Luke ‘Layman’ Donegan’s Lovely Physics Blog

Hey guys! Welcome back to my lovely physics blog! I was simply unable to sleep for the past week at the thought of writing this blog post for you all! This instalment relates to a project I had to complete for my careers and communications skills module a while ago. Me and three of my fellow Theoretical Physics buddies had to create, and present a poster project on a physics topic of our choice. We chose to complete it on the applications of physics in medicine, and my individual contribution centred around nuclear medicine. I found the whole field fascinating, and hence I thought that I should share the knowledge ‘round  and give you curious cats the rundown in relation to all things nuclear medicine 😎.

What (the hell!) is Nuclear Medicine anyways?

Nuclear medicine is a medical speciality that uses radioactive tracers or radiopharmaceuticals (I’ll explain what these are later) to assess the bodily function of organs and other tissues, to diagnose diseases, and to treat them. These radiopharmaceuticals (long word alert!) are typically injected into the patient, and their journey throughout the body tracked by specially designed cameras.

What Does Nuclear Medicine do, and how?

Nuclear medicine, in a sense is radiology done from the inside out. Tracers are usually chosen which are naturally used by a particular organ or tissue during its metabolic process. For example, in PET scans of the brain, glucose is ‘radiolabelled’ (which is what I call most musical artists nowadays! It’s all the freaking same, rap and snoop dog and all of that🙄) , which is the process of replacing individual, stable atoms with radioactive ones to obtain the molecule FDG (Fluoro-Deoxyl-Glucose) by introducing radioactive fluoride-18 in the place of a hydroxyl group. (It’s like if you put a little camera in a roll of ham and gave it to your dog, or cat, or lizard, or whatever pet you guys have got that enjoys salty slices of ham!) Glucose is chosen as it is the brain’s main source of energy. Thus, it travels to the brain and is metabolised. The rate at which cells consume glucose can signal the presence of cancer, as cancerous cells are rather active, metabolically speaking. This process can be tailored to each organ in the body, or specific areas of interest.

The History of Nuclear Medicine

The history of nuclear medicine naturally begins with the discoveries of Roentgen, Becquerel and Curie. Around 1930, George Hevesy was convinced that his cafeteria was reusing leftover meet. I used to wonder what they did with the leftover food in the dining hall here in Trinity College; then I got a job working as a waiter in the dining hall and they made me sign a piece of paper promising that I would never tell a single soul in my entire life what they actually do with it! Back to George: George decided to put his theory to the test, he came into the cafeteria on a Monday, ordered a hamburger, and returned a substantial plate of leftovers infused with a radioactive tracer. The next day, when the cafeteria was serving beef goulash, George brought in a little device lent to him by his lab partner Hans Geiger, and the device made quite a lot of noise!

George then went on to spike other things with tracers, such as plants and animals, and further down the line nuclear medicine effectively emerged.

Physics Role in Nuclear Medicine

PET stands for ‘positron emission topography(scanner)’. The isotopes (such as FDG) used in PET scanning experience Beta Decay. They release positrons (positively charged electrons), which then collide with electrons in their immediate surroundings, annihilating each other and converting their masses into two high-energy photons (remember , thanks Albert!). These photons then impact a pair of radiation detectors in the scanner walls, which can determine almost exactly where inside the body the collision occurred (Wow!)

Oliver W.Sacks (the neurologist and best selling author) said:

“In examining disease, we gain wisdom about anatomy, physiology and biology. In examining the person with disease, we gain wisdom about life.” My grandmother is currently beset with Alzheimer’s disease, and during my discussions with her I have gained an immense amount of wisdom relating to the apparent lengths to which the nurses treating her will go to put poison in her food (lol)!

Well, that’s the end of this week’s blog post.

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