Newly designed phantom for visual detection tests of intra-oral x-ray imaging systems

A new phantom set, which consists of ten acrylic plate phantoms with several kinds of holes, was designed for visual detection tests of intra-oral x-ray imagin systems. Detection tests of two kinds of dental x-ray films were performed using three kinds of phantoms, an aluminum test object, Burger's phantom and the new phantom set. Detection-ability curves generated against optical density were compared. Moreover, correlation between the SNR (signal-to-noise ratio) factor and detection ability was analyzed. False positive rates were also compared. To reduce the number of phantom plate that had to be tested in the new phantom set, the number of detected signals for each phantom plate was cumulatively added and statistically compared to the total number of detected signals. The signals produced with the aluminum test object were too large. The detection ability with Burger's phantom was affected by psychological effect. The detection ability with the new phantom set was most closely correlated to the SNR. False positive rates could be compared with the new phantom set but not with the aluminum test object. The new phantom with holoes smaller than 0.6mm in diameter did not figure into the results. In conclusion, the newly designed phantom set is useful for visual detection tests of intra-oral x-ray imaging systems.