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Proceedings Paper

Laser microbeam CT scanning of dosimetry gels
Author(s): Marek J. Maryanski; Manisha K. Ranade
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Paper Abstract

A novel design of an optical tomographic scanner is described that can be used for 3D mapping of optical attenuation coefficient within translucent cylindrical objects with spatial resolution on the order of 100 microns. Our scanner design utilizes the cylindrical geometry of the imaged object to obtain the desired paths of the scanning light rays. A rotating mirror and a photodetector are placed at two opposite foci of the translucent cylinder that acts as a cylindrical lens. A He-Ne laser beam passes first through a focusing lens and then is reflected by the rotating mirror, so as to scan the interior of the cylinder with focused and parallel paraxial rays that are subsequently collected by the photodetector to produce the projection data, as the cylinder rotates in small angle increments between projections. Filtered backprojection is then used to reconstruct planar distributions of optical attenuation coefficient in the cylinder. Multiplanar scans are used to obtain a complete 3D tomographic reconstruction. Among other applications, the scanner can be used in radiation therapy dosimetry and quality assurance for mapping 3D radiation dose distributions in various types of tissue-equivalent gel phantoms that change their optical attenuation coefficients in proportion to the absorbed radiation dose.

Paper Details

Date Published: 28 June 2001
PDF: 11 pages
Proc. SPIE 4320, Medical Imaging 2001: Physics of Medical Imaging, (28 June 2001); doi: 10.1117/12.430867
Show Author Affiliations
Marek J. Maryanski, MGS Research Inc. (United States)
Manisha K. Ranade, MGS Research Inc. (United States)

Published in SPIE Proceedings Vol. 4320:
Medical Imaging 2001: Physics of Medical Imaging
Larry E. Antonuk; Martin Joel Yaffe, Editor(s)

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