James M Galvin

Treatment Research Institute, Philadelphia PA, Filadelfia, Pennsylvania, United States

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Publications (132)497.85 Total impact

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    ABSTRACT: Transmission of Imaging and Data (TRIAD) is a standard-based system built by the American College of Radiology (ACR) to provide seamless exchange of images and data for accreditation of clinical trials and registries. Scripts of structures’ names validation profiles created in TRIAD are used in the automated submission process. It is essential for users to understand the logistics of these scripts for successful submission of radiotherapy cases with less iteration.
    No preview · Article · Jan 2016 · Practical Radiation Oncology

  • No preview · Article · Nov 2015 · International journal of radiation oncology, biology, physics

  • No preview · Article · Nov 2015 · International journal of radiation oncology, biology, physics

  • No preview · Article · Nov 2015 · International journal of radiation oncology, biology, physics
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    ABSTRACT: Purpose/Objective(s) A knowledge-based engineering tool is used to generate dose-volume histograms for organs-at-risk based on anatomical information of the patients and a model trained using a data base of high-quality plans. The primary objectives of this work were to use this tool to guide establishment of dosimetric evaluation criteria for the RTOG 1308 lung clinical trial (for patients with locally advanced non-small cell lung cancer) and for the quality assessment and improvement of treatment plans that fail to meet the dosimetric compliance criteria. Materials/Methods Twenty-six lung IMRT treatment plans, developed at two institutions, were included in the study. These plans were also used to guide the development of the dosimetric compliance criteria of the RTOG 1308 lung trial. Digital Imaging and Communications in Medicine planning CT, RT plan, RT dose, and RT structure data were imported to the tool. The tool required the matching of PTV and OARs and the prescription dose of a candidate review to select one or more plans among those in the data base of original plans. The tool then generated a modeled dose-volume histogram (DVH) for organs-at-risk for the candidate plan. The predicted DVHs were compared with the planned DVHs to assess the plan quality. Results Dose-volume histograms for OARs generated by the tool were compared to those of the respective treatment plans. The comparison of DVHs for organs included in the dosimetric compliance criteria of the trial (total lungs, heart, esophagus, and spinal cord) indicated some variations between the modeled and calculated DVHs; however, most of the variations were within the confidence limits of the predicted DVHs. The results also indicated that IMRT plans used during the design study of the RTOG 1308 trial were of good quality. Conclusion The quality of lung IMRT plans used during the development of the RTOG 1308 clinical trial was investigated using a knowledge-based engineering tool. The results indicated that plans are of good quality. We aim to eventually use this tool to provide real-time feedback for plan optimization, the process that will be tested in future studies. Acknowledgement(s) This project was supported by NIH grants U10CA180868, U10CA180822, U24CA180803, U24CA12014, and PA CURE Grant.
    No preview · Article · Nov 2015 · International journal of radiation oncology, biology, physics

  • No preview · Article · Nov 2015 · International journal of radiation oncology, biology, physics
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    ABSTRACT: Cancer treatment evolves through oncology clinical trials. Cancer trials are multi-modality and complex. Assuring high quality data are available to answer not only study objectives but also questions not anticipated at study initiation is the role of quality assurance. The National Cancer Institute reorganized its cancer clinical trials program in 2014. The National Clinical Trials Network (NCTN) was formed and within it, established a Diagnostic Imaging and Radiation Therapy Quality Assurance Organization. This organization is IROC, the Imaging and Radiation Oncology Core Group, comprised of six quality assurance centers that provide Imaging and Radiation Therapy Quality Assurance for the NCTN. Sophisticated imaging is used for cancer diagnosis, treatment, and management as well as for the image-driven technologies to plan and execute radiation treatment. Integration of imaging and radiation oncology data acquisition, review, management, and archive strategies are essential for trial compliance and future research. Lessons learned from previous trials are and provide evidence to support diagnostic imaging and radiation therapy data acquisition in NCTN trials.
