Measurement algorithm accuracy of the RVG-PCi in vertical and diagonal assessments at various beam energies

The Trophy RadioVisioGraphy model PCi was compared to Kodak Ektaspeed Plus film for accurate recording and estimation of the length of size 15 files placed vertically and diagonally across the receptor surface. Variations in kilovoltage (50, 70, and 75) and exposure were also factored. Eight observers estimated file lengths using the proprietary software measurement algorithm for the RVG-PCi and a millimeter rule for the film-based radiographs. Both modalities resulted in slight magnification for vertically oriented files; however, the RVG-PCi caused overestimation in the order of 6 to 8% with diagonally oriented instruments. Measurement interobserver variability was least when using the RVG-PCi. It was concluded that the proprietary software supplied with RVG-PCi is not sufficiently accurate for endodontic assessment. Furthermore, exposures above 0.15 s at 75 kVp resulted in pixel saturation resulting in apparent shortening of the instrument; hence, length calculations are particularly sensitive to overexposure when using the RVG-PCi.