A phantom study on bladder and rectum dose measurements in brachytherapy of cervix cancer using FBX aqueous chemical dosimeter.

Abstract

The ferrous sulphate-benzoic acid-xylenol orange (FBX) chemical dosimeter, due to its aqueous form can measure average volume doses and hence may overcome the limitations of point dosimetry. The present study was undertaken to validate the use of FBX dosimeter for rectum and bladder dose measurement during intracavitary brachytherapy (ICBT) and transperineal interstitial brachytherapy (TIB). We filled cylindrical polypropylene tubes (PT) and Foley balloons (FB) with FBX solution and used them as substitutes for rectum and bladder dose measurements respectively. A water phantom was fabricated with provision to place the Fletcher-type ICBT and MUPIT template applicators, and FBX filled PT and FB within the phantom. The phantom was then CT scanned for treatment planning and subsequent irradiation. Our results show that the average difference between DVH derived dose value and FBX measured dose is 3.5% (PT) and 13.7% (FB) for ICBT, and 9% (PT) and 9.9% (FB) for TIB. We believe that the FBX system should be able to provide accuracy and precision sufficient for routine quality assurance purposes. The advantage of the FBX system is its water equivalent composition, average volume dose measuring capability, and energy and temperature independent response as compared to TLD or semiconductor dosimeters. However, detailed studies will be needed with regards to its safety before actual in-vivo dose measurements are possible with the FBX dosimeter.

• Authors: Anil K Bansal, Manoj K Semwal, Deepak Arora, D N Sharma, P K Julka, G K Rath
• Journal: Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB) (Phys Med) Vol. 29 Issue 4 Pg. 368-73 (Jun 2013) ISSN: 1724-191X [Electronic] Italy
• PMID: 22687710 (Publication Type: Journal Article)
• Copyright: Copyright © 2012 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Chemical References

• Ferrous Compounds
• Phenols
• Sulfoxides
• Water
• ferrous sulfate
• Benzoic Acid
• xylenol orange

Topics

• Benzoic Acid (chemistry)
• Brachytherapy (adverse effects)
• Female
• Ferrous Compounds (chemistry)
• Humans
• Organs at Risk (radiation effects)
• Phantoms, Imaging
• Phenols (chemistry)
• Pregnancy
• Radiometry (instrumentation)
• Radiotherapy Planning, Computer-Assisted
• Rectum (radiation effects)
• Sulfoxides (chemistry)
• Urinary Bladder (radiation effects)
• Uterine Cervical Neoplasms (radiotherapy)
• Water (chemistry)