    No preview · Article · Oct 2015 · International journal of radiation oncology, biology, physics
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    ABSTRACT: This report describes the current state of flattening filter-free (FFF) radiotherapy beams implemented on conventional linear accelerators, and is aimed primarily at practicing medical physicists. The Therapy Emerging Technology Assessment Work Group of the American Association of Physicists in Medicine (AAPM) formed a writing group to assess FFF technology. The published literature on FFF technology was reviewed, along with technical specifications provided by vendors. Based on this information, supplemented by the clinical experience of the group members, consensus guidelines and recommendations for implementation of FFF technology were developed. Areas in need of further investigation were identified. Removing the flattening filter increases beam intensity, especially near the central axis. Increased intensity reduces treatment time, especially for high-dose stereotactic radiotherapy/radiosurgery (SRT/SRS). Furthermore, removing the flattening filter reduces out-of-field dose and improves beam modeling accuracy. FFF beams are advantageous for small field (e.g., SRS) treatments and are appropriate for intensity-modulated radiotherapy (IMRT). For conventional 3D radiotherapy of large targets, FFF beams may be disadvantageous compared to flattened beams because of the heterogeneity of FFF beam across the target (unless modulation is employed). For any application, the nonflat beam characteristics and substantially higher dose rates require consideration during the commissioning and quality assurance processes relative to flattened beams, and the appropriate clinical use of the technology needs to be identified. Consideration also needs to be given to these unique characteristics when undertaking facility planning. Several areas still warrant further research and development. Recommendations pertinent to FFF technology, including acceptance testing, commissioning, quality assurance, radiation safety, and facility planning, are presented. Examples of clinical applications are provided. Several of the areas in which future research and development are needed are also indicated.
    Full-text · Article · Jun 2015 · Journal of Applied Clinical Medical Physics
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    ABSTRACT: The purpose of this study was to quantify the frequency and clinical severity of quality deficiencies in intensity modulated radiation therapy (IMRT) planning in the Radiation Therapy Oncology Group 0126 protocol. A total of 219 IMRT patients from the high-dose arm (79.2 Gy) of RTOG 0126 were analyzed. To quantify plan quality, we used established knowledge-based methods for patient-specific dose-volume histogram (DVH) prediction of organs at risk and a Lyman-Kutcher-Burman (LKB) model for grade ≥2 rectal complications to convert DVHs into normal tissue complication probabilities (NTCPs). The LKB model was validated by fitting dose-response parameters relative to observed toxicities. The 90th percentile (22 of 219) of plans with the lowest excess risk (difference between clinical and model-predicted NTCP) were used to create a model for the presumed best practices in the protocol (pDVH0126,top10%). Applying the resultant model to the entire sample enabled comparisons between DVHs that patients could have received to DVHs they actually received. Excess risk quantified the clinical impact of suboptimal planning. Accuracy of pDVH predictions was validated by replanning 30 of 219 patients (13.7%), including equal numbers of presumed "high-quality," "low-quality," and randomly sampled plans. NTCP-predicted toxicities were compared to adverse events on protocol. Existing models showed that bladder-sparing variations were less prevalent than rectum quality variations and that increased rectal sparing was not correlated with target metrics (dose received by 98% and 2% of the PTV, respectively). Observed toxicities were consistent with current LKB parameters. Converting DVH and pDVH0126,top10% to rectal NTCPs, we observed 94 of 219 patients (42.9%) with ≥5% excess risk, 20 of 219 patients (9.1%) with ≥10% excess risk, and 2 of 219 patients (0.9%) with ≥15% excess risk. Replanning demonstrated the predicted NTCP reductions while maintaining the volume of the PTV receiving prescription dose. An equivalent sample of high-quality plans showed fewer toxicities than low-quality plans, 6 of 73 versus 10 of 73 respectively, although these differences were not significant (P=.21) due to insufficient statistical power in this retrospective study. Plan quality deficiencies in RTOG 0126 exposed patients to substantial excess risk for rectal complications. Copyright © 2015 Elsevier Inc. All rights reserved.
