Stripper Joke

Heard this joke at the local bar last night:

A neurosurgeon consulted with a prospective patient about brain transplant:

Neurosurgeon, "There are three brains available for your transplant surgery. Nuclear physicist - $1000; Philosophy professor - $2000; Blonde stripper - $50,000."

Patient, "Why is the stripper's brain so expensive?"

Neurosurgeon, "Never used."