Pretreatment verification of high dose rate brachytherapy plans using the ‘magic phantom’ system

High dose rate (HDR) brachytherapy treatments can be incorrectly administered to patients due to human error and equipment malfunction. While the incidence rates of these events are low, an additional redundancy check could include independent verification of the plan prior to treatment. This work describes the verification of six patient HDR treatment plans using the 'magic phantom' (MPh) silicon diode array, and a specialized HDR position-time gamma analysis criteria. The possibility of accelerated treatment plan verification is additionally investigated by reducing the prescription dose to shorten the total time needed for measurement. The MPh system was able to determine the measured dwell positions and times from the six patient plans to within 1.3 mm and 0.3 s, respectively. Using the position-time gamma analysis, the delivery of all measured patient plans were found to pass this metric with pass rates of 100%. The approach of decreasing prescription dose gave equal pass rates to the full dose plan when evaluated using the criteria. It was identified that the total time for treatment verification is dependent on the number of needles used, and that a substantial decrease in the total time for verification could be made by reducing the prescription dose for plans containing a low number of needles. The application of this method may have the ability to streamline pretreatment verification of the afterloader delivery within the clinical setting.

[1]  I. Fuduli,et al.  A comparative analysis of multichannel Data Acquisition Systems for quality assurance in external beam radiation therapy , 2014 .

[2]  J. Valentin.  Prevention of high-dose-rate brachytherapy accidents , 2005 .

[3]  J. Palta,et al.  Comprehensive QA for radiation oncology: report of AAPM Radiation Therapy Committee Task Group 40. , 1994, Medical physics.

[4]  Bongile Mzenda,et al.  Performance assessment of the BEBIG MultiSource® high dose rate brachytherapy treatment unit , 2009, Physics in medicine and biology.

[5]  J. Williamson,et al.  High dose-rate brachytherapy treatment delivery: report of the AAPM Radiation Therapy Committee Task Group No. 59. , 1998, Medical physics.

[6]  D. Low,et al.  A technique for the quantitative evaluation of dose distributions. , 1998, Medical physics.

[7]  M Petasecca,et al.  The evaluation of a 2D diode array in "magic phantom" for use in high dose rate brachytherapy pretreatment quality assurance. , 2015, Medical physics.

[8]  M Petasecca,et al.  The feasibility study and characterization of a two-dimensional diode array in "magic phantom" for high dose rate brachytherapy quality assurance. , 2013, Medical physics.

[9]  D. Bradley,et al.  Physics-aspects of dose accuracy in high dose rate (HDR) brachytherapy: source dosimetry, treatment planning, equipment performance and in vivo verification techniques , 2012, Journal of contemporary brachytherapy.

[10]  Rakesh R. Patel,et al.  A review of safety, quality management, and practice guidelines for high-dose-rate brachytherapy: executive summary. , 2014, Practical radiation oncology.

[11]  M. Petasecca,et al.  Characterization of a novel two dimensional diode array the "magic plate" as a radiation detector for radiation therapy treatment. , 2012, Medical physics.

[12]  Kari Tanderup,et al.  In vivo dosimetry in brachytherapy. , 2013, Medical physics.

[13]  Naoya Murakami,et al.  Dose error from deviation of dwell time and source position for high dose-rate 192Ir in remote afterloading system , 2014, Journal of radiation research.

[14]  C Liu,et al.  A quality assurance test tool for high dose-rate remote afterloading brachytherapy units. , 1998, Medical physics.

[15]  I. Fuduli,et al.  Multichannel Data Acquisition System comparison for Quality Assurance in external beam radiation therapy , 2014 .

[16]  J F Williamson,et al.  Code of practice for brachytherapy physics: report of the AAPM Radiation Therapy Committee Task Group No. 56. American Association of Physicists in Medicine. , 1997, Medical physics.

[17]  David Sasaki,et al.  A quality assurance tool for high-dose-rate brachytherapy. , 2010, Medical physics.

[18]  P. Pittet,et al.  Dosimetry systems based on Gallium Nitride probe for radiotherapy, brachytherapy and interventional radiology , 2015 .

[19]  A. Rosenfeld,et al.  In vivo dosimetry: trends and prospects for brachytherapy. , 2014, The British journal of radiology.