A direction-sensitive gamma camera with a rotary obstruction

Among the successful gamma camera designs with angular sensitivity, most rely either on Compton imaging or a coded aperture — in any case requiring a position-sensitive sensor and involved real-time data analysis. In some use scenarios, such as tracking of a point source of radiation, design constraints can be relaxed from full gamma imaging to a mere determination of the gamma radiation direction. We describe an extremely cost-effective camera design built around a single stationary scintillation counter and a single specifically shaped rotary obstruction that nevertheless measures both the azimuthal and the elevation coordinates of the impinging radiation, and report on preliminary quantitative performance of the prototype with its design parameters tuned to real-time monitoring of a typical pulsed HDR brachytherapy session. We could also foresee its use in homeland security applications.