Abstract: A method and system for constructing from volumetric CT or MRI scan data of a patient region, a virtual two-dimensional fluoroscopic image of the patient region as seen from a selected point in space are disclosed. In practicing the method, a plurality of rays are constructed between a selected view point and each of a plurality of points in an XY array, where at least some of the rays pass through the patient target region, the points in the XY array correspond to the XY array of pixels in a display screen, and each pixel in the display screen includes multiple N-bit registers for receiving digital-scale values for each of multiple colors. For each pixel element, a sum of all M-bit density values associated with voxels along a ray extending from the selected point to the associated pixel element is calculated.

Abstract: An apparatus, method and system for tracking a medical instrument, as it is moved in an operating space to a patient target site in the space, by constructing a composite, 3-D rendition of at least a part of the operating space based on an algorithm that registers pre-operative 3-D diagnostic scans of the operating space with real-time, stereo x-ray or radiograph images of the operating space. The invention has particular utility in tracking a flexible medical instrument and/or a medical instrument that moves inside the patient's body and is not visible to the surgeon.

Abstract: A method and system for registering volumetric scan data of a patient surgical site with actual patient position are disclosed. In practicing the method, position data relating to (i) the x,y,z coordinates of a detector screen in fixed coordinate system, and the x,y, coordinates of patient features on the screen are used to determine the x,y,z coordinates of the patient features in the fixed coordinate system. These coordinates are then matched with the coordinates of the same patient features taken from pre-op scan data, e.g., CT scan data, to place the CT scan data in the fixed coordinate system.

Abstract: A method and system for obtaining desired subsurface views of a patient target site are disclosed. The system includes a scan-data file for storing, in digital form, volumetric scan data of a surgical site of a patient, a pointer for indicating the position and orientation of desired views, and a display screen for placement near the patient target region. A computational device operatively connected to the data file, pointer, and display screen functions to reconstruct a 2-D shadowgraph images of the patient region from the position and orientation of the pointer. By moving the pointer to selected positions and orientations, the user can view optimal and desired shadowgraph images of the patient in real time.

Abstract: In a 3D graphics computer system, a method and system for efficient simplification of tetrahedral meshes used in 3D volumetric representations. The 3D computer system implements a method for manipulating a volumetric model of a 3D object to simplify the volumetric model by reducing the number of primitives within the volumetric model. To implement the method, the computer system accesses a volumetric model of a 3D object. The 3D object is modeled using a large number of volumetric primitives. After accessing, the volumetric model is analyzed to identify a plurality of sets of adjacent primitives within the model for processing. For each set of identified adjacent primitives, the set of primitives is transformed within the volumetric model to facilitate the simplification of the model. The resulting transformed set of primitives are then stored. This process is carried through to completion, until the entire volumetric model has been processed.

Abstract: A method and apparatus for modeling three-dimensional solid objects are provided. The method of the present invention uses the concept of volumetric objects. Each volumetric object is a decoupled combination of volumetric geometry and volumetric appearance. To be rendered, one or more volumetric objects are tessellated into a series of one or more volumetric primitives. The volumetric primitives are then polygonized. The result is a list of two-dimensional polygons. The list of polygons is then depth sorted, colored, shaded and texture-mapped with the voxel data that forms the basis for the volumetric object. The polygons are composited together in the frame buffer, or other device, to form the final displayable image.

Abstract: A method and system for constructing from volumetric CT or MRI scan data of a patient region, a virtual two-dimensional fluoroscopic image of the patient region as seen from a selected point in space are disclosed. In practicing the method, a plurality of rays are constructed between a selected view point and each of a plurality of points in an XY array, where at least some of the rays pass through the patient target region, the points in the XY array correspond to the XY array of pixels in a display screen, and each pixel in the display screen includes multiple N-bit registers for receiving digital-scale values for each of multiple colors. For each pixel element, a sum of all M-bit density values associated with voxels along a ray extending from the selected point to the associated pixel element is calculated.

Abstract: A method and system for obtaining desired subsurface views of a patient target site are disclosed. The system includes a scan-data file for storing, in digital form, volumetric scan data of a surgical site of a patient, a pointer for indicating the position and orientation of desired views, and a display screen for placement near the patient target region. A computational device operatively connected to the data file, pointer, and display screen functions to reconstruct a 2-D shadowgraph images of the patient region from the position and orientation of the pointer. By moving the pointer to selected positions and orientations, the user can view optimal and desired shadowgraph images of the patient in real time.

Abstract: An apparatus, method and system for tracking a medical instrument, as it is moved in an operating space to a patient target site in the space, by constructing a composite, 3-D rendition of at least a part of the operating space based on an algorithm that registers preoperative 3-D diagnostic scans of the operating space with real-time, stereo x-ray or radiograph images of the operating space. The invention has particular utility in tracking a flexible medical instrument and/or a medical instrument that moves inside the patient's body and is not visible to the surgeon.

Abstract: A method and system for registering volumetric scan data of a patient surgical site with actual patient position are disclosed. In practicing the method, position data relating to (i) the x,y,z coordinates of a detector screen in fixed coordinate system, and the x,y, coordinates of patient features on the screen are used to determine the x,y,z coordinates of the patient features in the fixed coordinate system. These coordinates are then matched with the coordinates of the same patient features taken from pre-op scan data, e.g., CT scan data, to place the CT scan data in the fixed coordinate system.

Abstract: A view port comprising an oblique slice intersecting a stack of textured images is defined. A polygon associated with the view port slice is divided into multiple polygons, wherein each polygon is clipped to the surface of each intersecting texture. Each intersecting texture is then enabled, one at a time. When each texture is enabled, each polygon intersecting with the enabled texture is drawn. The colors of the vertices that fall within the active textures are maintained according to the color of the active texture, and the colors of the vertices that fall within the inactive texture are set to zero. This process is repeated until all of the intersecting textures have been enabled. This causes each polygon to be drawn exactly twice. Additive blending is enabled so that the first and second polygons are blended together. When each polygon is drawn, bi-linear interpolation techniques are used to fill-in the colors of the texels that lie in between the vertices of the polygon.