central ray


Also found in: Dictionary, Thesaurus, Financial, Acronyms, Encyclopedia.

central ray

The theoretical center of an x-ray beam. The term designates the direction of the x-ray photons as projected from the focal spot of the x-ray tube to the radiographical film.
See also: ray
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
A tube angle of positive 60[degrees] is used and the central ray enters through the infraorbital foramen.
Central ray perpendicular to the IR and centered to the MSP at a level of T7 was determined by palpating her vertebra prominens at the level of T1 and then using the hand-spread method to place the central ray 7 inches below T1.
The mammographer then directs the central ray from the superior to the inferior lateral aspect of the breast, midway between the nipple and the lateral breast tissue.[7,20] (See Fig.
The median coronal plane of the patient must be parallel with the film and perpendicular to the central ray. The central ray must be perpendicular to the chest and the cassette.
A perpendicular central ray was directed through the acetabulum.
Table 1 shows the proportion of exposures recorded through the focused grid as a function of focal film distance changes and the degree of off-centeredness to the central ray. An elevated degree of grid "cutoff" due to off-focal distance is evident.
The central ray is directed perpendicular through the glenoliumeral joint.[4] (See Fig.
The central ray should be parallel to the spine with a 12 [degrees] caudal tilt.
In optics, an aperture is the maximum diameter of a light beam that can pass through an optical system, blocking the unfocused peripheral lights rays and focussing the central rays more closely on the fovea; this results in a sharper image and a more flexible depth of focus.
In atypical type of cleft hand, the central rays either are missing or have deficient components.

Full browser ?