bluuebunny/crossref_metadata_2025_split huggingface dataset:
SU‐F‐T‐248: FMEA Risk Analysis Implementation (AAPM TG‐100) in Total Skin Electron Irradiation Technique
Authors: Ibanez‐Rosello B , Bautista‐Ballesteros J , Bonaque J , Perez‐Calatayud J , Gonzalez‐Sanchis A , Lopez‐Torrecilla J , Brualla‐Gonzalez L , Garcia‐Hernandez T , Vicedo‐Gonzalez A , Granero D , Serrano A , Borderia B , Solera C , Rosello J 
Published: July 2016

Purpose:Total Skin Electron Irradiation (TSEI) is a radiotherapy treatment which involves irradiating the entire body surface as homogeneously as possible. It is composed of an extensive multi‐step technique in which quality management requires high consumption of resources and a fluid communication between the involved staff, necessary to improve the safety of treatment. The TG‐100 proposes a new perspective of quality management in radiotherapy, presenting a systematic method of risk analysis throughout the global flow of the stages through the patient. The purpose of this work has been to apply TG‐100 approach to the TSEI procedure in our institution.Methods:A multidisciplinary team specifically targeting TSEI procedure was formed, that met regularly and jointly developed the process map (PM), following TG‐100 guidelines of the AAPM. This PM is a visual representation of the temporal flow of steps through the patient since start until the end of his stay in the radiotherapy service.Results:This is the first stage of the full risk analysis, which is being carried out in the center. The PM provides an overview of the process and facilitates the understanding of the team members who will participate in the subsequent analysis. Currently, the team is implementing the analysis of failure modes and effects (FMEA). The failure modes of each of the steps have been identified and assessors are assigning a value of severity (S), frequency of occurrence (O) and lack of detection (D) individually. To our knowledge, this is the first PM made for the TSEI. The developed PM can be useful for those centers that intend to implement the TSEI technique.Conclusion:The PM of TSEI technique has been established, as the first stage of full risk analysis, performed in a reference center in this treatment.
SU‐F‐T‐249: Application of Human Factors Methods: Usability Testing in the Radiation Oncology Environment
Authors: Warkentin H , Bubric K , Giovannetti H , Graham G , Clay C 
Published: July 2016

Purpose:As a quality improvement measure, we undertook this work to incorporate usability testing into the implementation procedures for new electronic documents and forms used by four affiliated radiation therapy centers.Methods:A human factors specialist provided training in usability testing for a team of medical physicists, radiation therapists, and radiation oncologists from four radiotherapy centers. A usability testing plan was then developed that included controlled scenarios and standardized forms for qualitative and quantitative feedback from participants, including patients. Usability tests were performed by end users using the same hardware and viewing conditions that are found in the clinical environment. A pilot test of a form used during radiotherapy CT simulation was performed in a single department; feedback informed adaptive improvements to the electronic form, hardware requirements, resource accessibility and the usability testing plan. Following refinements to the testing plan, usability testing was performed at three affiliated cancer centers with different vault layouts and hardware.Results:Feedback from the testing resulted in the detection of 6 critical errors (omissions and inability to complete task without assistance), 6 non‐critical errors (recoverable), and multiple suggestions for improvement. Usability problems with room layout were detected at one center and problems with hardware were detected at one center. Upon amalgamation and summary of the results, three key recommendations were presented to the document's authors for incorporation into the electronic form. Documented inefficiencies and patient safety concerns related to the room layout and hardware were presented to administration along with a request for funding to purchase upgraded hardware and accessories to allow a more efficient workflow within the simulator vault.Conclusion:By including usability testing as part of the process when introducing any new document or procedure into clinical use, associated risks can be identified and mitigated before patient care and clinical workflow are impacted.
SU‐F‐T‐254: Dose Volume Histogram (DVH) Analysis of Breath Hold Vs Free Breathing Techniques for Esophageal Tumors
Authors: Badkul R , Doke K , Pokhrel D , Aguilera N , Lominska C 
Published: July 2016

