38 results about "Portal imaging" patented technology

The invention provides methods and apparatus for detecting radiation including x-ray, gamma ray, and particle radiation for nuclear medicine, radiographic imaging, material composition analysis, high energy physics, container inspection, mine detection and astronomy. The invention provides detection systems employing one or more detector modules comprising edge-on scintillator detectors with sub-aperture resolution (SAR) capability employed, e.g., in nuclear medicine, such as radiation therapy portal imaging, nuclear remediation, mine detection, container inspection, and high energy physics and astronomy. The invention also provides edge-on imaging probe detectors for use in nuclear medicine, such as radiation therapy portal imaging, or for use in nuclear remediation, mine detection, container inspection, and high energy physics and astronomy.

A radiotherapy apparatus comprises: a source for producing a beam of ionising radiation along an axis, the beam covering a maximum aperture of the source; a collimator for collimating the beam to produce a collimated beam covering a sub-part of the maximum aperture; a patient support positioned in the path of the beam; a rotatable gantry, on which the source is mounted, for rotating the source around the patient support thereby to deliver the beam from a range of directions; an imaging device located opposite the source and with the patient support between the source and the imaging device, and mounted on the gantry via a drive member allowing translational motion of the imaging device in at least one direction perpendicular to the axis; and a control unit adapted to control the drive member to move the imaging device within the maximum aperture and maintain coincidence between the imaging device and the sub-part of the maximum aperture. Accordingly, the EPID can be moved during the treatment in order to maintain the collimated field of the radiation beam within the bounds of the EPID. This ensures that the image is valid and prevents damage to the EPID as a result of exposure of more sensitive (or less shielded) parts to the beam.

The present invention provides a practical design of a megavoltage x-ray detector with both high quantum efficiency (QE) and high resolution. The x-ray detector disclosed herein has a QE that can be an order of magnitude higher than that of current flat panel systems and yet has a spatial resolution equivalent to that of current flat panel systems used for portal imaging. The x-ray detector includes a large number of micro-structured electrically conducting plates, packed together with thin spacers placed between neighboring plates with the micro-structured plates oriented to be parallel to the incident x-rays in operation. Each plate includes an electrically conductive substrate with a first planar surface, elongate electrically conductive strip electrodes separated from each other with strip spacers placed in between and sitting on an insulating layer interposed between the first planar surface of the electrically conductive substrate and the strip electrodes. A power supply applies a bias voltage between each electrically conductive substrate and the electrically conductive strip electrodes, whereby x-rays absorbed in the conductive substrate generates high energy electrons which produce ions in an ionization medium located in spaces between the conductive substrate and the electrically conductive strips. A detector detects an electrical current generated in the electrically conductive strip electrodes and a 2D active readout matrix is coupled to the detector.

The present invention provides a device for verifying radiotherapy dose, comprising: a memory for storing instructions executable by a processor; a processor for executing the instructions to implement the following method: acquiring the measurement detected by the electronic portal imaging device An image, the measurement image characterizes the dose distribution of the radiotherapy beam on the electronic portal imaging device; uses a dose algorithm to calculate the energy fluence distribution map of the beam on the electronic portal imaging device; according to the energy fluence distribution map and The energy response curve of the electronic portal imaging device calculates a predicted image, the predicted image characterizes the dose distribution of the virtual beam on the electronic portal imaging device; and compares the predicted image with the measurement image. The invention can quickly and accurately predict the dose distribution generated by the radiotherapy plan, thereby efficiently verifying the rationality of the radiotherapy plan.

The invention discloses a positioning device for an electronic portal image system for a medical accelerator, which belongs to the technical field of radiotherapy equipment. The overturning mechanism in the device is installed on the base, and the overturning mechanism realizes the rotation around the installation axis. The overturning positioning mechanism installed on the overturning positioning mechanism mechanically limits the overturning angle of the overturning mechanism. The clearance mechanism eliminates the transmission side clearance of the turning mechanism; the linear motion mechanism is installed on the turning mechanism, the ray detection device is installed on the linear moving mechanism, and the linear positioning mechanism installed on the turning mechanism mechanically limits the linear motion of the linear moving mechanism. Position, the linear positioning anti-backlash mechanism in the linear motion mechanism eliminates the transmission backlash of the linear transmission mechanism. The invention can quickly and reliably repeatedly locate the position of the radiation detection device through the turning mechanism and the linear movement mechanism.