Comparison of action levels for patient-specific quality assurance of intensity modulated radiation therapy and volumetric modulated arc therapy treatments.

PURPOSE To perform a comprehensive and systematic comparison of fixed-beam IMRT and volumetric modulated arc therapy (VMAT) patient-specific QA measurements for a common set of geometries using typical measurement methods. METHODS Fixed-beam IMRT and VMAT plans were constructed for structure set geometries provided by AAPM Task Group 119. The plans were repeatedly delivered across multiple measurement sessions, and the resulting dose distributions were measured with (1) radiochromic film and ionization chamber and (2) a commercial two-dimensional diode array. The resulting QA measurements from each delivery technique were then analyzed, compared, and tested for statistically significant differences. RESULTS Although differences were noted between QA results for some plans, neither modality showed consistently better agreement of measured and planned doses: of the 22 comparisons, IMRT showed better QA results in 11 cases, and VMAT showed better QA results in 11 cases. No statistically significant differences (p < 0.05) between IMRT and VMAT QA results were found for point doses measured with an ionization chamber, planar doses measured with radiochromic film, or planar doses measured with a two-dimensional diode array. CONCLUSIONS These results suggest that it is appropriate to apply patient-specific QA action levels derived from fixed-beam IMRT to VMAT.

[1]  James L Bedford,et al.  Evaluation of the Delta4 phantom for IMRT and VMAT verification , 2009, Physics in medicine and biology.

[2]  E. Schreibmann,et al.  Patient-specific quality assurance method for VMAT treatment delivery. , 2009, Medical physics.

[3]  Geoffrey G. Zhang,et al.  Initial dosimetric evaluation of SmartArc – a novel VMAT treatment planning module implemented in a multi‐vendor delivery chain , 2010, Journal of applied clinical medical physics.

[4]  J. Mechalakos,et al.  IMRT commissioning: multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119. , 2009, Medical physics.

[5]  Geoffrey G. Zhang,et al.  Evaluation of a new VMAT QA device, or the “X” and “O” array geometries , 2011, Journal of applied clinical medical physics.

[6]  Benjamin E Nelms,et al.  Moving from gamma passing rates to patient DVH-based QA metrics in pretreatment dose QA. , 2011, Medical physics.

[7]  Ke Sheng,et al.  Comparison of Elekta VMAT with helical tomotherapy and fixed field IMRT: plan quality, delivery efficiency and accuracy. , 2010, Medical physics.

[8]  Karl Otto,et al.  Volumetric modulated arc therapy: IMRT in a single gantry arc. , 2007, Medical physics.

[9]  James L Bedford,et al.  Treatment planning for volumetric modulated arc therapy. , 2009, Medical physics.

[10]  J. Deasy,et al.  Geometric interpretation of the gamma dose distribution comparison technique: interpolation-free calculation. , 2008, Medical physics.

[11]  Lei Dong,et al.  Rapid radiographic film calibration for IMRT verification using automated MLC fields. , 2002, Medical physics.

[12]  K. Otto,et al.  Volumetric modulated arc therapy for delivery of prostate radiotherapy: comparison with intensity-modulated radiotherapy and three-dimensional conformal radiotherapy. , 2008, International journal of radiation oncology, biology, physics.

[13]  Stefan Both,et al.  A study to establish reasonable action limits for patient‐specific quality assurance in intensity‐modulated radiation therapy , 2007, Journal of applied clinical medical physics.

[14]  Fang-Fang Yin,et al.  Volumetric-modulated arc therapy: effective and efficient end-to-end patient-specific quality assurance. , 2010, International journal of radiation oncology, biology, physics.

[15]  David A Jaffray,et al.  Novel dosimetric phantom for quality assurance of volumetric modulated arc therapy. , 2009, Medical physics.

[16]  P. Jursinic,et al.  MapCHECK used for rotational IMRT measurements: Step-and-shoot, Tomotherapy, RapidArc. , 2010, Medical physics.

[17]  J. Fontenot,et al.  Single-arc volumetric-modulated arc therapy can provide dose distributions equivalent to fixed-beam intensity-modulated radiation therapy for prostatic irradiation with seminal vesicle and/or lymph node involvement. , 2012, The British journal of radiology.

[18]  P Francescon,et al.  Quality assurance of volumetric modulated arc therapy: evaluation and comparison of different dosimetric systems. , 2011, Medical physics.

[19]  Aime M. Gloi,et al.  RapidArc quality assurance through MapCHECK , 2011, Journal of applied clinical medical physics.

[20]  Jon J Kruse,et al.  On the insensitivity of single field planar dosimetry to IMRT inaccuracies. , 2010, Medical physics.

[21]  Richard A Popple,et al.  RapidArc radiation therapy: first year experience at the University of Alabama at Birmingham. , 2010, International journal of radiation oncology, biology, physics.

[22]  Jan-Jakob Sonke,et al.  3D Dosimetric verification of volumetric-modulated arc therapy by portal dosimetry. , 2010, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[23]  M. Kaus,et al.  Development and evaluation of an efficient approach to volumetric arc therapy planning. , 2009, Medical physics.

[24]  Lei Dong,et al.  Dosimetry tools and techniques for IMRT. , 2011, Medical physics.

[25]  J. Bedford,et al.  Commissioning of volumetric modulated arc therapy (VMAT). , 2009, International journal of radiation oncology, biology, physics.

[26]  Benjamin E Nelms,et al.  Per-beam, planar IMRT QA passing rates do not predict clinically relevant patient dose errors. , 2011, Medical physics.

[27]  G. Mancuso.  Evaluation of volumetric modulated arc therapy (VMAT) patient specific quality assurance , 2011 .