Never heard of a query doctor, but some of the bigger writing conferences have query critique sessions (and pitch critique sessions), often with agents and editors sitting in and carping.
And, of course, the estimable Miss Snark occasionally (too often, for my taste, though she's a saint for doing it) runs her Query and Synopsis Crap-O-Meter.
Has your novel been through the critique-group/workshop mill?
Most writers need feedback other than from family and friends. In fact, semi-hostile feedback can be the best. But community college workshops and university extension classes are cheap--and usually have a fine selection of the semi-hostile.
In addition, a few of the better conferences--such as the venerable San Diego conference (
http://www.ces.sdsu.edu/writers/)-- have editorial advance reads, where, instead of pitch sessions (which they also have), you can submit your first ten pages (months in advance) to acquiring editors of your choice, and get their feedback. (You may also get their Best In Show Award--I did, WOOF! WOOF!--which then makes you suddenly sexier to all of the agents at the conference. You may also be invited to submit your mansucript, thereby hopping straight through the transom without landing in the slush pile.)
It is interesting that agents at the San Diego Conference don't do advance reads--only editors. Agents inhabit a more rarefied, red-carpet plane than the rest of us (see below).
------------------------
My advice on dealing with publishers: Let your agent do it. Agents are more important than publishers. Agents are more important than anyone. Which brings me to my advice on dealing with agents. You can’t. They won’t speak to you. They’re too important.
—P.J. O’Rourke