X-ray Imaging System (XIS) - The X-ray Imaging System controls the x-ray generation, image processing and patient registration of the McLaren Proton Treatment System. The software product described by this document is considered a sub-system of the MPTS.The software product integrates with the following components of the MPTS system:• X-ray generator & tube assembly• Amorphous silicon flat-panel detector• Electro-mechanical controls of the imaging c-ring to enable system positioning and rotation around the patientThe software will permit a radiation technician to set the desired energy levels and field of view. Once set the software can acquire orthogonal or CBCT x-ray images of the region of interest. When images are acquired the software will process them to create viewable images for patient location registration. The patient location registration workflow will locate the treatment isocenter, defined in the patient anatomy, relative to the desired position in the treatment room through which the beam passes. The location of the treatment isocenter is established during treatment planning with 3D planning images (CT simulation images). The patient’s position will be adjusted, if needed, based on a comparison of the current patient location, the defined treatment plan, and previously acquired Digitally Reconstructed Radiographs or CTs.There are two defined methods of registration,1. Digitally Reconstructed Radiographs (DRRs) from 3D planning images are compared to the 2D images taken during patient setup in order to compare the patient anatomy with the expected location and orientation given by the DRRs. The registration tool is implemented to display both the downloaded DRRs, provided by the treatment planning system, and the display of the new 2D images, acquired by x-ray imaging system.2. 3D planned volume images are compared to the CBCT volumetric (CTs) images taken during patient setup in order to compare the patient anatomy with the expected location and orientation. The regisEhmetDx LLC2025-03-21