radiation therapy safety standards stan mansfield, director of system safety varian medical systems
TRANSCRIPT
Radiation Therapy Safety Standards
Stan Mansfield, Director of System Safety
Varian Medical Systems
Overview
Applicable Normative Standards– International Standards Organization (ISO)– International Electrotechnical Commission
(IEC)MITA Consensus Standards Initiatives
– NEMA RT-1 Radiotherapy Gating Interface– NEMA RT-2 Radiotherapy Readiness Check– NEMA RT-3 Radiotherapy Machine
Characterization Integrating the Healthcare Enterprise
(IHE)– Radiation Oncology (IHE-RO)
RT Quality and Safety Standards
GeneralProcess standards covering design,
development, manufacturing, installation, servicing • Medical device quality management
systemsISO 13485
• Medical device risk managementISO 14971
• Medical device software lifecycle processesIEC 62304
• Application of usability engineering to medical devices IEC 62366
AcceleratorDevice-specific safety standards specify
and control device safety characteristics• Medical Electrical Equipment -
Part 1: General Requirements for Safety
IEC 60601-1
• Particular requirements for the safety of electron accelerators in the range 1 MeV to 50 MeV
IEC 60601-2-1
• Particular requirements for the safety of X-ray-based image-guided radiotherapy equipment
IEC 60601-2-68
RT Quality and Safety Standards
Other Delivery ModalitiesDevice-specific safety standards specify
and control device safety characteristics• Particular requirements for the
safety of gamma beam therapy equipment
IEC 60601-2-11
• Particular requirements for the safety of automatically-controlled brachytherapy afterloading equipment
IEC 60601-2-17
• Particular requirements for the safety of light ion beam therapy equipment
IEC 60601-2-64
RT Quality and Safety Standards
Treatment Planning and Information Systems
Safety standards governing other medical equipment (software medical devices)
• Information technology equipment – Safety Part 1: General requirements
IEC 60950-1
• Safety of radiotherapy treatment planning systemsIEC 62083
• Safety of radiotherapy record and verify systemsIEC 62274
RT Quality and Safety Standards
MITA / NEMA RT Standards Efforts
Status & industry participationDICOM - RT RT-1 Gating InterfaceRT-2 Radiotherapy Readiness CheckRT-3 Radiotherapy Machine
CharacterizationOther NEMA RT standards to followMITA members also support IHE-RO
MITA / NEMA RT Standards Status
DICOM– Initially Released in 1985 (ACR and NEMA)– Basic RT objects added in 1997 - DICOM 3.0– Regular updates and active industry
participationRT-1 Released 2014RT-2 Draft (Stakeholder Comment)RT-3 Working Draft in processOthers to follow
MITA / NEMA RT Industry Participation
NEMA RT-1:2014 Gating Interface
Standardized Real-time Interface– Treatment Delivery Device (TDD) – i.e.
Linac – Patient Position Monitoring System
(PPMS)– Detailed Signal and Timing
Specifications– Safety and Essential Performance
Specific Safety Checks– Pre-Beam Check– Signal Cross Checks– Beam Hold Verification– Plan Verification– Hard Interlock and Beam Hold - ‘Fail
Safe’
NEMA RT-2 Radiotherapy Readiness Check
Origin: FDA public meeting June 9-10, 2010
Three safety initiatives introduced by Industry– Radiation Therapy Pre-Treatment Quality
Assurance Verification and Approval– Verification of Beam Modifying Devices– Patient Positioning Confirmation
Based on collective experience of RT vendors– Includes MDR assessments and published
articles on safety Addresses needed standardization
– Essential Performance and Basic Safety– Specific requirements for each of the three
sections– Compliance statement to communicate
implementation details
Diverse Technology Drives Implementation
Diverse variety of technology by product and by manufacturer
Each vendor to publish a detailed Compliance Statement describing their implementation and rationale
Allows for wide variety of implementations of safety initiatives
Builds on existing Standards
#1 Pre-Treatment QA Verification & Approval
“Right plan with the right dose for the right patient” Goal:
– Assure treatment cannot be performed without explicit QA approval of the patient’s treatment plan
Solution:– Treatment delivery requires plan
QA approval by authorized physicist (via login & password).
