Please use this identifier to cite or link to this item: https://apo.ansto.gov.au/dspace/handle/10238/5004
Title: Radiological characterization and water equivalency of genipin gel for x-ray and electron beam dosimetry
Authors: Gorjiara, T
Hill, R
Kuncic, Z
Bosi, SG
Davies, JB
Baldock, C
Keywords: Beams
Phantoms
Plastics
Water
Dosimetry
Powders
Issue Date: 7-Aug-2011
Publisher: IOP Publishing
Citation: Gorjiara, T., Hill, R., Kuncic, Z., Bosi, S., Davies, J. B., & Baldock, C. (2011). Radiological characterization and water equivalency of genipin gel for x-ray and electron beam dosimetry. Physics in Medicine and Biology, 56 (15), 4685-4699. doi:10.1088/0031-9155/56/15/004
Abstract: The genipin radiochromic gel offers enormous potential as a three-dimensional dosimeter in advanced radiotherapy techniques. We have used several methods (including Monte Carlo simulation), to investigate the water equivalency of genipin gel by characterizing its radiological properties, including mass and electron densities, photon interaction cross sections, mass energy absorption coefficient, effective atomic number, collisional, radiative and total mass stopping powers and electron mass scattering power. Depth doses were also calculated for clinical kilovoltage and megavoltage x-ray beams as well as megavoltage electron beams. The mass density, electron density and effective atomic number of genipin were found to differ from water by less than 2%. For energies below 150 keV, photoelectric absorption cross sections are more than 3% higher than water due to the strong dependence on atomic number. Compton scattering and pair production interaction cross sections for genipin gel differ fromwater by less than 1%. The mass energy absorption coefficient is approximately 3%higher thanwater for energies<60 keVdue to the dominance of photoelectric absorption in this energy range. The electron mass stopping power and mass scattering power differ from water by approximately 0.3%. X-ray depth dose curves for genipin gel agree to within 1% with those for water. Our results demonstrate that genipin gel can be considered water equivalent for kilovoltage and megavoltage x-ray beam dosimetry. For megavoltage electron beam dosimetry, however, our results suggest that a correction factor may be needed to convert measured dose in genipin gel to that ofwater, since differences in some radiological properties of up to 3% compared to water are observed. Our results indicate that genipin gel exhibits greater water equivalency than polymer gels and PRESAGE formulations. © 2011 IOP Publishing LTD.
Gov't Doc #: 5284
URI: http://dx.doi.org/10.1088/0031-9155/56/15/004
http://apo.ansto.gov.au/dspace/handle/10238/5004
ISSN: 0031-9155
Appears in Collections:Journal Articles

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