Ge Medical Systems Global Technology Company, LLC

Ge Yokogawa Medical Systems, Limited

Tetsuya Horiuchi

Makoto Gohno

Akihiko Nishide

Akira Hagiwara

Junko Sekiguchi

Masatake Nukui

Kosuke Sasaki

Naoyuki Kawachi

Makoto Gono

The present invention provides an X-ray CT apparatus capable of obtaining each tomographic image indicative of X-ray tube voltage dependent information of a subject with the optimum image quality by less reduced exposure. The X-ray CT apparatus includes device for setting a plurality of X-ray tube voltages and sets imaging conditions used in the photography using the respective X-ray tube voltages in such a manner that respective image noise of tomographic images photographed at the X-ray tube voltages become substantially identical to one another. The setting of the imaging conditions is the setting of X-ray tube currents. The X-ray tube currents are set based on geometrical characteristic amounts of the subject determined from each scout image in such a manner that the respective image noise of the tomographic images photographed at the plurality of X-ray tube voltages become substantially identical to one another.

X-ray CT apparatus

The present invention aims to obtain a tomographic image similar in image quality to a tomographic image obtained by executing a scan at X-ray tube current value set by an X-ray automatic exposure function even when the X-ray tube current value set by the X-ray automatic exposure function are not within a standard range of the X-ray tube current values settable at the X-ray tube (). X-ray tube current value supplied to the X-ray tube () are set by the X-ray automatic exposure function. Thereafter, when the X-ray tube current value set by the X-ray automatic exposure function is not within in the standard range of the X-ray tube current value settable at the X-ray tube, the X-ray tube current value at a portion not within the standard range are changed so as to be within the standard range, and the set value of helical pitch is changed so as to correspond to the ratio between the pre-changed x-ray tube current value and the post-changed X-ray tube current value.

An X-ray CT image reconstruction method includes turning a fan-shaped X-ray beam, which is thick and irradiated to a subject, about the subject, detecting projection data items concerning an X-ray beam, which is transmitted by the subject, with the X-ray beam turned by a plurality of successive angles of rotation, enhancing fan-beam data, which includes projection data items detected with the X-ray beam turned by the angles of rotation, so as to sharpen projection data contained in the fan-beam data and acquired along each projection line, producing parallel-beam data, which has values thereof defined along parallel projection lines, in relation to each angle of projection using the enhanced fan-beam data, and reconstructing an image using the parallel-beam data.

X-ray CT image reconstruction method and X-ray CT system

To enable radiation rays to be efficiently used. A scout scan parameter setting unit sets a rotation movement position to which an X-ray tube and an X-ray detector are moved so as to rotate around a subject on the basis of subject information of a subject on which a scout scan is performed at the time of performing a scout scan. At the time of starting execution of the scout scan, a rotating unit moves the X-ray tube and the X-ray detector so as to rotate around the subject to the rotation movement position which is set by the scout scan parameter setting unit. After that, a scout scan is performed in the rotation movement position.

Radiographic apparatus and method of using the same

The quality of an image can be improved and radiation can effectively be utilized. In an imaging area of a subject where a main scan is performed, a specific scan area setting unit sets a specific scan area where a scan is performed under a specific scan condition allowing radiation exposure dose on the subject to be low. Then, the scan condition setting unit sets a main scan condition so that the specific scan area is scanned under the specific scan condition allowing the radiation exposure dose on the subject to be low.

Radiation tomography apparatus and scan condition setting device

A method for reconstructing an image that can be recognized stably during CAD. The method for reconstructing an image on the basis of a plurality of views of projection data items provided by X-rays having passed through a subject includes image reconstruction dedicated to a computer-aided detection (CAD) mode. The image reconstruction comprises a reconstruction function dedicated to the CAD mode, includes pre-processing that includes a noise removal filter for removing a noise from projection data, such as, a streaky artifact removal dedicated to the CAD mode, and also includes post-processing that includes a noise removal filter dedicated to the CAD mode.

Image reconstruction method and X-ray CT system

An object of the present invention is to acquire transmitted X-ray data by irradiating X-rays of appropriate doses determined for the portions of a section containing the major axis and the portions thereof containing the minor axis respectively. An X-ray irradiating/detecting device consists mainly of an X-ray irradiator that includes an X-ray tube and irradiates a fan-shaped X-ray beam, and an X-ray detector that has a plurality of X-ray detecting elements arrayed in a direction in which the fan-shaped X-ray beam spreads and that is opposed to the X-ray irradiator with an object of imaging between them. The X-ray irradiating/detecting device is rotated about the object in order to acquire transmission X-ray data stemming from a plurality of views. At this time, the dose of the X-ray beam is differentiated between predetermined angular ranges of a section of the object shaped like an oval, which extend with the minor axis of the oval section as a centerline, and the other angular ranges.

