How do doctors get subjects for medical photography?

[unicornspirit2008]

I was wondering where the subjects in medical photographs come from. Are they volunteers? Or are the photographs taken as part of other procedures? Or only in case studies?

Just asking for curiosity's sake.

[John S]

There are a few ways - the first way is that the doctor will ask you and they will promise to hide your identity (think black square over the face). The second way is you sign up for a study and as a part of the program you agree to allow all data for the study to be published (including pictures). Sometimes people are paid for the study or they want to try out an experimental drug to cure them and taking pictures maybe a part of that process.