Radiographs are photographs created by exposing an x-ray film to radiation. Special devices within image receptors provide adequate penetration, contrast and density to produce an image. The technologists that operate this equipment are responsible for performing regular quality assurance measures to achieve consistent performance and protect patients. Standard x-ray film is susceptible to many factors, which can cause overexposure.
External Light
X-ray film is similar to regular photographic film, in that light of most wavelengths can result in overexposure. This complication necessitates the use of darkrooms in which to process film properly. Red safety lights allow technologists to see without exposing films. Overexposure results if radiographic cassettes are warped, cracked or not completely closed.
Improper Technique
Inexperienced technologists often use excess imaging technique when producing radiographs. Imaging technique refers to two exposure factors, mAs (milliamperes per second) and kVp (kilovolts peak) used during the process. These two factors control the density and contrast of the film, respectively. X-ray exposure that exceeds the level needed results in overexposure, often termed "burning out" the radiograph.
Dosimeter Malfunction
Precision measuring devices called dosimeters are located within image receptors on x-ray tables and upright x-ray stands. Dosimeters are responsible for measuring image forming radiation that passes through a patient and terminating the exposure when the proper levels of mAs and kVp are achieved. Malfunctions in dosimeters, such as a fault in the back-up timer, can result in overexposure and delivery of excess radiation to patients.
Tags: image receptors, result overexposure, within image, within image receptors, x-ray film
