There are so many parts of that article/post about radiation that are meaningless, or just completely wrong that I'm not even sure where to start. What laws of physics are being broken?? X-ray or gamma ray radiation is not contagious. If people receiving a radiation treatment are recommended not to be around children because of radioactivity - its probably due to an injection of a radioactive isotope, not because they were exposed to an external beam.
You may want to note that every single person on earth receives a daily dose of background radiation, from the air, sun, and earth, and even organically grown non irradiated food. There are naturally occurring radiative isotopes all around us all of the time.
You may also wish to note that a chest x-ray (around 20mSv) is the equivalent of approximately 2.5 days of background radiation (based on 3mSv per year). Their comparison of 200,000,000 times that of a chest x-ray (a very low exposure) is pretty much meaningless since its a completely different application anyways.