Abstract: A portable survey meter for measuring radiation, the portable survey meter comprising: a radiation detector configured to perform measurements of radiation; a range sensor configured to measure range data of distances from the portable survey meter to real world structures in at least two dimensions; and a processing unit configured to align the measured range data with reference range data so as to determine an instantaneous position of the portable survey meter in at least two dimensions relative to the real world structures as a fixed frame of reference, whereby each measurement is performed at a known position.

Abstract: A radiation imaging apparatus comprising: a radiation detector; a field modulator that modulates the radiation that reaches the detector and is defined by a transmission function; a scanner system for changing the pose of at least the field modulator; and an image reconstruction section that receives a radiation reading from the radiation detector for each of a plurality of angular orientations of the field modulator, and is configured to process the received readings to derive an image representing the amount of radiation originating from each point in an image domain, wherein the transmission function of the field modulator comprises a low transmission region that attenuates radiation incident toward the detector from angular directions defined by that low transmission region, and a high transmission region that transmits to the detector radiation that is incident toward the detector from angular directions defined by that high transmission region, wherein said regions are arranged such that: for each incid

Abstract: A method of determining the distribution of radioactive material within a region is described. A plurality of radiological measurements and associated geometrical measurements taken at a plurality of positions in said region are input to a computer system. A 3D model of structures within said region is defined and the position within the model of each radiation measurement is obtained by using the geometrical measurements. The radiological measurements are then ascribed to a distribution of sources restricted to defined locations in the 3D model. The source distribution is parameterized over the defined source locations, and each parameter is related to the calculated observable radiation field, calculated using a physical model, at each measurement position. The parameters are adjusted to optimize the correspondence between the actual radiological measurements and the calculated observable radiation field, to yield the distribution of radioactive material as defined by the adjusted parameters.