I can't imagine you could ever deduct something like this - if you could then a software company would be able to deduct lost sales from people starting the purchase process on their web page but never actually completing it by submitting their credit card information. Taxi's could deduct the expense of driving out to pick someone up and being stiffed because they had already caught another taxi before the driver arrived. Etc. It seems absurd to even consider being able to deduct stuff like that - without a contract, revenue is created when the service is rendered, that's my understanding.
Edit, that said, I'm not an accountant and have no idea what I'm talking about, so ask a tax attorney.
Edit #2 .. for some reason it totally doesn't surprise me that a doctor might feel entitled to this, however lol