Image‐guided Therapy QA Center Research Articles

Quality assurance of radiotherapy in the ongoing EORTC 22042–26042 trial for atypical and malignant meningioma: results from the dummy runs and prospective individual case Reviews

BackgroundThe ongoing EORTC 22042–26042 trial evaluates the efficacy of high-dose radiotherapy (RT) in atypical/malignant meningioma. The results of the Dummy Run (DR) and prospective Individual Case Review (ICR) were analyzed in this Quality Assurance (QA) study.Material/methodsInstitutions were requested to submit a protocol compliant treatment plan for the DR and ICR, respectively. DR-plans (n=12) and ICR-plans (n=50) were uploaded to the Image-Guided Therapy QA Center of Advanced Technology Consortium server (http://atc.wustl.edu/) and were assessed prospectively.ResultsMajor deviations were observed in 25% (n=3) of DR-plans while no minor deviations were observed. Major and minor deviations were observed in 22% (n=11) and 10% (n=5) of the ICR-plans, respectively. Eighteen% of ICRs could not be analyzed prospectively, as a result of corrupted or late data submission. CTV to PTV margins were respected in all cases. Deviations were negatively associated with the number of submitted cases per institution (p=0.0013), with a cutoff of 5 patients per institutions. No association (p=0.12) was observed between DR and ICR results, suggesting that DR’s results did not predict for an improved QA process in accrued brain tumor patients.ConclusionsA substantial number of protocol deviations were observed in this prospective QA study. The number of cases accrued per institution was a significant determinant for protocol deviation. These data suggest that successful DR is not a guarantee for protocol compliance for accrued patients. Prospective ICRs should be performed to prevent protocol deviations.

Implementation of Remote 3-Dimensional Image Guided Radiation Therapy Quality Assurance for Radiation Therapy Oncology Group Clinical Trials

To report the process and initial experience of remote credentialing of three-dimensional (3D) image guided radiation therapy (IGRT) as part of the quality assurance (QA) of submitted data for Radiation Therapy Oncology Group (RTOG) clinical trials; and to identify major issues resulting from this process and analyze the review results on patient positioning shifts. Image guided radiation therapy datasets including in-room positioning CT scans and daily shifts applied were submitted through the Image Guided Therapy QA Center from institutions for the IGRT credentialing process, as required by various RTOG trials. A centralized virtual environment is established at the RTOG Core Laboratory, containing analysis tools and database infrastructure for remote review by the Physics Principal Investigators of each protocol. The appropriateness of IGRT technique and volumetric image registration accuracy were evaluated. Registration accuracy was verified by repeat registration with a third-party registration software system. With the accumulated review results, registration differences between those obtained by the Physics Principal Investigators and from the institutions were analyzed for different imaging sites, shift directions, and imaging modalities. The remote review process was successfully carried out for 87 3D cases (out of 137 total cases, including 2-dimensional and 3D) during 2010. Frequent errors in submitted IGRT data and challenges in the review of image registration for some special cases were identified. Workarounds for these issues were developed. The average differences of registration results between reviewers and institutions ranged between 2 mm and 3 mm. Large discrepancies in thesuperior-inferior direction were found for megavoltage CT cases, owing to low spatial resolution in this direction for most megavoltage CT cases. This first experience indicated that remote review for 3D IGRT as part of QA for RTOG clinical trials is feasible and effective. The magnitude of registration discrepancy between institution and reviewer was presented, and the major issues were investigated to further improve this remote evaluation process.

