| 摘要 |
1,240,583. X-ray exposure control. LITTON INDUSTRIES Inc. June 12, 1969 [Sept.13, 1968], No.29923/69. Heading G1A. [Also in Division G3] In a cinematographic X-ray equipment including an adjustable power supply 12 for the tube 11, and a cinematographic camera 22 for recording on film the images produced by the rays passing through a subject 17, means 29, 28 are provided for measuring the time-integral of light intensity on the film and for adjusting the power supply to bring the achievement of a desired time-integral within predetermined time limits for subsequent exposures, or for shutting off the tube when the time integral has reached a desired value. The system includes an automatic servo controlled collimator 14 in the ray path, an image producing phosphor 18a, an image intensifier with an output screen 18b, still camera apparatus 20, monitoring apparatus 21 which may be a vedicon and light cells 24, 29. The cine apparatus includes a shutter operated switch 33 which fires the tube through the bias switch 13 and the tube potential is adjusted by the density computer 30 to achieve an optimum time integral for subsequent frames at a time within limits set by maximum and minimum time limiters 31, 32. A basic brightness is set by a control 25 in response to a light cell 24 exposed to the image and the automatic arrangement compensates for changes in image intensity due to changes in X-ray attenuation arising within the patient. |