Purpose:Lung and heart doses and associated toxicity are of concern in radiotherapy for esophageal cancer. This study evaluates the dosimetry of deep‐inspiration‐breath‐hold (DIBH) technique as compared to freebreathing(FB) using 3D‐conformal treatment(3D‐CRT) of esophageal cancer.Methods:Eight patients were planned with FB and DIBH CT scans. DIBH scans were acquired using Varian RPM system. FB and DIBH CTs were contoured per RTOG‐1010 to create the planning target volume(PTV) as well as organs at risk volumes(OAR). Two sets of gross target volumes(GTV) with 5cm length were contoured for each patient: proximal at the level of the carina and distal at the level of gastroesophageal junction and were enlarged with appropriate margin to generate Clinical Target Volume and PTV. 3D‐CRT plans were created on Eclipse planning system for 45Gy to cover 95% of PTV in 25 fractions for both proximal and distal tumors on FB and DIBH scans. For distal tumors celiac nodes were covered electively. DVH parameters for lung and heart OARs were generated and analyzed.Results:All DIBH DVH parameters were normalized to FB plan values. Average of heart‐mean and heart‐V40 was 0.70 and 0.66 for proximal lesions. For distal lesions ratios were 1.21 and 2.22 respectively. For DIBH total lung volume increased by 2.43 times versus FB scan. Average of lung‐mean, V30, V20, V10, V5 are 0.82, 0.92, 0.76, 0.77 and 0.79 for proximal lesions and 1.17,0.66,0.87,0.93 and 1.03 for distal lesions. Heart doses were lower for breath‐hold proximal lesions but higher for distal lesions as compared to free‐breathing plans. Lung doses were lower for both proximal and distal breath‐hold lesions except mean lung dose and V5 for distal lesions.Conclusion:This study showed improvement of OAR doses for esophageal lesions at mid‐thoracic level utilizing DIBH vs FB technique but did not show consistent OAR sparing with DIBH for distal lesions.
SU‐F‐T‐264: VMAT QA with 2D Radiation Measuring Equipment Attached to Gantry
Authors: Fung A 
Published: July 2016

Purpose:To introduce a method of VMAT QA by 2D measuring device. The 2D device is attached to the gantry throughout measurement duration. This eliminates error caused by the angular dependence of the radiation detectors.Methods:A 2D radiation measuring device was attached to the gantry of linear accelerator. The center of the detector plane was at the isocenter. For each patient plan, two verification plans were created for QA purpose. One was like an ordinary VMAT plan, to be used for radiation delivery. The other is a plan with gantry angle fixed at zero, so the dose distribution as seen by the rotating 2D device. Points above 10% dose threshold were analyzed. Data is in tolerance if it fits within the 3 mm or 3% dose gamma criteria. For each patient, the plan was passed when 95% of all the points in the 2D matrix fit the gamma criteria. The following statistics were calculated: number of patient plans passed, percentage of all points passed, average percentage difference of all points.Results:VMAT QA was performed for patients during one year in our department, and the results were analyzed. All irradiation was with 6 MV photon beam. Each plan has calculated and measured doses compared. After collecting one year's result, with 81 patient plans analyzed, all (100%) of the plans passed the gamma criteria. Of the points analyzed from all plans, 98.8% of all points passed.Conclusion:This method of attaching a 2D measuring device on the linac gantry proves to be an accurate way for VMAT QA. It is simple to use and low cost, and it eliminates the problem of directional dependence.
SU‐F‐T‐296: Modulated Therapy Down Under: A Survey of IMRT & VMAT Physics Practice in Australia and New Zealand
Authors: Barber J , Vial P 
Published: July 2016

Purpose:A comprehensive survey of Australasian radiation oncology physics departments was undertaken to capture a snapshot of current usage, commissioning and QA practices for intensity‐modulated therapies.Methods:An online survey was developed and advertised to Australian and New Zealand radiation oncology physicists through the local college (ACPSEM) in April 2015. The survey consisted of 147 questions in total, covering IMRT, VMAT and Tomotherapy, and details specific to different treatment planning systems. Questions captured detailed information on equipment, policies and procedures for the commissioning and QA of each treatment technique.Results:41 partial or complete responses were collected, representing 59 departments out of the 78 departments operational. 137 and 84 linacs from these departments were using IMRT and VMAT respectively, from a total 150 linacs. 100% and 78% of respondents were treating with IMRT and VMAT respectively. There are at least 8 different treatment planning systems being used for IMRT or VMAT, and large variations in all aspects of QA policies and procedures. 29 responses indicated 72 methods routinely used for pre‐treatment QA, when breaking down by device and analysis type. Similar numbers of departments use field‐by‐field analysis compared to composite analysis (56% to 44%) while a majority use true gantry angle delivery compared to fixed gantry at 0° (72% to 28%). 19 different implementations of gamma index analysis parameters were reported from 33 responses. A follow‐up one‐day workshop to highlight the results, discuss the role of QA and share equipment‐specific knowledge across users was conducted in November 2015.Conclusion:While IMRT and VMAT are almost universally available in Australasia, large variations in practice indicate a need for national or consensus guidelines.
SU‐F‐T‐301: Planar Dose Pass Rate Inflation Due to the MapCHECK Measurement Uncertainty Function
Authors: Bailey D , Spaans J , Kumaraswamy L , Podgorsak M 
Published: July 2016

