Back at It

If any of you have ever had cancer, then you probably have experienced a PET scan. I think that I have covered the science of the PET scan in a previous post, but it would have been a long time ago so it doesn't hurt to have a quick review. PET is short for Positron Emission Tomography--yeah, say that 10 times fast. Basically, it's a test for the presence or absence of cancer. That is it's sole purpose.

To understand the theory behind it, you must first know that cancerous cells and tumors consume energy at a faster rate than the rest of your body (normal tissue). This energy comes in the form of sugar. The fluid for a PET scan is a molecularly-modified concoction of sugar with a radioactive tracer chemically attached to it. In preparation for a PET scan, you get hooked up to an IV and they pump some fluids into your system. Then, they bring out a stainless steel cancer that looks as if it came from a cheesy, futuristic, science fiction film. This canister contains the sugar concoction necessary for the scan. They hook the canister up to your IV and slowly inject the fluid into your body.

In all honesty, I think that this is the worst part. Imagine for a moment that someone gives you a shot and that the shot they give you consists of nothing but ice water. Essentially, that's the feeling you have when they inject this fluid into you because it is kept cold. A refrigerated liquid is being pushed through your blood vessels and it gives you a very specific, very cold feeling until it warms up to your body temperature.

So after the radioactive tracer/sugar solution is fully injected into your body, then you sit around for about an hour while it makes its way through your body. Now here is where the knowledge of the sugar-consuming habits of cancerous cells come into play. The more active the cancerous cells and tumors are, then the more they consume the sugar that they need to survive. And the more sugar they use, the more radioactivity will be present in that particular spot. So, after the hour of waiting and your body metabolizing the sugar solution, they run you through a machine that seems to be half MRI, half CT scan--that is, not as big as an MRI but bigger than a CT. The machine scans your body and measures the amounts of radiation in particular spots. If everything congregates in one place, then you probably have a tumor. If it is evenly dispersed, then you probably don't--this test is accurate with tumors as small as 1 centimeter. Anything smaller than that won't show up, thus the reason it is necessary for cancer patients to have regular check-ups every 6 months at a minimum.

Another thing to be aware of is the nature of false positives. They occur more often than you probably think. The reason for this is that other cells and tissues that use sugars (energy) at a greater speed than normal cells and tissues also force the radioactive tracer to congregate around it. An example of what may cause a false positive is muscles that have been exercised recently--in preparation for this treatment, I cannot exercise for a period of 24 hours prior to the scan. Also, tissue that is healing itself will also show up as a false positive. The latter example is precisely the reason that I have not yet had a PET scan. After looking at my mouth at my most previous check-up, my radiation oncologist informed me that my mouth was still in poor enough shape that undergoing a PET scan would be a huge waste of time and money. So, here I am, roughly a month later, getting mentally prepared to go in for a PET scan. My first PET scan since my cancer treatment ended.

What do I mean by mental preparation? Well, funny you should ask. There are two primary things that I need to be ready for. The first is a confined space. Prior to my radiation treatment, I never had any issues with claustrophobia. Now, I think about it all the time, even when I get on a plane. The second is the fact that if my cancer were to come back, it would most likely be within the one-year span from when my treatment ended. As many of you know, I just finished up last September 21--well within the one-year window. Therefore, I need to be mentally prepared for the slight possibility that it could have returned. HOWEVER, and let me be very clear on this, I do not feel as if I have cancer anymore. You may think it is impossible for me to know, but if there is one thing that I have learned throughout this process, it is that I need to listen to my gut instincts, because they are usually right.

If you are a reader of my blog, don't expect for any results to be posted for a few days. My scan will probably not be reviewed until the following week at the earliest. If, however, I were to find out anything, then I'll certainly post it so that you know what is going on. Thanks for reading!