Three-dimensional localization and radioactivity quantification of radiation sources through inverse estimation based on Compton camera measurements.

This article focuses on a method to accurately locate multiple radioactive sources in three dimensions and quantify their radioactivity levels using an inverse estimation technique applied to images captured by a Compton camera. The method involves dividing the target region into multiple regions of interest (ROIs), acquiring 3D images of known radiation sources in each ROI, and reconstructing images of unknown sources by summing these known-source images scaled by coefficients determined through inverse estimation. Tested with multiple cesium-137 (^137Cs) sources of varying radioactivity, the approach demonstrated the ability to identify source locations and estimate radioactivity, particularly for stronger sources, while weaker sources posed challenges due to overlapping signals and measurement fluctuations. The study highlights the method's potential application in decommissioning environments like the Fukushima Daiichi Nuclear Power Station and discusses factors affecting accuracy, such as shielding and gamma-ray attenuation, suggesting further research to refine threshold settings and improve quantification of weak sources.