Folie 1 - University of Applied Sciences Technikum Wien
last lecture: Biofeedback: Principles and Applications Brain Computer Interfaces Theory and Methods today: Design Standards for biomedical devices Device Certification File Formats and Data Transfer Standards Safety of medical devices Electrical Safety
double Isolation, safety grounding, clearence galvanic isolation, isolation barriers Electrostatic Discharge (ESD-) Protection prevention of device damage or degradation of protective circuits Electromagnetic Compatibility (EMC, EMV) capacitive or inductive coupling, resonance RF / radiation levels, device interference
Software Safety biocompatibility, radiation, riskmanagement, International and National Organisations: International Electrotechnical Commission (IEC) International Organization for Standardization (ISO) Institute of Electrical and Electronics Engineers (IEEE) Comit international spcial des perturbations radiolectriques (CISPR) (Internationales Sonderkomitee fr Funkstrungen)
European Committee for Electrotechnical Standardization (CENELEC) European Telecommunications Standards Institute (ETSI) American National Standards Institute (ANSI) sterreicisches Normungsinstitut Current European Union regulation based on the New Approach (CE marking) applicable processes depend on risk-category government-appointed Notified Bodies certify the conformity assessment procedures
improvements often result from user feedback Methods to assure Safety Certification and harmonization of design standards Directive 93/42/EWG Medical products Directive 90/385/EWG Active implants Directive 98/79/EG In-vitro diagnostic devices ISO / EN 60601-2 EN 540 (EN ISO 14155) clinical Evaluation EN 1041 Information by the manufacturer
Risk management and labelling EN 1441 risk analysis, EN ISO 14971 risk management EN 980 Graphical symbols and labeling Methods to assure Safety Safety-Zones No-Cell Phones in critical areas, no metallic objects near MRI, Dependability, Fail-Safety, Fault Tolerance
Redundancy in Hardware and Software Guidelines MEDDEVS of the European Comission NB-Med Recommendations Global Harmonization Task Force (GHTF) Law for the admission of medical devices: sterreichisches Medizinprodukte= gesetz (MPG), BGBl. Nr. 657/1996:
Definition of medical devices Classification of risk CE admission clinical evaluation Registration, responsibility: menufacturer, seller, intended usage Electrical Safety - some definitions Clearance: The shortest distance between two conductive parts, or between a
conductive part and the bounding surface of the equipment, measured through air Hazardous Energy Level: A stored energy level of 20J or more, or an available continuous power level of 240 VA or more, at a potential of 2V or more. Hazardous Voltage: A voltage exceeding 42.4V peak or 60V d.c., existing in a circuit which does not meet the requirements for either a Limited Current Circuit or a TNV Circuit. Limited Current Circuit: A circuit which is so designed and protected that , under both normal conditions and a likely fault condition, the current which can be drawn is not hazardous.
Safety Critical: A component which affects the safety of the equipment. All components in primary circuitry are safety critical. Other components which protect the equipment under normal and fault conditions, such as thermal switches, optocouplers, etc. are also safety critical. Electrical Safety - some definitions Touch Current: Electric current through a human body when it touches one or more accessible parts. (Touch current was previously included in the term 'leakage current') Insulation according to IEC 664 / VDE 0110 (1/89): Data for insulation
coordination requires values for rated voltage, pollution degree and overvoltage category. Overvoltage category: Classification of electrical equipment to the overvoltage to be expected. Surge voltage: Amplitude of a voltage impulse of short duration with a specified impulse form and polarity that is applied to test insulation paths in device/component. This proves that the device/component (for example relay) will withstand very high overvoltages for very short periods. Electrical Safety - some definitions
Class I: Equipment where protection against electric shock is achieved by using basic insulation, and also providing a means of connecting to the protective earthing conductor in the building wiring those conductive parts that are otherwise capable of assuming hazardous voltages if the Basic Insulation fails. Class II: Equipment in which protection against electric shock does not rely on basic insulation only, but in which additional safety precautions, such as double insulation or reinforced insulation, are provided, there being no reliance on either protective earthing or installation conditions. Medical types B and BF (EN60601): Maximum leakage 100 microamperes, 4000V voltage rating with 60 second test
