[Homogenized thoracic radiography]

Abstract

The major obstacle to optimal radiographic depiction of the chest has always been its anatomical features and, in particular, the considerable difference in X-ray beam attenuation between pulmonary and mediastinal structures. At least 40% of this region cannot be visualized in an optimal way. Therefore, much technological work was done to overcome this limitation, which has recently led to the development of electronic (Amber) and mechanical (homogenization) filtration systems. This study was aimed at assessing the capabilities of mechanical filtration, in terms of anatomical representation and lower biologic cost, the latter intended as lower exposure and absorbed doses. Therefore, eight radiologists studied 40 negative radiographs, i.e., a homogenized radiograph and a non-homogenized one per patient, twenty patients in all. The statistical analysis of the radiographs demonstrated the homogenized technique to allow better visualization of all the anatomical structures examined, i.e., trachea, carina, right and left main bronchi, aorta, spine and retrocardiac region. In contrast, the two radiographic techniques yielded much the same results in the depiction of the pulmonary pattern. As for dosimetry, good results were also obtained, because the homogenizer made it possible to reduce both exposure and absorbed doses to the lung and thyroid, while in the mediastinal region the absorbed dose remained similar to that measured with the non-homogenized even though exposure dose was increased mildly.