Skip to main content
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
The full text of this article is not currently available.
S. J. Doran, “The history and principles of chemical dosimetry for 3-D radiation fields: Gels, polymers and plastics,” Appl. Radiat. Isot. 67(3), 393398 (2009).
C. Baldock, Y. De Deene, S. Doran, G. Ibbot, A. Jirasek, M. Lepage, K. B. McAuley, M. Oldham, and L. J. Schreiner, “Polymer gel dosimetry,” Phys. Med. Biol. 55(5), R1R63 (2010).
M. Oldham, “Radiochromic 3D detectors,” J. Phys.: Conf. Ser. 573, 012006 (2015).
J. C. Gore, M. Ranade, M. J. Maryanski, and R. J. Schulz, “Radiation dose distributions in three dimensions from tomographic optical density scanning of polymer gels: I. Development of an optical scanner,” Phys. Med. Biol. 41(12), 26952704 (1996).
R. G. Kelly, K. J. Jordan, and J. J. Battista, “Optical CT reconstruction of 3D dose distributions using the ferrous–benzoic–xylenol (FBX) gel dosimeter,” Med. Phys. 25(9), 17411750 (1998).
W. G. Campbell, D. A. Rudko, N. A. Braam, D. M. Wells, and A. Jirasek, “A prototype fan-beam optical CT scanner for 3D dosimetry,” Med. Phys. 40(6), 061712 (12pp.) (2013).
J. G. Wolodzko, C. Marsden, and A. Appleby, “CCD imaging for optical tomography of gel radiation dosimeters,” Med. Phys. 26(11), 25082513 (1999).
T. Olding, O. Holmes, and L. J. Schreiner, “Cone beam optical computed tomography for gel dosimetry I: Scanner characterization,” Phys. Med. Biol. 55(10), 28192840 (2010).
S. J. Doran, K. K. Koerkamp, M. A. Bero, P. Jenneson, E. J. Morton, and W. B. Gilboy, “A CCD-based optical CT scanner for high-resolution 3D imaging of radiation dose distributions: Equipment specifications, optical simulations and preliminary results,” Phys. Med. Biol. 46(12), 31913213 (2001).
N. Krstajić and S. J. Doran, “Characterization of a parallel-beam CCD optical-CT apparatus for 3D radiation dosimetry,” Phys. Med. Biol. 52(13), 36933713 (2007).
H. S. Sakhalkar and M. Oldham, “Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation,” Med. Phys. 35(1), 101111 (2008).
J. Adamovics, “Three-dimensional dosimeter for penetrating radiation and method of use,” U.S. patent 20040211917 A1 (Oct. 28, 2004).
P. Y. Guo, J. A. Adamovics, and M. Oldham, “Characterization of a new radiochromic three-dimensional dosimeter,” Med. Phys. 33(5), 13381345 (2006).
T. Gorjiara, R. Hill, Z. Kuncic, J. Adamovics, S. Bosi, J.-H. Kim, and C. Baldock, “Investigation of radiological properties and water equivalency of PRESAGE® dosimeters,” Med. Phys. 38(4), 22652274 (2011).
J. Jackson, T. Juang, J. Adamovics, and M. Oldham, “An investigation of PRESAGE® 3D dosimetry for IMRT and VMAT radiation therapy treatment verification,” Phys. Med. Biol. 60(6), 22172230 (2015).
N. Krstajić and S. J. Doran, “Fast laser scanning optical-CT apparatus for 3D radiation dosimetry,” Phys. Med. Biol. 52(11), N257N263 (2007).
H. S. Sakhalkar, J. Adamovics, G. Ibbott, and M. Oldham, “A comprehensive evaluation of the PRESAGE/optical-CT 3D dosimetrysystem,” Med. Phys. 36(1), 7182 (2009).
H. Sakhalkar, D. Sterling, J. Adamovics, G. Ibbott, and M. Oldham, “Investigation of the feasibility of relative 3D dosimetry in the radiologic physics center head and neck IMRT phantom using presage/optical-CT,” Med. Phys. 36(7), 33713377 (2009).
A. Thomas, J. Newton, J. Adamovics, and M. Oldham, “Commissioning and benchmarking a 3D dosimetry system for clinical use,” Med. Phys. 38(8), 48464857 (2011).
C.-S. Wuu, S. J. Hoogcarspel, K. Deh, W.-Y. Hsu, and J. Adamovics, “3-D dose verification by cone-beam optical CT scanning of PRESAGE dosimeter,” J. Phys.: Conf. Ser. 444(1), 012044 (2013).
K. Chisholm, D. Miles, L. Rankine, and M. Oldham, “Investigations into the feasibility of optical-CT 3D dosimetry with minimal use of refractively matched fluids,” Med. Phys. 42(5), 26072614 (2015).
S. Bache, J. Malcolm, J. Adamovics, and M. Oldham, “Investigation of a low-cost optical-CT system with minimal refractive index-matching fluid,” J. Phys.: Conf. Ser. 573, 012052 (2015).
K. J. Jordan, D. Turnbull, and J. J. Battista, “Laser cone beam computed tomography scanner geometry for large volume 3D dosimetry,” J. Phys.: Conf. Ser. 444, 012062 (2013).
