Patient and Probe Tracking During Freehand Ultrasound

Abstract

Abstract. We present a system that measures the probe location with respect to the patient's body during an ultrasound exam. The system uses an inexpensive trinocular camera to track patches of points on a surface. The accuracy of the digital camera system is measured, using the Optotrak as a reference, and is less than ±2 mm for a 20 × 20 mm patch. Fiducials, which can be seen in both the ultrasound images and the camera images, are used for a consistency test producing values with a standard deviation under 3.2 mm.

Temporal calibration of freehand three-dimensional ultrasound using image alignment

“…Using a phantom has the benefit that the results can be analyzed without concern over other factors that might affect the quality of spatial compounding, such as patient motion (Atkinson et al 2001;Flaccavento et al 2004;Rohling et al 1997). Unlike a simulated scan (e.g., using field II), the phantom scan is subject to the same range of errors (in position measurement, time stamping and US artifacts) as an in vivo scan.…”

Panorama Ultrasound for Navigation and Guidance of Epidural Anesthesia

“…In [24] the transducer location was measured with respect to the body by tracking both the probe and the patient using textured features and patterns attached on both the patient and the transducer. The use of checkerboard patterns attached on the US transducer, for tracking with regular digital cameras, has also been explored [2].…”

“…To compensate for external patient movement in most tracking systems, the position of the transducer, obtained with respect2.3. Transducer-Mounted Camerasto the fixed external base of the tracker, is transformed into the coordinate system of the patient which is also tracked[24]. However, direct tracking of ultrasound to skin is preferred.…”