METHOD AND A DEVICE FOR COMPUTER ASSISTED SURGERY

摘要

A method for computer assisted determination of values of correction parameters for positioning a medical device relative to a target structure or to a reference base. The method includes a numerical procedure that includes the steps of:
i) automatic detection of the projection of a cylindrical reference means in a medical image and determination of a minimum of four characteristic landmarks within the projection of the cylindrical reference means;ii) generating a virtual geometric representation of the cylindrical reference means;iii) determining the virtual projection points representing the characteristic landmarks using a virtual geometric representation of the cylindrical reference means; andiv) iterative determination of the position and orientation of the cylindrical reference means by matching the virtual projection points of the virtual geometric representation of the cylindrical reference means with the characteristic landmarks of the projection of the cylindrical reference means.

主权项

1: A method for computer assisted determination of values of correction parameters for positioning a medical device relative to a target structure or to a reference base comprising the steps of:
A) obtaining a medical image of a medical device which comprises a cylindrical reference means and of a target structure by means of a radiographic device, wherein the cylindrical reference means has a different density than the surrounding material of the medical device; B) determining an actual first position of the medical device with respect to a local system of coordinates fixed with the radiographic device by calculating the position of the cylindrical reference means with respect to the local system of coordinates by means of a numerical procedure using a computer and the medical image; C) calculating the actual first position of the target structure relative to the medical device by using the computer; D) retrieving a desired second position of the medical device relative to the target structure and/or retrieving a virtual geometric representation of an additional medical device using the computer; and E) calculating values of one or more correction parameters between the actual first position and the desired second position of the medical device relative to the target structure and/or values defining a desired position of the additional medical device relative to the medical device by means of the computer, wherein F) the numerical procedure essentially comprises the steps of:
i) automatic detection of the projection of the cylindrical reference means in the medical image and determination of a minimum of four characteristic landmarks within the projection of the cylindrical reference means;ii) generating a virtual geometric representation of the cylindrical reference means;iii) determining the virtual projection points representing said characteristic landmarks using the virtual geometric representation of the cylindrical reference means; andiv) iterative determination of the position and orientation of the cylindrical reference means by matching the virtual projection points of the virtual geometric representation of the cylindrical reference means with the characteristic landmarks of the projection of the cylindrical reference means.