The accuracy and precision of the KIM motion monitoring system used in the multi-institutional TROG 15.01 Stereotactic Prostate Ablative Radiotherapy with KIM (SPARK) trial.

PURPOSE Kilovoltage Intrafraction Monitoring (KIM) allows for real-time image guidance for tracking tumor motion in six-degrees-of-freedom (6DoF) on a standard linear accelerator. This study assessed the geometric accuracy and precision of KIM used to guide patient treatments in the TROG 15.01 multi-institutional Stereotactic Prostate Ablative Radiotherapy (SPARK) trial and investigated factors affecting accuracy and precision. METHODS Fractions from 44 patients with prostate cancer treated using KIM-guided SBRT were analyzed across four institutions, on two different linear accelerator models and two different beam models (6MV and 10MV FFF). The geometric accuracy and precision of KIM was assessed from over 33,000 kV images (translation) and over 9,000 images (rotation) by comparing the real-time measured motion to retrospective kV/MV triangulation. Factors potentially affecting accuracy, including contrast-to-noise ratio (CNR) of kV images and incorrect marker segmentation, were also investigated. RESULTS The geometric accuracy and precision did not depend on treatment institution, beam model or motion magnitude, but was correlated with gantry angle. The centroid geometric accuracy and precision of the KIM system for SABR prostate treatments was 0.0±0.5, 0.0±0.4 and 0.1±0.3 mm for translation, and -0.1±0.6°, -0.1±1.4° and -0.1±1.0° for rotation in the AP, LR and SI directions respectively. Centroid geometric error exceeded 2 mm for 0.05% of this dataset. No significant relationship was found between large geometric error and CNR or marker segmentation correlation. CONCLUSIONS This study demonstrated the ability of KIM to locate the prostate with accuracy below other uncertainties in radiotherapy treatments, and the feasibility for KIM to be implemented across multiple institutions. This article is protected by copyright. All rights reserved.

[1]  Michalis Aristophanous,et al.  3-D fiducial motion tracking using limited MV projections in arc therapy. , 2011, Medical physics.

[2]  J. Fowler,et al.  Stereotactic hypofractionated accurate radiotherapy of the prostate (SHARP), 33.5 Gy in five fractions for localized disease: first clinical trial results. , 2007, International journal of radiation oncology, biology, physics.

[3]  M. Steinberg,et al.  Health-related quality of life after stereotactic body radiation therapy for localized prostate cancer: results from a multi-institutional consortium of prospective trials. , 2013, International journal of radiation oncology, biology, physics.

[4]  Peter B. Greer,et al.  Technical note: TROG 15.01 SPARK trial multi‐institutional imaging dose measurement , 2017, Journal of applied clinical medical physics.

[5]  P. Keall,et al.  The first clinical implementation of a real-time six degree of freedom target tracking system during radiation therapy based on Kilovoltage Intrafraction Monitoring (KIM). , 2017, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[6]  Paul J Keall,et al.  Real-time prostate trajectory estimation with a single imager in arc radiotherapy: a simulation study , 2009, Physics in medicine and biology.

[7]  Paul J Keall,et al.  Real-Time 3D Image Guidance Using a Standard LINAC: Measured Motion, Accuracy, and Precision of the First Prospective Clinical Trial of Kilovoltage Intrafraction Monitoring-Guided Gating for Prostate Cancer Radiation Therapy. , 2016, International journal of radiation oncology, biology, physics.

[8]  Paul J Keall,et al.  Multileaf Collimator Tracking Improves Dose Delivery for Prostate Cancer Radiation Therapy: Results of the First Clinical Trial. , 2015, International journal of radiation oncology, biology, physics.

[9]  P Keall,et al.  Quantifying the accuracy and precision of a novel real-time 6 degree-of-freedom kilovoltage intrafraction monitoring (KIM) target tracking system , 2017, Physics in medicine and biology.

[10]  Jason Wang,et al.  Stereotactic body radiotherapy for localized prostate cancer: pooled analysis from a multi-institutional consortium of prospective phase II trials. , 2013, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[11]  C Belka,et al.  Intra-fraction motion of the prostate is a random walk , 2015, Physics in medicine and biology.

[12]  Constantine Mantz,et al.  A Phase II Trial of Stereotactic Ablative Body Radiotherapy for Low-Risk Prostate Cancer Using a Non-Robotic Linear Accelerator and Real-Time Target Tracking: Report of Toxicity, Quality of Life, and Disease Control Outcomes with 5-Year Minimum Follow-Up , 2014, Front. Oncol..