    Full-text · Article · Apr 2015 · International journal of radiation oncology, biology, physics
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    ABSTRACT: BACKGROUND The authors analyzed a preliminary report of patient-reported outcomes (PROs) among men who received high-dose radiation therapy (RT) on Radiation Therapy Oncology Group study 0126 (a phase 3 dose-escalation trial) with either 3-dimensional conformal RT (3D-CRT) or intensity-modulated RT (IMRT).METHODS Patients in the 3D-CRT group received 55.8 gray (Gy) to the prostate and proximal seminal vesicles and were allowed an optional field reduction; then, they received 23.4 Gy to the prostate only. Patients in the IMRT group received 79.2 Gy to the prostate and proximal seminal vesicles. PROs were assessed at 0 months (baseline), 3 months, 6 months, 12 months, and 24 months and included bladder and bowel function assessed with the Functional Alterations due to Changes in Elimination (FACE) instrument and erectile function assessed with the International Index of Erectile Function (IIEF). Analyses included the patients who completed all data at baseline and for at least 1 follow-up assessment, and the results were compared with an imputed data set.RESULTSOf 763 patients who were randomized to the 79.2-Gy arm, 551 patients and 595 patients who responded to the FACE instrument and 505 patients and 577 patients who responded to the IIEF were included in the completed and imputed analyses, respectively. There were no significant differences between modalities for any of the FACE or IIEF subscale scores or total scores at any time point for either the completed data set or the imputed data set.CONCLUSIONS Despite significant reductions in dose and volume to normal structures using IMRT, this robust analysis of 3D-CRT and IMRT demonstrated no difference in patient-reported bowel, bladder, or sexual functions for similar doses delivered to the prostate and proximal seminal vesicles with IMRT compared with 3D-CRT delivered either to the prostate and proximal seminal vesicles or to the prostate alone. Cancer 2015. © 2015 American Cancer Society.
    No preview · Article · Mar 2015 · Cancer
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    ABSTRACT: RTOG 0933 was a phase II trial of hippocampal avoidance during whole brain radiation therapy for patients with brain metastases. The results demonstrated improvement in short-term memory decline, as compared with historical control individuals, and preservation of quality of life. Integral to the conduct of this trial were quality assurance processes inclusive of pre-enrollment credentialing and pretreatment centralized review of enrolled patients. Before enrolling patients, all treating physicians and sites were required to successfully complete a "dry-run" credentialing test. The treating physicians were credentialed based on accuracy of magnetic resonance imaging-computed tomography image fusion and hippocampal and normal tissue contouring, and the sites were credentialed based on protocol-specified dosimetric criteria. Using the same criteria, pretreatment centralized review of enrolled patients was conducted. Physicians enrolling 3 consecutive patients without unacceptable deviations were permitted to enroll further patients without pretreatment review, although their cases were reviewed after treatment. In all, 113 physicians and 84 sites were credentialed. Eight physicians (6.8%) failed hippocampal contouring on the first attempt; 3 were approved on the second attempt. Eight sites (9.5%) failed intensity modulated radiation therapy planning on the first attempt; all were approved on the second attempt. One hundred thirteen patients were enrolled in RTOG 0933; 100 were analyzable. Eighty-seven cases were reviewed before treatment; 5 (5.7%) violated the eligibility criteria, and 21 (24%) had unacceptable deviations. With feedback, 18 cases were approved on the second attempt and 2 cases on the third attempt. One patient was treated off protocol. Twenty-two cases were reviewed after treatment; 1 (4.5%) violated the eligibility criteria, and 5 (23%) had unacceptable deviations. Although >95% of the cases passed the pre-enrollment credentialing, the pretreatment centralized review disqualified 5.7% of reviewed cases, prevented unacceptable deviations in 24% of reviewed cases, and limited the final unacceptable deviation rate to 5%. Thus, pretreatment review is deemed necessary in future hippocampal avoidance trials and is potentially useful in other similarly challenging radiation therapy technique trials. Copyright © 2015 Elsevier Inc. All rights reserved.
