#Phototime in x ray manual#
Unlike manual timers, which simply stop the exposure after the preset time has elapsed.Ī major benefit of the AEC device is its ability to consistently obtain accurately exposed radiographs, even in the presence of pathology.
The AEC device differs from a manual timer because the AEC does not stop the exposure until the film has reached an appropriate density. When an AEC device is used to terminate an exposure, the technologist sets the kVp and mA, but the time of the exposure is automatically determined by the machine. The most important benefit being decreased repeat rate The advantages of this consistency are numerous and include: decreased repeat rate decreased patient exposure and increased department efficiency. mAs ALLOWABLE – 600 mAs UNLESS TUBE POTENTIAL IS LESS THAN 50 kVp – 2,000 mAs IS THE LIMIT.ĪUTOMATIC EXPOSURE CONTROL Automatic exposure control devices can assist the radiographer in producing consistent radiographic images from patient to patient, regardless of size or presence of pathology.
MONITORS THE PRODUCT OF mA & EXPOSURE TIME AND TERMINATES EXPOSURE WHEN THE DESIRED mAs VALUE IS ATTAINED.IT’S CIRCUITRY CONSISTS OF THYRATRON TUBE OR THYRISTOR.IN SYNCH WITH FREQUENCY OF THE A/C CURRENT (60 Hz in the US).DURING EXPOSURE THE SPRING UNWINDS AND TERMINATES EXPOSURE.
A MECHANICAL OR ELECTRONIC DEVICE WHOSE ACTION IS TO MAKE OR BRAKE THE HIGH VOLTAGE ACROSS THE X-RAY TUBE.IS SEPARATE FROM THE OTHER MAIN CIRCUITS OF THE IMAGING SYSTEM.
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