Say “Cheese” – PET CT vs CT vs MRI What is the big difference. First, let’s state fact, none of them are enjoyable. There’s no one telling you that the camera loves you or that you’ve just got that “look”. Face it, instead of a modeling contract, you basically are going to get good news that you are clear or bad news that no one wants to hear.
So what’s the best scan to get? Let’s start with the fact that different cancers show up on different types of scans. Different aspects of different cancers also show up differently on different types of scans. Confused?
Full disclaimer, I’m not a doctor, so here’s just what I have learned. Say you have a tumor, it will show up on a scan, however a blood cancer may or may not. Hold up now, some tumors can be too small to be detected on a scan, but they are there. I believe they must be 4mm to be detected. To add to the confusion, some things may light up on a scan and be nothing more than inflammation or infection. So what’s a cancer patient to do??
Here’s what I do. We do regular CT scans to watch for changes in the size or shape of things in my body. We look at lymph glands, organs, prior surgical sites etc and see if there are any changes. If you are watching a tumor, you see if it’s getting bigger or growing legs and attaching to things nearby. If we notice changes, we dig further either with a PET CT or MRI.
Once a year, we do a PET CT. If I stress about anything, it’s waiting to see what my PET CT results are. The PET CT sees the most detail. Here’s my Junior Doctor explanation. On a CT, you may see a lymph gland that looks perfectly normal in size and shape, no changes. This same lymph gland on a PET CT, may light up on the inside. This light up indicates activity. This activity can be cancer brewing and it also can be infection, left over radiation that is healing, inflammation etc. Depending on your cancer type, this light up most likely is cause for further investigation. Mine indicated that cancer had spread. By catching it early on a PET CT, we were able to do 10 days of radiation and zap it. Bye bye!
An MRI is a loud machine. You should wear ear plugs or headphones at least. Also, any metal is attracted to the super powerful magnets in the machine, so they should be removed first. In my case, the MRI is used to confirm what we find on a CT or PET CT. It is a scan that causes the least harm to you because you are not getting a dose of radiation. Don’t fear the MRI, just protect your ears!
For your PET CT or CT, wear clothing that does not have any metal in it. You don’t want your doctor to think that guitar shaped belt buckle is a very cool tumor. Ladies, wear sports bras that don’t have any metal hooks or adjustment straps. Your wedding ring should be fine, because they usually are not scanning your hands. Bring socks, because if you take your shoes off, remember they keep those rooms at about 55 degrees!
Get ready to lay still and breathe naturally. Some tests will require you to hold your breath for a few seconds and release. All in all, they take about 15 to 20 minutes start to finish. If you have to drink the chalky liquid that mildly resembles Orange flavored Tang, just grin and bear it.