Evaluation of Eye Lens Dose Reduction Technics in Head CT

Abstract

The purpose of this study is to find the best protocol to reduce the X-ray dose to the eye lens during head diagnostic computed tomography (CT) without decreasing image quality in the organs of interest according to the type of scanner. The lens of the eye is one of radiosensitive tissues in the body. Radiation induced cataract has been demonstrated among staff involved in interventional procedures using X-rays. This study compares the absorbed dose and image quality of several dose reduction technics to the eye lens during head CT exam namely bismuth shielding, organ-based dose modulation, tube current modulation, tube voltage modulation and the combination of a number of these techniques. Compared to the reference scan (Fixed tube current without bismuth shielding), the dose to the eye lens was reduced by 29.91% with bismuth shield, 14.55% with tube current modulation, 37.76% with tube current modulation and bismuth shield. The combination of organ-based dose modulation with tube voltage modulation reduced the dose by 44.93% that of tube current modulation with tube voltage modulation reduced by 19.03% and that of tube current modulation with tube voltage modulation and shield by 46.73%.

The combination of organ-based dose with tube voltage modulation provided superior image quality than that of tube current modulation with tube voltage modulation and shield while similarly reducing dose to the eye lens.