title: On the development and comparative evaluation of an ultrasound B-mode probe calibration method.
abstract: OBJECTIVE
  Precise transducer calibration is an essential prerequisite for reliable surface registration based on ultrasound B-mode imaging devices. The clinical usage of a novel B-mode transducer calibration technique was evaluated and its attainable calibration precision assessed.
  
  
  METHODS
  The Three Wire Method and the Cambridge Calibration Method were used as reference techniques to compare the efficiency, calibration precision and spatial requirements of the different techniques. A total of 20 calibration trials were performed using each technique and were statistically evaluated for accuracy and speed.
  
  
  RESULTS
  The mean error characterizing the calibration precision of the Three Wire Method was 3.2 mm, obtained in a phantom with a volume of 14 x 10(6) mm(3) in 18.48 min. The Cambridge method resulted in a mean calibration error of 2.2 mm, but required a larger phantom with a volume of 35 x 10(6) mm3 to be used for a duration of 9.30 min. The proposed method yielded an average calibration error of 1.9 mm and was performed, on average, in 2 min using a phantom with a size smaller than 1 x 10(6) mm3.
  
  
  CONCLUSIONS
  The suggested calibration method offers decreased time and space while retaining an equivalent calibration precision when compared to established reference methods.
authors.affiliation: M.E. Müller Research Center for Orthopaedic Surgery, Institute for Surgical Technology and Biomnechanics, University of Bern, Switzerland. jk@MEMcenter.unibe.ch
authors.forename: Jens
authors.initials: J
authors.lastname: Kowal
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Amstutz
authors.forename: Marco
authors.initials: M
authors.lastname: Caversaccio
authors.forename: Lutz P
authors.initials: LP
authors.lastname: Nolte
mesh_terms: D002138:Calibration; D006801:Humans; D008722:Methods; D019060:Minimally Invasive Surgical Procedures / Q000295:instrumentation / Q000592:standards; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000592:standards; D014159:Transducers; D018084:Ultrasonography, Interventional / Q000295:instrumentation* / Q000592:standards