| 摘要 |
<p>This invention relates to a filter for x-ray examining devices. An x-ray examining apparatus comprises a source of an ionizing and penetrative radiation (e.g. an x-ray tube), an object plane wherein the patient is positioned, and an image plane on the opposite side of the object plane relative to the radiation source. The image recording medium is disposed in the image plane. When exposing chest x-rays, if the source of radiation is kept at a level that will provide a proper viewing density to the lungs, the level of radiation will not be sufficient to provide acceptable exposure of parts of the body that are composed of dense tissue, e.g., the spine and the heart. The filter of this invention comprises a sheet of radiation absorbing material having an opening therein, said opening corresponding to the spine and central portion of the heart. Accordingly the upper portion of the filter exhibits a relatively narrow opening which becomes gradually wider toward the lower portion of the filter. This filter will permit an acceptable density level of x-ray exposure for the lungs while allowing a higher level of x-ray exposure for the mediastinum areas of the body.</p> |