Purpose:To quantify the effect of the Measurement Uncertainty function on planar dosimetry pass rates, as analyzed with Sun Nuclear Corporation analytic software (“MapCHECK” or “SNC Patient”). This optional function is toggled on by default upon software installation, and automatically increases the user‐defined dose percent difference (%Diff) tolerance for each planar dose comparison.Methods:Dose planes from 109 IMRT fields and 40 VMAT arcs were measured with the MapCHECK 2 diode array, and compared to calculated planes from a commercial treatment planning system. Pass rates were calculated within the SNC analytic software using varying calculation parameters, including Measurement Uncertainty on and off. By varying the %Diff criterion for each dose comparison performed with Measurement Uncertainty turned off, an effective %Diff criterion was defined for each field/arc corresponding to the pass rate achieved with MapCHECK Uncertainty turned on.Results:For 3%/3mm analysis, the Measurement Uncertainty function increases the user‐defined %Diff by 0.8–1.1% average, depending on plan type and calculation technique, for an average pass rate increase of 1.0–3.5% (maximum +8.7%). For 2%, 2 mm analysis, the Measurement Uncertainty function increases the user‐defined %Diff by 0.7–1.2% average, for an average pass rate increase of 3.5–8.1% (maximum +14.2%). The largest increases in pass rate are generally seen with poorly‐matched planar dose comparisons; the MapCHECK Uncertainty effect is markedly smaller as pass rates approach 100%.Conclusion:The Measurement Uncertainty function may substantially inflate planar dose comparison pass rates for typical IMRT and VMAT planes. The types of uncertainties incorporated into the function (and their associated quantitative estimates) as described in the software user's manual may not accurately estimate realistic measurement uncertainty for the user's measurement conditions. Pass rates listed in published reports or otherwise compared to the results of other users or vendors should clearly indicate whether the Measurement Uncertainty function is used.
SU‐F‐T‐305: Clinical Effects of Dosimetric Leaf Gap (DLG) Values Between Matched Varian Truebeam (TB) Linacs
Authors: Mihailidis D , Mallah J , Zhu D 
Published: July 2016

Purpose:The dosimetric leaf gap (DLG) is an important parameter to be measured for dynamic beam delivery of modern linacs, like the Varian Truebeam (TB). The clinical effects of DLG‐values on IMRT and/or VMAT commissioning of two “matched” TB linacs will be presented.Methods and Materials: The DLG values on two TB linacs were measured for all energy modalities (filtered and FFF‐modes) as part of the dynamic delivery mode commissioning (IMRT and/or VMAT. After the standard beam data was modeled in eclipse treatment planning system (TPS) and validated, IMRT validation was performed based on TG1191 benchmark, IROC Head‐Neck (H&N) phantom and sample of clinical cases, all measured on both linacs. Although there was a single‐set of data entered in the TPS, a noticeable difference was observed for the DLG‐values between the linacs. The TG119, IROC phantom and selected patient plans were furnished with DLG‐values of TB1 for both linacs and the delivery was performed on both TB linacs for comparison.Results:The DLG values of TB1 was first used for both linacs to perform the testing comparisons. The QA comparison of TG119 plans revealed a great dependence of the results to the DLG‐values used for the linac for all energy modalities studied, especially when moving from 3%/3mm to 2%/2mm γ‐analysis.Conclusion:The DLG‐values have a definite influence on the dynamic dose, delivery that increases with the plan complexity. We recommend that the measured DLG‐values are assigned to each of the “matched” linacs, even if a single set of beam data describes multiple linacs. The user should perform a detail test of the dynamic delivery of each linac based on end‐to‐end benchmark suites like TG119 and IROC phantoms.1Ezzel G., et al., “IMRT commissioning: Multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119.” Med. Phys. 36:5359–5373 (2009).partly supported by CAMC Cancer Center and Alliance Oncology
SU‐F‐T‐307: Peripheral Dose Comparison Between Static and Dynamic Jaw Tracking On a High Definition MLC System
Authors: Perez‐Andujar A , Cheung J , Chuang C 
Published: July 2016

