Radiographic Terminology
Terms
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- Anode
- a positively charged electrode
- Cathode
- A negatively charged electrode.
- Electron
- A negatively charged particle that travels around the nucleus of an atom.
- Gamma Rays
- Electromagnetic radiation emitted from the nucleus of radioactive substances.
- Infrared Rays
- Electromagnetic radiation, beyond the red end of the spectrum, characterized by LONG wavelengths.
- Ionization
- A process in which an outer electron is removed from the atom so that the atom is left positively charged.
- Radiograph
- A visible photographic record on film produced by x-rays passing through an object.
- Wavelength
- The distance between two consecutive corresponding points on a wave.
- X-rays
- A form of electromagnetic radiation similar to visible light but of a shorter wavelength.
- X-ray Beam
- A number of x-rays traveling together through space at a rapid speed.
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Kilovoltage (kV)
-
The amount of electrical energy being applied to the anode and cathode to accelerate the electrons from the cathode to the anode.
(1kV = 1000 Volts) - Kilovoltage Peak (kVp)
-
The peak energy of the x-rays which determines the quality (penetrating power) of the x-ray beam.
- Milliamperage (mA)
- The amount of electrical energy being applied to the filament. Milliamperage describes the number of x-rays produced during the exposure.
- Rotating Anode
- An anode that turns on an axis to increase x-ray production while dissipating heat.
- Stationary Anode
- A non-moving anode, usually found in dental or small portable radiography units.
- Target
- Anode
- X-ray Tube
- A mechanism consisting of an anode and a cathode in a vacuum that produces a controlled x-ray beam.
- Absorbed Dose
- The quantity of energy imparted by ionizing radiations to matter.
- Dose Equivalent
- The quantity obtained by multiplying the absorbed dose in tissue by the quality factor.
- Dosimeter
- A device used to measure radiation exposure to personnel.
- Genetic Damage
- Effects of radiation that occur to the genes of reproductive cells.
- Gray (Gy)
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The unit of absorbed dose imparted by ionizing radiations to matter.
(1 gray = 100 rad) - Maximum Permissible Dose (MPD)
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The maximum dose of radiation a person may receive in a given time period.
- MPD for Occupationally Exposed Individuals
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0.05 Sv/year
- Primary Beam
- The path that the x-rays follow as they leave the tube.
- Secondary Radiation
- Commonly called \"Scatter radiation\". It is caused by the interaction of the primary beam with objects in its path.
- Sievert (Sv)
-
The dose of radiation equivalent to the absorbed dose in tissue.
(1Sv = 100 rem) - Somatic Damage
- Damage tot eh body induced by radiation that manifests within the lifetime of the recipient.
- Caliper
- A device used to measure the thickness of anatomic parts.
- Contrast
- The measurable difference between two adjacent densities.
- Density
- The degree of blackness on a radiograph.
- Exposure Time
- The period of time during which x-rays are permitted to leave the x-ray tube.
- Milliamperage-Seconds (mAs)
- The number of x-rays produced over a given period. Calculated by multiplying the milliamperage by the time.
- Source-Image Distance (SID)
- Formerly called \"Focal-Film Distance\"; the distance between the source of the x-rays and the image receptor or film.
- Crossed Grid
-
Two parallel or two focused grids that are set at right angles.
- Elongation
- Distortion of anatomic structures so that the image appears longer than actual size, owning to the x-ray beam not being perpendicular to the film surface.
- Focused Grid
- A grid with a parallel center lead strip and inclined strips on either side that radiate at progressively greater angles.
- Foreshortening
- Distortion of anatomic structures when the image appears shorter than actual size due to the plane of interest not being parallel to the film surface.
- Grid
- A device made of lead strips embedded in a spacing material, placed between the patient and the film, designed to absorb non-image-forming radiation.
- Grid Cutoff
- A progressive decrease in transmitted x-ray intensity caused by the absorption of primary x-rays by the grid lines
- Grid Efficiency
- The ability of a grid to absorb non-image-forming radiation in the production of a quality radiograph.
- Grid Factor
- The amount the exposure need to be increased to compensate for the grid\'s absorption of a portion of the primary beam.
- Grid Ratio
- The relation of the height of the lead strips to the distance between them.
- Linear Grid
- Grid in which the lead strips are parallel.
- Magnification
- Distortion of anatomic structures when the image appears larger than actual size.
- Potter-Bucky Diaphragm
- A mechanical device that consists of a focused grid within a diaphragm, which moves the grid across the x-ray beam during the exposure.
- Pseudofocused Grid
- A grid with parallel lead strips that are progressively reduced in height toward the edges of the grid.
- Radiographic Contrast
- The density difference between two adjacent areas on a radiograph.
- Radiographic Density
- The degree of blackness or \"darkness\" on a radiograph.
- Scatter Radiation
- Non-image-forming radiation that is scattered in all directions because of objects in the path of the x-ray beam.
- Subject Contrast
- The difference in density and mass of two adjacent anatomic structures.
- Unfocused Grid
- A grid with lead strips that are parallel and at right angles to the film. Also called a \"Parallel Grid\".
- Cassette
- A lightproof encasement designed to old x-ray film and intensifying screens in close contact.
- Intensifying Screen
- Sheets of luminescent phosphor crystals bound together and mounted on a cardboard or plastic base.
- Non-Screen Film
- Film that is more sensitive to ionizing radiation than to fluorescent light.
- Screen Film
- Film with silver crystals that is more sensitive to fluorescent light emitted from intensifying screens than to ionizing radiation.