Backprojection filtering algorithms are presented for three variable orbit fan-beam geometries. Expressions for the fanbeam projection and backprojection operators are given for a flat detector fan-beam geometry with fixed focal length, with variable focal length, and with fixed focal length and off-center focusing. Backprojection operators are derived for each geometry using transformation of ...

The design features of a 17 GHz chopper prebuncher injection system are described, and initial test results operating with a 500 kV low emittance electron gun and single section 17 GHz linac are presented. The 17 GHz traveling wave relativistic klystron that provides RF power to the linac structure, and the 500 kV electron gun that forms the low emittance (βγ ε = 3π mm-mradian) source for the i...

Treatment planning in radiosurgery and radiation therapy involves a large number of medical and technical constraints. The main technical constraints stem from the gantry kinematics and the type of collimator available. The gantry kinematics (i.e. number and spatial arrangement of movable joint axes) determines the type of motion which can be performed by the therapeutic beam. The collimator de...

Machine performance check (MPC) is an automated and integrated image-based tool for verification of beam and geometric performance of the TrueBeam linac. The aims of the study were to evaluate the performance of the MPC geometric tests relevant to beam collimation (MLC and jaws) and mechanical systems (gantry and collimator). Evaluation was performed by comparing MPC to QA tests performed routi...

Proton radiotherapy represents a potential major advance in cancer therapy. Most current proton beams are spread out to cover the tumor using passive scattering and collimation, resulting in an extra whole-body high-energy neutron dose, primarily from proton interactions with the final collimator. There is considerable uncertainty as to the carcinogenic potential of low doses of high-energy neu...

In this paper, we present a unified framework to reconstruct images for both fan beam and cone beam projections. The important feature of our theoretical framework is that it does not depend on the classical concept of the Radon transform at all. This property allows us to directly generalize the ideas and techniques developed in this paper to the cone beam reconstruction problem. In this paper...