Pelvic Normal Tissue Contouring Guidelines for Radiation Therapy: A Radiation Therapy Oncology Group Consensus Panel Atlas

To define a male and female pelvic normal tissue contouring atlas for Radiation Therapy Oncology Group (RTOG) trials. One male pelvis computed tomography (CT) data set and one female pelvis CT data set were shared via the Image-Guided Therapy QA Center. A total of 16 radiation oncologists participated. The following organs at risk were contoured in both CT sets: anus, anorectum, rectum (gastrointestinal and genitourinary definitions), bowel NOS (not otherwise specified), small bowel, large bowel, and proximal femurs. The following were contoured in the male set only: bladder, prostate, seminal vesicles, and penile bulb. The following were contoured in the female set only: uterus, cervix, and ovaries. A computer program used the binomial distribution to generate 95% group consensus contours. These contours and definitions were then reviewed by the group and modified. The panel achieved consensus definitions for pelvic normal tissue contouring in RTOG trials with these standardized names: Rectum, AnoRectum, SmallBowel, Colon, BowelBag, Bladder, UteroCervix, Adnexa_R, Adnexa_L, Prostate, SeminalVesc, PenileBulb, Femur_R, and Femur_L. Two additional normal structures whose purpose is to serve as targets in anal and rectal cancer were defined: AnoRectumSig and Mesorectum. Detailed target volume contouring guidelines and images are discussed. Consensus guidelines for pelvic normal tissue contouring were reached and are available as a CT image atlas on the RTOG Web site. This will allow uniformity in defining normal tissues for clinical trials delivering pelvic radiation and will facilitate future normal tissue complication research.

Process and Initial Experience of Remote Credentialing of 3D IGRT Data for Institutions Participating in RTOG Clinical Trials

To report the process and initial experience of a remote credentialing of 3D image-guided radiation therapy (IGRT) as part of quality assurance (QA) of submitted data by institutions participating in Radiation Therapy Oncology Group (RTOG) clinical trials. The following data sets were submitted through Image-Guided Therapy QA Center (ITC) from institutions for IGRT credentialing process as required by various RTOG trials: planning CT, plan, structures, positioning CT for one or a number of days, all in DICOM format. Daily shifts were also collected, along with descriptions of the imaging techniques. A centralized virtual environment is established at RTOG core laboratory containing analysis tools and database infrastructure for remote review by Physics Principal Investigators (Physics-PI). Appropriateness of IGRT technique (visibility of anatomical structures of interest) and volumetric image registration accuracy were evaluated. Registration accuracy was verified by repeat registration with a third party registration software and comparison with the institution's submitted data. With the accumulated review results, registration differences between those obtained by Physics-PI and from institutions were analyzed for different trial protocols (imaging sites), shift directions, and imaging modalities. This remote review process was successfully carried out for 87 3D cases (out of 137 total cases including 2D and 3D) during 2010. Differences of registration results between reviewers and institutions were 1.80 ± 1.06mm, 2.05 ± 1.05mm, 2.01 ± 0.93mm (mean ± SD; in left-right, superior-inferior, and anterior-posterior directions respectively) for lung cases; 0.69 ± 0.61mm, 2.89 ± 3.84mm, 0.40 ± 0.07mm for spine cases; and 1.52 ± 1.03mm, 2.51 ± 2.24mm, 1.45 ± 1.12mm for head and neck cases. The registration differences for kV CBCT cases were 1.73 ± 1.09mm, 1.59 ± 0.95mm, 1.74 ± 1.10mm, and for MVCT cases were 1.51 ± 0.98mm, 3.71 ± 1.67mm, 1.87 ± 0.86mm. Relatively large discrepancy in superior-inferior direction was found for MVCT cases due to the low spatial resolution (6mm slice spacing) in this direction for most MVCT cases. Major issues in repeating the registration included difficulty in reproducing initial patient setup position in some CBCT cases with pre-imaging couch shift and in some MVCT cases where the setup laser center was unknown. Additional information was requested from the institution if necessary and workarounds for these issues were developed. Preliminary review experience and clinical data indicated that remote review for 3D IGRT as part of QA for RTOG clinical trials is feasible and effective. Further improvements are expected to mature this remote evaluation process.

