The technical solution refers to a device for single-photon emission computed gamma tomography, 

enabling a three-dimensional view into the interior of small radioactive samples with a diameter in the order of units to tens of millimeters, 

with a resolution better than 1 mm3. 

The device is intended to display radioactivity's spatial distribution inside the samples. 

It uses radiation emitted by the sample itself, which is first narrowly collimated and then detected.