An investigation into dose optimisation for imaging root canal anatomy using cone beam CT

Abstract

OBJECTIVES: To identify a dose as low as diagnostically acceptable and a threshold level of image quality for CBCT imaging root canals, using maxillary first molar (M1M) second mesio-buccal (MB2) canals of varying complexity for two CBCT scanners. METHODS: Dose-area product (DAP) and contrast-to-noise ratio (CNR) were measured for two scanners at a range of exposure parameters. Subjective-image-quality assessment (SIQA) at the same exposures was performed for 3 M1M's of varying MB2 complexity, positioned in a anthropomorphic phantom. Nine raters (three endodontists, three dental radiologists and three junior staff) assessed canal visibility, using a five-point confidence scale rating (CSR). RESULTS: Identification of simple-moderate MB2 canal complexity was achieved at a range of protocols, with DAP values of /=209.3 mGy cm(2) and "/=203.2 mGy cm(2) and CNRs of 3 and 7.6 for Promax((R))3D and Accuitomo-F170((R)) respectively. For complex canal anatomy