From the age of 14 (and a bit younger) I spent most of my school holidays in the Medical Physics Electronics/Mechanical workshop of Mount Vernon Hospital in Northwood, UK.
Their main reason for being was to look after the Radiation Therapy Cancer Treatment department.
Radiotherapy Linear Accelerators.
Linear Particle Accelerators are not just used in medical treatment, they are used in physics research.
There are Linear accelerators competing with the LHC, which is the same technology in a circle rather than a straight line.
Or as one of my colleagues used to explain it, "a drain pipe with a light bulb at the end"
Most people never see one of these machines.
Patients normally see them like this:-
We would have to service but more importantly fix these lethal machines, and I ended up installing them during "Holidays" whilst doing my Electronics Degree, meaning they look more familiar to me like this:-
Either way, being capable of keeping these machines going meant the Engineers I worked with were capable of tackling just about any problem.
Some other work I ended up being involved in was studying nerve re growth following a cut (in particular wrist cuts), and developing a battery powered TENS machine that was used on patients, along with an impedance measuring device that monitored blood flow in newly grafted skin.