ADVANCED COLLIMATOR APERTURE CURVE

摘要

A CT imaging system and a method for determining a CT collimator slit profile. The method includes determining a profile of two opposite edges of the collimator slit in a longitudinal direction thereof based on the following: a vertical distance between a focus of a radiation source to the collimator slit, a vertical distance between the focus and the radiation detector, an inclination angle between adjacent detector elements, a length of each detector element, a desired width of projection on the radiation detector by the radiation rays passing through the slit whose longitudinal edge profile is to be determined, and an offset angle of a connecting line from a point on a longitudinal center line of the slit to the focus relative to a plane passing said focus and perpendicular to the slit.

主权项

1. A radiation CT imaging system, comprising:
a radiation source arranged on a scan gantry and at a side of a subject to be examined, the radiation source configured to emit radiation rays to the subject; a collimator disposed between the subject and the radiation source, the collimator configured to beamform the radiation rays from the radiation source before projecting the radiation rays to the subject; and a radiation detector disposed on the scan gantry and another side of the subject, the radiation detector configured to detect the radiation rays transmitted through the subject; wherein the radiation detector comprises a plurality of detector elements arranged in a row, and there is an inclination angle between adjacent detector elements, wherein the collimator comprises a planar gating device comprising at least one slit for passage of the radiation rays, and wherein the width distribution of each of the at least one slit in the longitudinal direction of the collimator is determined jointly by the following: a vertical distance between a focus of the radiation source and the slit, a vertical distance between the focus and the radiation detector, the inclination angle between adjacent detector elements, a length of each detector element, a desired width of projection on the radiation detector formed by the radiation rays passing through the slit, and an offset angle of a connecting line from a point on a longitudinal center line of the slit to the focus relative to a plane passing the focus and perpendicular to the slit.