Multi-System Verification of Registrations for Image-Guided Radiotherapy in Clinical Trials

To provide quantitative information on the image registration differences from multiple systems for image-guided radiotherapy (IGRT) credentialing and margin reduction in clinical trials. Images and IGRT shift results from three different treatment systems (Tomotherapy Hi-Art, Elekta Synergy, Varian Trilogy) have been sent from various institutions to the Image-Guided Therapy QA Center (ITC) for evaluation for the Radiation Therapy Oncology Group (RTOG) trials. Nine patient datasets (five head-and-neck and four prostate) were included in the comparison, with each patient having 1-4 daily individual IGRT studies. In all cases, daily shifts were re-calculated by re-registration of the planning CT with the daily IGRT data using three independent software systems (MIMvista, FocalSim, VelocityAI). Automatic fusion was used in all calculations. The results were compared with those submitted from institutions. Similar regions of interest (ROIs) and same initial positions were used in registrations for inter-system comparison. Different slice spacings for CBCT sampling and different ROIs for registration were used in some cases to observe the variation of registration due to these factors. For the 54 comparisons with head-and-neck datasets, the absolute values of differences of the registration results between different systems were 2.6±2.1 mm (mean±SD; range 0.1-8.6 mm, left-right [LR]), 1.7±1.3 mm (0.0-4.9 mm, superior-inferior [SI]), and 1.8±1.1 mm (0.1-4.0 mm, anterior-posterior [AP]). For the 66 comparisons in prostate cases, the differences were 1.1±1.0 mm (0.0-4.6 mm, LR), 2.1±1.7 mm (0.0-6.6 mm, SI), and 2.0±1.8 mm (0.1-6.9 mm, AP). The differences caused by the slice spacing variation were relatively small, and the different ROI selections in FocalSim and MIMvista also had limited impact. The extent of differences was reported when different systems were used for image registration. Careful examination and quality assurance of the image registration process are crucial before considering margin reduction using IGRT in clinical trials.

SU-GG-T-262: Open-Source Tool for Assessing Variability in DICOM Data

Purpose: To develop tools and methodology for analyzing the variability of DICOM attributes in advanced technology radiotherapytreatment planning datasets. Method and Materials: The POSDA open‐source toolkit (www.posda.com) and PostgreSQL database (www.postgresql.org) were used to create a tool for analyzing DICOM datasets, consisting of CT, MR, and PET images, RT Structure Sets, RT Plan, and RT Dose objects. All images and RT objects for a patient were anonymized together to maintain referential integrity. These anonymized datasets were used to populate a database tracking components of each object type; e.g., RT Structure Sets were represented in terms of the ROIs, ROI contours, and ROI observations. Results: This tool has been used to examine DICOM attributes in datasets submitted to the Image Guided Therapy QA Center from a variety of commercial treatment planning systems. Query parameters include image pixel spacing, the number and type of ROIs in RT Structure Sets, ROI Name, ROI Observation Label, and RT ROI Interpreted Type values, the number of beams and control points in RT Plan objects, and RT Dose grid spacing, The database created by this tool will be used to find inconsistencies in the use of DICOM unique identifiers and DICOM data model, e.g., multiple modalities in a single Series, to assess the use of optional attributes, and to check completeness and referential integrity in clinical trials submissions. Conclusion: The tool developed in this effort provides an efficient means for studying variability in the content and encoding of DICOM RT treatment planning data. Analyzing clinical trial datasets from a variety of treatment planning systems provides important information for designing data quality assurance tools and will be helpful in developing IHE‐RO profiles for improving interoperability among treatment planning systems. Supported in part by NIH U24 grant CA081647.

An Electronic Phantom for Testing and Quality Assurance of Dose Volume Histogram Calculations used in Data Analysis for Multi Institutional Clinical Trials

Digitally submitted DVHs lack consistency due to algorithmic differences among treatment planning systems (TPS). To maintain consistency among cases in multi institutional clinical trials, the Image Guided Therapy QA Center (ITC) recalculates DVHs from submitted 3D dose distributions and structures. In instances where there are steep dose gradients and small structures, the DVHs calculated at an institution can be significantly different from those recalculated at the ITC (Straube, et al. AAPM 2005).

