Assessment of physical frame-based abdominal thickness estimation by evaluating conditions with fuzzy control: automatic exposure control (AEC) in diagnostic X-ray apparatus

Abstract

In digital X-ray photography of the abdomen and lumbar vertebrae, the automatic exposure control(AEC)system installed in the radiographic stand is essential for imaging at an appropriate dose. The AEC system has been used in many medical facilities. As patient size needs to be adapted, currently available AEC systems are equipped with a mechanism that enables an increase/decrease, by stages of 7-9, in AEC for X-ray dose. Adjustment of this function, however, depends largely on the radiologist's experience, as such X-ray dose control is lacking in reproducibility and quantification. We performed fuzzy reasoning using a measure of obesity(body-mass index: BMI)that was determined from the patient's height and body weight and estimated his/her abdominal thickness. On the basis of this estimated value, we established a methodology to define the conditions for X-ray photography of abdominal thickness in the area of increased patient thickness. We speculated that this methodology might provide better reproducibility and quantification for X-ray dose control in the area of increased patient thickness than the conventional AEC system.