CORRELATING ANGIOGRAMS WITH CT MRI SCANS FOR RADIOSURGERY/

A mathematical solution is described to reconstruct 3-D objects in the stereotactic space from angiographic, not necessarily perpendicular 2 -D projections, The mathematical calculation requires 6 markers, whose coordinates should be known within the stereotactic frame reference s ystem. This method was developed to improve the planning in stereotact ic radiosurgery of AVM. An AVM nidus can be geometrically described as delineated on plane film angiography. This approach provides a more a ccurate determination of the lesion shape, size, angulation and positi on when using information from stereotactic planar angiograms. Further more this technique supports a stereotactically accurate projection o f the surface volume model of the AVM nidus on to the corresponding CT and MRI scans images.