SU-GG-T-374: Update On Digital Data Integrity Quality Assurance for Multi-Institutional Advanced Technology Clinical Trials

Purpose: Report on that part of the cooperative group clinical trial quality assurance (QA) review process referred to as Digital Data Integrity QA (DDIQA). Method and Materials: Participants in advanced technology clinical trials supported by the Image-guided Therapy QA Center (ITC) must be able to submit 3D digital datasets (images, contours, and dose distributions) to the ITC. Protocol QA review responsibility has been divided between ITC (DDIQA review) and the cooperative group (CG) for Protocol Compliance QA Review (PCQA). DDIQA consists of review of the completeness of protocol required elements, format, spatial registration, and data corruption. For consistency, structures are renamed and dose volume histograms are recalculated. Data are posted to the web-based Remote Review Tool (RRT) a component of the ITC's clinical trial QA system (called QuASA2R) for PCQA review, which includes compliance review of target volume and organ at risk contours as well as review of dose compliance by CG reviewers. Results: ITC has over 13 years experience in receiving/processing over 6000 digital datasets submitted by institutions participating in advanced technology clinical trials. DDIQA metrics show that approximately 30 % of submissions are problematic. Problems can be divided into three categories: (1) misunderstanding of protocol requirements, (2) misuse of treatment planning system (TPS) data export feature, and (3) updated TPS software whose data export feature is no longer compliant with QuASA2R requirements. The time and effort required to perform DDIQA and prepare a case for PCQA varies, depending on protocol complexity. Conclusion: DDIQA has proven to be essential for QA of advanced technology clinical trials. Thus, total automation of data submission for rapid QA review of clinical trial datasets is not realistic at this time. Work is currently focused on developing tools that help ITC personnel perform DDIQA more efficiently. Supported by NIH U24 CA81647.

SU-GG-T-385: QuASA2R - a Digital Data Quality Assurance Submission, Archive, Analysis, and Review System for Advanced Technology Clinical Trials in Radiation Therapy

Purpose: The QuASA2R clinical trials quality assurance (QA) system, developed by the Image‐guided Therapy QA Center (ITC), provides multiple cooperative groups one of the most advanced medical informatics infrastructures currently in use for radiation therapy clinical trials QA. The recently renewed ATC grant has provided funds for further refinement/development of this system. A status update of QuASA2R for protocol case data QA, submission, archive,analysis, and review is presented. Method and Materials: Development of QuASA2R is guided by the considerable experience and success of ITC computer scientists and QA personnel in supporting advanced technology clinical trials, recognition of QA tool needs for future protocols involving emerging technologies (e.g. IGRT, ART), and compatibility with caBIG infrastructure. ITC has embraced a flexible, modular architecture with emphasis on well‐defined interfaces, which allows integration of commercial “off‐the‐shelf” and open‐source software and focuses custom software development/enhancements on features not otherwise available. This approach enables step‐wise implementation and upgrading of system components while providing continuous support of ongoing protocols. Results: A major update of QuASA2R is underway involving replacement of current treatment‐planning‐system‐based imaging/treatment planning/verification database with specialized DICOM archivesoftware supporting a tiered storage structure. The DICOM archive supports diagnostic imaging, DICOM RT objects, and meta‐data related to diagnosis, treatment, and outcomes assessment for protocol patients. Updates to QA utilities that aid ITC staff in performing Digital Data Integrity QA (DDIQA) continue to be implemented. The open‐source CERR software system has been integrated into QuASA2R for format conversion, QA review, and secondary data analysis.Conclusion: The QuASA2R system has demonstrated a continuing robustness, having archived over 6000 datasets. Its modular design allows updates to meet changing requirements of advanced technology clinical trials. Experience with new updates and a roadmap for future upgrades over the next 12 months will be presented. Supported by NIH U24 Grant CA81647.

