Device for determining a radiation attenuation distribution in a plane of a body
US4374419A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 8, 1980 |
| Grant date | Feb 15, 1983 |
| Priority date | — |
| Expiry date | Jul 8, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S378/901
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
For the backprojection of the convoluted measurement signals in a cartesian coordinate system in a computer tomography device, it is necessary to recalculate the weighting factors for each position of the source in order to determine the contribution of a convoluted measurement signal to the attenuation value associated with a given element of the output image matrix. This is a time consuming and hence expensive form of reconstruction, and can be avoided by storing all the weighting factors required; this, however, implies a very large memory, and is also expensive. The invention relates to the use of a matrix of elements organised in polar coordinates, which is stored in the memory, the origin central coordinate of said matrix coinciding with the center of rotation of the X-ray source about the object section. The weighting factors are also stored in a polar organized memory. The angular component of the address of the weighting factors is incremented with a rotational increment in the corresponding position of the X-ray source, so that for each group of measurement values, the same weighting factors can be used. The invention enables all the weighting factors to be stored in a me…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.