Abstract: Disclosed herein is a method of characterising physical properties of an attenuating element in a radiotherapy device having a radiotherapy radiation source and a radiotherapy radiation detector on respective sides of the attenuating element. The method comprises obtaining an average detected radiotherapy radiation intensity at two or more locations around the attenuating element, comparing the detected intensity at one location with the average intensity, and characterising a corresponding physical property based on the comparison.

Abstract: Systems and methods for generating a radiotherapy treatment plan using information about gantry angle-indexed dose (GAID) variation are discussed. An exemplary system can include an interface to receive a beam model for use in the radiation machine, and a processor that can determine, for the radiation machine, a GAID variation represented by a plurality of radiation doses at different gantry angles. The processor can determine a radiation treatment plan for the patient using the beam model and the GAID variation.

Abstract: A method for measurement of dose distribution in a radiotherapy apparatus includes providing a detector holder situated at least partially within a tank, the detector holder comprising a radio-opaque marker and a visual reference point, the marker and the reference point being separated and in a fixed spatial relationship to each other; locating the tank within a bore of the radiotherapy apparatus; rotating a gantry and monitoring the position of the detector holder with an imaging apparatus; vertically displacing the detector holder until the reference point is positioned at a desired level, and adding liquid to or removing liquid from the tank until the surface of the liquid is level with the reference point. Features of the detector holder and tank are also described.

Abstract: A method for measurement of dose distribution in a radiotherapy apparatus includes providing a detector holder situated at least partially within a tank, the detector holder comprising a radio-opaque marker and a visual reference point, the marker and the reference point being separated and in a fixed spatial relationship to each other; locating the tank within a bore of the radiotherapy apparatus; rotating a gantry and monitoring the position of the detector holder with an imaging apparatus; vertically displacing the detector holder until the reference point is positioned at a desired level, and adding liquid to or removing liquid from the tank until the surface of the liquid is level with the reference point. Features of the detector holder and tank are also described.