Quality Assurance Issues in Conducting Multi-Institutional Advanced Technology Clinical Trials

The National Cancer Institute-sponsored Advanced Technology Quality Assurance (QA) Consortium, which consisted of the Image-Guided Therapy QA Center, Radiation Therapy Oncology Group, Radiological Physics Center, Quality Assurance Review Center, and Resource Center for Emerging Technologies, has pioneered the development of an infrastructure and QA method for advanced technology clinical trials that requires volumetric digital data submission of a protocol patient's treatment plan and verification data. In particular, the Image-Guided Therapy QA Center has nearly 15 years experience in facilitating QA review for Radiation Therapy Oncology Group advanced technology clinical trials. This QA process includes (1) a data integrity review for completeness of protocol required elements, the format of data, and possible data corruption, and recalculation of dose-volume histograms; (2) a review of compliance with target volume and organ-at-risk contours by study chairs; and (3) a review of dose prescription and dose heterogeneity compliance by the Radiation Therapy Oncology Group Headquarters Dosimetry Group or the Radiological Physics Center dosimetrists (for brachytherapy protocols). This report reviews the lessons learned and the QA challenges presented by the use of advanced treatment modalities in clinical trials requiring volumetric digital data submission.

A Survey of the ITC Volumetric Treatment Planning Data Archive Supporting RTOG Advanced Technology Clinical Trials

Purpose: Survey of volumetric treatment planning (TP) data, linked to outcomes, collected by the Image-guided Therapy QA Center (ITC) in 15 years of facilitating QA review for RTOG multi-institutional advanced technology (AT) clinical trials. Materials & Methods: The ITC as part of the Advanced Technology QA Consortium (ATC) collects volumetric TP data sets linked to outcomes for RTOG Advanced Technology clinical trials. CT images, target-volume/organ-at-risk contours, and 3D dose distributions exported from commercial TP systems are submitted to the ITC using either DICOM or RTOG Data Exchange format. ITC staff evaluates dataset integrity and completeness, and requests re-submission as needed. DoseVolume Histograms (DVHs) for required volumes are recalculated from submitted contours and dose distributions. RTOG dosimetrists and study chairs review contours and dose distributions for protocol compliance using ITC’s web-based Remote Review Tool (RRT). Clinical outcomes are reported to RTOG headquarters using protocol-specific forms. Results: The ITC has collected over 5000 complete TP data sets quantifying the relationship between image-based anatomy and planned doses. Disease sites treated in the 10 closed protocols (1800 cases) include prostate, lung, brain, head/neck, and breast. An additional 13 active protocols (>3500 cases) also include liver, cervix, and anus. A sample of data sets available for analysis is listed below. (Doses (Gy) and % volumes are the minimum/maximum/average values.) Prostate (3DCRT, N=984; PTV D98: 52.2/81.6/75.0, bladder Dmean: 4.9, 75.9, 37.7, rectum Dmean: 12.9, 72.5, 42.7, femoral heads Dmean: 1.8, 49.5, 32.4), HeadN PTV D98: 58.0/73.4/67.6, spinal cord D2: 32.8/44.8/39.6, parotid Dmean: 21.2/50.3/32.4, larynx Dmean: 3.9/57.7/32.9), Lung (3DCRT, N=158; PTV D98: 50.3/98.2/77.4, spinal cord D2: 0.1/60.1/26.0, esophagus Dmean: 0/63.8/15.9, heart Dmean: 0/45.3/10.5, liver Dmean: 0/19.3/1.2, brachial plexus Dmean: 0/57.7/4.6, lung V20: 5.3/46.6 /21.2 %,). The ITC has provided access to these TP protocol data sets for secondary analysis by: (1) export of entire TP data sets as RTOG data exchange files and (2) online data analysis using the RRT. External investigators have used these data for dose escalation trials in prostate (RTOG 9406) and lung cancer (RTOG 9311) and obtained two NIH R01 grants focused on the development of normal tissue complication probability (NTCP) models. Also, online access to RTOG 9406 TP data has been used to analyze erectile dysfunction following 3DCRT for prostate cancer. Using the contour editing feature in the RRT, penile bulb structures, not originally contoured for RTOG 9406, were delineated on these datasets. New DVHs were computed from the stored 3D dose distributions and compared with reported clinical outcomes (impotence). Such an analysis would have required an entirely new study if the volumetric TP data had not been archived in the ITC database. Conclusion: The ITC archive of volumetric images and dosimetry for RTOG Advanced Technology Clinical Trials is a rich resource for developing and testing models of tissue response to ionizing radiation. The value of this archive continues to grow with the incorporation of new data sets from new anatomical sites, and new imaging modalities. Supported by NIH U24 grant CA81647 and U10 grant CA21661

