium tungstate (CaWO4)

Traditional phosphor material used in intensifying screens; blue emission.

Rare earth phosphors

Modern phosphors (e.g., lanthanum oxybromide, gadolinium oxysulfide) with high light output and spectral efficiency.

Phosphor efficiency (CE)

Conversion efficiency; how effectively a phosphor converts X-ray energy to light.

Phosphor afterglow (lag)

continued emission of light after X-ray exposure has stopped.

Intensifying screen speed

Rate at which a screen emits light; higher speed reduces patient dose but can increase blur.

Crossover

Light emitted by the screen that crosses to the opposite emulsion side, potentially reducing sharpness.

Crossover control layer

A layer designed to absorb crossover light to preserve image sharpness.

Parallax

Apparent misregistration or blurring caused by separation between screen and film or dual emulsion layers.

Parallax reduction methods

Blue tinting, monochromatic film, or anti-crossover layers to minimize parallax.

Film base

Support for the emulsion; commonly polyester; provides stability and transparent support.

Base tinting

Blue dye tint in base to reduce parallax and eye strain.

Duplitized film

Film with emulsions on both sides of the base.

Grain (globular vs tabular)

Crystal morphology in emulsion; globular grains are round, tabular grains are plate-like, affecting speed and sharpness.

Silver halide crystals (AgBr/AgI)

Active ingredients in emulsion that store latent image centers and form metallic silver during development.

Sensitivity specks/centers

Imperfections in the emulsion where latent image centers form during exposure.

Gurney-Mott theory

Classical theory explaining latent image formation via ionization, electron trapping, and silver deposition.

Mitchell theory

Modern explanation of latent image formation and development processes.

Processing cycle

Sequence of development, fixing, washing, drying to produce a radiographic image.

Developer

Solution that reduces exposed silver halide crystals to metallic silver, forming visible image.

Hydroquinone

Developing agent providing high-contrast development in later stages.

Phenidone/Metol/Elon

Developing agents; Metol and Phenidone are common; Elon is a noted term in this set.

Activator/Alkalinizer/Buffer

Agents (e.g., sodium hydroxide) that maintain alkaline pH to promote development.

Restraint/Restrainer (sodium bromide/iodide)

Controls development, reduces fog, and stabilizes the process.

Preservative/Cycon

Antioxidants and stabilizers (e.g., sulfites) that prevent oxidation and protect developing agents.

Hardener

Chemical that hardens the gelatin to prevent swelling and improve handling.

Sequestering agents

Chelating agents (e.g., EDTA) that prevent precipitation and sludge in solutions.

Wetting agents

Agents that reduce surface tension to promote even spreading of chemicals.

Fixer

Agent (sodium thiosulfate or ammonium thiosulfate) that dissolves unexposed silver halide and clears the image.

Hyporetention

Retention of thiosulfate or waste in the film after fixing, leading to fog or staining.

Replenishment

Process of restoring chemical activity in automatic processors by adding fresh chemicals.

Replenisher

Concentrated solution added to processing tanks to maintain chemical activity.

Washing

Rinsing to remove residual chemicals and prevent fog and staining; essential for archival quality.

Drying

Final step that removes most moisture; essential for handling and storage.

Temper control (processor temperature)

Maintaining precise temperatures during development to ensure consistent results.

Reciprocity law

OD is proportional to the total energy imparted, valid mainly for direct exposure, not screen-film.

Reciprocity failure

Deviation from the reciprocity law when exposure time is altered widely.

Density (OD)

Optical density; measure of how dark the radiograph is.

Contrast (soft/hard)

Difference in OD between areas; affected by kVp, filtration, and processing.

Remnant x-rays

X-rays that exit the patient and are still capable of exposing the receptor.

Collimation

Restriction of the beam to the area of interest to reduce patient dose and scatter.

Grid

Device consisting of lead strips and interspace material used to reduce scatter and improve contrast.

Grid ratio

Height of lead strips divided by interspace width; higher ratio improves scatter cleanup but increases patient dose.

Grid frequency

Number of grid lines per centimeter or inch; higher frequency reduces visible grid lines.

Bucky factor

Ratio of incident to transmitted radiation when a grid is used; indicates required exposure increase.

Grid patterns (linear vs cross-hatch)

Types of grid lead line arrangements; linear are parallel, cross-hatch have perpendicular lines.

Focused vs parallel grids

Focused grids align with the tube’s path to minimize cutoff; parallel grids have lines parallel and are easier to position but more cutoff risk.

Air-gap technique

Distance between patient and receptor to reduce scatter without a grid; increases image sharpness and patient dose considerations.

Film sensitivity/response

How film responds to light and X-rays; influenced by grain, emulsion, and spectral sensitivity.

Spectral sensitivity

Range of wavelengths to which a film is most responsive.

Crossover control layer

Layer designed to absorb crossover light, reducing image blur.

Capsules: silver halide crystals (AgBr/AgI)

The core active components of radiographic emulsion that store latent image centers.

Sulfide/oxide phosphors vs rare earth phosphors

Different phosphor materials with varying emission spectra and efficiency that influence speed and dose.

Dmax and Dmin values

The highest and lowest densities achieved on a radiographic image, defining dynamic range.

Fog (types)

Unwanted densities caused by age, chemical fog, safelight fog, heat fog, or secondary radiation fog.

Remnant radiation

X-ray photons that reach the receptor after tissue attenuation and scattering.

Medical film storage (FIFO/temperature)

Storage guidelines: FIFO first in, first out; maintain controlled temperature and humidity.

Sensitivity specks/centers

Physical imperfections in emulsion that act as latent image centers.

Photo-inert packaging

Film packaging that protects from moisture and light.

Grain technology (globiar vs tabular)

Crystal morphology affecting speed and resolution; tabular grains provide higher speed and resolution in some films.

Film base transparency and tinting

Blue-tinted, semi-rigid, uniform lucency base to reduce parallax and improve viewing.

Remnant vs exit beam

Remnant: the portion forming the final image; exit beam refers to X-ray exiting the patient and reaching the receptor.

Exposure latitude

The acceptable range of exposures that still yields usable diagnostic density.