    Full-text · Article · Jan 2015 · International journal of radiation oncology, biology, physics
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    ABSTRACT: To review the various radiation therapy quality assurance (RTQA) procedures used by the Global Clinical Trials RTQA Harmonization Group (GHG) steering committee members and present the harmonized RTQA naming conventions by amalgamating procedures with similar objectives. A survey of the GHG steering committee members' RTQA procedures, their goals, and naming conventions was conducted. The RTQA procedures were classified as baseline, preaccrual, and prospective/retrospective data capture and analysis. After all the procedures were accumulated and described, extensive discussions took place to come to harmonized RTQA procedures and names. The RTQA procedures implemented within a trial by the GHG steering committee members vary in quantity, timing, name, and compliance criteria. The procedures of each member are based on perceived chances of noncompliance, so that the quality of radiation therapy planning and treatment does not negatively influence the trial measured outcomes. A comparison of these procedures demonstrated similarities among the goals of the various methods, but the naming given to each differed. After thorough discussions, the GHG steering committee members amalgamated the 27 RTQA procedures to 10 harmonized ones with corresponding names: facility questionnaire, beam output audit, benchmark case, dummy run, complex treatment dosimetry check, virtual phantom, individual case review, review of patients' treatment records, and protocol compliance and dosimetry site visit. Harmonized RTQA harmonized naming conventions, which can be used in all future clinical trials involving radiation therapy, have been established. Harmonized procedures will facilitate future intergroup trial collaboration and help to ensure comparable RTQA between international trials, which enables meta-analyses and reduces RTQA workload for intergroup studies. Copyright © 2014 Elsevier Inc. All rights reserved.
    Full-text · Article · Dec 2014 · International journal of radiation oncology, biology, physics
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    ABSTRACT: As part of the consolidation of the cooperative group clinical trial program of the National Clinical Trials Network (NCTN) of the National Cancer Institute (NCI), an Imaging and Radiation Oncology Core services organization (IROC) has been formed from current leading quality assurance (QA) centers to provide QA, along with clinical and scientific expertise, for the entire NCTN (1). An integrated information technology (IT) infrastructure, the IROC cloud, has been implemented to foster collaborative and effective interactions among participating institutions, QA centers, NCTN cooperative groups and statistics data management centers, and the IT infrastructure of the NCI (Fig. 1).
    No preview · Article · Oct 2014 · International journal of radiation oncology, biology, physics
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    ABSTRACT: Purpose/Objective(s) To evaluate the feasibility of the ABAS for the automatic delineation of cardiac structures (pericardium, atria, ventricles) when compared with the manually contoured cardiac structures. Furthermore, we explored using the ABAS contouring as a quality assurance (QA) tool. Materials/Methods CT scans and treatment plans from 470 cases were used in this project. Five experienced thoracic radiation oncologists independently delineated the cardiac structures, blinded to submitted contours, following a consistent guideline. A total of 100 such recontoured cases, 20 from each oncologist, were chosen, and their CT images with the cardiac structure contours were used to build the heart atlas libraries for each cardiac structure using commercially available software (MIMvista Corp., Cleveland, OH). The atlas template voxel size was 3×3×3mm3. To quantify the precision of the automatically delineated cardiac structures using ABAS, they were compared with the manually delineated structures from experts. The discrepancies between the manual and automatic contouring were evaluated for 470 cases, and the Dice Similarity Coefficient (DSC), Jaccard Index (JI) and Housdorff Distance (HD) between the two types of contouring were calculated for geometrical comparisons. The fractional volume dose factors, (VD’s, D = 5, 15, 25, 35, 45, 55 Gy) were calculated for pericardium, for dosimetric comparison. To test the feasibility of using the ABAS for quality assurance, we used 373 patient cases with heart contours that result in discrepancy of more than 5% in mean heart dose. DSC between the test and ABAS contours were calculated. We tested the sensitivity of three different thresholds of DSC for picking out these discrepant contours. Results The results were shown in Table 1. There is minimal difference between different VD’s for automatically and manually delineated pericardium contours. Using threshold value of 0.86, 0.87 and 0.88, the rate with which we can pick out discrepant contours is 0.85, 0.90 and 0.93, respectively. Conclusions ABAS demonstrates great potentials to accurately delineate the cardiac structures automatically, and it is feasible to be used for cost-effective QA for clinical trials. Extensive investigations are planned to comprehensively evaluate the operating characteristics (e.g., sensitivity and specificity) of ABAS as a QA tool.
