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Title: SU-G-JeP4-04: Commissioning and Acceptance Testing of Optical Surface Monitoring System On TrueBEAM STx as Per Task Group 147

Abstract

Purpose: Optical Surface Monitoring system (OSMS) have been recently introduced by Varian for initial patient positioning and real-time monitoring during complex radiotherapy treatment. The purpose of this work was to implement TG 147 with OSMS. Methods: Recently we installed OSMS first of its kind in India on trueBEAM STx at our Institue. The OSMS is composed of a three cameras ceiling mounted and a Workstation. The following tests were performed to validate the system a. Calibration b. System reproducibility and drift c. Static localization displacement accuracy and d. Dynamic radiation gating delivery. The Calibration procedure consists of Daily,Monthly and MV Radiation Isocenter Calibration. The reproducibility of system was tested by monitoring the varian gating phantom test pattern for at least 120 min. Each recorded pattern was registered to the reference surface to calculate the required couch adjustment. To measure the static localization displacement accuracy of the system to detect and quantify patient shift relative to a reference image,we compared the shift detected by the surface imaging system with known couch transitions in a phantom study. The phantom was set in a motion and the radiation beam was holded by changing the threshold in the software for different clinical setups tomore » test the dynamic radiation gating capability. Results: Daily calibration was within ±0.5 mm. The MV radiation isocentre with respect to cameras was less than 1 mm in translational axis and less than 0.5° for rotational axis. The reproducibility was found to be 0.4 mm. The maximum static displacement accuracy was 0.75 mm for the three translational axis, and less than 0.5° for rotational axis. The system was able to hold the beam with a minimum threshold of 1 mm. Conclusion: A quality assurance process has been developed as per TG 147 for the clinical implementation of an OSMS in radiation therapy.« less

Authors:
; ;  [1]
  1. Sir HN RF Hospital, Mumbai, Maharashtra (India)
Publication Date:
OSTI Identifier:
22649454
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; ACCURACY; BIOMEDICAL RADIOGRAPHY; CALIBRATION; COMPUTER CODES; MONITORING; PHANTOMS; QUALITY ASSURANCE; TESTING

