Category: C

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.  

A ray composed of negatively charged electrons discharged by a cathode through a vacuum, moving in a straight line and producing x-ray photons upon hitting solid matter. The flow of electrons traversing from the cathode to the anode within an x-ray or valve tube, commonly referred to as the tube current, is quantified in milliamperes.…

A radiograph of the jaws, teeth, and skull, used to demonstrate dental occlusion and its relation to other craniofacial structures.  

The application of radiation therapy to tumors that have been imaged three-dimensionally. The objective is to deliver the radiation directly to the tumor (to make the energy “conform” to the unique shape of the tumor), leaving neighboring healthy tissues unaffected by the damaging effects of radiation.  

Radiation composed of discrete elements or particles such as elements of atomic nuclei (i.e., alpha, beta, neutron, positron, or proton particles). Electromagnetic radiation encompasses a cascade of elemental entities, including electrons, protons, neutrons, and various counterparts, journeying at the velocity of light devoid of any electrical polarity.  

In radiology, the production of radiation in an anode caused by an interaction between an electron from the electron stream and an inner-shell electron of the target material. The result is an ejected electron, a positive atom, and an x-ray photon characteristic of the difference in binding energies between the atomic shells. Radiation that arises…

Pyemia of an origin that is hidden in the deeper tissues.  

Dilated pupils found in agricultural workers who are exposed to dust from jimsonweed. The dust contains stramonium, a mydriatic.  

A puncture of the meninges to collect cerebrospinal fluid, or to inject contrast media or medications. Puncture sites include the spaces around the spinal cord (lumbar puncture), the cisterna magna (cisternal puncture), or open fontanelles in infants (ventricular puncture).  

A pulse recorded near the origin of the carotid or subclavian arteries.