a series of steps that collectively produces a visible permanent image on a dental radiograph
purposes of film processing
convert the latent (invisible) image on the film into a visible image
to preserve the visible image so that it is permanent and does not disappear from the denta radiograph
the portion of a processed radiograph that is dark or black
what type of structures appear radiolucent on an x-ray?
structures that lack densiy and permit the passage of the x-ray beam with little or no resistance
the portion of a processed radiograph that appears lightr white
what type of structures appear radiopaque?
structures that are dense and absorb or resist the passage of the x-ray beam including, enamel,dentin, and bone
Diagnostic radiograph produces images that;
exhibit proper density and contrast
have sharp outlines
are the same shape and size as the object being radiographed
visual characteristics of dental radiograph
the overall blackness or darkness of a dental radiograph
what 3 things does a radiograph with correct density allow the radiographer to view?
black areas - air space
white areas - enamel, dentin, and bone
gray areas - soft tissue
3 exposure factors that control the density of a radiograph
operating kilovoltagepeak (kVp)
true or false. Subject thickness/size and density of the bone also affect the overall density of a radiograph
How does an increase in milliamperage affect the film density of a radiograph?
it produces more x-rays exposed to the film and increases the film density, so it appears darker
How does an increase in operating kilovoltage peak affect the density of the radiograph?
it increases the film density by increasing the average energy of the x-rays by producing x-rays with higher energy. the film appears darker
How does an increase of exposure time affect the densiy of the radiograph?
it increases the film density by increasing the total number of x-rays that reach the film surface. the film appears darker
the difference in the degrees of blackness (densities) between adjacent areas on a dental radiograph
the difference in the amount of light transmitted through adjacent areas of a radiograph
very light and very dark areas that are strikingly different
many shades of gray
how is contrast determined?
by film contrast and subject contrast
characteristics of the film that influence radiographic contrast
what type of characteristics influence the contrast of the film?
who controls the inherent qualities of the film
who controls film processing of the radiograph?
the dental radiographer
true or false. an increase in development time or temperature increases the contrast of the film.
the characteristics of the subject that influences radiographic contrast
what type of characteristics is subject contrast determined by?
composition (atomic number) of subject
how is subject contrast altered? And how does this affect the outcome?
by adjusting the kVp
high operating kilovoltage peak (more than 90) = low contrast
low operating kilovoltage peak (60-75) = high contrast
what is the one exposure factor that has a direct influence on contrast of the radiograph?
How does the kilovoltage peak directly affect the contrast?
increasing the kilovoltag peak increases the average energy of the x-rays produced allowing them to penetrate tissue better which results in more variations in tissue on the film with varying shades of gray, or low contrast
the range of useful densities seen on a dental radiograph
scale of contrast
a dental radiograph that shows only 2 densities, areas of black and white show what scale of contrast
a lower kVp results in a radiograph with ____________-scale contrast, which can also be described as having______________ contrast.
a dental radiograph that exhibits many densities or many shades of grey exhibits which kind of contrast?
a higher kVp range results in a radiograph with _________-scale contrast and ______________contrast
a device used to demonstrate short-scale and long-scale contrast
name the 3 geometric characteristics of the radiographic image
the capability of the x-ray film to reproduce the distinct outlines of an object or, in other words, to how well the smallest details of an object are reproduced on dental radiograph
unsharpness, or blurring of the radiographic image that is present in every radiograph.
what are the 3 factors that influence sharpness of a radiograph?
focal spot size
what are the meanings of the latin words pene, and umbra?
the tungsten target of the anode, which converts bombarding electron into x-ray photons, and concentrates the electrons and creates an enormous amount of heat.
what is the size of the focal
.6mm2 to 1.0mm2
the smaller the focal spot area, the ___________the image appears; the larger the focal point size, the_____________the loss of image sharpness.
what is relative to the size of the crystals found in the film emulsion?
what type of crystals does the emulsion of faster film contain?
larger crystals that produce less image sharpness
what type of crystals does the emulsion of slower film contain?
smaller crystals that produce that produce more image sharpness
true or false. Movement of either the film or the patient influences film sharpness
a radiographic image that appears larger than the actual size of the object it represents
what are the 2 factors that influence the image magnification on a target radiograph?
distance between the source of x-rays (focal spot on the tungsten target) and the film
what determines the target-film distance?
the length of the position indicating device
a longer PID and target-film distance result in__________image magnification, and a shorter PID and target-film distance result in____________image magnification
distance between object being radiographed (tooth) and the dental x-ray film
a decrease in object-film distance results in a______________in magnification, and an increase in object-film distance results in an___________ in magnification
a variation in the true size and shape of the object being radiographed
what causes a distorted image?
unequal magnification of different parts of the same object
improper film alignment or angulation of x-ray beam
what influences the dimensional distortion of a radiograph?
x-ray beam angulation
how must the object and film be situated to avoid distortion?
parallel to eachother
how should the x-ray beam angulation be situated to the tooth to prevent distortion?