Impacting Radiotherapy Safety and QA with Device Improvements Benedick A Fraass, PhD, FAAPM, FASTRO,...

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

Need 1: Process-based Analysis + QA

Sequencing

Tx Delivery

Planning,

AutomatedTx

Delivery,

Verification

e-chart,

Billing

Patient Setup

Imaging

Inverse

Planning

Imaging,

Targets, Normal

Anatomy, Beams

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

Leaf Sequencing

Tx Delivery

Planning,

AutomatedTx

Delivery,

Verification

e-chart,

BillingPatient Setup

Imaging

Inverse

Planning

Imaging,

Targets, Normal

Anatomy, Beams

Evaluation

Download to

Delivery System

Patient-specific

IMRT QA

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!

Automating Patient-Specific IMRT QA:

By having the flexibility to combine devices and techniques in novel ways:

Litzenberg

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

The clinical workflow is directly related to the QA needed for modern RT: modifications can make crucial improvements

MLC Leaf

Sequencing

Tx Delivery

Planning,

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

Arrangement+

Technique

Dose to

Points

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,

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

Arrangement+

Technique

Dose to

Points

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,

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

Arrangement+

Technique

Dose to

Points

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 Benedick A Fraass, PhD, FAAPM, FASTRO,...

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