title: A system for simultaneously measuring contact force, ultrasound, and position information for use in force-based correction of freehand scanning.
abstract: During freehand ultrasound imaging, the sonographer places the ultrasound probe on the patient's skin. This paper describes a system that simultaneously records the position of the probe, the contact force between the probe and skin, and the ultrasound image. The system consists of an ultrasound machine, a probe, a force sensor, an optical localizer, and a host computer. Two new calibration methods are demonstrated: a temporal calibration to determine the time delay between force and position measurements, and a gravitational calibration to remove the effect of gravity on the recorded force. Measurements made with the system showed good agreement with those obtained from a standard materials testing machine. The system's uses include three-dimensional (3-D) ultrasound imaging, force-based deformation correction of ultrasound images, and indentation testing.
authors.affiliation: Medical Vision Laboratory, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK. michael.burcher@philips.com
authors.forename: Michael R
authors.initials: MR
authors.lastname: Burcher
authors.forename: J Alison
authors.initials: JA
authors.lastname: Noble
authors.forename: Lianghao
authors.initials: L
authors.lastname: Han
authors.forename: Mark
authors.initials: M
authors.lastname: Gooding
mesh_terms: D000465:Algorithms; D016477:Artifacts; D004548:Elasticity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D008365:Manometry / Q000295:instrumentation*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D018511:Systems Integration; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods