K Araki1, A Endo, T Okano. 1. Department of Oral Radiology, Showa University School of Dentistry, Kitasenzoku 2-1-1, Ohta-ku, Tokyo, 145-8515, Japan.
Abstract
OBJECTIVES: To compare the sensitometric properties and resolution of four digital intra-oral radiographic systems. METHODS: Three CCD-based systems were evaluated, RVG-4 (Trophy Radiologic, Paris, France) CDR (Schick Technologies Inc, Long Island, NY, USA) and Dixel (Morita, Kyoto, Japan) and a photostimulable phosphor system (Digora, Soredex-Orion, Helsinki, Finland). The sensitometric properties were determined by measuring the gray levels at increasing exposures without making any gray-scale adjustments. MTF was measured using images of a 10 microns width slit inclined to the long and short axes of the detectors. RESULTS: The CCD-based systems showed a linear relationship between exposure and gray level although there were some differences in sensitivity. In RVG-4, the gray level saturated at a lower exposure. Digora showed a logarithmic relationship at uniform exposure. However, there was a linear relationship when it was exposed below the calibration dose. The MTF was highest with RVG-4 and the lowest with the Digora. CONCLUSIONS: Each system has its own specific properties; RVG-4 has the highest resolution with the narrowest latitude, whereas Digora has the wider latitude but the lowest resolution.
OBJECTIVES: To compare the sensitometric properties and resolution of four digital intra-oral radiographic systems. METHODS: Three CCD-based systems were evaluated, RVG-4 (Trophy Radiologic, Paris, France) CDR (Schick Technologies Inc, Long Island, NY, USA) and Dixel (Morita, Kyoto, Japan) and a photostimulable phosphor system (Digora, Soredex-Orion, Helsinki, Finland). The sensitometric properties were determined by measuring the gray levels at increasing exposures without making any gray-scale adjustments. MTF was measured using images of a 10 microns width slit inclined to the long and short axes of the detectors. RESULTS: The CCD-based systems showed a linear relationship between exposure and gray level although there were some differences in sensitivity. In RVG-4, the gray level saturated at a lower exposure. Digora showed a logarithmic relationship at uniform exposure. However, there was a linear relationship when it was exposed below the calibration dose. The MTF was highest with RVG-4 and the lowest with the Digora. CONCLUSIONS: Each system has its own specific properties; RVG-4 has the highest resolution with the narrowest latitude, whereas Digora has the wider latitude but the lowest resolution.
Authors: Madhu K Nair; James C Pettigrew; Jeffrey S Loomis; Robert E Bates; Stephen Kostewicz; Boyd Robinson; Jean Sweitzer; Teresa A Dolan Journal: J Digit Imaging Date: 2008-09-03 Impact factor: 4.056