| 摘要 |
An adjustable diaphragm arrangement, or device, for defining an aperture which confines a beam of radiation, especially for radiation therapy, in which cup shaped diaphragm elements, the edges of which define the edge of the aperture and which elements are concave toward a common point at or near the source of radiation, are tiltably mounted for simultaneous movement to control the size of the aperture, and may, in addition, be rotatable to vary the orientation of the aperture, all of the aforesaid movements being carried out without change in the axis of the beam of radiation. The parts of the device may be formed of a material which strongly absorbs radiation.
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