S. J. Doran and D. N. B. Yatigammana, “Eliminating the need for refractive index matching in optical CT scanners for radiotherapy dosimetry: I. Concept and simulations,” Phys. Med. Biol. 57(3), 665683 (2012).
L. Rankine and M. Oldham, “On the feasibility of optical-CT imaging in media of different refractive index,” Med. Phys. 40(5), 051701 (8pp.) (2013).
S. J. Doran, “Novel method and apparatus for 3-D scanning of translucent samples for radiation,” U.S. patent 20120170049 A1 (July 5, 2012).
K. H. Dekker, J. J. Battista, and K. J. Jordan, “Stray light in cone beam optical computed tomography: II. Reduction using a convergent light source,” Phys. Med. Biol. 61(7), 29102925 (2016).
Y. Cho, D. J. Moseley, J. H. Siewerdsen, and D. A. Jaffray, “Accurate technique for complete geometric calibration of cone-beam computed tomography systems,” Med. Phys. 32(4), 968983 (2005).
M. Xu, C. Zhang, X. Liu, and D. Li, “Direct determination of cone-beam geometric parameters using the helical phantom,” Phys. Med. Biol. 59(19), 56675690 (2014).
D. Ramm, T. P. Rutten, J. Shepherd, and E. Bezak, “Optical CT scanner for in-air readout of gels for external radiation beam 3D dosimetry,” Phys. Med. Biol. 57(12), 38533868 (2012).
U. Jochen Birk, A. Darrell, N. Konstantinides, A. Sarasa-Renedo, and J. Ripoll, “Improved reconstructions and generalized filtered back projection for optical projection tomography,” Appl. Opt. 50(4), 392398 (2011).
G. C. Antonopoulos, D. Pscheniza, R.-A. Lorbeer, M. Heidrich, K. Schwanke, R. Zweigerdt, T. Ripken, and H. Meyer, “Correction of image artifacts caused by refractive index gradients in scanning laser optical tomography,” Proc. SPIE 8949, 894907-1894907-6 (2014).
L. F. Hoyt, “New table of the refractive index of pure glycerol at 20 °C,” Ind. Eng. Chem. 26(3), 329332 (1934).
T. Olding and L. J. Schreiner, “Cone-beam optical computed tomography for gel dosimetry II: Imaging protocols,” Phys. Med. Biol. 56(5), 12591279 (2011).
W. J. Palenstijn, K. J. Batenburg, and J. Sijbers, “Performance improvements for iterative electron tomography reconstruction using graphics processing units (GPUs),” J. Struct. Biol. 176(2), 250253 (2011).
W. van Aarle, W. J. Palenstijn, J. De Beenhouwer, T. Altantzis, S. Bals, K. J. Batenburg, and J. Sijbers, “The astra toolbox: A platform for advanced algorithm development in electron tomography,” Ultramicroscopy 157, 3547 (2015).
P. Gilbert, “Iterative methods for the three-dimensional reconstruction of an object from projections,” J. Theor. Biol. 36(1), 105117 (1972).
G. MacBeth and A. R. Thompson, “Densities and refractive indexes for propylene glycol-water solutions,” Anal. Chem. 23(4), 618619 (1951).
D. Matenine, Y. Goussard, and P. Després, “GPU-accelerated regularized iterative reconstruction for few-view cone beam CT,” Med. Phys. 42(4), 15051517 (2015).
J. Adamovics (private communication, 2015).
J. R. Taylor, An Introduction to Error Analysis: The Study of Uncertainties in Physical Measurements (University Science Books, New York, NY, 1997).
S. Babic, J. Battista, and K. Jordan, “Three-dimensional dose verification for intensity-modulated radiation therapy in the radiological physics centre head-and-neck phantom using optical computed tomography scans of ferrous xylenol–orange gel dosimeters,” Int. J. Radiat. Oncol., Biol., Phys. 70(4), 12811291 (2008).
M. Oldham, J. H. Siewerdsen, S. Kumar, J. Wong, and D. A. Jaffray, “Optical-CT gel-dosimetry I: Basic investigations,” Med. Phys. 30(4), 623634 (2003).
M. J. Maryanski, Y. Z. Zastavker, and J. C. Gore, “Radiation dose distributions in three dimensions from tomographic optical density scanning of polymer gels: II. Optical properties of the BANG polymer gel,” Phys. Med. Biol. 41(12), 27052717 (1996).
S. J. Doran, A. T. Abdul Rahman, E. Bräuer-Krisch, T. Brochard, J. Adamovics, A. Nisbet, and D. Bradley, “Establishing the suitability of quantitative optical CT microscopy of PRESAGE® radiochromic dosimeters for the verification of synchrotron microbeam therapy,” Phys. Med. Biol. 58(18), 62796297 (2013).
E. Hecht, Optics (Addison-Wesley, Reading, MA, 2002).

