Unmet Need
Ultrasound imaging is a popular image guidance modality due to its ability for safe, inexpensive, and real-time imaging in the operating room. One method of using ultrasound for guidance is creating 3D volumes from 2D image data and relating the position of surgical tools to the reconstructed volume, which involves tracking the ultrasound probe in 3D space. However, ultrasound probe calibration is required to compute the spatial transformation between the image pixels and the tracking sensor on the probe. Traditionally, calibration consists of collecting and processing many images of prefabricated phantoms. Not only can the phantom be difficult to fabricate and store (to prevent any geometrical changes), but the calibration process can also be lengthy and difficult to repeat. Furthermore, calibration is typically performed before the procedure, and can become inaccurate due to operational hazards, like a mechanical alteration of the tracking sensors during the procedure. Thus, there exists a need for a new method of ultrasound calibration for quality assurance during surgical, interventional, and biopsy procedures.
Technology Overview
Johns Hopkins researchers have developed a novel and robust method for 2D and 3D ultrasound probe calibration using a closed form solution. The method consists of using a position sensor that is attached to the probe and is used to record the position and orientation of each image/volume. The calibration procedure uses the image position/orientation in space and the target location in probe coordinates to determine the transformation of the scanning plane with respect to the position sensor. This method significantly improves on other methods because the closed form framework requires very few motions (2 or more) and provides intra-procedural quality control via in vivo re-calibration.
Stage of Development
Proof of concept.
Patent
US7867167B2
Publication
Boctor E, et al. “A Novel Closed Form Solution for Ultrasound Calibration.” ISBI 2004.
Viswanathan A, et al. “Immediate Ultrasound Calibration from Two Poses and Minimal Image Processing.” MICCAI 2004.
