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dc.creatorHan, Hsiang-Jung
dc.descriptionDue to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to, referencing the URI of the item.en
dc.descriptionIncludes bibliographical references: p.70-72.en
dc.descriptionIssued also on microfiche from Lange Micrographics.en
dc.description.abstractA single dosimeter is commonly worn on a radiation worker's chest to monitor radiation exposure. However, when a radiation worker is exposed to a posterior photon beam, effective dose equivalent (HE) can be severely underestimated using a single dosimeter on the chest. A new method, based on two dosimeters, for the estimation of effective dose equivalent has been developed. Although the use of two dosimeters, one on the chest and the other on the back, successfully corrected the underestimation problem for posterior photon beams, the two-dosimeter approach still produces overestimation of lateral, overhead, and underfoot irradiation geometries by a factor of two to three times the actual effective dose equivalent received when isotropic-responding dosimeters are used for measurement. A solution to this problem is to intentionally make dosimeters that underrespond as the incident photon beam approaches lateral, overhead, and underfoot directions. One objective of this research is to develop an optimal anisotropic responding (OAR) dosimeter which does not significantly overestimate effective dose equivalentfor lateral, overhead, and underfoot irradiation geometries, and maintains good performance for anterior and posterior beams. Several dosimeter geometries were investigated using Monte Carlo simulation to find the best geometry for the dosimeter attenuator using aluminum oxide (AI203) as the dosimeter attenuator material. The final developed OAR dosimeter did not overestimate effective dose equivalent by more than 80% over all photon energies and incident angles in the investigation, which is much less than the overestimation from isotropic-responding dosimeters (202%). The other objective in this research was to explore the dosimeters on estimating effective dose equivalent. This part of the research used the same code and approach as described above for estimating effective dose equivalent. Two kinds of misposition problems were simulated and discussed. Overall, the misposition problems in which the dosimeters were mispositioned only a small distance (2 cm) from the standard position have little influence on estimating effective dose equivalent for normally incident beam directions.en
dc.publisherTexas A&M University
dc.rightsThis thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries in 2008. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use.en
dc.subjecthealth physics.en
dc.subjectMajor health physics.en
dc.titleDevelopment of an optimal anisotropic responding (OAR) dosimeter for two-dosimeter dosimetry for better estimation of effective dose equivalent (He) and the impact of dosimeter misposition on estimating effective dose equivalent using isotropic dosimetersen
dc.typeThesisen physicsen
dc.format.digitalOriginreformatted digitalen

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