While I was getting radiation treatments, a number of people asked if I was still radioactive after the treatments.
No. I don't glow in the dark, either, though it would be cool if I did!
There are quite a few different methods of radiation treatment. The most common and typical treatment, which I underwent, is x-ray therapy. This involves a machine, not unlike an overgrown x-ray machine, that shoots x-rays at you. These are, of course, hundreds of times more powerful than what is used to generate an x-ray image. Similar to this is a treatment called HDR, or High-Dose Radiation. This is similar to what happens in the typical radiation therapy, excepct it is even stronger. These machines are computer controlled and can deliver a precise dosage of radiation to specific areas in three dimensions.
Another type of treatment is the implantation of radioactive seeds around the affected area. They insert little tubular reservoirs down to the affected location, then drop in the seeds...oftentimes particles of material suspended in a liquid...for a predetermined amount of time. This type of therapy allows a higher dose of radiation in a shorter amount of time. This is generally used in areas that need more localized treatments, such as prostate cancer.
X-rays are, essentially, photons...radio waves...electromagnetic radiation just like light. Think of it as a microwave oven, just much stronger, more specifically directed and of a much higher frequency. Any form of electromagnetic energy can cause problems to a body, just ask any ham radio operator that has gotten an "RF Burn"...they'll tell you right quick.
For interests sake, it is important to know that microwave ovens operate in the 2.4 GHz band. This is because water molecules oscillate at 2.4 GHz...thus causing heating. Other items in this area: cordless phones and 802.11b, g and n wireless network devices. This is one reason that the FCC has limits on the field strength of both licensed and Part 15 unlicensed transmitters in this frequency range.
Your wi-fi could be cooking you! Not really, though...the power is so low that it wouldn't really affect anything. Now the internet flowing through the wi-fi just might kill you, however.
You may have heard in the news about people being exposed to antennas or something similar and being hurt or killed. I seem to remember hearing a story a while back about a security guard that worked somewhere where there was a microwave transmitter...like a telecommunications microwave link tower or TV station link. This dingleberry found out that they could stay warm if they stood in front of the antenna. Of course, this is true, it will keep you warm...
you stay warm because it is cooking you like a morning bowl of oatmeal! They supposedly found him dead on the ground, and exploded beer cans next to the antenna. This may be an urban legend, but could happen. It is not just the frequency that can determine the safety of a generated signal, but the power of the transmitter and the distance to the antenna and type of antenna. This is why the FCC has, and enforces quite severely, rules pertaining to radiation exposure from transmitter antennas...both licensed and unlicensed.
Interestingly enough, my engineer friend McA has a complete set of 6 GHz radios from an AT&T microwave relay station that was upgraded. Now tell me he's not planning something...
With regular radiation therapy, there is no residual radioactivity. Once the beam is turned off, the radiation is completely gone, just like turning off a light switch. Other than the side effects that develop over time, no one would be the wiser that you were getting any treatment at all.
With therapy using radioactive seeds, these are highly radioactive materials and they stay radioactive. If the seed materials are not handled properly, there could be radioactive particles left to float around in the facility where the treatment happens. Of course, any radiation technician that is good will take all required and necessary precautions.
So, don't be afraid of anyone getting radiation therapy. They won't radiate you, they won't fog your film, they won't erase your credit cards, they won't mess up your TV...
Now, someone that just had a PET scan...yes, they
are radioactive for a short time after the treatment, usually about 18-24 hours. The radioactive materials are not dangerous, and are eliminated quickly through pee-pee. The radioactive materials are such a low level emitter that only really sensitive detectors would know, like the ones at a nuclear power plant or a nuclear-materials-enrichment facility. If you didn't have a "get out of jail free" card, like in my last post, they would go all
Silkwood on your ass.
There is a very slim chance, however, that they could fog camera film. I came across a website about a guy that experiments with a variety of low-emission radioactive sources to make "x-rays" using Polaroid film. One of his subjects was a person that had a cardio stress-test, and this poor guniea pig walked around with a Polaroid film cartridge strapped to him for hours. It was all in the name of science, after all. You can read more about this here:
http://www.omnimatter.com/2007/12/making-your-own.html. This is pretty cool stuff. Just be careful with anything radioactive, otherwise you may just need that stuff to give yourself some do-it-yourself cancer treatments!
Here is a tip from an amateur photographer who still loves film, and used to manage a photo lab. When traveling, use a lead lined bag to hold your film. In the US, the x-ray machines are pretty powerful, but won't really hurt any film lower than 800 speed. In foreign airports, the x-ray machines can be much, much "hotter" and can ruin film as low as 200 speed. I had a relatively expensive roll of Kodak T-Max P3200 black-and-white film completely fogged by the newer x-ray machines at the Dayton airport. Specialty films, like black-and-white and infrared-sensitive films, can be especially sensitive.
So there.