X-ray installation comprising an image intensifier/image pick-up tube system and an automatic X-ray exposure device
US4061920A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 1976 |
| Grant date | Dec 6, 1977 |
| Priority date | — |
| Expiry date | Mar 15, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05G1/64
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The invention relates to an X-ray installation which comprises a television display device and an automatic exposure device and in which dominant selection is no longer required. The television image produced during fluoroscopy is sub-divided into a large number of sub-fields, a storage position being assigned to each sub-field. In each storage position the part of the video signal is stored which corresponds to the assigned sub-field. The sub-fields are then determined which contain the regions of the maximum and the minimum brightness. An effective, organ-programmed intermediate value is derived therefrom. Moreover, the mean value of the video signal is obtained in the part of the television image assigned to the sole central measuring field of the automatic exposure device. The mean value is compared with the intermediate value, and the switch-off dose or switch-off voltage is corrected in dependence of the difference thus found.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.