There has been quite some debate about how dangerous it is to keep these luminous disks in your collection. So I was very glad to finally get some concrete scientific advice on this.
Jon Korsmo finally provided a clear and conclusive explanation that I can share with you here. He is a certified nuclear medicine technologist and works with radiation all day as a job.
Jon isn’t really worried about the radiation of one disk or two on display, but it depends on what you do with these disks and the condition they are in.