2QA for Advanced Technology, Dallas, February 2007
Learning Objectives Role of RPC in support of clinical trials
Sources of requirements for credentialing
Goals of credentialing Procedures for credentialing Results from credentialing procedures
Remaining challenges in credentialing
QA for Advanced Technology, Dallas, February 2007
4QA for Advanced Technology, Dallas, February 2007
Brief Background Formed by agreement between AAPM and CRTS
Founded in 1968 to monitor institution participation in clinical trials
Funded continuously by NCI as structure of cooperative group programs have changed
Credentialing added as complexity of trials has increased
Now 38 years of experience of monitoring institutions and reporting findings to study groups and community
QA for Advanced Technology, Dallas, February 2007
NCINCI
QARCQARC
RPCQA PROGRAM
RPC QA PROGRAM
ITC(High tech Protocols)
ITC
RTOG/ACRRTOG/ACR
RCETRCET
RPC has relationships with all study groups and with Advanced Technology Consortium
ACOSOGCOGSWOGCALGBECOGNSABPNCCTGGOG
ACRINRTOGCOMSCTSU
QA for Advanced Technology, Dallas, February 2007
Activities specific to advanced
technology trials Measurements specifically addressing advanced technologies: dynamic wedges, MLC-shaped fields, small fields, etc.
Credentialing using benchmarks (compatibility with QARC maintained where relevant)
Credentialing using phantoms Independent recalculation of dose distributions with Eclipse planning system and RPC “standard” data
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Digital Data Submission
>300 institutions have demonstrated ability to submit digital data to ITC
Data-quality QA by ITC; Contour review Dosimetry QA review by
RPC online using RRT RPC compares plan and
phantom data, MD conducts clinical review
QA for Advanced Technology, Dallas, February 2007
• Education
• Evaluate ability to deliver dose
• Improve understanding of protocol
• Reduce deviation rate
Purposes of Credentialing
QA for Advanced Technology, Dallas, February 2007
General Credentialing Process
Feedback to Institution
Previous patients treated with technique Facility questionnaire Knowledge assessment questionnaire Benchmark case or phantom Electronic data submission RPC QA & dosimetry review Clinical review by radiation oncologist
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Questionnaires
Facility QuestionnaireDocuments equipment Allows evaluation of QA
procedures
Knowledge AssessmentTests physician’s
knowledge of the protocol
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QA for Advanced Technology, Dallas, February 2007
Brachytherapy Credentialing
Paper- or CT-based benchmark
RPC uses ATC remote review tool
Evaluate single source calculation
Prostate or breast HDR or LDR
QARC used identical methods for prostate LDR
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QA for Advanced Technology, Dallas, February 2007
3D Conformal Radiation Therapy
(3D CRT)
Evaluate 3D treatment planning process and ability to provide documentation
Conducted by QARC and RPC
~500 institutions credentialed to date
Some through NSABP/RTOG partial breast irradiation protocol
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QA for Advanced Technology, Dallas, February 2007
IMRT Benchmark for Credentialing
Institution transfers structures to CT data set
Prepares and submits IMRT plan
Demonstrates ability to plan using IMRT
Meet constraints on doses to PTV and OAR
Supplies results of QA measurements
QA for Advanced Technology, Dallas, February 2007
RPC Phantoms
prostate IMRT: 4, incl. prosthesis
thorax SBRT: 3 phantoms, 6 under construction
liver SBRT: 3, incl. motion
H&N IMRT: 25 in service
SRS: 2 in service, others sent by RDS
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Phantom Mailings by Year
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IMRT Credentialing
250+ institutions have successfully irradiated an RPC IMRT phantom
QA for Advanced Technology, Dallas, February 2007
QA for Advanced Technology, Dallas, February 2007
Plan vs. Treatment
QA for Advanced Technology, Dallas, February 2007
Phantom ResultsComparison between institution’s plan and delivered dose.
Criteria for agreement: 7% or 4 mm DTA
* 30% of institutions failed H&N phantom on the first attempt
Phantom H&NProstat
eThorax Liver
Irradiations 254 73 30 6Pass 179* 55 17 3Fail 71 9 7 1
Under analysis or at
institution30 6 6 1
Year introduced
2001 2004 2004 2005
Explanations for Failures
ExplanationMinimum # of occurrences
incorrect output factors in TPS 1
incorrect PDD in TPS 1
Software error 1
inadequacies in beam modeling at leaf ends (Cadman, et al; PMB 2002)
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not adjusting MU to account for dose differences measured with ion chamber
3
errors in couch indexing with Peacock system
3
2 mm tolerence on MLC leaf position 1
setup errors 7
target malfunction 1
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QA for Advanced Technology, Dallas, February 2007
Credentialing for Lung Protocols
RPC evaluates dose to TLDs Criteria: ± 0.05
Evaluate DTA from film data ± 5 mm at all sides of target
Analysis neglects variation across target RPC has proposed to include evaluation of dose across target
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RPC Lung Phantom
PTV
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QA for Advanced Technology, Dallas, February 2007
Modifications to Phantoms for IGRT
Presently rely on surface markers and laser alignment
IGRT systems require internal fiducials and/or anatomy for image-based alignment
QA for Advanced Technology, Dallas, February 2007
Evaluation of Heterogeneity Corrections with RPC Thorax Phantom
Convolution/superposition algorithm showing good agreement with measurements
Pencil-beam algorithm showing poor agreement with measurements
QA for Advanced Technology, Dallas, February 2007
Results of Credentialing(closed studies)
Study MajorDeviations
MinorDeviations
Number ofPatients
GOG 165HDR Cervix
Credentialed inst0 15 70
RTOG 95-17HDR & LDR Breast
(all)0 4 100
RTOG 0019LDR Prostate
(values for dose only)0 6 117 reviewed
(total 129 eligible)
QA for Advanced Technology, Dallas, February 2007
Results of Credentialing(closed studies)
Study MajorDeviations
MinorDeviations
Number ofPatients
GOG 165HDR Cervix
Credentialed inst0 15 70
Non-credentialed 57 87 275
RTOG 95-17HDR & LDR Breast
(all)0 4 100
RTOG 0019LDR Prostate
(values for dose only)0 6 117 reviewed
(total 129 eligible)
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QA for Advanced Technology, Dallas, February 2007
Challenges in Credentialing Need to streamline process Status of institution submission Need additional phantoms
To meet demand To evaluate new techniques (protons, IGRT)
CT benchmarks to be readable by all TPSs
Working to develop: Monte Carlo calculations Improved software to compare plan with film/TLD data
Improved dosimetry systems
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Credentialing Status Inquiry
QA for Advanced Technology, Dallas, February 2007
Status of RPC Preparations for Monitoring Proton Facilities
RPC visited PTC-H during construction to learn about facility design and operation
Visits to PTC-H and to UF/Jacksonville to measure and verify beam output, depth dose characteristics
Irradiated TLD at 3 facilities under more than 30 combinations of energy, field size, depth
Evaluated radiochromic film for use in proton beams
Presently testing BANG® gel & Presage™ dosimeters Evaluating OSL dosimeters
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