Impacting Radiotherapy Safety and QA with Device Improvements Benedick A Fraass, PhD, FAAPM, FASTRO, FACR Allen S. Lichter Professor of Radiation Oncology and Director of Radiation Physics, Dept. of Radiation Oncology, University of Michigan Chair: ASTRO Multidisciplinary QA Subcommittee AAPM Science Council, Therapy Physics Committee, TG100, Chair: Research Committee FDA Public Meeting: Device Improvements to Reduce the Number of Under-Doses, Over-Doses, and Misaligned Exposures From Therapeutic Radiation
Transcript
Impacting Radiotherapy Safety and QA with Device Improvements
Benedick A Fraass, PhD, FAAPM, FASTRO, FACR
Allen S. Lichter Professor of Radiation Oncology and Director of Radiation Physics, Dept. of Radiation Oncology, University of Michigan
Chair: ASTRO Multidisciplinary QA Subcommittee
AAPM Science Council, Therapy Physics Committee, TG100, Chair: Research Committee
FDA Public Meeting: Device Improvements to Reduce the Number of Under-Doses, Over-
Doses, and Misaligned Exposures From Therapeutic Radiation
Goal: Describe several issues in which vendor or FDA efforts may help us improve patient safety and QA efficiency and effectiveness
Impacting Radiotherapy Safety and QA with Device Improvements
Need 1: Process-based Analysis + QA
MLC
Leaf
Sequencing
Tx Delivery
Planning,
Prep
AutomatedTx
Delivery,
Verification
e-chart,
Billing
Patient Setup
w/
Imaging
Inverse
Planning
Imaging,
Targets, Normal
Anatomy, Beams
Dose
Calcs
Plan
Evaluation
Download to
Delivery
System
Patient-
specific
IMRT QA •RT process is complex: we need process-oriented QA to deal with that complexity
• The vendor can never “provide” all the QA needed for each potential technique
•Vendors, regulators and clinicians all must recognize that we need more than just QA tests for machine features
Patient-specific IMRT QA
Need 2: Flexibility to put together new and more effective QA processes
MLC
Leaf Sequencing
Tx Delivery
Planning,
Prep
AutomatedTx
Delivery,
Verification
e-chart,
BillingPatient Setup
w/
Imaging
Inverse
Planning
Imaging,
Targets, Normal
Anatomy, Beams
Dose
Calcs
Plan
Evaluation
Download to
Delivery System
Patient-specific
IMRT QA
IMRT
Leaf Sequencing
Download to
Delivery System
Patient-specific
IMRT QA
Typical Patient-Specific IMRT QA Check:
• Apply IMRT plan to QA phantom
• Deliver plan to QA phantom + ion chamber
• Check each beam’s intensity (+ dose distrib?) vs calc (with film or 2-D electronic system)
• Result: Total dose at one point + confirmation of beam intensities – after lots of work!
Need 2: Flexibility to put together new and more effective QA processes
Automating Patient-Specific IMRT QA:
Need 2: Flexibility to put together new and more effective QA processes
By having the flexibility to combine devices and techniques in novel ways:
Litzenberg
Automating Patient-Specific IMRT QA:
Need 2: Flexibility to put together new and more effective QA processes
When we are driven by clinical needs to look for better ways to do things – we need the flexibility to do things that individual vendors will not have the resources or motivation to do
Automating Patient-Specific IMRT QA:
Need 2: Flexibility to put together new and more effective QA processes
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The clinical workflow is directly related to the QA needed for modern RT: modifications can make crucial improvements
MLC Leaf
Sequencing
Tx Delivery
Planning,
Prep
Automated
Tx Delivery,
Verification
e-chart,
Billing(Automated)
Patient Setup w/
Imaging
Prescription,
Inverse
Planning
MLC Leaf
Sequencing
Download to
Delivery
System
Patient-
specific
IMRT QA
Imaging,
Targets,
Normal Anat
Beam
Arrangement+
Technique
Dose to
Points
Calcs
Plan
Evaluation
Need 3: Flexibility to rearrange clinical process workflow
If we identify a process change that can improve safety/quality, we need to have flexibility to implement that change
We need better workflow adjustment tools...
Need 4: Vendor-provided QA Tools, Updates
• Vendors must make new QA-related devices, tools, methods quickly accessible to users• Note: QA devices must be used routinely before
their value, or best uses can be known or proven• FDA: A slow or difficult marketing approval
process can make potential products impossible to get, test, develop or implement• This is particularly problematic for software
enhancements or modifications that can fix important bugs or make a hardware device or technique useful
MLC Leaf
Sequencing
Tx Delivery
Planning,
Prep
Automated
Tx Delivery,
Verification
e-chart,
Billing(Automated)
Patient Setup w/
Imaging
Prescription,
Inverse
Planning
MLC Leaf
Sequencing
Download to
Delivery
System
Patient-
specific
IMRT QA
Imaging,
Targets,
Normal Anat
Beam
Arrangement+
Technique
Dose to
Points
Calcs
Plan
Evaluation
•Tx delivery QA and monitoring must involve RTTs and convey both qualitative + quantitative info easily and clearly•Monitoring must be integrated for efficiency•Monitoring must be independent for safety
Need 5: Treatment Delivery QA and Monitoring: Integrated or Independent ?
about to move move finished
UM CCRS System: IJROBP 95
MLC Leaf
Sequencing
Tx Delivery
Planning,
Prep
Automated
Tx Delivery,
Verification
e-chart,
Billing(Automated)
Patient Setup w/
Imaging
Prescription,
Inverse
Planning
MLC Leaf
Sequencing
Download to
Delivery
System
Patient-
specific
IMRT QA
Imaging,
Targets,
Normal Anat
Beam
Arrangement+
Technique
Dose to
Points
Calcs
Plan
Evaluation
(Relatively) independent verification is possible:
Need 5: Treatment Delivery QA and Monitoring: Integrated or Independent ?
Need 6: Collaborative + independent input into vendor design, hazard analyses, usability, and workflow efforts…
•Detailed checks of software or hardware design at the end of the product development process are too late to fix problems or weaknesses
•Vendors should incorporate independent input (by clinically knowledgeable experts) into design, hazard analyses, test plan designs, usability
•The earlier this happens in the development process, the better for everyone !
Need 7: Vendor support for user groups for sharing of QA methods, issues
Users of a given vendor’s system all have much in common:
• QA needs and techniques• Experience with system-specific issues• Knowledge how to solve or avoid problems• Improvements to suggest
Vendors should support user’s groups which help with sharing of this info!
• Support process-based analysis and QA• Flexibility for new + more effective QA
processes• Flexibility to rearrange clinical process workflow• More vendor-provided QA tools + methods• Integrated vs independent monitoring• Vendors need collaborative + independent input
into design, hazard analysis, usability, workflow • Support of user groups for QA: sharing
processes, methods, issues
Impacting Radiotherapy Safety and QA with Device Improvements