Transmitted X-ray data acquisition system and X-ray computed tomography system

For the purpose of displaying a more accurate exposure dose value without imposing additional work on an imaging operator, an exposure dose calculating method in an X-ray CT apparatus comprises the steps of: inputting the age and a region to be examined of a subject; calculating the head or chest diameter of the subject based on the age and region to be examined of the subject input at the inputting step, and on statistics on the head or chest circumference of a human body; calculating an exposure dose of a phantom having a diameter equivalent to the calculated diameter of the head or chest, based on prior information on an exposure dose to a phantom having a predetermined diameter when a predetermined X-ray dose is applied to the phantom; and displaying the exposure dose value.

X-ray CT Apparatus and exposure dose calculating method

For the purpose of reducing exposure of a subject to unnecessary radiation by controlling the tube current according to the X-ray emitting direction with respect to a region to be examined in the subject, a transmission area S is calculated from a cross-sectional plane (S ) and an ellipticity R is calculated for the cross-sectional plane (S , S ). An image SD of a region having the transmission area S is then calculated (S ), and a SD ratio of a region having the ellipticity R is calculated (S ). An image SD of a region having the transmission area S and ellipticity R is then calculated using the image SD and the SD ratio (S ). Next, a target SD is specified (S ), and the tube current that controls X-rays emitted in the major-axis direction in the cross-sectional plane of the subject is calculated using the image SD obtained at S and the target SD (S ), and the tube current that controls X-rays emitted in the minor-axis direction in the cross-sectional plane of the subject is calculated using the obtained tube current and R (S ).

X-ray CT system, gantry apparatus and operation console

In order to obtain an image with artifacts suppressed when a helical scan is conducted employing a multi-row detector with a scan plane tilted, preprocessing such as sensitivity correction is applied to data collected by a helical scan employing a multi-row detector with a scan plane tilted (S ), tilt correcting processing is applied for correcting view-to-view variation of the positions of channels in the detector rows relative to an axis of translation due to the tilt of the scan plane (S ), multi-slice/helical interpolation processing is applied for calculating interpolated data from proximate data in an image reconstruction plane (S ), and backprojection processing is applied to the interpolated data to produce an image (S ).

Image producing method and X-ray CT apparatus

In order to obtain an X-ray tomographic image with high quality while minimizing the exposed dose to a subject by employing the most suitable filter according to the region of the subject to be scanned, a filter unit having filters having different transmission properties are provided below an X-ray tube in a gantry apparatus. To obtain an X-ray tomographic image, upon determining the scan region of the subject, a motor is driven to position one of the filters corresponding to the scan region just below the X-ray tube for employing the filter, and X-rays are applied to the subject through the filter.

X-ray CT system, gantry apparatus, console terminal, method of controlling them, and storage medium

In order to provide a projection data correction method and apparatus that prevents artifact generation in the direction which provides a low count of penetrating radiation, and a radiation tomographic imaging method employing such a projection data correction method and a radiation tomographic imaging apparatus comprising the projection data correction apparatus, projection data Proj_ij is individually corrected by a weighted addition ( ) with an average value ( ) containing the proximate data. The weight SGij of the projection data is decreased as the count of the penetrating radiation from which the projection data is derived becomes smaller.

Projection data correction method and apparatus, and radiation tomographic imaging method and apparatus

For the purpose of reconstructing a plurality of X-ray tomographic images having a plurality of practical slice thicknesses while reducing the number of X-ray detector arrays and simplifying configuration, X-rays generated by an X-ray tube are emitted via a slit of a collimator toward a detector disposed opposite to the X-ray tube the length (width) of the collimator 's slit in the D direction and the position of the collimator in the D direction are adjustable; the detector is comprised of four X-ray detector arrays; and the widths of the two outer X-ray detector arrays in the D direction are larger than the widths of the two center X-ray detector arrays.

Multi-slice X-ray CT apparatus and method of controlling the same

For the purpose of determining a radiation dose without excess or insufficiency with respect to an allowed value of image noise in performing a helical scan by a CT apparatus comprising a multi-detector, a method comprises the steps of: selecting an image thickness of an X-ray tomographic image to be produced by a helical scan by an X-ray CT apparatus comprising a multi-detector (Step ST1); provisionally determining an X-ray dose in obtaining the X-ray tomographic image having the image thickness by single-slice CT using a single-slice CT radiation dose determining algorithm (Step ST2); selecting a scan protocol (Step ST3); reading a dose correction factor from a dose correction factor table that matches the selected image thickness (Step ST4); correcting the X-ray dose by the dose correction factor (Step ST5); determining tomographic imaging scan conditions by specifying at least one of the tube current and the emission time (Step ST6); and performing the helical scan and displaying an X-ray tomographic image (Step ST7). Consequently, a disadvantage that a subject is exposed more than necessary can be prevented.

Tomographic imaging scan condition determining method, tomographic imaging method and X-ray CT apparatus

In order to provide a projection data correction method and apparatus that prevents artifact generation in the direction which provides a low count of penetrating radiation, and a radiation tomographic imaging method employing such a projection data correction method and a radiation tomographic imaging apparatus comprising the projection data correction apparatus, projection data Proj is individually corrected by a weighted addition ( ) with an average value ( ) containing the proximate data. The weight SG of the projection data is decreased as the count of the penetrating radiation from which the projection data is derived becomes smaller.

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Tokyo, Japan

Tetsuya Horiuchi