Performance comparison between three intraoral image receptors of different technology at a variety of tube potential, tube current and exposure time settings using a stepwedge phantom

Purpose: To comparatively evaluate the per-formance of three intraoral image receptors of different technology when exposed to different X-ray beam spectra, dose and dose rate levels using a stepwedge phantom. Materials and methods: The intraoral radiographic receptors evaluated were: the Kodak Insight F speed class film, the Kodak RVG 6000, and the Duerr Vis-tascan Combi PSP system. A dental quality control phantom made of Plexiglas, containing an aluminium stepwedge with 12 steps and 7 holes drilled in each step was radiographed using a dental X-ray unit offering a wide range of tube potential, tube current and exposure time settings. The visibility of the holes in the images produced with each one of the three receptors was assessed by three independent observers. For each image the total image quality score (TS) was derived from the summation of the number of visible holes in each step. The numbers of perceptible holes in each experimental condition (TSs) were statistically analyzed through use of analysis of variance. Intraobserver and interobserver agree-ment was also measured. Results: Vistascan ex-hibited the most extended useful exposure range, followed by RVG 6000 and Insight. RVG 6000 exhibited the largest TS values in all tube potential settings except 70 kV where the Vistascan performed better. Insight performed better than Vistascan only at 60 and 63 kV. Vistascan performed better at 66 and 70 kV, Insight at 60 and 66 kV, whereas RVG performed equally well at all tube potential settings, except than at 52 and 70 kV. For the Insight the largest TS values were obtained with the smallest ESAK values whereas with the Vistascan the largest TS were obtained with ESAK values that where the largest observed. Conclusions: The performance of all receptors tested was greatly dependent on the exposure parameters and mainly on the kV settings. Overall, the RVG 6000 offered the best image quality at doses somewhere in between those required by the Insight and the Vistascan.

Exploring the useful exposure range limits of three intraoral image receptors for various tube potential, tube current and exposure time settings

Objectives: To determine the useful exposure range limits of three intraoral image receptors of different technology when exposed to different X-ray beam spectra, dose and dose rate levels. Study Design: A dental X-ray unit offering a wide range of tube potential, tube current and exposure time settings was used to expose a dental quality control phantom. The receptors that were used to capture the radiographic images of the phantom were: the Kodak Insight, the Kodak RVG-6000 and the Duerr Vistascan system. The images that were produced over a wide range of exposure factor settings were evaluated in terms of diagnostic quality by three experienced radiologists. Results: The number of images with acceptable diagnostic quality was in total 1257;310 with Insight, 331 with RVG 6000 and 616 with Vistascan. At 60 kV, diagnosable images were produced with doses ranging from 0.44-1.56 mGy for the Insight film 0.44-2.82 mGy for the RVG 6000 and 0.22-4.93 mGy for the Vistascan system. At 70 kV, the respective ranges were 0.39-1.28 mGy for the Insight film 0.31-2.55 mGy for the RVG6000 and 0.30-3.46 mGy for the Vistascan system. Conclusions: The Vistascan exhibited the widest useful exposure range and required the least exposure to produce a diagnosable image at almost all tube potential settings. The RVG 6000 exhibited a slightly wider useful exposure range than the Insight film, with almost the same dose requirements especially in higher Kv settings.