Dr Michael MD treated 24 (11)
I believe the answer is:
middlemarch
'24' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's an association between them I don't understand?
'dr michael md treated' is the wordplay.
'treated' indicates an anagram.
'dr'+'michael'+'md'='drmichaelmd'
'drmichaelmd' is an anagram of 'MIDDLEMARCH'.
(Other definitions for middlemarch that I've seen before include "Novel by female author" , "George Eliot novel" , "Book by George Eliot" .)