Investigation of a low-cost optical-CT system with minimal refractive index-matching fluid


Conference Paper

© 2015 IOP Publishing Ltd. Optical computed tomography (optical-CT) is a method for visualizing 3dimensional dose distributions in radiochromic dosimeters. Projection images are acquired by collimating a visible light point source into parallel-beam geometry and imaging differential absorption through the sample dosimeter. Practical challenges involved in optical-CT imaging were addressed through the investigation of an in-house Fresnel-based optical-CT system with considerably less refractive index-matching fluid. The "DFOS" (Duke Fresnel-based Optical- CT System) system differed from current optical-CT systems by replacing cumbersome convex telecentric lenses with a lighter and much less expensive Fresnel system. A second major modification was the replacement of the refractive index-matching fluid bath with a solid polyurethane tank. PRESAGE radiochromic dosimeters were irradiated with orthogonal parallel-opposed treatments and dose distributions were readout by the DFOS system and compared to both treatment planning software prediction and two other in-house optical-CT systems. Gamma index passing rate at the 3%/3mm threshold in relation to Eclipse treatment planning software for the treatment was 92.2%%, compared to 96.8% and 95.6% for two other systems featuring a traditional setup. The DFOS system showed promise for 3D dosimetry, but the performance is still substantially inferior at present to the gold-standard systems.

Full Text

Duke Authors

Cited Authors

  • Bache, S; Malcolm, J; Adamovics, J; Oldham, M

Published Date

  • January 1, 2015

Published In

Volume / Issue

  • 573 / 1

Electronic International Standard Serial Number (EISSN)

  • 1742-6596

International Standard Serial Number (ISSN)

  • 1742-6588

Digital Object Identifier (DOI)

  • 10.1088/1742-6596/573/1/012052

Citation Source

  • Scopus