title: Invited commentary.
authors.affiliation: Teaching & Research Unit, Gosford Hospital, Bldg 14, Corner of Holden Rd and Racecourse Rd, Gosford, New South Wales 2250, Australia.
authors.forename: Val J
authors.initials: VJ
authors.lastname: Robertson
mesh_terms: D002138:Calibration; D019544:Equipment Failure Analysis; D006801:Humans; D013997:Time Factors; D014159:Transducers; D014464:Ultrasonic Therapy / Q000009:adverse effects* / Q000295:instrumentation* / Q000592:standards; D014465:Ultrasonics