Re: Invited here first!
With the exception of the neutron detector, symetrica's technology is nothing new, though refined with respect to previous implementations.
There are a couple of potential advantages to the IR laser based detection. The first is a much larger detector volume, since sensitivity is related to how many of the particles or photons interact with the detector - that's why neutrino detectors are HUGE. The flip side is that the detector can affectively b placed close to the source, getting around the inverse square law. The second is getting much quicker localization of the source.
One item not discussed in the article was spectral response, identifying a specific radionuclide may require energy resolution of better than 1%, and the method of operation suggests a very broad peak for a given energy (e.g. Tc99m at 140keV).