Using controlled case material (n = 55), the weighted value of xerotomography is compared with that of conventional film tomography for the examination of mediastinum and lung. The validity of information of both methods for the final diagnosis is compared. In the visualisation of bronchial units and vascular structures, xerotomography is slightly superior to tomography with silver halogenide films, due to high degree of sharpness of detail, great object range and amplification of the marginal areas. Nodular hilar processes which are in spatial relationship to plane, pulmonary infiltrations or are overshadowed by the cardiac shadow, can be better clarified via conventional technique because of the differences in film density. Overshadowing of linear structures can simulate calcifications in the xeroradiographic image. In our opinion, a combination of film tomography in two planes with xerotomography in an optimal sectional plane can be recommended as a suitable procedure.