The Invisible Man

A couple of weeks ago I obtained the disc with my PET and CT scans on it but I haven't had the energy to get the images posted. Until now.

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The first image is my whole body PET scan. Remember how PET works: they injected me with a weakly radioactively tagged sugar and waited 50 minutes for the sugar to be taken up by the cells in the body that are metabolizing most rapidly. They they put me in a scanner that can detect the radiation being emitted from within my body and can also locate those emissions.

The radioactive tag is circulating in the blood so it shows up in organs that are involved in circulating and filtering blood: the heart, kidneys, liver and bladder. The brain is the most highly metabolically active organ in the body so it lights up brightly.

What we really care about are areas of the body that are not on the list yet still lit up. In my image, there is a very bright blob in my throat. That is my tongue tumor, Pappy the Papilloma.

Of course at the time of this scan we already knew Pappy was there and was malignant because the biopsy had taken physical pieces of him. The real purpose of this scan was to see whether the cancer had spread anywhere else. The most common place for my tongue cancer to spread would be the lungs. You can see that the lungs contain no bright spots whatsoever. Good news.

The PET scanner is fairly low resolution, mostly due to the low radioactivity signal available (you want to put the minimum radioactivity possible into the patient). To get a more precise sense of what anatomical structures are involved, the combine PET with CT. CT is x-ray based and produces a detailed anatomical picture.

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This image shows the combined PET and CT. You are looking at me from the front. Imagine I was laid on a table and then sliced like a hoagie roll. You're looking at the bottom half of the sliced roll. You can see along the edges of my chest that the imaginary knife passed through my ribs. You can see muscles in my legs, abdominal wall and shoulders. And you can see the PET data glowing through in my neck.

This is a single slice that I chose. Using the real software, the doctors can move the slice planes around wherever they want to focus on particular structures or areas. They can get a very precise picture of exactly where the tumor is and how it is attached to or involved with the surrounding non-cancer tissue. That helps them plan how to attack it.