Like fire, radiation can be good and bad. How can it both cure cancer and cause cancer? It’s all about how much, and how controlled.
Control fire, and it can warm you on a cold night and cook your food. Uncontrolled it burns down your house. Control radiation, and it can sterilize your food, detect a cancerous tumor with a PET scan (last month’s SC) or destroy it. Uncontrolled, it can destroy you or even your city. If you could distinguish a little from a lot, as you distinguish a cozy fire from a blazing inferno, you would know when to not worry.
By “radiation” I mean particles, so tiny they are smaller than the smallest atom, zipping along at high speed: subatomic bullets. This includes photons – particles of light – wonderful on a sunny day, bad if you get sunburned. Gamma-rays are much higher energy photons.
When radioactivity was discovered 120 years ago, scientists found three different types of particle emitted from atomic nuclei. They named them after the first letters of the Greek alpha-bet: alpha-rays, beta-rays and gamma-rays. These are very different things, but all can damage living cells, and all are invisible, and cannot be felt or smelt. No wonder many people are afraid of “radiation.”
A Geiger counter gives a click when hit by an alpha or beta-particle (or ‘ray’). Carry one around with you, and it will give an occasional click, as you are continually being bombarded by natural radiation from rocks and from space. Over the millennia those particles changed our genetic code, causing mutations, spurring on evolution. Without that radiation you would not be here.
These tiny particles can zip through you harmlessly – until an unlucky molecule gets smashed up. That’s good if it was in a cancer cell, bad if it was in a healthy liver cell. These “bullets” cannot discriminate, but I would sacrifice half a liver to kill a cancer.
We used to implant radioactive sources in people, to “burn” nearby tumors without doing too much damage to the surrounding organs. Now we normally use controlled beams of gamma-rays or protons from particle accelerators. Proton therapy for cancer treatment was invented in the 1940s by Robert Wilson, Fermilab’s founding director, and now there are more than 30 proton therapy centers in the USA.
Radiation therapy can supplement or replace surgery. So bullets can be good for you, but only if they are subatomic.
