Quality of shadowgraphic x-ray images
US4773087A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 14, 1986 |
| Grant date | Sep 20, 1988 |
| Priority date | — |
| Expiry date | Apr 14, 2006 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B6/4291
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The quality of x-ray shadowgraphic images is improved by beam equalization controlled to ensure that just the right amount of radiation is used to accomplish the desired result, be it a desired image density and contrast or a desired signal-to-noise ratio or some other desired characteristic. The new techniques include: (1) maintaining a substantially constant signal-to-noise ratio throughout the image by measuring both scattered and primary radiation and using the results in a feedback loop to control the x-ray tube output, (2) raster scanning an x-ray beam along straight lines at constant velocity within a line by using a curved slit rotating aperture, (3) simultaneously controlling each of the intensity and hardness of a scanned x-ray beam as determined by post-patient x-ray measurements, and (4) using a segmented fan to scan the patient in a direction transverse to the plane of the fan and individually modulating each beam segment to achieve desired image characteristics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.