TMS is generally prescribed by a psychiatrist and the initial treatment, called a ‘mapping session’ is performed by a psychiatrist, physician, or a psychiatric nurse practitioner (NP). In this first session, the doctor or NP will map (locate) the area of the brain to be treated. The subsequent treatments are most often performed or administered by a certified TMS technician under the supervision of the physician. The technician should always be present in the treatment room to monitor the patient during treatment.