Correction of intraoral radiography with dual imaging plates using enlargement of the horizontal direction with division into 12 blocks

Abstract

Purpose:The dual imaging plate (DIP) method, which synthesizes intraoral radiographs from a front imaging plate (FIP) and a back imaging plate (BIP), produces adequate image quality and allows the radiation dose to be reduced. However, there are slight errors in superimposition and alignment between the FIP and BIP. The aim of this study was to establish positional correction in the DIP method and evaluate the effect. Methods: Six sets of two imaging plates were used for imaging a mesh plate and a porcine mandible phantom. Subtraction images between FIP and BIP images were synthesized in four steps: correcting horizontal and vertical direction, rotation, enlargement ratio, and enlargement ratio into 12 blocks. Variance of the pixel value on the subtraction images at each step was compared to evaluate the alignment of FIP and BIP images. Results: The variance of the pixel values in the subtraction images was gradually and significantly decreased by each step of image processing (P < 0.01), indicating that the degree of alignment of FIP and BIP images improved during the image processing. Conclusion:The present study revealed that it is possible to synthesize more precise DIP images using an additional four-step image processing technique.

Reduction of cervical vertebra ghost images in panoramic radiography using vertical dual exposure

“…If the X-ray focus is elevated too much, the geometric distortion of the image will increase. If the difference between the 0 mm PR image and the upshifted PR image becomes too large, blurring may occur because the least squares method may not converge [11]. Therefore, Fig.…”

“…Several authors have reported the usefulness of merging the images of dual imaging plate intraoral radiographs to improve image quality and reduce exposure dose [9][10][11], and it has been speculated that such merging of images would minimize the adverse effects of ghost images in the incisor region in PR. This aims of this study were: 1) to test a new vertical dual-exposure PR method that merges the images of two PRs taken at different heights to reduce CV and IVS ghost images in the incisor region, and 2) to evaluate the image quality of this dual-exposure PR method.…”

Vertical magnification correction in vertical dual-exposure panoramic radiography

“…Original software developed by C# (Microsoft, Redmond, WA, USA) was used to subtract and merge images by applying the least squares method [12][13][14][15][16][17]. The PR images taken at H 0 were matched to those taken at heights of 5, 10, 15, and 20 mm by tilting from 0° to 10°, 20°, and 30°.…”

“…The greater the tilt angle, the higher was the X-ray focus position, and the higher the position of the steel ball, the greater was the vertical displacement of the subtracted image. F0, X-ray focus and detector at original position (0 mm); FH, X-ray focus and detector at a height of H mm from F0 shifts the position of the image until the minimum value of the sum of the squares of each subtracted pixel value is reached [12][13][14][15][16][17], and is used in the energy subtraction method and dual imaging plate (DIP) method. Sekiguchi et al [17] reported that DIP intraoral radiography can reduce noise and artifacts such as scratches and dust.…”

“…F0, X-ray focus and detector at original position (0 mm); FH, X-ray focus and detector at a height of H mm from F0 shifts the position of the image until the minimum value of the sum of the squares of each subtracted pixel value is reached [12][13][14][15][16][17], and is used in the energy subtraction method and dual imaging plate (DIP) method. Sekiguchi et al [17] reported that DIP intraoral radiography can reduce noise and artifacts such as scratches and dust. In DIP intraoral radiography, the front and back imaging plate images were merged.…”