By a News Reporter-Staff News Editor at Clinical Trials Week -- A new study on Drugs and Therapies is now available. According to news originating from Houston, Texas, by NewsRx correspondents, research stated, "The aim of this work was to create a mailable phantom with measurement accuracy suitable for Radiological Physics Center (RPC) audits of high dose-rate (HDR) brachytherapy sources at institutions participating in National Cancer Institute-funded cooperative clinical trials. Optically stimulated luminescence dosimeters (OSLDs) were chosen as the dosimeter to be used with the phantom."
Our news journalists obtained a quote from the research from the University of Texas, "The authors designed and built an 8 x 8 x 10 cm(3) prototype phantom that had two slots capable of holding Al2O3:C OSLDs (nanoDots; Landauer, Glenwood, IL) and a single channel capable of accepting all Ir-192 HDR brachytherapy sources in current clinical use in the United States. The authors irradiated the phantom with Nucletron and Varian Ir-192 HDR sources in order to determine correction factors for linearity with dose and the combined effects of irradiation energy and phantom characteristics. The phantom was then sent to eight institutions which volunteered to perform trial remote audits. The linearity correction factor was k(L) = (-9.43 x 10(-5) x dose) + 1.009, where dose is in cGy, which differed from that determined by the RPC for the same batch of dosimeters using Co-60 irradiation. Separate block correction factors were determined for current versions of both Nucletron and Varian Ir-192 HDR sources and these vendor-specific correction factors differed by almost 2.6%. For the Nucletron source, the correction factor was 1.026 [95% confidence interval (CI) = 1.023-1.028], and for the Varian source, it was 1.000 (95% CI = 0.995-1.005). Variations in lateral source positioning up to 0.8 mm and distal/proximal source positioning up to 10 mm had minimal effect on dose measurement accuracy. The overall dose measurement uncertainty of the system was estimated to be 2.4% and 2.5% for the Nucletron and Varian sources, respectively (95% CI). This uncertainty was sufficient to establish a +/- 5% acceptance criterion for source strength audits under a formal RPC audit program. Trial audits of four Nucletron sources and four Varian sources revealed an average RPC-to-institution dose ratio of 1.000 (standard deviation = 0.011). The authors have created an OSLD-based Ir-192 HDR brachytherapy source remote audit tool which offers sufficient dose measurement accuracy to allow the RPC to establish a remote audit program with a 5% acceptance criterion."
According to the news editors, the research concluded: "The feasibility of the system has been demonstrated with eight trial audits to date."
For more information on this research see: Development and implementation of a remote audit tool for high dose rate (HDR) Ir-192 brachytherapy using optically stimulated luminescence dosimetry. Medical Physics, 2013;40(11):542-549. Medical Physics can be contacted at: Amer Assoc Physicists Medicine Amer Inst Physics, Ste 1 No 1, 2 Huntington Quadrangle, Melville, NY 11747-4502, USA. (American Association of Physicists in Medicine - www.aapm.org; Medical Physics - online.medphys.org/)
The news correspondents report that additional information may be obtained from K.E. Casey, Univ Texas Grad Sch Biomed Sci Houston, Houston, TX 77030, United States. Additional authors for this research include P. Alvarez, S.F. Kry, R.M. Howell, A. Lawyer and D. Followill (see also Drugs and Therapies).
Keywords for this news article include: Texas, Houston, Radiotherapy, United States, Brachytherapy, Drugs and Therapies, North and Central America, Clinical Trials and Studies
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