    No preview · Article · Sep 2014 · International journal of radiation oncology, biology, physics
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    ABSTRACT: Purpose/Objective(s) RTOG 1308 is a phase III randomized trial comparing overall survival after photon versus proton chemoradiation therapy for inoperable stage II-IIIB NSCLC, to determine if proton therapy can improve overall survival by reducing the risk of severe toxicity to organs at risk compared to photon-based IMRT. More stringent dose constraints are being used for RTOG 1308 than prior NSCLC RTOG studies. The purpose of this work is to establish the feasibility of the dosimetric criteria of this trial through testing against photon IMRT and passively scattered proton therapy (PSPT) plans and to assess the effect of different definitions of normal lungs (lungs minus GTV (DVHG), lungs minus CTV (DVHC) and lungs minus PTV (DVHP)) on lungs dose parameters. Materials/Methods Paired lung IMRT and PSPT (n = 26) plans were collected from two different institutions regularly treating NSCLC with PSPT. Plans were loaded into MIM, scaled to 70 Gy (RBE) (95% of PTV receives 70 Gy) and their DVHs were analyzed and tested against the dosimetric compliance criteria of RTOG 1308. Lungs dose parameters based on different definitions for the normal lung were also compared. Results Most of the RTOG 1308 protocol dosimetric criteria were achieved by both IMRT and PSPT plans, with a relatively high deviation unacceptable rate in the heart maximum dose (HMD). A deviation unacceptable rate of over 60% was scored for the HMD. However, the passing rate of the HMD was increased to 80% using the protocol allowable variations. Dose parameters for the target volume were very similar for IMRT and PSPT plans. PSPT plans led to lower lung V5Gy (%); maximum spinal cord dose; and heart V5Gy (%); V30Gy (%); V45Gy (%) and mean heart dose as compared with IMRT plans. The average percentage relative differences in lungs V5Gy (%) were 3.3 ± 0.4 (IMRT) and 5.6± 0.5 (PSPT) for DVHG Vs. DVHC and 7.1 ± 0.6 (IMRT) and 12.00 ± 1(PSPT) for DVHG Vs. DVHP; in lungs V20Gy (%) were 7.6 ± 0.7 (IMRT) and 7.8 ± 0.8 (PSPT) for DVHG Vs. DVHC and 16 ± 1 (IMRT) and 17 ± 1 (PSPT) for DVHG Vs. DVHP and in mean lung dose were 9.2 ± 0.8 (IMRT) and 10.8 ± 0.9 (PSPT) for DVHG Vs. DVHC and 19 ± 1 (IMRT) and 22 ± 2 (PSPT) for DVHG Vs. DVHP. Conclusions Most of the RTOG 1308 protocol dosimetric criteria were achieved with IMRT and PSPT. Both IMRT and PSPT lead to similar PTV dose parameters. However, PSPT plans led to lower dose parameters for most normal structures as compared with IMRT plans. Different definitions of normal lung (lungs minus GTV, lungs minus CTV and lungs minus PTV) led to different lungs doses and these differences can be as high as 15-22%.
    No preview · Article · Sep 2014 · International Journal of Radiation OncologyBiologyPhysics
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    ABSTRACT: Purpose: Combining cisplatin or cetuximab with radiation improves overall survival (OS) of patients with stage III or IV head and neck carcinoma (HNC). Cetuximab plus platinum regimens also increase OS in metastatic HNC. The Radiation Therapy Oncology Group launched a phase III trial to test the hypothesis that adding cetuximab to the radiation-cisplatin platform improves progression-free survival (PFS). Patients and methods: Eligible patients with stage III or IV HNC were randomly assigned to receive radiation and cisplatin without (arm A) or with (arm B) cetuximab. Acute and late reactions were scored using Common Terminology Criteria for Adverse Events (version 3). Outcomes were correlated with patient and tumor features and markers. Results: Of 891 analyzed patients, 630 were alive at analysis (median follow-up, 3.8 years). Cetuximab plus cisplatin-radiation, versus cisplatin-radiation alone, resulted in more frequent interruptions in radiation therapy (26.9% v. 15.1%, respectively); similar cisplatin delivery (mean, 185.7 mg/m2 v. 191.1 mg/m2, respectively); and more grade 3 to 4 radiation mucositis (43.2% v. 33.3%, respectively), rash, fatigue, anorexia, and hypokalemia, but not more late toxicity. No differences were found between arms A and B in 30-day mortality (1.8% v. 2.0%, respectively; P = .81), 3-year PFS (61.2% v. 58.9%, respectively; P = .76), 3-year OS (72.9% v. 75.8%, respectively; P = .32), locoregional failure (19.9% v. 25.9%, respectively; P = .97), or distant metastasis (13.0% v. 9.7%, respectively; P = .08). Patients with p16-positive oropharyngeal carcinoma (OPC), compared with patients with p16-negative OPC, had better 3-year probability of PFS (72.8% v. 49.2%, respectively; P < .001) and OS (85.6% v. 60.1%, respectively; P < .001), but tumor epidermal growth factor receptor (EGFR) expression did not distinguish outcome. Conclusion: Adding cetuximab to radiation-cisplatin did not improve outcome and hence should not be prescribed routinely. PFS and OS were higher in patients with p16-positive OPC, but outcomes did not differ by EGFR expression.
