The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 28, 1982
Filed:
Jan. 02, 1980
Isao Horiba, Nagoya, JP;
Shigenobu Yanaka, Kashiwa, JP;
Yasuo Kuwabara, Kashiwa, JP;
Kouichi Koike, Kashiwa, JP;
Hitachi Medical Corporation, Tokyo, JP;
Abstract
In the X-ray CT system, the X-ray detectors vary in output characteristics such as linearity, directivity and radiation quality from one detector to another. To make compensations for such irregularities, a plurality of phantoms of different absorption is prepared in the CT system according to the present invention. Namely, this plurality of phantoms is set one by one in the measuring space in the same manner as in the examination of an examinee or subject to be examined; the coefficient of X-ray absorption is determined for each of these phantoms. Further, theoretical values of absorption for each phantom are compared to the actual absorption measurements on each phantom to provide an absorption error value for each detector at differing absorption levels. The actual subject absorption value for each detector is used to pick the two error values closest to the actual value. The two error values are interpolated or extrapolated to find an error value for correcting the actual absorption value. The above method steps are advantageously implemented by one or more digital computers. The corrected subject absorption values are provided to a conventional image reconstruction device to provide the desired X-ray video image.