QUANTITATIVE ASPECTS OF IMAGE INTENSIFIER-TELEVISION-BASED DIGITAL X-RAY IMAGING.

In this chapter, we have discussed the various physical factors which cause the video densitometric measurements performed with II-TV-based digital X-ray systems to be inaccurate. Experimental and simulation results demonstrating the contribution of each degradation factor were presented. We have shown that the degradation factors in increasing order of importance are beam hardening, veiling glare, and X-ray scatter within the patient. Various techniques for reducing the errors were introduced and discussed. In developing correction techniques, we avoided empirical methods such as background subtraction, lead disk placement on the object for scatter correction, and so on, since these methods work in limited situations and are not based on any sound physical principle. We believe that empirical methods result in unpredictable results when the experimental conditions are altered.