1011: A Review of the Activities of the ITC in Support of RTOG Advanced Technology Clinical Trials

1011: A Review of the Activities of the ITC in Support of RTOG Advanced Technology Clinical Trials

SU‐FF‐T‐308: ITC Assists Developers of ATC Compliant DICOM Export for Clinical Trials

Purpose: The Image‐guided Therapy QA Center (ITC) as part of the Advanced Technology QA Consortium (ATC) has played a key role in assisting treatment planning system (TPS) developers in verifying that their DICOM implementations (CT, RT Structure Set, RT Dose, RT Plan, and RT Image) match ATC's conformance statement. This presentation will review lessons learned in this important effort. Methods and Materials: ITC hosted a series of DICOM Implementers' Workshops to assist TPS vendors in implementing RT objects needed for clinical trials. A system of software (“ATC Method 1”) developed at ITC to receive, process, and review volumetric treatment planning data for advanced technology clinical trials was used to assist vendors in their implementation of DICOM export. ATC's DICOM conformance statement specifies requirements for using DICOM RT objects in these clinical trials. ITC's DICOM fileset reader converts incoming data to an internal format for efficient display and review using the ITC web‐based Remote Review Tool (RRT). The RRT was used by TPS developers to visualize/compare submitted images, structure sets, and dose distributions, thus greatly facilitating their DICOM implementations. Results: Interactions with developers have exposed several problems in interpretation and implementation of the DICOM standard resulting from the complexity of DICOM RT objects and differences in design/capabilities of TPSs. Examples of problems seen include CT/Structure/Dose miss‐registration and DVH‐calculation discrepancies. To date, 6 TPSs have released ATC‐compliant DICOM export software. ITC has received DICOM data matching the ATC conformance statement from a total of 15 TPSs. ITC has worked with 8 additional TPS developers. Conclusions: The ITC web‐based Remote Review Tool has proven to be of great help to vendors in developing and verifying implementations. More effort is needed by vendors to make digital data submission for clinical trials a simpler process. Support: NIH U24 CA81647.

SU‐FF‐T‐167: Digital Data Integrity QA for Multi‐Institutional Clinical Trials

Purpose: The Image‐guided Therapy QA Center (ITC) as part of the NCI‐sponsored Advanced Technology QA Consortium (ATC) has nearly 15 years experience in performing data integrity QA review for multi‐institutional advanced technology clinical trials that require digital data submission. This presentation will report on that experience. Method and Materials: Participants in some advanced technology multi‐institutional clinical trials must be able to submit imaging data as well as RT objects (CT, RT Structure Set, RT Dose, and RT Plan) to the ITC for protocol compliance QA review of contoured volumes and dose coverage/heterogeneity. Data are sent via FTP or on media. However, prior to that QA review, experienced personnel at the ITC carefully review each digital data set in regard to completeness of protocol required elements, format of data, and possible data corruption. Results: Thus far over 3000 data sets have been submitted to ITC. Unfortunately, data often need resubmission due to problems discovered by ITC. Errors in submission can be divided into five categories: 1) misuse of UI of treatment planning system (TPS), 2) misunderstanding of protocol requirements, 3) non‐uniformity of DICOM export implementations by TPS vendors, 4) user error with digital data transfer software, and 5) updated TPS software, whose data export feature no longer is ATC compliant. Statistics of number of resubmissions required as well as specific details of these problems will be presented. Conclusion: Digital data submission of complete 3D data set is essential for QA of advanced technology clinical trials. However, collection of these data requires review and troubleshooting by experienced personnel to ensure subsequent protocol compliance QA and later still, quality data analysis. A significant portion of the ITC workload involves digital data integrity QA to ensure quality of submitted digital data. Support: NIH U24 Grant CA81647.

