Scatter removal using modified air gap method: spectral composition technique

Abstract

A new scatter rejection technique using the modified air gap method is presented. Two x-ray cassettes are used per exposure. One cassette (front cassette) was placed immediately behind the object. The other (back cassette) was positioned 60 cm behind the object. Thefront radiograph has good spatial resolution but includes a relatively large amount of scatter. The back radiograph has poor high frequency resolution but little scatter due to the air gap. The spectral composition technique extracts highfrequency informationfrom thefront radiograph and combines it with the lowfrequency information of the back radiograph to produce an improved composite synthesized image. No artifacts due to the spectral composition technique were observed. In the lung and heart regions, the modified air gap method resulted in comparable or superior scatter rejection performance as compared to the conventional grid technique.