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