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Title: Poster — Thur Eve — 57: Evaluation of laryngeal mucosal dose with conventional linac and TomoTherapy

Abstract

The purpose of this study was to examine whether or not underdosing occurs in the mucosal layer during treatment of glottis cancer. A larynx phantom was produced and regions at risk of recurrence due to suspected underdosing were identified and wells drilled into the phantom for flush placement of TLDs. Seven interest points were chosen. CT simulation was completed prior to the wells being drilled, and again afterwards with the TLD locations indicated using BBs. Treatment plans created for this investigation included: 3DCRT using Elekta-XiO (n=9) and VMAT created using Elekta-Monaco (n=9), both delivered on an Elekta linac; standard TomoTherapy plan (n=11) and a directionally blocked TomoTherapy plan to approximate a 3D-conformal approach (n=5). Imaging dose during TomoTherapy deliveries was accounted for. The average TLD result at each interest point was compared to the planned value using a paired t-test. There was no significant difference between the planned and measured 3DCRT dose (268.9 vs. 267.0 cGy, respectively; p>0.05). Similarly, the planned and measured TomoTherapy treatment did not show any significant differences (271.7 vs 269.7 cGy; p>0.05). In the blocked TomoTherapy plan, significant overdosing was seen (274.5 vs 294.9 cGy; p<0.05) and underdosing was not seen in the VMAT treatment (303.5more » vs 321.8 cGy; p>0.05). Further investigation is ongoing to ensure appropriate normalization of results and to investigate the overdosing noted with the blocked TomoTherapy plan. Results from this study suggest that significant underdosing does not occur in the conventional treatment of early glottic cancer using 6MV photons.« less

Authors:
;  [1];  [2]
  1. Department of Medical Physics, The Ottawa Hospital Cancer Centre, Ottawa, Ontario (Canada)
  2. Department of Radiation Oncology, The Ottawa Hospital Cancer Centre, Ottawa, Ontario (Canada)
Publication Date:
OSTI Identifier:
22407896
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 41; Journal Issue: 8; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; COMPUTERIZED TOMOGRAPHY; CT-GUIDED RADIOTHERAPY; LARYNX; LINEAR ACCELERATORS; NEOPLASMS; PHANTOMS

Citation Formats

Nusrat, H, Lekx, K, and Eapen, L. Poster — Thur Eve — 57: Evaluation of laryngeal mucosal dose with conventional linac and TomoTherapy. United States: N. p., 2014. Web. doi:10.1118/1.4894917.
Nusrat, H, Lekx, K, & Eapen, L. Poster — Thur Eve — 57: Evaluation of laryngeal mucosal dose with conventional linac and TomoTherapy. United States. doi:10.1118/1.4894917.
Nusrat, H, Lekx, K, and Eapen, L. Fri . "Poster — Thur Eve — 57: Evaluation of laryngeal mucosal dose with conventional linac and TomoTherapy". United States. doi:10.1118/1.4894917.
@article{osti_22407896,
title = {Poster — Thur Eve — 57: Evaluation of laryngeal mucosal dose with conventional linac and TomoTherapy},
author = {Nusrat, H and Lekx, K and Eapen, L},
abstractNote = {The purpose of this study was to examine whether or not underdosing occurs in the mucosal layer during treatment of glottis cancer. A larynx phantom was produced and regions at risk of recurrence due to suspected underdosing were identified and wells drilled into the phantom for flush placement of TLDs. Seven interest points were chosen. CT simulation was completed prior to the wells being drilled, and again afterwards with the TLD locations indicated using BBs. Treatment plans created for this investigation included: 3DCRT using Elekta-XiO (n=9) and VMAT created using Elekta-Monaco (n=9), both delivered on an Elekta linac; standard TomoTherapy plan (n=11) and a directionally blocked TomoTherapy plan to approximate a 3D-conformal approach (n=5). Imaging dose during TomoTherapy deliveries was accounted for. The average TLD result at each interest point was compared to the planned value using a paired t-test. There was no significant difference between the planned and measured 3DCRT dose (268.9 vs. 267.0 cGy, respectively; p>0.05). Similarly, the planned and measured TomoTherapy treatment did not show any significant differences (271.7 vs 269.7 cGy; p>0.05). In the blocked TomoTherapy plan, significant overdosing was seen (274.5 vs 294.9 cGy; p<0.05) and underdosing was not seen in the VMAT treatment (303.5 vs 321.8 cGy; p>0.05). Further investigation is ongoing to ensure appropriate normalization of results and to investigate the overdosing noted with the blocked TomoTherapy plan. Results from this study suggest that significant underdosing does not occur in the conventional treatment of early glottic cancer using 6MV photons.},
doi = {10.1118/1.4894917},
journal = {Medical Physics},
number = 8,
volume = 41,
place = {United States},
year = {Fri Aug 15 00:00:00 EDT 2014},
month = {Fri Aug 15 00:00:00 EDT 2014}
}
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