Abstract: The invention relates to a tomosynthesis process in the context of mammography, in which several individual images of a breast are taken at different projection angles and in which of information thus acquired, tomographic images are synthesized with the help of an applicable image processing software. The mutual geometry of the imaging means of the imaging apparatus when taking these individual images is determined according to the invention by arranging in the imaging apparatus a calibration structure (20), which includes balls (21) or other small objects absorbing X-radiation which are such placed that their projections will become imaged on said individual images.

Abstract: A patient movement correction method for cone-beam computed tomography wherein a set of X-ray projection images of the patient is acquired using the X-ray imaging means. An initial projection geometry estimate describing the spatial positions and orientation of the X-ray source and the X-ray detector during the acquisition of an X-ray projection images is defined. An intermediate CBCT reconstruction using the X-ray projection images and the initial projection geometry estimate is computed. Projection-image-specific corrective geometric transformations are determined for the initial projection geometry estimate and the intermediate CBCT reconstruction.

Abstract: A patient movement correction method for cone-beam computed tomography wherein a set of X-ray projection images of the patient is acquired using the X-ray imaging means. An initial projection geometry estimate describing the spatial positions and orientation of the X-ray source and the X-ray detector during the acquisition of an X-ray projection images is defined. An intermediate CBCT reconstruction using the X-ray projection images and the initial projection geometry estimate is computed. Projection-image-specific corrective geometric transformations are determined for the initial projection geometry estimate and the intermediate CBCT reconstruction.

Abstract: The invention relates to a tomosynthesis process in the context of mammography, in which several individual images of a breast are taken at different projection angles and in which of information thus acquired, tomographic images are synthesized with the help of an applicable image processing software. The mutual geometry of the imaging means of the imaging apparatus when taking these individual images is determined according to the invention by arranging in the imaging apparatus a calibration structure (20), which includes balls (21) or other small objects absorbing X-radiation which are such placed that their projections will become imaged on said individual images.

Abstract: To create a digital surface model of an intra-oral anatomy, a recess or a hole in an impression material having a predetermined shape and size is scanned. The scanning results and information on the predetermined shape and size are used for determining a threshold value representing interface between the impression material and another material. The threshold value is then used in generating the digital surface model from CT scanning data of an impression of an intra-oral anatomy on said impression material.

Abstract: The invention relates to a medical computed tomography apparatus which includes a support construction (1) supporting a substantially ring-shaped O-arm (2), which in turn supports imaging means (21, 22). The cross-section of the outer cover (3) of the O-arm in a direction perpendicular with respect to the central axis of said ring-shaped structure (2) is for its prevailing portion arranged substantially of the shape of an arch of a circle but to comprise a cut, and within the sector covered by the cut the distance from the center of said arch of a circle to the edge of the outer cover (3) is shorter than within said portion of the outer cover (3) substantially of the shape of an arch of a circle.

Abstract: A dental CT apparatus includes a control system arranged to move a radiation source and an imaging sensor on the opposite sides of an imaging station. The control system includes at least a first imaging mode designed for imaging patients and means for selecting at least one second imaging mode in which the source of radiation and the imaging sensor are driven during an exposure at an angular velocity of less than 4 degrees/second. A digital three dimensional models of teeth are generated based on imaging impressions or models of teeth by a CT apparatus provided with at least one specific imaging mode for the purpose.

Abstract: To create a digital surface model of an intra-oral anatomy, a recess or a hole in an impression material having a predetermined shape and size is scanned. The scanning results and information on the predetermined shape and size are used for determining a threshold value representing interface between the impression material and another material. The threshold value is then used in generating the digital surface model from CT scanning data of an impression of an intra-oral anatomy on said impression material.

Abstract: The invention relates to a medical computed tomography apparatus which includes a support construction (1) supporting a substantially ring-shaped O-arm (2), which in turn supports imaging means (21, 22). The cross-section of the outer cover (3) of the O-arm in a direction perpendicular with respect to the central axis of said ring-shaped structure (2) is for its prevailing portion arranged substantially of the shape of an arch of a circle but to comprise a cut, and within the sector covered by the cut the distance from the centre of said arch of a circle to the edge of the outer cover (3) is shorter than within said portion of the outer cover (3) substantially of the shape of an arch of a circle.

Abstract: A dental CT apparatus includes a control system arranged to move a radiation source and an imaging sensor on the opposite sides of an imaging station. The control system includes at least a first imaging mode designed for imaging patients and means for selecting at least one second imaging mode in which the source of radiation and the imaging sensor are driven during an exposure at an angular velocity of less than 4 degrees/second. A digital three dimensional models of teeth are generated based on imaging impressions or models of teeth by a CT apparatus provided with at least one specific imaging mode for the purpose.