SU‐FF‐T‐267: Implementation of ATC Method 1 for Clinical Trials Data Review at the Quality Assurance Review Center

Purpose: To develop the capability at the Quality Assurance Review Center (QARC) to receive and review digital radiation therapy treatment planning data (TPD) for clinical trial case review. Method and Materials: A system of software (“ATC Method 1”) developed at the Image‐guided Therapy QA Center (ITC) as part of the Advanced Technology QA Consortium (ATC) to receive, process, and review volumetric TPD for clinical trials was ported to a Linux workstation at QARC. The system includes an FTP server for receiving TPD (in DICOM or RTOG data exchange format) from protocol participants, utilities for importing TPD into a local file format, and the web‐based Remote Review Tool (RRT) for QA of ROIs, isodoses, DVHs, and dose statistics. (Proprietary software components were used by special arrangement with CMS, Inc.) Results: Software installation and maintenance were performed remotely at QARC by ITC personnel, with weekly teleconferences to coordinate the development effort. ITC software was adapted to better support the QARC QA process. RRT enhancements include selectable DVHs, distance measurement tool, and image grayscale presets. QARC software was adapted to support RRT invocation directly from the QARC database user interface. The system is in use for six COG, CALGB, ACOSOG, and ECOG protocols; 28 cases from 15 institutions have been received and reviewed (3/1/06). Conclusion: Widespread use of new treatment modalities such as IMRT, makes use of 3D datasets essential for complete evaluation of ROI delineation and assessment of agreement of dosimetric parameters with protocol requirements. This project demonstrates that ATC Method 1, successfully used in support of RTOG trials for many years at ITC, can be implemented at other QA centers. The effort required, however, was significant and tools must be tailored to each individual QA center's computer infrastructure/QA process. Supported by NIH U24 Grant CA81647 and NCI‐H Grant 5U10CA02951.

SU‐FF‐T‐406: Testing of ATC Method 2 for Supporting QA of Cooperative Group Advanced Technology Clinical Trials Requiring Digital Data Submission

Purpose: To test the readiness of a system of software (“ATC Method 2‐v.2.3”) developed by the Resource Center for Emerging Technologies (RCET) for supporting QA of cooperative group clinical trials within the Advanced Technology QA Consortium (ATC). Method and Materials: ATC Method 2‐v.2.3 includes WebSys client and server for secure data upload/download/archiving of volumetric imaging and radiotherapy treatment planning data, a web‐based Rapid Image Viewer (RIV) tool, and web‐based tools for server administration. The software was implemented on a test server at the Image‐guided Therapy QA Center (ITC), and underwent rigorous testing by ITC personnel. Tests conducted included examination of user interface behavior, as well as systematic comparison of submitted/retrieved copies of 16 representative test data sets (in DICOM and RTOG Data Exchange format) from nine different treatment planning system vendors. Results: Evaluation tests of version 2.3 of the ATC Method 2 software identified improvements in the usability of software over the previous version, and provided general suggestions for further improvement. These tests also identified specific input that led to failure of the WebSys client, usability issues in the RIV tool, database changes needed to support case identifiers in ATC trails, and corrections needed in handling certain DICOM objects. These test results have contributed to improvements in version 2.4 of this software in preparation for its use to support clinical trials. Version 2.4 is expected to be ready for testing beginning March 2006. The National Cancer Institute of Canada (NCIC) Clinical Trials Group (CTG) will participate in the new round of testing. Conclusion: Since this software is intended to play a major role in QA of data submitted for future ATC‐supported clinical trials, rigorous testing is essential to its ongoing development. Future testing is expected to benefit from collaborative efforts of NCIC CTG.Supported by NIH U24 Grant CA81647.

