Forming X=ray film of malignant tissue - by overexposing and copying with reduced illumination onto high-contrast emulsion

摘要

A comparatively over-exposed radiograph of the tissue is made and this is then copied by contact using illumination several times less than that which normally would be required, e.g. one-tenth of the normall illumination. The radiograph is pref. copied onto a photographic emulsion which provides high contrast, on a transparent support. During copying a light-attenuating filter may be inserted between the X-ray photograph and the emulion. When the contrast is increased gradually in clarity, the malignant tissue can be depicted standing out with clarity from the healthy tissue. By successively increasing the illumination time or intensity of light used, the malignant tissue can be brough out in all its parts until finally the healthy tissue is revealed.