Planmeca Oy

Mikko Lilja

Kustaa Nyholm

Timo Muller

Jaakko Lahelma

Juhamatti Malm

Jaakko Lähelmä

Kalle Karhu

Tarek Mohsen

Ari Hietanen

Sakari Kettunen

Timo MÜLLER

The invention relates to a calibration process specifically applicable for limited angle digital breast tomosynthesis (DBT). The method includes acquiring a set of X-ray projection exposure images, forming an initial estimate of the projection geometry corresponding to each of X-ray projection exposure images, computing an intermediate DBT reconstruction, establishing a set of rigid transformation parameters applied to an initial projection geometry estimate for each X-ray projection exposure image corresponding to calibration result, and computing a final DBT reconstruction using the set of X-ray projection exposure images and a final calibrated estimate of the projection geometry.

Self-calibration procedure for digital breast tomosynthesis imaging apparatus

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. A final CBCT reconstruction is computed using the X-ray projection images and a corrected estimate of the projection geometry corresponding to the determined corrective geometric transformations wherein the corrective geometric transformations for the initial projection geometry estimate are determined in a projection-image-specific rotating coordinate system corresponding to the spatial positions and orientations of the X-ray source and X-ray detector during the acquisition of the X-ray projection images.

Patient movement correction method for cone-beam computed tomography

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Helsinki, Finland

Mikko Lilja