A physician who performs an operation on the body of a patient, generally employs a real-time imaging system, in order to view the location and orientation of the medical intervention device (e.g., catheter, needle), within the body of the patient during the operation. Such real-time imaging systems are known in the art. These systems generally enable a display to display a representation of the medical intervention device superimposed on an image of the body of the patient.
U.S. Pat. No. 6,351,513 issued to Bani-Hashemi et al., and entitled “Fluoroscopy Based 3-D Neural Navigation Based on Co-Registration of Other Modalities with 3-D Angiography Reconstruction Data”, is directed to a method for displaying a real-time 3-D reconstruction of a catheter within a 3-D angiography reconstruction of a vessel. The method includes the procedures of acquiring a 3-D angiography image of the arterial tree by a computed tomography device and registering the 3-D angiography image with a 2-D fluoroscopic image of a vessel, according to the structural similarities (i.e., anatomical landmarks).
The method further includes the procedures of determining the projecting lines of the catheter by using an X-ray apparatus, determining the location of the catheter, by intersecting the 3-D angiography image with the projecting lines and displaying a 3-D visualization of the 3-D reconstruction of the catheter within the 3-D angiography reconstruction of the vessel. The 3-D visualization of the catheter is updated as the catheter is moved.
U.S. Pat. No. 6,314,310 issued to Ben-Haim et al., and entitled “X-Ray Guided Surgical Location System with Extended Mapping Volume”, is directed to a system for inserting a needle into a selected location of the vertebrae of a patient. The system includes a reference element, a plurality of magnetic field generator coils, a driver circuitry, a computer, a user interface control, a display, a fluoroscope and a computer tomography (CT) device. The reference element is in form of a plastic disc transparent to visible light and X-rays, which includes three equally spaced metal fiducial marks at the periphery thereof, a first position and orientation sensing device at the center thereof and another fiducial mark adjacent the first position and orientation sensing device. The needle includes a second position and orientation sensing device.
The magnetic field generator coils are placed on or adjacent to a bed on which the patient lies. The fluoroscope irradiates the patient from one side of the body of the patient. The computer controls multiple aspects of the system. The first position and orientation device and the second position and orientation device sends signals to the computer, respective of the time-varying magnetic fields generated by the magnetic field generator coils. The computer analyzes the signals to determine the six-dimensional position and orientation coordinates of the first position and orientation device and the second position and orientation device, relative to a common frame of reference defined by the magnetic field generator coils. The computer enables the display to display an image of the vertebrae, a representation of the first position and orientation device and the second position and orientation device and a representation of the needle and the fiducial marks. The location and the angular orientation of the reference element are determined by determining the two-dimensional coordinates of the representation of the fiducial marks. A scaling factor is determined for the images displayed on the display, by comparing the determined coordinates with the known positions of the fiducial marks.
While acquiring CT images of the body of the patient, the reference element is fixed to the body and remains fixed to the body in this position during the surgery. The CT images are registered with the X-ray images, by comparing the image-derived coordinates of the fiducial marks of the reference element, which appear in the CT images, with the image-derived coordinates of the fiducial marks in the X-ray images. The fiducial marks of the reference element and the fiducial marks in the X-ray images are visible marks. The three-dimensional CT images are rotated or scaled, in order to align the CT images with the X-ray images and the CT images are projected onto the plane of the X-ray images and superimposed on the X-ray images or displayed alongside the X-ray images.
U.S. Pat. No. 6,421,551 issued to Kuth et al., and entitled “Method for Registering Images of a Subject with a Magnetic Resonance System and Magnetic Resonance System for the Implementation of the Method”, is directed to a system for readjusting the tomogram plane of an image of the body of a patient. The system includes a control console, a magnetic resonance system, a stereoscopic camera and a marking element. The control console includes a control unit, an image data generator and processor, a coordinate transformation unit, a readjustment unit and a tomogram selecting unit. The magnetic resonance system includes two pole shoes which are located opposite one another.
The control console is connected to the magnetic resonance system and to the stereoscopic camera. The marking element is composed of three reflective balls and is arranged at the patient in the region of the knee joint, in a first coordinate system. The stereoscopic camera acquires an image of the reflective balls and sends the respective position data to the control console. The coordinate transformation unit transforms the position data from the first coordinate system to a second coordinate system of the magnetic resonance system. When the relative movement of the patient is known, the readjustment unit readjusts the previously defined tomogram plane, such that it again lies relative to the marking element with respect to the knee joint, as it did in the preceding joint position.
One way to destroy tumors in a patient, and to prevent metastasis, is by subjecting the target tissue to radiation therapy. One type of radiation therapy is known as linear acceleration, whereby a beam of x-rays or electrons is directed at the target tissue from different directions. Each time the linear accelerator directs a beam towards the target tissue it also irradiates healthy tissue which surrounds the target tissue, along the path of the irradiation beam. Accordingly, such surrounding tissue is irradiated significantly less than the target tissue.
The linear accelerator is programmed to irradiate a specific volume which is generally similar to the shape of the target tissue. Accordingly, the portion of the body including the target tissue, has to be placed such that the target tissue is located within that specific volume. A conventional linear acceleration treatment includes a plurality of recurring procedures, usually over a period of several days or weeks. Each time, the portion of the body including the target tissue, has to be placed exactly as it was placed in the first treatment.
For this purpose, during the first radiation session, after locating the portion of the body which contains the target tissue at a location appropriate for irradiation, a plurality of non-hazardous laser beams, for example four beams, are directed from fixed locations, toward that portion of the body. These four points are marked by a permanent marker, such as a waterproof marker, on the skin of the patient. At every subsequent session, that portion of the body is re-positioned to the position and orientation determined at the first session, by directing the same four laser beams toward the same portion of the body and repositioning that portion, until the four permanent marks line up with the four laser beams.