Biomedical subjects

George Stetten

Publications and source records attributed to George Stetten.

3 recordsLinked to original sources

PubMed2005

Teaching medical image analysis with the Insight Toolkit.

We present several case studies which examine the role that the Insight Toolkit (ITK) played in three medical image analysis courses and several conference tutorials. These courses represent the first use of ITK in a teaching environment, and we believe that a discussion of the teaching approach in each case and the benefits and challenges of ITK will be useful to future medical image analysis course development. ITK was found to provide significant value in a classroom setting since it provides both working "canned" algorithms, including some recently developed methods that are unavailable elsewhere, as well as a framework for developing new techniques and applications. Several areas of difficulty, particularly in regards to code complexity and advanced object-oriented design techniques, have been identified which may make the learning curve of ITK somewhat more complex than a language such as Matlab.

Algorithms↗

PubMed2005

Laser needle guide for the sonic flashlight.

We have extended the real-time tomographic reflection display of the Sonic Flashlight to a laser guidance system that aims to improve safety and accuracy of needle insertion, especially for deep procedures. This guidance system is fundamentally different from others currently available. Two low-intensity lasers are mounted on opposite sides of a needle aimed parallel to the needle. The needle is placed against a notch in the Sonic Flashlight mirror such that the laser beams reflect off the mirror to create bright red spots on the flat panel display. Due to diffuse reflection from these spots, the virtual image created by the flat panel display contains the spots, identifying the projected destination of the needle at its actual location in the tissue. We have implemented our design and validated its performance, identifying several areas for potential improvement.

Equipment Design↗

PubMed2005

C-mode real-time tomographic reflection for a matrix array ultrasound sonic flashlight.

RATIONALE AND OBJECTIVES: Real-time tomographic reflection (RTTR) permits in situ visualization of tomographic images so that natural hand-eye coordination can be used directly during invasive procedures. The method uses a half-silvered mirror to merge the visual outer surface of the patient with a simultaneous scan of the patient's interior without requiring a head-mounted display or tracking. A viewpoint-independent virtual image is reflected precisely into its actual location. When applied to ultrasound, we call the resulting RTTR device the sonic flashlight. We previously implemented the sonic flashlight using conventional two-dimensional ultrasound scanners that produce B-mode slices. Real-time three-dimensional (RT3D) ultrasound scanners recently have been developed that permit RTTR to be applied to slices with other orientations, including C-mode (parallel to the face of the transducer). Such slice orientation may offer advantages for image-guided intervention. MATERIALS AND METHODS: Using a prototype scanner developed at Duke University (Durham, NC) with a matrix array that electronically steers an ultrasound beam at high speed in 3D, we implemented a sonic flashlight capable of displaying C-mode images in situ in real time. RESULTS: We present the first images from the C-mode sonic flashlight, showing bones in the hand and the cardiac ventricles. CONCLUSION: The extension of RTTR to matrix array RT3D ultrasound offers the ability to visualize in situ slices other than the conventional B-mode slice, including C-mode slices parallel to the face of the transducer. This orientation may provide a broader target, facilitating certain interventional procedures. Future work is discussed, including display of slices with arbitrary orientation and use of a holographic optical element instead of a mirror.

Calibration↗