Effect of Surface Irregularities on Dose Distribution from Leipzig and Valencia HDR Skin Applicators

Effect of Surface Irregularities on Dose Distribution from Leipzig and Valencia HDR Skin Applicators

Bibliographic Details
Main Author: Horne, Stephanie Marie Torok
Language:English
Published: University of Toledo Health Science Campus / OhioLINK 2011
Subjects:
Physics
Leipzig Applicator
Valencia Applicator
HDR Skin
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=mco1321477600
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-mco13214776002021-08-03T05:38:54Z Effect of Surface Irregularities on Dose Distribution from Leipzig and Valencia HDR Skin Applicators Horne, Stephanie Marie Torok Physics Leipzig Applicator Valencia Applicator HDR Skin <p>Skin cancer is the most common form of cancer in the United States today and safer, more accurate treatment methods are needed to combat this disease. Radiation therapy has proven to be one of the best options for managing this disease. Specifically, high-dose rate (HDR) brachytherapy utilizing surface applicators provides an excellent choice for physicians in treating small superficial lesions, limiting the irradiation to the target area. The Leipzig and Valencia HDR applicators (accessories of the Varian microSelectron-HDR afterloader) are designed to be used on a flat skin surface, for which case the isodose distributions have been well characterized. However, surface irregularities arising from natural facial contours (e.g., nose or ears) may introduce air gaps affecting the dose distribution. Investigation of the dosimetric impact of air gaps between skin and an applicator, for both cases of the Leipzig and Valencia applicators, is the main objective of this study. The systematic evaluation of dose distributions resulting from air gaps of various thickness (1, 3, and 5 mm) introduced under half of the applicator area was performed both experimentally and through Monte Carlo modeling. The latter approach allows for calculation of a detailed dose distribution under more complex surfaces. Utilizing a well developed model we have obtained dose distributions for situations that are possible in the clinic yet difficult to measure.</p><p>Our simulations suggest that a significant amount of the dose (~20%) is contributed by scatter from applicator. This mitigates the dose change at the edges of air gaps, resulting in partial “filling” of gaps evident in the shape of dose profiles.</p><p>We have found that use of the Leipzig and Valencia applicators over non-flat areas with air gaps up to 5mm deep, and less than 5mm wide should be clinically acceptable, as these surface irregularities do not generate significant changes in dose distribution. Detail results of this investigation will be presented.</p> 2011-12-27 English text University of Toledo Health Science Campus / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=mco1321477600 http://rave.ohiolink.edu/etdc/view?acc_num=mco1321477600 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Physics
Leipzig Applicator
Valencia Applicator
HDR Skin
spellingShingle Physics
Leipzig Applicator
Valencia Applicator
HDR Skin
Horne, Stephanie Marie Torok
Effect of Surface Irregularities on Dose Distribution from Leipzig and Valencia HDR Skin Applicators
author Horne, Stephanie Marie Torok
author_facet Horne, Stephanie Marie Torok
author_sort Horne, Stephanie Marie Torok
title Effect of Surface Irregularities on Dose Distribution from Leipzig and Valencia HDR Skin Applicators
title_short Effect of Surface Irregularities on Dose Distribution from Leipzig and Valencia HDR Skin Applicators
title_full Effect of Surface Irregularities on Dose Distribution from Leipzig and Valencia HDR Skin Applicators
title_fullStr Effect of Surface Irregularities on Dose Distribution from Leipzig and Valencia HDR Skin Applicators
title_full_unstemmed Effect of Surface Irregularities on Dose Distribution from Leipzig and Valencia HDR Skin Applicators
title_sort effect of surface irregularities on dose distribution from leipzig and valencia hdr skin applicators
publisher University of Toledo Health Science Campus / OhioLINK
publishDate 2011
url http://rave.ohiolink.edu/etdc/view?acc_num=mco1321477600
work_keys_str_mv AT hornestephaniemarietorok effectofsurfaceirregularitiesondosedistributionfromleipzigandvalenciahdrskinapplicators
_version_ 1719423005665263616

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