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Title: Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source

Abstract

Purpose: To present design aspects and acceptance tests performed for clinical implementation of electronic brachytherapy treatment of early stage rectal adenocarcinoma. A dosimetric comparison is made between the historically used Philips RT-50 unit and the newly developed Axxent{sup Registered-Sign} Model S700 electronic brachytherapy source manufactured by Xoft (iCad, Inc.). Methods: Two proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Two custom surface applicators were manufactured by Xoft and were designed to fit and interlock with the proctoscope cones from ESI. Dose rates, half value layers (HVL), and percentage depth dose (PDD) measurements were made with the Xoft system and compared to historical RT-50 data. A description of the patient treatment approach and exposure rates during the procedure is also provided. Results: The electronic brachytherapy system has a lower surface dose rate than the RT-50. The dose rate to water on the surface from the Xoft system is approximately 2.1 Gy/min while the RT-50 is 10-12 Gy/min. However, treatment times with Xoft are still reasonable. The HVLs and PDDs between the two systems were comparable resulting in similar doses to the target and to regions beyond the target. The exposure rate levels around a patient treatment were acceptable. The standard uncertaintymore » in the dose rate to water on the surface is approximately {+-}5.2%. Conclusions: The Philips RT-50 unit is an out-of-date radiotherapy machine that is no longer manufactured with limited replacement parts. The use of a custom-designed proctoscope and Xoft surface applicators allows delivery of a well-established treatment with the ease of a modern radiotherapy device. While the dose rate is lower with the use of Xoft, the treatment times are still reasonable. Additionally, personnel may stand farther away from the Xoft radiation source, thus potentially reducing radiation exposure to the operator and other personnel.« less

Authors:
; ; ; ;  [1];  [2];  [2]
  1. Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22099082
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 39; Journal Issue: 11; Other Information: (c) 2012 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; 62 RADIOLOGY AND NUCLEAR MEDICINE; 60 APPLIED LIFE SCIENCES; BRACHYTHERAPY; CARCINOMAS; DEPTH DOSE DISTRIBUTIONS; DOSE RATES; MEDICAL PERSONNEL; PATIENTS; RADIATION DOSES; RADIATION SOURCES; RECTUM; SURFACES; WATER

Citation Formats

Richardson, Susan, Garcia-Ramirez, Jose, Lu Wei, Myerson, Robert J., Parikh, Parag, Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201, and Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110. Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source. United States: N. p., 2012. Web. doi:10.1118/1.4757915.
Richardson, Susan, Garcia-Ramirez, Jose, Lu Wei, Myerson, Robert J., Parikh, Parag, Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201, & Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110. Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source. United States. doi:10.1118/1.4757915.
Richardson, Susan, Garcia-Ramirez, Jose, Lu Wei, Myerson, Robert J., Parikh, Parag, Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201, and Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110. Thu . "Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source". United States. doi:10.1118/1.4757915.
@article{osti_22099082,
title = {Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source},
author = {Richardson, Susan and Garcia-Ramirez, Jose and Lu Wei and Myerson, Robert J. and Parikh, Parag and Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110},
abstractNote = {Purpose: To present design aspects and acceptance tests performed for clinical implementation of electronic brachytherapy treatment of early stage rectal adenocarcinoma. A dosimetric comparison is made between the historically used Philips RT-50 unit and the newly developed Axxent{sup Registered-Sign} Model S700 electronic brachytherapy source manufactured by Xoft (iCad, Inc.). Methods: Two proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Two custom surface applicators were manufactured by Xoft and were designed to fit and interlock with the proctoscope cones from ESI. Dose rates, half value layers (HVL), and percentage depth dose (PDD) measurements were made with the Xoft system and compared to historical RT-50 data. A description of the patient treatment approach and exposure rates during the procedure is also provided. Results: The electronic brachytherapy system has a lower surface dose rate than the RT-50. The dose rate to water on the surface from the Xoft system is approximately 2.1 Gy/min while the RT-50 is 10-12 Gy/min. However, treatment times with Xoft are still reasonable. The HVLs and PDDs between the two systems were comparable resulting in similar doses to the target and to regions beyond the target. The exposure rate levels around a patient treatment were acceptable. The standard uncertainty in the dose rate to water on the surface is approximately {+-}5.2%. Conclusions: The Philips RT-50 unit is an out-of-date radiotherapy machine that is no longer manufactured with limited replacement parts. The use of a custom-designed proctoscope and Xoft surface applicators allows delivery of a well-established treatment with the ease of a modern radiotherapy device. While the dose rate is lower with the use of Xoft, the treatment times are still reasonable. Additionally, personnel may stand farther away from the Xoft radiation source, thus potentially reducing radiation exposure to the operator and other personnel.},
doi = {10.1118/1.4757915},
journal = {Medical Physics},
issn = {0094-2405},
number = 11,
volume = 39,
place = {United States},
year = {2012},
month = {11}
}