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Title: SU-F-T-379: Dosimetric Impacts of Topical Agents and Dressings On Skin in Radiotherapy

Abstract

Purpose: This study investigated the superficial dose enhancement in the application of topical agents, clinical materials (thermal mask and bolus) and dressings in megavoltage photon beam radiotherapy. Different topical skin agents, clinical materials and dressings were evaluated and compared for their skin dosimetric impacts on the patients during radiation treatment. Methods: Superficial dose enhancements, or percentage doses with and without the studying materials, were measured using the 6 MV (Field size = 10×10 cm{sup 2}) photon beams produced by a Varian TrueBeam linear accelerator. Twelve topical agents, five dressings (dry and wet conditions) and three clinical materials were studied. A solid water phantom was used with a MOSFET dose detector (TN-1002RD, Thomson and Nielsen Electronic, Ottawa, Ontario, Canada) located under a 1-mm PMMA slab to measure the skin dose. The distance between the radiation source and phantom surface was set to 100 cm in all measurements. The topical agents were distributed evenly with 1.5 mm thickness using our specific sample holder on the phantom surface. Extrapolations were made of 0.5 mm thickness for the agents to provide meaningful clinical value. Results: By comparing surface doses without studying materials, it is found that no topical agents had superficial dose enhancement highermore » than the clinical materials namely, thermoplastic mask (128%), 5-mm Superflab™ bolus (158%) and 10-mm Superflab™ bolus (171%) regarding the same thickness. Superficial dose enhancement of dry dressing did not exceed 110.5%, while wet dressings produced higher dose enhancements (133% for wet Mepilex lite and 141% for wet Mepilex Ag transfer). Conclusion: It is concluded that the evaluated topical agents and dry dressings did not increase the superficial dose to a concerning level, even using excessive thickness in every fraction of radiation treatment. Wet dressings were found producing the bolus effect, but was still substantially less than applying a thin 5-mm bolus.« less

Authors:
; ; ; ; ;  [1]
  1. Princess Margaret Cancer Centre, Toronto, ON (Canada)
Publication Date:
OSTI Identifier:
22648977
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 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; 61 RADIATION PROTECTION AND DOSIMETRY; 43 PARTICLE ACCELERATORS; LINEAR ACCELERATORS; PHANTOMS; PHOTON BEAMS; RADIATION SOURCES; RADIOTHERAPY; SKIN; THICKNESS

Citation Formats

Tse, K, Morley, L, Cashell, A, Sperduti, A, McQuestion, M, and Chow, J. SU-F-T-379: Dosimetric Impacts of Topical Agents and Dressings On Skin in Radiotherapy. United States: N. p., 2016. Web. doi:10.1118/1.4956564.
Tse, K, Morley, L, Cashell, A, Sperduti, A, McQuestion, M, & Chow, J. SU-F-T-379: Dosimetric Impacts of Topical Agents and Dressings On Skin in Radiotherapy. United States. doi:10.1118/1.4956564.
Tse, K, Morley, L, Cashell, A, Sperduti, A, McQuestion, M, and Chow, J. 2016. "SU-F-T-379: Dosimetric Impacts of Topical Agents and Dressings On Skin in Radiotherapy". United States. doi:10.1118/1.4956564.
@article{osti_22648977,
title = {SU-F-T-379: Dosimetric Impacts of Topical Agents and Dressings On Skin in Radiotherapy},
author = {Tse, K and Morley, L and Cashell, A and Sperduti, A and McQuestion, M and Chow, J},
abstractNote = {Purpose: This study investigated the superficial dose enhancement in the application of topical agents, clinical materials (thermal mask and bolus) and dressings in megavoltage photon beam radiotherapy. Different topical skin agents, clinical materials and dressings were evaluated and compared for their skin dosimetric impacts on the patients during radiation treatment. Methods: Superficial dose enhancements, or percentage doses with and without the studying materials, were measured using the 6 MV (Field size = 10×10 cm{sup 2}) photon beams produced by a Varian TrueBeam linear accelerator. Twelve topical agents, five dressings (dry and wet conditions) and three clinical materials were studied. A solid water phantom was used with a MOSFET dose detector (TN-1002RD, Thomson and Nielsen Electronic, Ottawa, Ontario, Canada) located under a 1-mm PMMA slab to measure the skin dose. The distance between the radiation source and phantom surface was set to 100 cm in all measurements. The topical agents were distributed evenly with 1.5 mm thickness using our specific sample holder on the phantom surface. Extrapolations were made of 0.5 mm thickness for the agents to provide meaningful clinical value. Results: By comparing surface doses without studying materials, it is found that no topical agents had superficial dose enhancement higher than the clinical materials namely, thermoplastic mask (128%), 5-mm Superflab™ bolus (158%) and 10-mm Superflab™ bolus (171%) regarding the same thickness. Superficial dose enhancement of dry dressing did not exceed 110.5%, while wet dressings produced higher dose enhancements (133% for wet Mepilex lite and 141% for wet Mepilex Ag transfer). Conclusion: It is concluded that the evaluated topical agents and dry dressings did not increase the superficial dose to a concerning level, even using excessive thickness in every fraction of radiation treatment. Wet dressings were found producing the bolus effect, but was still substantially less than applying a thin 5-mm bolus.},
doi = {10.1118/1.4956564},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}
  • Lewisite is a potent chemical warfare arsenical vesicant that can cause severe skin lesions. Today, lewisite exposure remains possible during demilitarization of old ammunitions and as a result of deliberate use. Although its cutaneous toxicity is not fully elucidated, a specific antidote exists, the British anti-lewisite (BAL, dimercaprol) but it is not without untoward effects. Analogs of BAL, less toxic, have been developed such as meso-2,3-dimercaptosuccinic acid (DMSA) and have been employed for the treatment of heavy metal poisoning. However, efficacy of DMSA against lewisite-induced skin lesions remains to be determined in comparison with BAL. We have thus evaluated inmore » this study the therapeutic efficacy of BAL and DMSA in two administration modes against skin lesions induced by lewisite vapor on SKH-1 hairless mice. Our data demonstrate a strong protective efficacy of topical application of dimercapto-chelating agents in contrast to a subcutaneous administration 1 h after lewisite exposure, with attenuation of wound size, necrosis and impairment of skin barrier function. The histological evaluation also confirms the efficacy of topical application by showing that treatments were effective in reversing lewisite-induced neutrophil infiltration. This protective effect was associated with an epidermal hyperplasia. However, for all the parameters studied, BAL was more effective than DMSA in reducing lewisite-induced skin injury. Together, these findings support the use of a topical form of dimercaprol-chelating agent against lewisite-induced skin lesion within the first hour after exposure to increase the therapeutic management and that BAL, despite its side-effects, should not be abandoned. - Highlights: • Topically applied dimercapto-chelating agents reduce lewisite-induced skin damage. • One topical application of BAL or DMSA is sufficient to reverse lewisite effects. • Topical BAL is more effective than DMSA to counteract lewisite-induced skin damage.« less
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