SU-FF-T-310: DVH Analysis: Consequences for Quality Assurance of Multi-Institutional Clnical Trials

Purpose: The submission of digital treatment planning data is essential for quality assurance (QA) of multi-institutional clinical trials involving advanced technology delivery techniques. Digitally submitted Dose Volume Histograms (DVHs), however, lack consistency due to algorithmic differences among Treatment Planning Systems (TPSs). To maintain consistency among cases in multi-institutional clinical trials, the Image Guided Therapy QA Center (ITC) re-calculates DVHs from submitted 3-D dose distributions and structure contours. In some recent trials involving high dose gradients, sizeable discrepancies have been observed between DVHs re-calculated by the ITC and DVHs submitted by participating institutions, making QA review of these data more difficult. Method and Materials: Digitally submitted DVH data were collected from various commercial TPSs for protocols requiring digital data submission. Submitted structure volumes and DVHs were compared to those calculated by the ITC. Comparisons were performed for anatomic structures ranging in size from < 1cc (optic chiasm) to > 450 cc (Lung PTV). Results: Agreement between submitted and re-calculated DVHs varied with the spatial sampling algorithms used by TPSs and improved as the volume of structures increased. Discrepancies in excess of 15% were observed for structures with volumes < 50 cc. Conclusion: Discrepancies in DVHs calculated by various commercial TPSs have long necessitated re-calculation of DVHs by the ITC for consistent correlation of dosimetry with outcomes. With increasing dose gradients, however, small changes in computed volumes can result in significant differences between dose coverage statistics reported by the treating institution and those computed for QA review. As a result, apparently protocol-compliant plans may be judged to violate QA criteria when submitted data are reviewed. Our analysis of DVH discrepancies among various TPSs can help to set QA criteria for present and future protocols, especially those in which high dose gradients are required. Support: NCI grant U24 CA 81647

SU-FF-T-306: Credentialing Requirements for NSABP B-39 / RTOG 0413

Purpose: NSABP B‐39 / RTOG 0413 is a Phase III trial comparing Whole Breast Irradiation versus Partial Breast Irradiation (PBI). The partial breast arm consists of 3 techniques, 3D Conformal Radiation Therapy, MammoSite and multi‐catheter HDR. For each of these techniques an institution, radiation oncologist and physicist “team” must be credentialed. Credentialing requires completing knowledge assessment and facility questionnaires, importing a DICOM CTimage set, performing a treatment plan using the image set and exporting the images, structures and isodoses to the Image‐Guided Therapy QA Center (ITC). Method & Materials: An institution can obtain the Knowledge Assessment and Facility Questionnaires from the RPC's website (http://rpc.mdanderson.org). These questionnaires can be completed online, emailed, faxed or mailed directly to the RPC. An institution may be credentialed for one or more of the PBI techniques. A CT benchmark case exists for each PBI technique. The institution is required to import the appropriate CTimage set into their treatment planning system. The benchmark must be planned per protocol. The benchmark must then be digitally exported to the ITC along with all required hard copy data. The RPC will review each benchmark case submitted. Once the RPC has completed its review NSABP will be informed that the institution has met the requirements for credentialing and will be allowed to enter patients onto the protocol. Conclusion: The purpose of credentialing is to verify that the radiation oncologist and other personnel involved are familiar with the protocol and can plan a case per protocol prior to placing a patient on protocol. This process enables us to give a “team” feedback prior to treating a patient on the trial potentially enabling us to reduce the number of deviations incurred on the trial. This work was supported by PHS grant CA 10953 awarded by NCI, DHHS.