[13]  P. Keall,et al.  Dosimetric impact of intrafraction rotations in stereotactic prostate radiotherapy: A subset analysis of the TROG 15.01 SPARK trial. , 2019, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[14]  V. Weinberg,et al.  Outcomes of hypofractionated stereotactic body radiotherapy boost for intermediate and high-risk prostate cancer , 2016, Radiation Oncology.

[15]  Anurag K. Singh,et al.  Stereotactic radiotherapy for prostate cancer: A review and future directions , 2017, World journal of clinical oncology.

[16]  Haoran Jin,et al.  Virtual HDR CyberKnife treatment for localized prostatic carcinoma: dosimetry comparison with HDR brachytherapy and preliminary clinical observations. , 2008, International journal of radiation oncology, biology, physics.

[17]  Zdenka Kuncic,et al.  Markerless tumor tracking using short kilovoltage imaging arcs for lung image-guided radiotherapy , 2015, Physics in medicine and biology.

[18]  Michael J. Zelefsky,et al.  Continuous monitoring and intrafraction target position correction during treatment improves target coverage for patients undergoing SBRT prostate therapy. , 2015, International journal of radiation oncology, biology, physics.

[19]  Fang-Fang Yin,et al.  A technique for estimating 4D-CBCT using prior knowledge and limited-angle projections. , 2013, Medical physics.

[20]  Paul J Keall,et al.  A deep learning framework for automatic detection of arbitrarily shaped fiducial markers in intrafraction fluoroscopic images. , 2019, Medical physics.

[21]  Jung-Ha Kim,et al.  The accuracy and precision of Kilovoltage Intrafraction Monitoring (KIM) six degree-of-freedom prostate motion measurements during patient treatments. , 2018, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[22]  Paul J Keall,et al.  A method for robust segmentation of arbitrarily shaped radiopaque structures in cone-beam CT projections. , 2011, Medical physics.

[23]  Paul J Keall,et al.  Three-dimensional prostate position estimation with a single x-ray imager utilizing the spatial probability density , 2008, Physics in medicine and biology.

[24]  G. Mageras,et al.  Simultaneous MV‐kV imaging for intrafractional motion management during volumetric‐modulated arc therapy delivery* , 2016, Journal of applied clinical medical physics.

[25]  Timothy D. Solberg,et al.  Dosimetric consequences of intrafraction prostate motion. , 2008, International journal of radiation oncology, biology, physics.

[26]  P J Keall,et al.  Quality assurance for the clinical implementation of kilovoltage intrafraction monitoring for prostate cancer VMAT. , 2014, Medical physics.

[27]  Paul J Keall,et al.  Implementation of a new method for dynamic multileaf collimator tracking of prostate motion in arc radiotherapy using a single kV imager. , 2010, International journal of radiation oncology, biology, physics.

[28]  Mark K Buyyounouski,et al.  Stereotactic body radiotherapy for primary management of early-stage, low- to intermediate-risk prostate cancer: report of the American Society for Therapeutic Radiology and Oncology Emerging Technology Committee. , 2010, International journal of radiation oncology, biology, physics.

[29]  P J Keall,et al.  Determining appropriate imaging parameters for kilovoltage intrafraction monitoring: an experimental phantom study , 2015, Physics in medicine and biology.

[30]  V. Gebski,et al.  Stereotactic prostate adaptive radiotherapy utilising kilovoltage intrafraction monitoring: the TROG 15.01 SPARK trial , 2017, BMC Cancer.

[31]  Paul Keall,et al.  Real-time estimation of prostate tumor rotation and translation with a kV imaging system based on an iterative closest point algorithm , 2013, Physics in medicine and biology.

[32]  Cai Grau,et al.  Robust automatic segmentation of multiple implanted cylindrical gold fiducial markers in cone-beam CT projections. , 2011, Medical physics.

[33]  P J Keall,et al.  DMLC tracking and gating can improve dose coverage for prostate VMAT. , 2014, Medical physics.

[34]  P. Munro,et al.  Evaluation of a new six degrees of freedom couch for radiation therapy. , 2013, Medical physics.

[35]  Herbert Cattell,et al.  Electromagnetic detection and real-time DMLC adaptation to target rotation during radiotherapy. , 2012, International journal of radiation oncology, biology, physics.