Tomography

course applicable to other parts as well; but, it is in chest radiology that the method is of particular use. In his introduction the author points out that one of the main sources of difficulty in interpreting an ordinary skiagram of the chest is the superimposition of the shadows of the bony framework and blood vessels, bronchioles and alveoli. It is not generally appreciated, for instance, that the ribs cover two-thirds of the pulmonary fields. In the pathological chest pulmonary fibrosis, displacement of the mediastinum, pleural thickening and distorted rib shadows further increase the difficulty of interpretation. At one time it was thought that stereoscopy would solve our problems in this respect; but for various reasons, more especially the personal factor, this method has never been widely adopted. Following this _ general discussion the geometrical principles underlying the method are discussed and the technique of examination described. These call for no special remarks. The rest of the book is occupied by a collection of tomograms with accompanying notes. '