Citation Formats

Mhatre, V, Patwe, P, and Dandekar, P. SU-G-JeP4-04: Commissioning and Acceptance Testing of Optical Surface Monitoring System On TrueBEAM STx as Per Task Group 147. United States: N. p., 2016. Web. doi:10.1118/1.4957114.
Mhatre, V, Patwe, P, & Dandekar, P. SU-G-JeP4-04: Commissioning and Acceptance Testing of Optical Surface Monitoring System On TrueBEAM STx as Per Task Group 147. United States. doi:10.1118/1.4957114.
Mhatre, V, Patwe, P, and Dandekar, P. 2016. "SU-G-JeP4-04: Commissioning and Acceptance Testing of Optical Surface Monitoring System On TrueBEAM STx as Per Task Group 147". United States. doi:10.1118/1.4957114.
@article{osti_22649454,
title = {SU-G-JeP4-04: Commissioning and Acceptance Testing of Optical Surface Monitoring System On TrueBEAM STx as Per Task Group 147},
author = {Mhatre, V and Patwe, P and Dandekar, P},
abstractNote = {Purpose: Optical Surface Monitoring system (OSMS) have been recently introduced by Varian for initial patient positioning and real-time monitoring during complex radiotherapy treatment. The purpose of this work was to implement TG 147 with OSMS. Methods: Recently we installed OSMS first of its kind in India on trueBEAM STx at our Institue. The OSMS is composed of a three cameras ceiling mounted and a Workstation. The following tests were performed to validate the system a. Calibration b. System reproducibility and drift c. Static localization displacement accuracy and d. Dynamic radiation gating delivery. The Calibration procedure consists of Daily,Monthly and MV Radiation Isocenter Calibration. The reproducibility of system was tested by monitoring the varian gating phantom test pattern for at least 120 min. Each recorded pattern was registered to the reference surface to calculate the required couch adjustment. To measure the static localization displacement accuracy of the system to detect and quantify patient shift relative to a reference image,we compared the shift detected by the surface imaging system with known couch transitions in a phantom study. The phantom was set in a motion and the radiation beam was holded by changing the threshold in the software for different clinical setups to test the dynamic radiation gating capability. Results: Daily calibration was within ±0.5 mm. The MV radiation isocentre with respect to cameras was less than 1 mm in translational axis and less than 0.5° for rotational axis. The reproducibility was found to be 0.4 mm. The maximum static displacement accuracy was 0.75 mm for the three translational axis, and less than 0.5° for rotational axis. The system was able to hold the beam with a minimum threshold of 1 mm. Conclusion: A quality assurance process has been developed as per TG 147 for the clinical implementation of an OSMS in radiation therapy.},
doi = {10.1118/1.4957114},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}
  • Purpose: To provide commissioning and acceptance test data of the Varian Eclipse electron Monte Carlo model (eMC v.11) for TrueBeam linac. We also investigated the uncertainties in beam model parameters and dose calculation results for different geometric configurations. Methods: For beam commissioning, PTW CC13 thimble chamber and IBA Blue Phantom2 were used to collect PDD and dose profiles in air. Cone factors were measured with a parallel plate chamber (PTW N23342) in solid water. GafChromic EBT3 films were used for dose calculation verifications to compare with parallel plate chamber results in the following test geometries: oblique incident, extended distance, smallmore » cutouts, elongated cutouts, irregular surface, and heterogeneous layers. Results: Four electron energies (6e, 9e, 12e, and 15e) and five cones (6×6, 10×10, 15×15, 20×20, and 25×25) with standard cutouts were calculated for different grid sizes (1, 1.5,2, and 2.5 mm) and compared with chamber measurements. The results showed calculations performed with a coarse grid size underestimated the absolute dose. The underestimation decreased as energy increased. For 6e, the underestimation (max 3.3 %) was greater than the statistical uncertainty level (3%) and was systematically observed for all cone sizes. By using a 1mm grid size, all the calculation results agreed with measurements within 5% for all test configurations. The calculations took 21s and 46s for 6e and 15e (2.5mm grid size) respectively distributed on 4 calculation servants. Conclusion: In general, commissioning the eMC dose calculation model on TrueBeam is straightforward and thedose calculation is in good agreement with measurements for all test cases. Monte Carlo dose calculation provides more accurate results which improves treatment planning quality. However, the normal acceptable grid size (2.5mm) would cause systematic underestimation in absolute dose calculation for lower energies, such as 6e. Users need to be cautious in this situation.« less
  • Introduction: With the increasing use of surface-based, nonionizing image-guided radiotherapy (IGRT) systems, a comprehensive set of clinical acceptance and commissioning procedures are needed to ensure correct functionality and proper clinical integration. Although TG-147 provides a specific set of parameters, measurement methodologies have yet to be described. The aim of this study was to provide a comprehensive overview of the commissioning and acceptance analysis performed for the C-Rad CatalystHD imaging system. Methods and Materials: Methodology for the commissioning and acceptance of the C-Rad CatalystHD imaging system was developed using commercially available clinical equipment. Following TG-147 guidelines, the following tests were performed:more » integration of peripheral equipment, system drift, static spatial reproducibility and localization accuracy, static end-to-end analysis, static rotational accuracy, dynamic spatial accuracy, dynamic temporal accuracy, dynamic radiation delivery and a comprehensive end-to-end analysis. Results: The field of view (FOV) of the CatalystHD was 105×109×83 cm3 in the lateral, longitudinal and vertical directions. For thermal equilibrium and system drift, a thermal drift of 1.0mm was noted. A 45 min warmup time is recommended if the system has been shut off an extended period of time (>24 hours) before the QA procedure to eliminate any thermal drift. Spatial reproducibility was found to be 0.05±0.03 mm using a rigid phantom. For the static localization accuracy, system agreement with couch shifts was within 0.1±0.1 mm and positioning agreement with kV-CBCT was 0.16±0.10 mm. For static rotational accuracy, system agreement with a high precision rotational stage (0.01 deg precision) was within 0.10±0.07 deg. Dynamic spatial and temporal localization accuracy was found to be within 0.2±0.1 mm. Conclusion: A comprehensive commissioning and acceptance study was performed using commercially available phantoms and in-house methodologies to provide a performance evaluation of the CatalystHD imaging system.« less
