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Proceedings Paper

Low-dose magnetic-field-immune biplanar fluoroscopy for neurosurgery
Author(s): P. A. Ramos; Michael A. Lawson; Kevin G. Wika; Stephen W. Allison; E. G. Quate; J. A. Molloy; Rogers C. Ritter; George T. Gilles
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Paper Abstract

The imaging chain of a bi-planar fluoroscopic system is described for a new neurosurgical technique: the Video Tumor Fighter (VTF). The VTF manipulates a small intracranially implanted magnet, called a thermoseed, by a large external magnetic field gradient. The thermoseed is heated by rf-induction to kill proximal tumor cells. For accurately guiding the seed through the brain, the x-ray tubes are alternately pulsed up to four times per second, each for as much as two hours. Radio-opaque reference markers, attached to the skull, enable the thermoseed's three dimensional position to be determined and then projected onto a displayed MRI brain scan. The imaging approach, similar to systems at the University of Arizona and the Mayo Clinic, includes a 20 cm diameter phosphor screen viewed by a proximity focused microchannel plate image intensifier coupled via fiberoptic taper to a solid state camera. The most important performance specifications are magnetic field immunity and, due to the procedure duration, low dosage per image. A preliminary arrangement designed in the laboratories yielded usable images at approximately 100 (mu) R exposure per frame. In this paper, the results of a series of studies of the effects of magnetic fields on microchannel plate image intensifiers used in the image detection chain are presented.

Paper Details

Date Published: 1 July 1991
PDF: 11 pages
Proc. SPIE 1443, Medical Imaging V: Image Physics, (1 July 1991); doi: 10.1117/12.43438
Show Author Affiliations
P. A. Ramos, Univ. of Virginia (United States)
Michael A. Lawson, Univ. of Virginia (United States)
Kevin G. Wika, Univ. of Virginia (United States)
Stephen W. Allison, Univ. of Virginia (United States)
E. G. Quate, Univ. of Virginia (United States)
J. A. Molloy, Univ. of Virginia (United States)
Rogers C. Ritter, Univ. of Virginia (United States)
George T. Gilles, Univ. of Virginia (United States)

Published in SPIE Proceedings Vol. 1443:
Medical Imaging V: Image Physics
Roger H. Schneider, Editor(s)

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