Patent ID: 7763858

Claim:
A method of measuring emissions from a single package containing radioactive material in a matrix, the method comprising: (i) providing a detector for the emissions; (ii) providing the matrix, at least in part, within the field of view of the detector, the matrix having an axis of rotation, the matrix extending in a first direction and the matrix extending in a second direction, the first direction and the second direction being perpendicular to one another and to the axis of rotation, the matrix in the first direction and in the second direction being entirely within the field of view of the detector; (iii) measuring the emissions at a first orientation of the matrix about the axis of rotation, the emissions and orientation forming a first data set; (iv) measuring the emissions at one or more further orientations of the matrix about the axis of rotation, the emissions and orientation at the one or more further orientations forming one or more further data sets; (v) comparing the emissions detected in the first data set with the emissions detected in one or more of the one or more further data sets to calculate a variation in emissions detected between data sets, wherein a) the variation is the difference between a highest level of emissions detected and a lowest level of emissions detected, or b) the variation is a shape of a plot of a count or count rate of emissions with rotation, and wherein the radioactive material has a radial position in the matrix and information on the radial position of the radioactive material within the matrix of the single package relative to the axis of rotation being is derived from the variation in the emissions detected between data sets; and (vi) repeating steps (ii), (iii), (iv), and (v) for one or more different parts of the matrix by moving the detector and/or single package longitudinally relative to the axis of rotation, thereby providing information on a longitudinal position of the radioactive material within the single package.