x-ray beam (redirected from principal plane radiographic beam)

x-ray beam,

n the spatial distribution of radiation emerging from a radiograph generator or source. The colloquial term for radiographic beam. See radiographic beam.

radiographic beam, central,

n the straight line passing through the center of the source and the center of the final beam-limiting diaphragm.

radiographic beam, edges,

n the lines joining the center of the anterior face of the source to the diaphragm edges farthest from the source.

radiographic beam, field size,

n the geometric projection, on a plane perpendicular to the central ray, of the distal end of the limiting diaphragm as seen from the center of the front surface of the source. The field is thus the same shape as the aperture of the collimator, and it can be defined at any distance from the source.

radiographic beam, principal plane,

n a plane that contains the central ray and, in the case of rectangular section beams, is parallel to one side of the rectangle.