  • Purpose: This study aimed to assess inter- and intra-fractional motion for extremity Soft Tissue Sarcoma (STS) patients, by using in-house real-time optical image-based monitoring system (ROIMS) with infra-red (IR) external markers. Methods: Inter- and intra-fractional motions for five extremity (1 upper, 4 lower) STS patients received postoperative 3D conformal radiotherapy (3D-CRT) were measured by registering the image acquired by ROIMS with the planning CT image (REG-ROIMS). To compare with the X-ray image-based monitoring, pre- and post-treatment cone beam computed tomography (CBCT) scans were performed once per week and registered with planning CT image as well (REG-CBCT). If the CBCT scanmore » is not feasible due to the large couch shift, AP and LR on-board imager (OBI) images were acquired. The comparison was done by calculating mutual information (MI) of those registered images. Results: The standard deviation (SD) of the inter-fractional motion was 2.6 mm LR, 2.8 mm SI, and 2.0 mm AP, and the SD of the intra-fractional motion was 1.4 mm, 2.1 mm, and 1.3 mm in each axis, respectively. The SD of rotational inter-fractional motion was 0.6° pitch, 0.9° yaw, and 0.8° roll and the SD of rotational intra-fractional motion was 0.4° pitch, 0.9° yaw, and 0.7° roll. The derived averaged MI values were 0.83, 0.92 for REG-CBCT without rotation and REG-ROIMS with rotation, respectively. Conclusion: The in-house real-time optical image-based monitoring system was implemented clinically and confirmed the feasibility to assess inter- and intra-fractional motion for extremity STS patients while the daily basis and real-time CBCT scan is not feasible in clinic.« less
  • Purpose: A TrueBeam linear accelerator (TB-LINAC) is designed to deliver traditionally flattened and flattening-filter-free (FFF) beams. Although it has been widely adopted in many clinics for patient treatment, limited information is available related to commissioning of this type of machine. In this work, commissioning data of three units were measured, and multiunit comparison was presented to provide valuable insights and reliable evaluations on the characteristics of the new treatment system. Methods: The TB-LINAC is equipped with newly designed waveguide, carousel assembly, monitoring control, and integrated imaging systems. Each machine in this study has 4, 6, 8, 10, 15 MV flattenedmore » photon beams, and 6 MV and 10 MV FFF photon beams as well as 6, 9, 12, 16, 20, and 22 MeV electron beams. Dosimetric characteristics of the three new TB-LINAC treatment units are systematically measured for commissioning. High-resolution diode detectors and ion chambers were used to measure dosimetric data for a range of field sizes from 10 Multiplication-Sign 10 to 400 Multiplication-Sign 400 mm{sup 2}. The composite dosimetric data of the three units are presented in this work. The commissioning of intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), image-guided radiation therapy, and gating systems are also illustrated. Critical considerations of P{sub ion} of FFF photon beams and small field dosimetric measurements were investigated. Results: The authors found all PDDs and profiles matched well among the three machines. Beam data were quantitatively compared and combined through average to yield composite beam data. The discrepancies among the machines were quantified using standard deviation (SD). The mean SD of the PDDs among the three units is 0.12%, and the mean SD of the profiles is 0.40% for 10 MV FFF open fields. The variations of P{sub ion} of the chamber CC13 is 1.2 {+-} 0.1% under 6 MV FFF and 2.0 {+-} 0.5% under 10 MV FFF from dmax to the 18 cm-off-axis point at 35 cm depth under 40 Multiplication-Sign 40 cm{sup 2}. The mean penumbra of crossplane flattened photon beams at collimator angle of 0 Degree-Sign is measured from 5.88 {+-} 0.09 to 5.99 {+-} 0.13 mm from 4 to 15 MV at 10 cm depth of 100 Multiplication-Sign 100 mm{sup 2}. The mean penumbra of crossplane beams at collimator angle of 0 Degree-Sign is measured as 3.70 {+-} 0.21 and 4.83 {+-} 0.04 mm for 6 MV FFF and 10 MV FFF, respectively, at 10 cm depth with a field size of 5 Multiplication-Sign 5 cm{sup 2}. The end-to-end test procedures of both IMRT and VMAT were performed for various energy modes. The mean ion chamber measurements of three units showed less than 2% between measurement and calculation; the mean MultiCube ICA measurements demonstrated over 90% pixels passing gamma analysis (3%, 3 mm, 5% threshold). The imaging dosimetric data of KV planar imaging and CBCT demonstrated improved consistency with vendor specifications and dose reduction for certain imaging protocols. The gated output verification showed a discrepancy of 0.05% or less between gating radiation delivery and nongating radiation delivery. Conclusions: The commissioning data indicated good consistency among the three TB-LINAC units. The commissioning data provided us valuable insights and reliable evaluations on the characteristics of the new treatment system. The systematically measured data might be useful for future reference.« less
  • Purpose: Accuray recently released a new collimator, the InCise™ Multileaf Collimator (MLC), for clinical use with the CyberKnife M6™ System. This work reports the results of acceptance testing and commissioning measurements for this collimator. Methods: The MLC consists of 41 pairs of 2.5 mm wide leaves projecting a clinical maximum field size of 110 mm x 97.5 mm at 800 mm SAD. The leaves are made of tungsten, 90 mm in height and tilted by 0.5 degree. The manufacturer stated leaf positioning accuracy and reproducibility are 0.5 mm and 0.4 mm respectively at 800 mm SAD. The leaf over-travel ismore » 100% with full interdigitation capability. Acceptance testing included, but are not limited to, the verification of the specifications of various parameters described above, leakage measurements and end-to-end tests. Dosimetric measurements included, but not limited to, measurements of output factors, open beam profiles, tissue-phantom ratios, beam flatness and symmetry, and patient specific QA. Results: All measurements were well within the manufacturer specifications. The values of output factors ranged from 0.804 (smallest field size of 7.6 mm x 7.5 mm) to 1.018 (largest field size of 110.0 mm x 97.5 mm). End-to-end test results for the various tracking modes are: Skull (0.27mm), fiducial (0.16mm), Xsight Spine (0.4mm), Xsight Lung (0.93 mm) and Synchrony (0.43mm). Measured maximum and average leakage was 0.37% and 0.3%, respectively. Patient-specific QA measurements with chamber were all within 5% absolute dose agreement, and film measurements all passed 2%/2mm gamma evaluation for more than 95% of measurement points. Conclusion: The presented results are the first set of data reported on the InCise™ MLC. The MLC proved to be very reliable and is currently in clinical use.« less