METHOD AND APPARATUS FOR ADAPTIVE X-RAY EQUALIZATION
The present invention pertains to an apparatus and method for adaptive exposure in imaging systems. An x-ray source for producing x-ray radiation and an x-ray detector for measuring amount of x-ray radiation passing through the human patient and striking the detector can be used. A tomographic image of the human patient or a tomosynthetic image of the human patient can be generated. Region of interest filtering and equalization filtering can be utilized. Filtering can be accomplished with a mechanical shield or shutter or with electronic control of the x-ray source.
1 . An x-ray imaging system for imaging a human patient comprising:
an x-ray source for producing x-ray radiation;
an x-ray detector for measuring amount of said x-ray radiation passing through said human patient and striking said detector; and
a dwell controller coupled to said x-ray source configured to control total dwell time of said x-radiation for a focal spot.
2 . The x-ray imaging system of claim 1 wherein said dwell controller adjusts a number of non-zero duration dwells.
3 . The x-ray imaging system of claim 1 wherein said dwell controller adjusts a number of repetitions of fixed-length exposures.
4 . The x-ray imaging system of claim 1 wherein said dwell controller adjusts a dwell exposure time of each exposure.
5 . The x-ray imaging system of claim 1 further comprising:
an x-ray tube controller configured to adjust a tube voltage of said x-ray source.
6 . The x-ray imaging system of claim 1 further comprising:
an x-ray tube controller configured to adjust a beam current of said x-ray source.
7 . The x-ray imaging system of claim 1 further comprising:
a dwell change limiter configured to limit changes in number of dwells between subsequent focal spots.
8 . The x-ray imaging system of claim 1 further comprising:
an image equalization filter configured to utilize a preliminary image reconstruction during a subset of said total dwell time for said focal spot.
9 . The x-ray imaging system of claim 1 further comprising:
a dynamic range limiter configured to compress dynamic range of said x-ray radiation striking said detector.
10 . A method for producing an x-ray image of a human patient comprising:
producing a beam of x-ray radiation from an x-ray source;
controlling total dwell time of said beam of x-ray radiation for a focal spot of said x-ray source;
measuring amount of said x-ray radiation passing through said human patient and striking a detector.
11 . The method of claim 10 further comprising:
performing image equalization from a preliminary interim reconstruction during a subset of said total dwell time for said focal spot.
12 . The method of claim 10 further comprising:
limiting change in number of dwells between a plurality of subsequent focal spots.
13 . The method of claim 10 further comprising:
performing image equalization from a previously acquired image frame.
14 . The method of claim 10 further comprising:
adjusting number of non-zero duration dwells.
15 . The method of claim 10 further comprising:
modifying an x-ray photon threshold to reduce change in a number of dwells between a plurality of subsequent focal spots.
16 . The method of claim 10 further comprising:
adjusting a tube voltage of said x-ray source.
17 . The method of claim 10 further comprising:
adjusting a beam current of said x-ray source.
18 . The method of claim 10 further comprising:
adjusting a dwell exposure time of each exposure.
19 . The method of claim 10 further comprising:
compressing dynamic range by limiting x-ray exposure in a partial image.
20 . The method of claim 10 further comprising:
limiting exposure in a partial image to a desired exposure threshold.