subtraction radiography

radiography (rā´dēog´rfē),

n the making of shadow images on photographic emulsion by the action of ionizing radiation. The image is the result of the differential attenuation of the radiation in its passage through the object being radiographed.
Roentgenography refers to production of film by the use of roentgen rays only.

radiography, bone in,

n radiography of bone and marrow tissue. Translucencies and opacities in bone in radiographs depend on the different densities that bone and marrow spaces present to the roentgen rays. The configuration of bone tissue represents the topography and arrangement of bone trabeculae, which register as opaque in contrast to the translucency of the marrow spaces.

radiography, computerized digital,

n a radiography machine using computer technology to produce a digital image instead of using film; a digital sensor is placed in a disposable sheath inside the patient's oral cavity; then the sensor is exposed to radiation as in a traditional radiograph, except that the sensor produces an immediately accessible digital image that can be viewed on a computer screen.

radiography, digital subtraction,

n a technique for eliminating unnecessary anatomic structures on a radiographic image by storing the pre- and postprocedure images in a computer and then combining them together digitally to display the final subtracted image, which emphasizes the differences between the two original films.

radiography, oral,

n the specialized operative and technical procedures and practices for making successful radiographic surveys, with the understanding that it involves the selection of the dental radiography unit and its adjustments as well as the generation and application of roentgen rays to all phases of interest to the dental profession. It also takes into consideration all the processes necessary for the production of finished radiographs of the teeth and their supporting tissues, adjacent regions, and associated parts. See also radiograph(s).

radiography, subtraction,

n the digital or photographic manipulation of a radiograph in which background images are eliminated to highlight areas for pre- and postoperative comparison.

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subtraction radiography

highlighting the differences between two radiographs by covering one film of a part with a diapositive film of the same part. A photograph of this compilation will produce one which has grayed out the background but reinforced the differences. The method removes distracting material in the ordinary film. Used in angiography where the vessels are difficult to see, e.g. in the skull.