Okla. Stat. tit. 59, § 887.14

Any person holding a license pursuant to the provisions of the Physical Therapy Practice Act as a physical therapist may use the title "Physical Therapist", "Registered Physical Therapist", or "Licensed Physical Therapist", or the letters "P.T.", "R.P.T.", or "L.P.T.", as authorized by the license obtained from the State Board of Medical Licensure and Supervision. Any person holding a license pursuant to the provisions of the Physical Therapy Practice Act as a physical therapist who has earned a Doctor of Physical Therapy degree from a program approved by a national accrediting body recognized by the Board may use the title "Doctor of Physical Therapy" or the letters "D.P.T.".