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Unfolding patient motion with biplane radiographs
Author(s) -
Li Shidong,
Pelizzari Charles A.,
Chen George T. Y.
Publication year - 1994
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597188
Subject(s) - biplane , imaging phantom , translation (biology) , radiography , point (geometry) , computer vision , artificial intelligence , coordinate system , point of interest , computer science , motion (physics) , mathematics , geometry , physics , optics , medicine , radiology , biochemistry , chemistry , messenger rna , engineering , gene , aerospace engineering
A method of unfolding patient movement between biplane radiographs is presented. This method requires biplane projections of two points with a known separation to determine a translation motion or biplane projections of two or three point pairs to determine a general patient motion. Such a point pair can be provided by two ends of a line source or two radiopaque marks, with a fixed distance between them. The point pairs can be taped on skin, implanted in the target volume, or embedded in the bony structures. After obtaining the point locations on each film, the three‐dimensional coordinates of points of interest at the instant of each view can be reconstructed, with an error of less than 0.5 mm. The motion parameters, characterized by a pseudotranslation vector and three axial rotational angles for the region of interest relative to the machine coordinate system, are also provided. In comparing with some other reconstruction algorithms, the point pair method can significantly improve source localization or point reconstruction in the presence of patient motion. Computer simulations and phantom experiments demonstrates the feasibility and accuracy of the method.