    Full-text · Article · Aug 2014 · Journal of Clinical Oncology
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    ABSTRACT: Purpose: To review IGRT credentialing experience and unexpected technical issues encountered in connection with advanced radiotherapy technologies as implemented in RTOG clinical trials. To update IGRT credentialing procedures with the aim of improving the quality of the process, and to increase the proportion of IGRT credentialing compliance. To develop a living disease site-specific IGRT encyclopedia. Methods: Numerous technical issues were encountered during the IGRT credentialing process. The criteria used for credentialing review were based on: image quality; anatomy included in fused data sets and shift results. Credentialing requirements have been updated according to the AAPM task group reports for IGRT to ensure that all required technical items are included in the quality review process. Implementation instructions have been updated and expanded for recent protocols. Results: Technical issues observed during the credentialing review process include, but are not limited to: poor quality images; inadequate image acquisition region; poor data quality; shifts larger than acceptable; no soft tissue surrogate. The updated IGRT credentialing process will address these issues and will also include the technical items required from AAPM: TG 104; TG 142 and TG 179 reports. An instruction manual has been developed describing a remote credentialing method for reviewers. Submission requirements are updated, including images/documents as well as facility questionnaire. The review report now includes summary of the review process and the parameters that reviewers check. We have reached consensus on the minimum IGRT technical requirement for a number of disease sites. RTOG 1311(NRG-BR002A Phase 1 Study of Stereotactic Body Radiotherapy (SBRT) for the Treatment of Multiple Metastases) is an example, here; the protocol specified the minimum requirement for each anatomical sites (with/without fiducials). Conclusion: Technical issues are identified and reported. IGRT guidelines are updated, with the corresponding credentialing requirements. An IGRT encyclopedia describing site-specific implementation issues is currently in development.
    No preview · Article · Jun 2014 · Medical Physics
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    ABSTRACT: Purpose To quantify variations in target and normal structure contouring and evaluate dosimetric impact of these variations in non-small cell lung cancer (NSCLC) cases. To study whether providing an atlas can reduce potential variation. Methods and materials Three NSCLC cases were distributed sequentially to multiple institutions for contouring and radiation therapy planning. No segmentation atlas was provided for the first 2 cases (Case 1 and Case 2). Contours were collected from submitted plans and consensus contour sets were generated. The volume variation among institution contours and the deviation of them from consensus contours were analyzed. The dose-volume histograms for individual institution plans were recalculated using consensus contours to quantify the dosimetric changes. An atlas containing targets and critical structures was constructed and was made available when the third case (Case 3) was distributed for planning. The contouring variability in the submitted plans of Case 3 was compared with that in first 2 cases. Results Planning target volume (PTV) showed large variation among institutions. The PTV coverage in institutions’ plans decreased dramatically when reevaluated using the consensus PTV contour. The PTV contouring consistency did not show improvement with atlas use in Case 3. For normal structures, lung contours presented very good agreement, while the brachial plexus showed the largest variation. The consistency of esophagus and heart contouring improved significantly (t test; P < .05) in Case 3. Major factors contributing to the contouring variation were identified through a survey questionnaire. Conclusions The amount of contouring variations in NSCLC cases was presented. Its impact on dosimetric parameters can be significant. The segmentation atlas improved the contour agreement for esophagus and heart, but not for the PTV in this study. Quality assurance of contouring is essential for a successful multi-institutional clinical trial.
