Optimization in radiography

Frequently asked questions by the health professionals

» What can I do to ensure that the X-ray beam spectrum is optimized for the various clinical procedures performed in our facility? 
» Does the use of automatic exposure control (AEC) always ensure the correct exposure to patients during radiography? 

» What can I do to ensure that the X-ray beam spectrum is optimized for the various clinical procedures performed in our facility?

An optimized X-ray beam spectrum is one that provides the appropriate balance between image quality (contrast, detail, noise) and patient exposure. For a specific X-ray machine, the spectrum is determined by a combination of the filter in the beam and the kV value. The first step is to have the machine periodically evaluated in the quality control programme for the equipment by a physicist or engineer to confirm appropriate filtration and to calibrate the kV control. The second step is to ensure that the staff is using kV values and filtration that are optimum for the specific types of examinations. The appropriate technique factors (kV, image size, etc) should be specified for each type of clinical examination in the procedure manual and technique charts for the facility.

» Does the use of automatic exposure control (AEC) always ensure the correct exposure to patients during radiography?

No, not always. The appropriate use of a properly calibrated and adjusted AEC is helpful in minimizing unnecessary exposure. However, if the AEC is not properly calibrated and the sensors are correctly located within the anatomical area being examined, it would result in incorrect exposures. Special attention has to be paid in installations used for paediatric patients since some exposure settings might be higher than necessary. Also, an improperly exposed film might mean repeating the radiography and subjecting the patient to additional exposure. The appropriate action is to ensure that the AEC is correctly evaluated and calibrated in the equipment quality control programme and that the staff has acquired appropriate training and experience.