I have not heard of him. Best way is to ask him. He may not have a precise answer, but he should be able to give some range of magnitude. Like less than 50 or more than 50, or several hundred, etc. If he does not want to give a reasonable answer, that tells you something also. Doctors sometimes do not like a question like this. But you have a right to know, so ask. It is your head, after all.