At this point, I had only known of the existence of medical physics for about six months. Approximately 30 seconds after finding out about it, I wanted to do it, and by December I had arranged two work experience visits and a tour of a third department, but I still had no idea how to describe it.
I've now been in the job around two and a half years, and it's still hard to describe. It's so big! It really is. My standard answer has become 'anything involving radiation in hospitals', and that's a fair simplification, but doesn't really explain to anyone what I do all day. It also tends to lead to a stock series of responses, including 'oh, you're a radiographer?' (no) 'oh, you're a radiologist?' (no) and 'oh, you fix [insert medical machine here]??' (no). In order: radiographers push buttons which make images (or treat patients, in radiotherapy); radiologists are doctors specialising in radiology (medical imaging), and engineers fix machines. (We just tell the engineer it's broken...)
Wikipedia1 helpfully describes medical physics as follows:
Medical physics is generally speaking the application of physics concepts, theories and methods to medicine.This must be very helpful for people who don't understand the adjectival suffix, but not otherwise. What physics concepts?
Well, as I said above, mainly radiation; to be specific, ionising radiation. That is, x-rays, radioactive materials, etc. Since that's the bulk of it, and that's what I'm working in, I'll come to the details of that later.
But as well as ionising radiation, we also work with non-ionising radiation: lasers (used to break up kidney stones, remove tattoos, etc.), ultrasound (obviously used in imaging, but also in interventional medicine), UV dermatological treatments (for psoriasis and certain skin cancers), and magnetic resonance imaging (MRI).
The main roles in a lot of this are quality assurance, and safety. We test machines; we look for patterns in response, for abnormalities, and we try to explain them. (Then we call the engineers...) We advise doctors, and other medical staff, on the safety issues with various types of non-ionising radiation (don't shine lasers into your eyes; don't take metallic power tools into an MRI room2; in terms of ultrasound, well, there's very little safety to advise on, which is one of the reasons I personally find it dull).
We also try to optimise imaging: obtaining the best quality image possible (for a definition of quality which depends on the clinical purpose), and writing computer programs to help with image processing and analysis. This is also to do with safety, in terms of reducing the dose of radiation needed to achieve an appropriate image quality.
In ionising radiation, there are three main areas: nuclear medicine, radiotherapy, diagnostic radiology; and covering all of these, radiation protection. I'll explain these in more detail in following posts.
1. en.wikipedia.org/wiki/Medical_physics [quotation retrieved 14/03/2013]. ↩
2. This really happened; it destroyed a very expensive machine which had only just been installed. ↩
