As long as I am given the opportunity to keep performing and keep exploring in whatever medium I'll be happy. As long as I get to spend time with my family I'll be happy. As long as I can write in some form I'll be happy. It is the essential things like that I equate with happiness.
The growth of technology is such that it is not possible today for a nuclear physicist to switch into medical physics without training. The field is now much more technical. More training is needed to do the job.
