If you are interested in this topic and happen to be involved in the medical part of disaster response, I highly recommend taking the Advanced Radiology Life Support Course. It's usually quite expensive as a freestanding course, but sometimes you can catch one offered as a conference pre-course at much lower cost, and the training is focused and excellent.

Also, if you are any sort of medical, LEO, Fire/rescue or other emergency responder, you are probably eligible to attend the National Center for Domestic Preparedness. They offer several different radiological/CBRNE related courses, and all expenses are always free of charge, including housing and meals. https://cdp.dhs.gov/