MO-D-213-08: Remote Dosimetric Credentialing for Clinical Trials with the Virtual EPID Standard Phantom Audit (VESPA)

Journal Article · Mon Jun 15 04:00:00 EDT 2015 · Medical Physics

DOI:https://doi.org/10.1118/1.4925324· OSTI ID:22555293

Lehmann, J ^[1]; Miri, N ^[2]; Vial, P ^[3]; Hatton, J ^[4]; Zwan, B; Sloan, K ^[5]; Craig, A; Beenstock, V ^[6]; Molloy, T ^[7]; Greer, P ^[1]

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1. Calvary Mater Newcastle, Newcastle, NSW (Australia)
2. University of Newcastle, Newcastle, NSW (Australia)
3. Liverpool Hospital, Liverpool, NSW (Australia)
4. Trans Tasman Radiation Oncology Group (TROG), Newcastle, NSW (Australia)
5. Gosford Hospital, Gosford, NSW (Australia)
6. Canterbury Regional Cancer and Haematology Service, Christchurch (New Zealand)
7. Orange Hospital, Orange, NSW (Australia)

Purpose: Report on implementation of a Virtual EPID Standard Phantom Audit (VESPA) for IMRT to support credentialing of facilities for clinical trials. Data is acquired by local facility staff and transferred electronically. Analysis is performed centrally. Methods: VESPA is based on published methods and a clinically established IMRT QA procedure, here extended to multi-vendor equipment. Facilities, provided with web-based comprehensive instructions and CT datasets, create IMRT treatment plans. They deliver the treatments directly to their EPID without phantom or couch in the beam. They also deliver a set of simple calibration fields. Collected EPID images are uploaded electronically. In the analysis, the dose is projected back into a virtual phantom and 3D gamma analysis is performed. 2D dose planes and linear dose profiles can be analysed when needed for clarification. Results: Pilot facilities covering a range of planning and delivery systems have performed data acquisition and upload successfully. Analysis showed agreement comparable to local experience with the method. Advantages of VESPA are (1) fast turnaround mainly driven by the facility’s capability to provide the requested EPID images, (2) the possibility for facilities performing the audit in parallel, as there is no need to wait for a phantom, (3) simple and efficient credentialing for international facilities, (4) a large set of data points, and (5) a reduced impact on resources and environment as there is no need to transport heavy phantoms or audit staff. Limitations of the current implementation of VESPA for trials credentialing are that it does not provide absolute dosimetry, therefore a Level 1 audit still required, and that it relies on correctly delivered open calibration fields, which are used for system calibration. Conclusion: The implemented EPID based IMRT audit system promises to dramatically improve credentialing efficiency for clinical trials and wider applications. VESPA for VMAT will follow soon.

• OSTI ID: 22555293
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 6 Vol. 42; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
61 RADIATION PROTECTION AND DOSIMETRY
CALIBRATION STANDARDS
CLINICAL TRIALS
COMPUTERIZED TOMOGRAPHY
DATA ACQUISITION
DATASETS
DOSIMETRY
PHANTOMS
RADIATION DOSES
RADIOTHERAPY