| 摘要 |
A universal X-ray film marker is formed by taking a fairly thin sheet of transparent plastic, for example, 1/8th inch thick, and applying a colored layer or coating to one side of it, which will be the rear side of the X-ray marker. A tapered cutting tool in the order of a milling cutter, is then employed to cut recesses from the rear of the plate through the colored coating to form letters which are visible in their correct form from the front of the marker. After the recesses are formed, finally divided lead powder is mixed with a binder which may, if desired, include other material, and the recesses are filled with the mixture. Following drying, a thin layer of plastic material is secured over the back of the unit. The resulting tapered letters which have a relatively broad base toward the rear of the marker which will be adjacent the film may be used for all X-ray applications and gives a particularly clear and sharp image when used in tomography or in other X-ray applications where the angle of incidence of the X-rays on the film changes in the course of the exposure.
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