Purpose:To investigate the effect of dynamic and static jaw tracking on patient peripheral doses.Materials and Methods:A patient plan with a large sacral metastasis (volume 800cm3, prescription 600cGyx5) was selected for this study. The plan was created using 2‐field RapidArc with jaw tracking enabled (Eclipse, V11.0.31). These fields were then exported and edited in MATLAB with static jaw positions using the control point with the largest field size for each respective arc, but preserving the optimized leaf sequences for delivery. These fields were imported back into Eclipse for dose calculation and comparison and copied to a Rando phantom for delivery analysis. Points were chosen in the phantom at depth and on the phantom surface at locations outside the primary radiation field, at distances of 12cm, 20cm, and 30cm from the isocenter. Measurements were acquired with OSLDs placed at these positions in the phantom with both the dynamic and static jaw deliveries for comparison. Surface measurements included an additional 1cm bolus over the OSLDs to ensure electron equilibrium.Results:The static jaw deliveries resulted in cumulative jaw‐defined field sizes of 17.3% and 17.4% greater area than the dynamic jaw deliveries for each arc. The static jaw plan resulted in very small differences in calculated dose in the treatment planning system ranging from 0–16cGy. The measured dose differences were larger than calculated, but the differences in absolute dose were small. The measured dose differences at depth (surface) between the two deliveries showed an increase for the static jaw delivery of 2.2%(11.4%), 15.6%(20.0%), and 12.7%(12.7%) for distances of 12cm, 20cm, and 30cm, respectively. Eclipse calculates a difference of 0–3.1% for all of these points. The largest absolute dose difference between all points was 6.2cGy.Conclusion:While we demonstrated larger than expected differences in peripheral dose, the absolute dose differences were small.
SU‐F‐T‐311: Comparison of Measurements From Two Diode Array QA Devices to Deep Point Dose Measurements with Two Treatment Planning Model Settings for Brain VMAT SRT Patient‐Specific QA
Authors: Weethee B , Cheung J , Perez‐Andujar A , Sudhyadhom A , Chen J 
Published: July 2016

Purpose:To investigate the sensitivity of traditional gamma‐index‐based analysis using diode arrays to detect significant dosimetric errors in patientspecific measurements for VMAT brain SRT plans.Methods:Quality assurance measurements were performed using an ion chamber and two different diode array devices for four brain SRT treatment plans. All cases were planned with Eclipse AAA RapidArc using 6MV VMAT for a TrueBeam STx. Ion chambers measurements were performed with a PinPoint 3D micro‐ion chamber in both the Standard Imaging Stereotactic Dose Verification (SI) Phantom and in the ArcCheck (AC) cavity plug. Point dose measurements were taken at isocenter within the target. Array measurements were acquired with the ArcCheck and gantry‐mounted MapCheck (MC) and assessed using the SNC patient software with a 3%/3mm absolute dose gamma‐index analysis with global normalization and a 10% dose threshold. Calculations and their corresponding measurements were performed and compared before and after a dynamic leaf gap (DLG) adjustment.Results:The measured doses at isocenter dropped from 6.3%–8.7% in the SI phantom and 4.0%–9.3% for AC down to −0.1%–1.1% in the SI phantom and 0.8%–2.9% in the AC after adjusting the DLG. However, the cumulative dose differences to MC's central diode ranged −2.0%–1.9% before the DLG adjustment and were −7.7%–0.2% afterwards. Similarly, the gamma‐index analysis results for MC were found to be 94.1%–100% before the DLG adjustment and 94.4%–100% afterwards. The gamma‐index results from AC were 72.9%–98.7% before and 95.9%–99.7% after.Conclusion:Our data suggest that traditional passing criteria using gantry‐mounted MapCheck may not have the sensitivity to catch significant dose errors introduced by DLG settings. ArcCheck measurements did flag some dose differences, however there appears to be a possibility that dose discrepancies may not always be observed for VMAT SRT treatments, and point dose measurements are recommended for verification.
SU‐F‐T‐317: Skin Exposure Outside the Treatment Field During Treatment of Breast Cancer with Tri‐Co‐60 MR‐IGRT System
Authors: Park J , Kim J , Park S , Kim S , Shin K 
Published: July 2016