– QA authorization becomes part of the patient record.
– Treatment cannot be delivered without approval – It is Interlocked!
– Plan changes require re-approval– Explicit requirements by system:
• Treatment Planning System (TPS)• Treatment Management System
(TMS)• Treatment Delivery System (TDS)• Quality Assurance System (QAS)
Figure: Plan QA Approval Check – Authorized user must approve plan QA prior to patient treatment delivery.
#2: Verification of Beam Modifying Devices
“Prevent beam modifier errors” Goal:– Detect the correct state
(presence/absence, identity, attachment and preconditions) of all removable beam modifiers.
• SRS Cones, Wedges, Blocks, Applicators, Boli etc.
Solution:– Display and Independent Verification
• Description & Identification• Machine settings (jaw settings, beam type,
energy)
– Interlock if inconsistent with treatment plan
Interlock Sensor Technologies:– Electro-mechanical – Bar-code– RFID
#3 Patient ID & Positioning Confirmation
“Right patient, right procedure, right site” Goal:– Verify correct patient
identification, set-up, orientation, and position prior to treatment
Solution:– Display at least 2 forms of
Patient Identifying Information (PII)
• Patient Name, Photo, Date of Birth etc.
• User acknowledgement and sign-off
– Transmit and verify 3 forms of PII
• Patient Name, ID and Date of Birth• Biometrics or other automated
systems
– Image Guided Radiation Therapy• Unambiguous references and display• Position and Orientation
– IGRT is proven to enhance accuracy and consistency of patient set-up
NEMA RT-3 Machine Characterization
Goal:– Provide information to develop or compare
a software model that captures the characteristics of a Treatment Delivery Device (TDD)
Challenge:– Errors in machine modeling are ‘systematic’– DICOM and IHE-RO don’t handle this
Solution:– Standardized (HTML) template– Automatically generated by TDD– Allows for automated cross-checking – Explicitly includes FDA’s Unique Device
Identification (UDI) code– Currently under development
TDD
Manufacturer
New MC instance
New TDD released
TPS Vendor
Clinic TPS
Supported MC instance
MC Update
New MC instance
TDD
Clinical MC instance
Treatment MC instance
Commissioning & QA
Clinical MC instanceClinic R&V Physicist
IHE-RO Integrating the Healthcare Enterprise (IHE) is an initiative to improve
Interoperability, how computer systems share information in healthcare Promotes the coordinated use of established standards (such as DICOM &
HL-7) to address specific clinical needs in support of optimal patient care IHE-RO addresses specific needs of the Radiation Oncology (RO) Domain
Sponsored by ASTRO Founded in 2004
Facilitating Interoperability – Identify Real-World Interoperability Opportunities– Develop Technical Descriptions of Device Behavior – “Profiles”
• Advanced Radiation Therapy Objects Interoperability (ARTI)• Quality Assurance with Plan Veto (QAPV)
Creating Interoperability– Direct Stakeholder Involvement– Manufacturers Create Solutions
Testing Interoperability– Testing to the Profiles– Annual “Connectathon” – Judge the Working Solutions
Users expectations – The market drives support
Interoperability and Interconnectivity Challenges
Addressed(http://www.ihe.net/Radiation_Oncology/index.cfm) Simple/Advanced Treatment Planning use case
(NTPL-S / ARTI)– allows seamless connectivity between different
treatment planning systems – reducing errors Multimodality Image Registration use case
(MMRO)– Integrates PET and MRI data into the contouring and
dose review process – ehancing clinical effectiveness RT Treatment Workflow use case (TRWF)
– Integrates daily imaging with radiation therapy treatments using workflow – reducing errors
Conclusions & Summary
Safety is embedded in the design of RT products
Standards play a major role in safe design in RT– The CDRH currently recognizes many of these
Standards build on each other – Newer consensus standards fill some key gaps
• Interoperability between devices & manufacturers
• Fast turnaround and specific situationsRT manufacturers are committed to safety