US 2003/0118224 A1Published application

Method of reconstructing a 3D image data set of an examination zone

OwnerThomas Koehler, Michael Grass +1inventors

InventorsThomas Koehler, Michael Grass, Volker Rasche

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Abstract

A method of reconstructing a 3D image data set of an examination zone (13) in which a substantially periodically moving object to be examined is positioned. Segments (40, 50, 60) of the examination zone (13) are reconstructed from a measuring data set acquired by the detector unit (16), said measuring data set being acquired in segments during a number n of periodically successive time intervals Δt which are smaller than the period T and succeed one another with the period T. The rotation of the radiation source (S) about the axis of rotation (14) is controlled in such a manner that during the time intervals Δt the radiation source (S) is rotated around the axis of rotation (14) through an overall angular range which is larger than or equal to a sum of 180° and an angle β, which angle β is an angle of aperture of the conical radiation beam (4) in a plane perpendicular to the axis of rotation (14). The translation of the radiation source (S) relative to the examination zone (13), in the direction of the axis of rotation (14), is controlled in such a manner that the conical radiation beam (4) completely irradiates the segment (40, 50, 60) of the examination zone (13) at all times during the n time intervals Δt.

Claims10

Dependent claims

A method of reconstructing a 3D image data set of an examination zone (13) in which a substantially periodically moving object to be examined is positioned, which method includes the steps of:

measuring a period T of the motion of the object to be examined,
detecting a conical radiation beam (4), emitted by a radiation source (S), after its passage through an examination zone (13) which is situated between the radiation source (S) and a detector unit (16) of a scanning unit,
generating, using a drive unit (2, 5), a helical relative motion, taking place around an axis of rotation (14), between the scanning unit (1) and the object to be examined,
reconstructing a 3D image data set of a segment (40, 50, 60) of the examination zone (13) from a measuring data set acquired by the detector unit (16), which measuring data set is acquired in segments during a number n of periodically successive time intervals Δt, the time intervals Δt being smaller than the period T and succeeding one another with the period T, characterized in that the rotation of the radiation source (S) around the axis of rotation (14) is controlled in such a manner that during the n time intervals Δt the radiation source (S) overall is rotated through an angular range around the axis of rotation (14) which is larger than or equal to a sum of 180° and an angle β, the angle β representing an angle of aperture of the conical radiation beam (4) in a plane perpendicular to the axis of rotation (14), the translation of the radiation source (S), relative to the examination zone (13), in the direction of the axis of rotation (14) being controlled in such a manner that the conical radiation beam (4) completely irradiates the segment (40, 50, 60) of the examination zone (13) at all times during the n time intervals Δt.

1 more element

A device for reconstructing a 3D image data set of an examination zone (13) in which a substantially-periodically moving object to be examined is positioned, which device includes

an acquisition unit (12) for measuring a period T of the motion of the object to be examined,
a scanning unit (1) for detecting a conical radiation beam (4), after its passage through the examination zone (13), by means of a detector unit (16) and a radiation source (S), the radiation source (S) being arranged to emit a conical radiation beam (4) and the radiation source (S), the detector unit (16) and the examination zone (13) being positioned in such a manner that the conical radiation beam (4) traverses the examination zone (13) and is subsequently detected by the detector unit (14),
a drive unit (2, 5) for producing a helical relative motion, taking place around an axis of rotation (14), between the radiation source (S) and the objet to be examined,
a reconstruction unit (1) for reconstructing a 3D image data set of a segment (40, 50, 60) of the examination zone (13) from a measuring data set acquired by the detector unit (16), which measuring data set is acquired in segments during a number n of periodically successive time intervals Δt, the time intervals Δt being smaller than the period T and succeeding one another with the period T, and
a control unit (7) for controlling the drive unit (2, 5), characterized in that the control unit (7) is arranged to rotate the radiation source (S) around the axis of rotation (14) in such a manner that during the n time intervals Δt the radiation source (S) overall is rotated through an angular range around the axis of rotation (14) which is larger than or equal to a sum of 180° and an angle β, the angle β representing an angle of aperture of the conical radiation beam (4) in a plane perpendicular to the axis of rotation (14), and that the radiation source (S) is moved, relative to the examination zone (13), in the direction of the axis of rotation (14) in such a manner that the conical radiation beam (40) completely irradiates the segment (40, 50, 60) of the examination zone (13) at all times during the n time intervals Δt.

2 more elements

Dependencies are inferred from the claim text.