Purpose:To investigate exposure outside the treatment field when treating breast cancer with tri‐Co‐60 magnetic resonance (MR) image guided radiation therapy (IGRT) system.Methods:A total of 7 patients who treated with accelerated partial breast irradiation (APBI) technique were selected prospectively for this study (prescription dose = 38.5 Gy in 10 fractions). Every patient treated with two plans, one was an initial plan and the other was an adaptive plan generated after finishing 5 fractions (a total of 14 plans). Every plan was calculated with and without magnetic field in the treatment planning system. The EBT3 films were attached on the front and the back of 1 cm bolus, and then it was placed on the patient body vertically to cover patient's jaw and shoulder. After measurements, the maximum point dose and the mean dose of whole area of EBT3 film were acquired.Results:In the treatment plan with magnetic field, low dose stream outside the patient body was observed, almost reaching the patient's jaw or shoulder, while it was not observed without magnetic field. The average values of the measured maximum and mean doses at the front of bolus were 30.1 ± 11.1 cGy (7.8% of the daily dose) and 14.7 ± 3.3 cGy (3.8%), respectively. At the back of bolus, those values were 6.0 ± 1.9 cGy (1.6%) and 5.1 ± 1.6 cGy (1.3%), respectively. The largest maximum dose at the front was 54.2 cGy (14.1%) while it was 20.7 cGy (5.4%) at the back. The average decrease of the maximum dose by the bolus was 24.0 ± 11.0 cGy.Conclusion:Due to magnetic field, dose stream outside the patient body can be generated during breast cancer treatment with the tri‐Co‐60 MR‐IGRT system. Since this dose stream irradiated skin outside the treatment field, it should be shielded.This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2015R1C1A1A01054192).
SU‐F‐T‐318: Sensitivity and Stability of OSLDs with Filled Deep Electron/hole Traps Under Pre‐Irradiation and Bleaching Conditions
Authors: Kim J , Park S , Lee H , Kim H , Choi C , Park J 
Published: July 2016

Purpose:This work evaluated the characteristics of optically stimulated luminescence dosimeters (OSLDs) with fully filled deep electron/hole traps (OSLDfull) with the bleaching conditions according to the accumulated dose.Methods:The OSLDs were first pre‐irradiated with a Co‐60 gamma ray at more than 5 kGy, so as to fill the deep electron and hole traps. Using a 6‐MV beam, the OSLDfull characteristics were investigated in terms of the full bleaching, fading, dose linearity, and dose sensitivity obtained in response to the accumulated dose values. To facilitate a comparison of the dose sensitivity, OSLDs with un‐filled deep electron/hole traps (OSLDempty) were investigated in the same manner. A long‐pass filter was used to exclude bleaching‐source wavelengths of less than 520 nm. Various bleaching time and wavelength combinations were used in order to determine the optimal bleaching conditions for the OSLD full.Results:The fading for the OSLDfull exhibited stable signals after 8 min, for both 1‐ and 10‐Gy. For 4‐h bleaching time and an unfiltered bleaching device, the supralinear index values for the OSLDfull were 1.003, 1.002, 0.999, and 1.001 for doses of 2, 4, 7, and 10 Gy, respectively. For a 65‐Gy accumulated dose with a 5‐Gy fraction, no variation in dose sensitivity was obtained for the OSLDfull, within a standard deviation of 0.85%, whereas the OSLDempty dose sensitivity decreased by approximately 2.3% per 10 Gy. The filtered bleaching device yielded a highly stable sensitivity for OSLDfull, independent of bleaching time and within a standard deviation of 0.71%, whereas the OSLDempty dose sensitivity decreased by approximately 4.2% per 10 Gy for an accumulated dose of 25 Gy with a 5‐Gy fraction.Conclusion:Under the bleaching conditions determined in this study, clinical dosimetry with OSLDfull is highly stable, having an accuracy of 1% with no change in dose sensitivity or linearity at clinical doses.This work was supported by a National Research Foundation of Korea (NRF) grant, funded by the Korea government (MISP) (No. 2014M2B2A4031164), and by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (HI14C3459).