JP2792987B

PURPOSE:To easily and accurately measure a bone by irradiating the aluminum step and image of a bone to be examined in an X-ray photographic film with light to detect transmitted light. CONSTITUTION:A bone to be examined is measured using the quantity of transmitted light obtained by applying light the X-ray photographic film 1 of a bone to be examined photographed along with a standard substance changing in its thickness. Herein, as the standard substance changing in its thickness, an aluminum step is used generally. In this measuring method, the quantity of transmitted light is measured along an x-axis from the edge detected while light with quantity L of light higher than L0 is applied to obtain the relation between the thickness of the aluminum step and the data related to the quantity of transmitted light. On the basis of the relation between the obtained data related to the quantity of transmitted light and the thickness of the aluminum step, the quantity of transmitted light is measured with respect to the image 2 of the bone to be examined in the film while the light with the quantity L of light is applied and converted to the thickness of the aluminum step to make it possible to accurately measure the bone.