Development of coded-aperture imaging with a compact gamma camera

In the 1990s, CEA has developed a very compact operational gamma camera, CARTOGAM, capable of mapping the surrounding radioactivity and representing it superimposed onto a visible-light image. Since then, the camera has been successfully industrialized and commercialized. In the same time, the Kurchatov Institute has developed a coded-aperture gamma camera. Both teams have joined their efforts to develop a compact coded-aperture gamma camera. This paper presents the first results obtained with a coded mask adapted to the existing CARTOGAM camera. Simulations have been carried out to design small-sized coded masks for high-energy gamma imaging (¹³⁷Cs or ⁶⁰Co). Innovative tungsten-alloy masks have been achieved that lead to the following results: a significant increase in the sensitivity (up to 10 times), an improved angular resolution (2° to 3°) and a large field of view (about 30°). The laboratory results of ¹³⁷Cs and ⁶⁰Co imaging, including shadowgrams and reconstructed images for point sources, are presented.