Putting my recently practiced skillz of keyboard to SUV mileage conversion to use, I compute that you would need to decorticate 100 brushes (it's micro curies, not milli curies). It's not that many but I suspect the difficulty is in the "metal matrix" term. I don't know what it means but it's probably there to make absolutely sure the radioactive particles don't go flying all around the dark chamber. I don't have an opinion on who did it.