Laser microbeam CT scanning of dosimetry gels

Marek J. Maryanski; Manisha K. Ranade

doi:10.1117/12.430867

28 June 2001 Laser microbeam CT scanning of dosimetry gels

Marek J. Maryanski, Manisha K. Ranade

Proceedings Volume 4320, Medical Imaging 2001: Physics of Medical Imaging; (2001) https://doi.org/10.1117/12.430867
Event: Medical Imaging 2001, 2001, San Diego, CA, United States

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.

Citation Download Citation

Marek J. Maryanski and Manisha K. Ranade "Laser microbeam CT scanning of dosimetry gels", Proc. SPIE 4320, Medical Imaging 2001: Physics of Medical Imaging, (28 June 2001); https://doi.org/10.1117/12.430867

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