Patent ID: 9693751
Date: 2017-07-04
CPC Classifications: A61B,A61N,G01T

Claim:
1. A method for calibrating a positron emission tomography detector of a radiation therapy device, the method comprising: applying, using a radiotherapy device, at least one defined radiation dose in a living sample body to induce a defined activity in the living sample body, the at least one defined radiation dose being applied by irradiating the living sample body with a treatment radiation beam of the radiotherapy device; where the positron emission tomography detector comprises at least one bin; measuring the activity generated by the at least one defined radiation dose in the at least one bin; taking projection data of the measured activity; calculating crystal efficiency from the projection data; re-estimating the measured activity of each bin based on the calculated crystal efficiency; and calibrating the bin based on the re-estimated measured activity, where the taking projection data of the measured activity and calculating crystal efficiency from the projection data comprises maximizing the Equations: where ε is the crystal efficiency, g is the geometrical component of the normalization array, f is the activity image, a represents the attenuation, y represents the measured prompts, S represents the scatter estimation, r represents the smoothed randoms, C represents the system matrix, g represents the geometrical part of normalization, L represents the line of response, Equation (2) represents rebinning of a line or responses connecting two crystals i and i′ into the projection bin of index j, whereω is the line of response contribution factor and where for the Equation (2), where Equation (2) represents the mashing and rebinning of the line of responses connecting two crystals i and i′ into the projection bin of index j; where for the Equation (2):