[en] Development has been made of a new X-ray intensifier tube (abbreviated to Metal X-I.I.) which produces images much better than ever in cardiac diagnosis. Unlike the conventional type of intensifier tube using a glass layer 3- to 4-mm thick as the input-window material, the new type employs a titanium layer only 250-μm thick for the window, with remarkable reduction in X-ray scattering and marked improvement of contrast, resolution and corpuscular quality obtained as the results. The development of the X-I.I. has been made on a number of technical improvements, such as regarding to binding titanium with other metals; the qualities of the pentode electron lens and the 25-mm-diameter output phosphor screen; the methods of manufacturing photocathodes and the input-and-output phosphor screen. The X-I.I. is especially noticeable in the improvement of the contrast and characteristics including intermediate tones; even in cases imaging is made under fairly high voltage or the object is very thick, it is possible for the X-I.I. to produce images with very good quality. It is expected that this image intensifier tube will contribute greatly to the diagnosis of heart diseases. (author)