Data & Media loading...


Article metrics loading...



The practical use of the PRESAGE® solid plastic dosimeter is limited by the inconvenience of immersing it in high-viscosity oils to achieve refractive index matching for optical computed tomography (CT) scanning. The oils are slow to mix and difficult to clean from surfaces, and the dosimeter rotation can generate dynamic Schlieren inhomogeneity patterns in the reference liquid, limiting the rotational and overall scan speed. Therefore, it would be beneficial if lower-viscosity, water-based solutions with slightly unmatched refractive index could be used instead. The purpose of this work is to demonstrate the feasibility of allowing mismatched conditions when using a scanning laser system with a large acceptance angle detector. A fiducial-based ray path measurement technique is combined with an iterative CT reconstruction algorithm to reconstruct images.

A water based surrounding liquid with a low viscosity was selected for imaging PRESAGE® solid dosimeters. Liquid selection was optimized to achieve as high a refractive index as possible while avoiding rotation-induced Schlieren effects. This led to a refractive index mismatch of 6% between liquid and dosimeters. Optical CT scans were performed with a fan-beam scanning-laser optical CT system with a large area detector to capture most of the refracted rays. A fiducial marker placed on the wall of a cylindrical sample occludes a given light ray twice. With knowledge of the rotation angle and the radius of the cylindrical object, the actual internal path of each ray through the dosimeter can be calculated. Scans were performed with 1024 projections of 512 data samples each, and rays were rebinned to form 512 parallel-beam projections. Reconstructions were performed on a 512 × 512 grid using 100 iterations of the SIRT iterative CT algorithm. Proof of concept was demonstrated with a uniformly attenuating solution phantom. PRESAGE® dosimeters (11 cm diameter) were irradiated with Cobalt-60 irradiator to achieve either a uniform dose or a 2-level “step-dose” pattern.

With 6% refractive index mismatching, a circular field of view of 85% of the diameter of a cylindrical sample can be reconstructed accurately. Reconstructed images of the test solution phantom were uniform (within 3%) inside this radius. However, the dose responses of the PRESAGE® samples were not spatially uniform, with variations of at least 5% in sensitivity. The variation appears as a “cupping” artifact with less sensitivity in the middle than at the periphery of the PRESAGE® cylinder. Polarization effects were also detected for these samples.

The fiducial-based ray path measurement scheme, coupled with an iterative reconstruction algorithm, enabled optical CT scanning of PRESAGE® dosimeters immersed in mismatched refractive index solutions. However, improvements to PRESAGE® dose response uniformity are required.


Full text loading...


Access Key

  • FFree Content
  • OAOpen Access Content
  • SSubscribed Content
  • TFree Trial Content
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd