@rkklinger last week I also returned from a Canadian fishing trip and set off the radiation detectors at the US border. It was one month after my 4th treatment and the drive through gate, large and small hand held detectors all registered high levels. One of the dectectors said the radiation source was plutonium which got them pretty excited. Fortunately, I had a letter from Mayo describing my treatment. The agents still had to fax the letter and radiation readings back to DC to get approval for me to return. It took 45 minutes.