A PET scan measures tissue function (not structure like the CT and MRI). Tumours behave differently to other tissues in the body because tumour cells replicate quickly and gobble up sugar.
Sugar molecule emitting radioactive funk |
Watching sugar being used is hard because sugar molecules are tiny. They're also everywhere in the body, and once they get sucked up out of the blood stream, they're buried deep in tissue. For the doctors to 'see' the sugar they need to make it different and obvious. That's how I ended up 'eating' radioactive sugar.
Active radio
Radioactive sugar is made by substituting one part of the sugar molecule with a radioactive one.
The term radioactive means that something is not stable and emits certain particles. In my case, the radioactive sugar had a funky Fluorine ion attached to it that emits positrons. Positrons are positively charged electrons and can be measured by the PET scanner.
Sugar in, sugar out?
To the body this radioactive molecule looks like sugar and is sucked up by cells. But it isn't sugar and so once inside the cell it can't be gobbled up and broken down. This means the radioactive sugar remains stuck inside the cell that first took it in. Over time the radioactive part emits enough positrons to become stable again, stops being radioactive, becomes normal and dull, and is broken down by the cell.
I heart my pet
PETs can pick up small tumours that aren't big enough to be seen on a CT or MRI. They can also help clarify what is and what is not actual tumour tissue around the major tumour. In my case, there is one other structure that may or may not be tumour near the greedy tumour already in my sigmoid colon. The PET should help resolve this.
I like the radioactive squirrel - here's hoping for a good PEt result :)
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