Effect of K-shell absorption edge filters on image quality in digital intraoral radiography

Objective. The purpose of this study was to investigate the effects of K-shell absorption edge filters on the image quality of a charge-coupled device-based digital intraoral radiographic system. Study design. NIOBI-X, Dental X-ray Beam Filter Kit, and KEY filter were added to a 1-mm thick aluminum filter. The half-value layer and the corresponding effective energy were measured. Digital x-ray images were obtained by using a Computed Dental Radiography (CDR). The sensitivity and the image contrast were compared for each filter. Visual detection tests were conducted to evaluate the depiction ability by using 2 kinds of phantoms. Results. The highest effective energy was produced with the KEY filter, and this high effective energy tended to increase the sensitivity of the CDR. The KEY filter also produced the greatest contrast and had the best depiction ability. Conclusions. The appropriate combination of a charge-coupled device-based digital intraoral radiographic system and an additional filter can reduce the patient dosage and increase the diagnostic information.