Abstract: A patient is automatically accurately positioned relative to a fixed refece of a treatment/diagnostic device by an optical system which operates a patient positioning assembly to bring fiducials or skin markers on the patient into coincidence with impingement points of laser beams projected in a fixed pattern relative to the device. Cameras record images of the fiducials and laser impingement points from which alignment error and velocity error in pixel space are determined. The velocity error in pixel space is converted to a velocity error in room space by the inverse of an Image Jacobian. The Image Jacobian is initially derived using rough values for system parameters and is continuously updated and refined using the calculated errors in pixel space derived from the camera images and errors in room space derived from position encoders on the treatment/diagnostic device.

Abstract: X-ray images such as radiotherapy portal images and simulation images are matched by apparatus which digitizes the images and automatically processes the digitized signals to generate matched digitized signals which can be displayed for comparison. The digitized images are first coarse aligned using a transform generated from seed points selected interactively from the two images or through detection and identification of x-ray opaque fiducials placed on the patient. A fine alignment is then performed by first selecting intersecting regions of the two images and enhancing those regions. Secondly, an updated transform is generated using robust motion flow in these regions at successive ascending levels of resolution. The updated transform is then used to align the images which are displayed for comparison. The updated transform can also be used to control the radiotherapy equipment.

Abstract: A camera generates digital image signals representing an image of one or more natural or artificial fiducials on a patient positioned on treatment or diagnosis equipment. A processor applies multiple levels of filtering at multiple levels of resolution to repetitively determine successive fiducial positions. A warning signal is generated if movement exceeds certain limits but is still acceptable for treatment. Unacceptable displacement results in termination of the treatment beam. Tracking templates can be generated interactively from a display of the digital image signals or through automatic selection of an image having the median correlation to an initial template. A gating signal synchronized to patient breathing can be extracted from the digital image signals for controlling the radiation beam generator.