A Simple Scatter Reduction Method in Cone-Beam Computed Tomography for Dental and Maxillofacial Applications Based on Monte Carlo Simulation

Abstract

The quality of images obtained from cone-beam computed tomography (CBCT) is important in diagnosis and treatment planning for dental and maxillofacial applications. However, X-ray scattering inside a human head is one of the main factors that cause a drop in image quality, especially in the CBCT system with a wide-angle cone-beam X-ray source and a large area detector. In this study, the X-ray scattering distribution within a standard head phantom was estimated using the Monte Carlo method based on Geant4. Due to small variation of low-frequency scattering signals, the scattering signals from the head phantom can be represented as the simple predetermined scattering signals from a patient's head and subtracted the projection data for scatter reduction. The results showed higher contrast and less cupping artifacts on the reconstructed images of the head phantom and real patients. Furthermore, the same simulated scattering signals can also be applied to process with higher-resolution projection data.

Quantitative evaluation of scatter correction in 128-slice fan-beam computed tomography scan using geant4 application for tomographic emission Monte Carlo simulation

“…Perhaps the most important and common method to evaluate and ensure a simulation results using experimental examination is to compare the intensity pattern of the pixels of simulated and simple experimental phantom images. However, in a study conducted by Thanasupsombat et al ,[ 29 ] a human-like head phantom was used. In addition, in a study by Najafi Darmian et al ,[ 36 ] GATE validation was done by comparing the scattering profile on a row detector of a CT scan between the simulation and the experimental exams.…”

“…However, the Monte Carlo technique has been highly effective due to its statistical and random nature. [ 29 , 37 , 38 ] In order to evaluate the success of GATE in scatter estimation more comprehensively, four quantities were investigated for scatter correction. The middle row, filled with water, has been chosen for pixel intensity evaluation in a uniform environment.…”

Effects of Exposure Parameters and Voxel Size for Cone-Beam Computed Tomography on the Image Matching Accuracy with an Optical Dental Scan Image: An In Vitro Study

“…Diverse results have been reported, depending on the standard used to evaluate scan devices, image quality, amount of dose reduction, and exposure parameters. Most studies have found that a substantial dose reduction using exposure parameters below the manufacturer's guidelines is possible with adequate visibility [ 24 – 26 ]. Rivas et al found that dose reductions to 50% lower than the manufacturer's default settings could be achieved by decreasing the X-ray tube voltage [ 27 ].…”

CAD-based x-ray CT calibration and error compensation

“…Methods using signal processing techniques have been developed to estimate and correct for scattering effects. The scattered x-ray distribution can be predicted via Monte-Carlo (MC) simulations [26,27]. Although it is a powerful tool, the poor convergence properties of MC sampling leads to timeconsuming calculations.…”