This is an extremely interesting mug.
It features the same artwork on its front and rear surface consisting of an image of a boxing glove striking a radiation symbol that has a frightened looking face formed within it.
On the boxing glove is printed "ALARA." I believe this is an acronym for "As Low As Reasonably Achievable" which is the principle adhered to by those that are exposed to radiation on a regular basis.
When all the clues are considered in my opinion this is a mug that shows radiation being knocked out and hence the ALARA designation.