The document below is a set of Frequently Asked Questions about Civil Defense Radiation Detection Survey Meters. I used to work in radiological safety and trained a lot of people in using meters as well as the biological effects and worker safety when it comes to radiation. I can tell you that there is a lot of misinformation, confusion, and questions on in this area.
While radiation is something I respect and treat with caution, as a former haz-mat technician, and operations officer that has worked probably a thousand haz mat spills in my career at TEMA I would say that radiological incidents are probably the easiest. Get a marker, get a meter, walk till it registers a set amount, drop marker, repeat until the area is surrounded. Don’t go past the markers. Its easy… Well that is an oversimplification, but you get my point.