Profile

I work in the field of Medical Imaging. This means we use techniques like X-ray, CT, MRI (you might have heard of these ones!), and PET and SPECT imaging (these might be new to you) to SEE inside the body, but from the outside, to find disease (without cutting you open!). Some of these techniques, such as MRI and CT, allows us only to visual anatomical changes. But other techniques such as POSITRON EMISSION TOMOGRAPHY (or PET for short) allow us to look at physiological processes and tissue function on a molecular level. So, for example, in the case of cancer, with PET, we might be able to understand how those cancer cells are functioning and growing. Or in Alzheimers disease, what is happening, what does this disease look like on a molecular level?

I work mainly with positron emission tomography (PET). But how does it work? What is Positron emission tomography?

Take a molecule that targets a specific molecular process in the body, it could be a small molecule like an amino acid, or a bigger molecule like a peptide, protein, or antibody. This is the bit of the molecule that is involved in the molecular process and will have different behaviours depending on how the cells or tissue is functioning.

This is all going on INSIDE you so now we need a way to SEE what this molecule is doing, from outside the body. And we do this by essentially sticking a “flash-light” on the molecule. This flash-light comes in the form of radioactivity.

We can observe the location of the radioactive isotope from outside the body because radioactivity exhibits an important physical characteristic: it decays

The decay process involves the radioactive atoms, spitting out particles or energy as the nucleus is transformed into something else. Radioactive substances become less radioactive overtime. This is expressed by the property called half-life, defined as the time it takes for half of the radioactive atoms to undergo decay.

When a radioactive PET isotope enters the body two things happen:

The molecule will move around the body, hopefully ending up at its target (e.g. cancer).

And, because it is radioactive, the molecule will decay. When it does so, radiation is released which can pass through your body and can be detected outside your body by a special camera – a PET scanner.

So essentially, we are taking a special photo of the radiation coming out of your body and so we have a picture of where these radioactive molecules are in your body.

EXAMPLE!

The most commonly-used PET molecule is RADIOACTIVE SUGAR. You take normal sugar, a simple everyday molecule that’s in your food, and is the fuel needed by every cell in your body. Your whole body spends all day, every day using sugar.

Now, it was found that some cancers are more hungry for sugar than normal healthy tissue – something that makes cancers different from normal tissue. Scientists used this observation to make a radioactive molecule to SEE this process from OUTSIDE the body, without an operation.

So they took the sugar molecules and stuck on a “flash-light” in the form of a radioactive atom. We now have a radioactive sugar molecule, so if we inject this into a person, we will be able to see where this sugar goes (hopefully to the cancer!).

We can use this technique to answer important medical questions about disease.

My job is to make different kinds of radioactive molecules and test them to see if they work, before testing them in patients.

My job is very varied, which is one of the reasons I love it. I spend a lot of my time teaching students – this could be lecturing, or teaching them how to do experiments in the lab, or cheering them up if they’ve had a difficult day when things go wrong (this happens a lot in science!). Other days I am doing research in the lab, doing chemistry with radioactivity to make the radioactive molecules, and testing them in cells to check that they work. Other days I will be sitting at my desk, doing calculations, planning new experiments, writing reports and presentations, or reading about new research. We also have lots of meetings so we can talk to lots of scientists about our work and share information and get new ideas.