exposure (redirected from chronic exposure)

exposure /ex·po·sure/ (eks-po´zher)

1. the act of laying open, as surgical exposure.

2. the condition of being subjected to something, as to infectious agents, extremes of weather, or radiation, which may have a harmful effect.

3. in radiology, a measure of the amount of ionizing radiation at the surface of the irradiated object, e.g., the body.

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air exposure  radiation exposure measured in a small mass of air, excluding backscatter from irradiated objects.

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exposure

(ikspō´zhr),
n uncovering: subjection to viewing or radiation.

exposure, accidental pulp,

n a pulp exposure unintentionally created during instrumentation.

exposure, air,

n the radiation exposure measured in a small mass of air under conditions of electronic equilibrium with the surrounding air, i.e., excluding backscatter from irradiated parts or objects.

exposure, cariogenic

(karēōjen´ik),
n an incident in which teeth come into contact with foods that tend to create a favorable environment for development of dental caries.

exposure, carious pulp,

n a pulp exposure occasioned by extension of the carious process to the pulp chamber wall.

exposure, chronic,

n a radiation exposure of long duration, either continuous (protraction exposure) or intermittent (fractionation exposure); usually referring to exposure of relatively low intensity.

exposure, cumulative,

n the total accumulated exposure resulting from repeated radiation exposures of the whole body or of a particular region.

exposure, double,

n the two superimposed exposures on the same radiographic or photographic film.

exposure, entrance,

n an exposure measured at the surface of an irradiated body, part, or object. It includes both primary radiation and backscatter from the irradiated underlying tissue or material.

exposure, erythema

(erthē´m),
n the radiation exposure necessary to produce a temporary redness of the skin. The exposure required varies with the quality of the radiation to which the skin is exposed.

exposure incident,

n an event in which a health care professional's potential for infection is heightened after coming into contact with a patient's blood, body fluids, mucous membranes, or broken skin.

exposure, mechanical pulp,

n See exposure, pulp, surgical.

exposure, parenteral,

n exposure of the internal systems of the body due to the puncturing of the skin by a needle or other sharp instrument.

exposure, protraction,

n the continuous exposure to radiation over a relatively long period at a low exposure rate.

exposure, pulp,

n an opening through the wall of the pulp chamber uncovering the dental pulp.

exposure, radiographic,

n a measure of the x or g radiation to which a person or object, or part of either, is exposed at a certain place, this measure being based on its ability to produce ionization. The unit of x- or g-radiation exposure is the roentgen (R).

exposure, radiographic, entrance (surface),

n the radiation exposure measured at the external surface of a person or thing that has been ir-radiated. Measurement includes both backscatter radiation from the exposed tissues and primary radia-tion.

exposure rate, output,

n the exposure to radiation at a specified point per unit of time, usually expressed in roentgens per minute.

exposure, surface,

n See exposure, entrance.

exposure, surgical pulp,

n (mechanical pulp exposure) the pulp exposure created intentionally or unintentionally during instrumentation.

exposure, threshold,

n the minimum exposure that will produce a detectable degree of any given effect.

exposure time,

n the time during which a person or object is exposed to radiation, expressed in one of the conventional units of time.

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exposure

1. the act of laying open, as surgical exposure.

2. the condition of being subjected to something, as to infectious agents or extremes of weather or radiation, which may have a harmful effect.

3. in radiology, a measure of the amount of ionizing radiation at the surface of the irradiated object, e.g. the body.

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exposure button

of an x-ray machine. Usually on a 4 to 5 ft cable so that the operator can stand at a distance away from the primary beam. Combined with a timing device that is preset and controls the exposure time. The button is usually a two-stage mechanism, the first causing preheating of the cathode filament and/or rotating the anode, the second closing the electrical circuit and the creation of the x-ray beam.

exposure chart

a chart set up after a preliminary trial that sets out the best arrangement of exposure factors for a particular set of radiological equipment in order to obtain the best results.

climatic exposure

exposure to the weather without provision of shelter. See hypothermia, hyperthermia.

exposure error

under- or overexposure in radiography causing inferior contrast and detail.

exposure factors

the milliampere-seconds and kilovoltage for radiography of a particular animal. The factors are influenced by the speed of the film to be used, the anode to film distance, the grid to be used and the size of the subject. The exposure factors should be kept constant as far as possible.

exposure latitude

degree of over- or underexposure tolerable in a correctly developed film to still produce an acceptable radiographic image.

provocative exposure

in testing for possible hypersensitivity, the exposure to a suspected offensive agent to see if there is a recurrence of clinical signs.

exposure time

in radiography variable but fastest is best with animals because of the difficulty of holding the animal quite still or of delaying its breathing for any length of time. The milliamperage used should be as high as possible to keep the exposure time short.