operating theatre vs treatment

operating theatre

noun
  • A room in a hospital used for performing surgery (originally designed for operations in front of observers). 

treatment

noun
  • Medical care for an illness or injury. 

  • A brief, third-person, present-tense summary of a proposed film. 

  • A treatise; a formal written description or characterization of a subject. 

  • The use of a substance or process to preserve or give particular properties to something. 

  • The process or manner of treating someone or something. 

How often have the words operating theatre and treatment occurred in a corpus of books? (source: Google Ngram Viewer )