John W. Strohbehn

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A computer-based system has been developed for the integration and display of computerized tomography (CT) image data in the operating microscope in the correct perspective without requiring a stereotaxic frame. Spatial registration of the CT image data is accomplished by determination of the position of the operating microscope as its focal point is(More)
A new system, which we call the frameless stereotaxic operating microscope, is discussed. Its purpose is to display CT or other image data in the operating microscope in the correct scale, orientation, and position without the use of a stereotaxic frame. A nonimaging ultrasonic rangefinder allows the position of the operating microscope and the position of(More)
PURPOSE Microwave antennas of various designs were inserted into arrays of nylon catheters implanted in brain tumors with the goal of raising temperatures throughout the target volume to 43.0 degrees C. METHODS AND MATERIALS All antennas were flexible, and included dipole, choke dipole, modified dipole, and helical designs driven at 915 or 2450 MHz.(More)
Dipole antennas are commonly used in interstitial clinical hyperthermia treatments because of their compatibility with brachytherapy techniques and their good power deposition patterns when used in arrays. For accurate treatment planning, however, there must be a comprehensive knowledge base to predict the power deposition patterns when insertion depth is a(More)
Recently, there has been increased interest in the use of hyperthermia (temperatures, 42 to 45 degrees) as an adjuvant modality to radiation therapy or chemotherapy for the treatment of cancer. This paper discusses the use of the finite element method as a technique for calculating the power deposited per unit volume of tissue for two regional-type(More)
The Dartmouth interstitial microwave antenna array hyperthermia (IMAAH) system was evaluated based on its ability to heat idealized three-dimensional cylindrical and ellipsoidal tumour models with lengths between 2 and 16 cm. The evaluation was based on computer simulations of the three-dimensional temperature distributions produced by the explicit(More)
In order to increase understanding of artefacts caused by patient motion in computed tomography, rigid translational and rotational motions in the plane of reconstruction have been considered. Motion artefacts were simulated on a digital computer and demonstrated in actual CT scans of a phantom. The types of motion artefacts observed included streaking,(More)
An oncolytic effect of hyperthermia in the 42 degrees to 43 degrees C range has been previously demonstrated in cell culture and animal models. To apply this modality clinically, an interstitial microwave antenna array system has been developed for the delivery of controlled hyperthermia to an intracranial tumor volume, and a Phase I clinical trial(More)