In case you want to do something like an autocomplete that would pre-populate a suggestion list, say for example, by typing in a Doctor's first name and / or last name, you can do this using the starting_with keyword in sunspot. Let the code speak for itself?

class Doctor
  # this model should have the typical Sunspot.setup clause somewhere else
  
  include Suggestions
end

Doctor.suggestions "John Smith D"

So the result would include all people who has John, Smith or have a first or last name starting with D. (Note that I assume you have indexed the first name and last name as text fields)

You can get the code for the whole suggestion library here at my gist.