X-ray scatter correcting methods for digital radiographic imaging

Abstract

          X-ray scattering correction method has been the primary means of enhancing radiographic images for quite some time. X-ray scattering is major deterioration factor that decreases image contrast and increases the image granularity in a radiographic image. However, this can be eliminated by using scatter reduction techniques like air gaps and anti-scatter grids, but the two techniques are cumbersome, and increases patient’s radiation dosages. Moreover, it can also cause artifacts whenever anti-scatter grids are used. Recently, commercial software packages have been developed from various x-ray equipment manufacturers that have eliminated the need for anti-scatter grid usage. These recent advancements also allow lower patient dosages. Objective of this review is to summarize and review x-ray scattering and image processing algorithms used for enhancing the performance of the digital image in general radiography. Articles on digital image processing and commercial software for x-ray scatter correcting were thoroughly reviewed to complete this summary. These articles indicate that scatter correcting methods are based on principles of physics which involve of mathematical models of radiographic formation and x-ray scattering estimation methods. One simple model has the total energy absorbed at an image detector forming a primary x-ray plus a scattered x-ray whereby the point spread function of the scattered x-ray is used. Almost all estimations of x-ray scatter are computer simulations. The digital image post-pro­cessing algorithms are important factors in the x-ray scattering correction process. Their algorithms are related to mathematical models and the amount of scattering x-rays in an image, and are selected for use based on these considerations. These algorithms include subtraction, de-convolution, and anti-scatter grid simulation techniques. Therefore, x-ray scatter correcting methods for a digital radiographic imaging may be used in general radiography since their image quality is comparable to the images that have used anti-scatter grids, but are also beneficial since radiation dosage can be reduced using this process.