    No preview · Article · Jun 2014 · Practical Radiation Oncology
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    Full-text · Article · May 2014 · Radiotherapy and Oncology
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    ABSTRACT: To provide quantitative and qualitative image quality metrics and imaging dose for modern Varian On-board Imager (OBI) (ver. 1.5) and Elekta X-ray Volume Imager (XVI) (ver. 4.5R) cone-beam computed tomography (CBCT) systems in a clinical adaptive radiation therapy environment by accounting for varying patient thickness. Image quality measurements were acquired with Catphan 504 phantom (nominal diameter and with additional 10 cm thickness) for OBI and XVI systems and compared to planning CT (pCT) (GE LightSpeed). Various clinical protocols were analyzed for the OBI and XVI systems and analyzed using image quality metrics, including spatial resolution, low contrast detectability, uniformity, and HU sensitivity. Imaging dose measurements were acquired in Wellhofer Scanditronix i'mRT phantom at nominal phantom diameter and with additional 4 cm phantom diameter using GafChromic XRQA2 film. Calibration curves were generated using previously published in-air Air Kerma calibration method. The OBI system full trajectory scans exhibited very little dependence on phantom thickness for accurate HU calculation, while half-trajectory scans with full-fan filter exhibited dependence of HU calculation on phantom thickness. The contrast-to-noise ratio (CNR) for the OBI scans decreased with additional phantom thickness. The uniformity of Head protocol scan was most significantly affected with additional phantom thickness. The spatial resolution and CNR compared favorably with pCT, while the uniformity of the OBI system was slightly inferior to pCT. The OBI scan protocol dose levels for nominal phantom thickness at the central portion of the phantom were 2.61, 0.72, and 1.88 cGy, and for additional phantom thickness were 1.95, 0.48, and 1.52 cGy, for the Pelvis, Thorax, and Spotlight protocols, respectively. The XVI system scans exhibited dependence on phantom thickness for accurate HU calculation regardless of trajectory. The CNR for the XVI scans decreased with additional phantom thickness. The uniformity of the XVI scans was significantly dependent on the selection of the proper FOV setting for all phantom geometries. The spatial resolution, CNR, and uniformity for XVI were lower than values measured for pCT. The XVI scan protocol dose levels at the central portion of the phantom for nominal phantom thickness were 2.14, 2.15, and 0.33 cGy, and for additional phantom thickness were 1.56, 1.68, and 0.21 cGy, for the Pelvis M20, Chest M20, and Prostate Seed S10 scan protocols, respectively. The OBI system offered comparable spatial resolution and CNR results to the results for pCT. Full trajectory scans with the OBI system need little-to-no correction for HU calculation based on HU stability with changing phantom thickness. The XVI system offered lower spatial resolution and CNR results than pCT. In addition, the HU calculation for all scan protocols was dependent on the phantom thickness. The uniformity for each CBCT system was inferior to that of pCT for each phantom geometry. The dose for each system and scan protocol in the interior of the phantom tended to decrease by approximately 25% with 4 cm additional phantom thickness.
    Full-text · Article · Mar 2014 · Medical Physics

Publication Stats

4k Citations
497.85 Total Impact Points

Institutions

  • 2013-2015
    • Treatment Research Institute, Philadelphia PA
      Filadelfia, Pennsylvania, United States
  • 2001-2015
    • Thomas Jefferson University Hospitals
      • Department of Radiation Oncology
      Filadelfia, Pennsylvania, United States
  • 1998-2015
    • Thomas Jefferson University
      • Department of Radiation Oncology
      Filadelfia, Pennsylvania, United States
  • 2011-2014
    • American College of Radiology
      Filadelfia, Pennsylvania, United States
  • 2010
    • University of Texas Southwestern Medical Center
      • Department of Radiation Oncology
      Dallas, Texas, United States
  • 1985-2009
    • Jefferson College
      Хиллсборо, Missouri, United States
  • 2004
    • American Association of Physicists in Medicine
      Filadelfia, Pennsylvania, United States
  • 1992-1996
    • NYU Langone Medical Center
      • • Department of Radiology
      • • Department of Radiation Oncology
      New York City, New York, United States
  • 1993-1995
    • CUNY Graduate Center
      New York City, New York, United States
    • Massachusetts General Hospital
      Boston, Massachusetts, United States
  • 1981-1993
    • University of Pennsylvania
      • • Department of Radiation Oncology
      • • Department of Medicine
      Filadelfia, Pennsylvania, United States
  • 1980-1993
    • Hospital of the University of Pennsylvania
      • Department of Radiation Oncology
      Filadelfia, Pennsylvania, United States