Medical type CF (EN60601): Maximum leakage 10 microamperes, 4000V voltage rating with 60 second test Electrical safty - IEC 60601 examples Safety Class I metallic enclosure grounded via earth wire Safety Class II enclosure seperated with double or hardened isolation
Example guidelines for electrical isolation Safety Class III Power Supply <= 25V AC Device types, labels - IEC 60601 examples device type B (body) Leakage current < 0.1 mA Can be grounded
device type BF (body floating) Leakage current < 0.1 mA Isolated from ground device type CF (cardiac floating) Leakage current < 0.01 mA special Isolation EMC - European standards EN 55011 Interference emission from industrial, scientific and medical devices (ISM appliances) EN 55013 Interference emission from radio receivers and consumer electronic appliances
EN 55020 Interference immunity of radio receivers and consumer electronic appliances EN 55014-1 Interference emission from household appliances EN 55014-2 Interference immunity of household appliances EN 55015 Interference emission from electric lighting equipment EN 61547 Interference immunity of electric lighting equipment EN 55022 Interference emission from information technology equipment (IT appliances) EN 55024 Interference immunity of information technology equipment (IT appliances) EN 61000-4-2 Interference immunity to electrostatic discharge (ESD) EN 61000-4-3 Interference immunity to electromagnetic fields EN 61000-4-4 Interference immunity to fast transient orders of interference (burst)
EN 61000-4-5 Interference immunity to surge voltage EN 61000-4-6 Interference immunity to conducted orders of interference induced by high frequency fields EN 61000-4-8 Interference immunity to magnetic fields with energy technology frequencies EN 61000-4-11 Interference immunity to voltage drops, short-time interruptions and voltage fluctuations EN 50081-1 Interference emission from appliances in the household area EN 50081-2 Interference emission from appliances in the industrial area EN 50082-1 Interference immunity of appliances in the household area EN 50082-2 Interference immunity of appliances in the industrial area EN 61000-6-2 Interference immunity of appliances in the industrial area EN 61000-3-2 Reactions in electricity supply systems - harmonic oscillations
EN 61000-3-3 Reactions in electricity supply systems - voltage fluctuations EN 60601-1-2 EMC medical electric appliances ESD Protection - Standards ANSI ESD STM5.1:2001Electrostatic discharge sensitivity testingHuman body model. ANSI ESD STM5.2:1999Electrostatic discharge sensitivity testingMachine model. ANSI ESD STM5.3.1:1999Charged device model (CDM)Component level. ESD Association Advisory Documents : ESD ADV1.0:2004Glossary of terms. IEC 61000-4-2:1995Electromagnetic compatibility (EMC)Part 4: Testing and measurement techniques Section 2: Electrostatic discharge immunity test; Amendment 2:2001.
IEC 61340-2-2:2000ElectrostaticsPart 2-2: Measurement methodsMeasurement of chargeability. IEC 61340-2-3:2000ElectrostaticsPart 2-3: Methods of test for determining the resistance and resistivity of solid planar materials used to avoid electrostatic charge accumulation. IEC 61340-3-1:2002ElectrostaticsPart 3-1: Methods for simulation of electrostatic effectsHuman body model (HBM)Component testing (IEC/101/33/CD). IEC 61340-3-2:2002ElectrostaticsPart 3-2: Methods for simulation of electrostatic effectsMachine model (MM)Component testing (IEC/101/34/CD). IEC 61340-4-1:2003ElectrostaticsPart 4-1: Standard test methods for specific applicationsSection 1: Electrostatic behavior of floor coverings and installed floors.
Product Safety Standards IEC 60601 IEC 60601-1:2005Medical electrical equipmentPart 1: General requirements for safety. IEC 60601-1-2:2004Medical electrical equipmentPart 1: General requirements for safetySection 2: Collateral standardElectromagnetic compatibilityRequirements and tests; Amendment 1:2004. IEC 60601-1-3:1994Medical electrical equipmentPart 1: General requirements for safetySection 3: Collateral standardGeneral requirements for radiation protection in diagnostic x-ray equipment. IEC 60601-1-4:2000Medical electrical equipmentPart 1-4: General requirements for safetyCollateral standard: Programmable electrical medical systems. IEC 60601-2-1:1998Medical electrical equipmentPart 2-1: Particular requirements for the safety of electron accelerators in the range of 1 to 50 MeV; Amendment 1:2002.
IEC 60601-2-2:1998Medical electrical equipmentPart 2-2: Particular requirements for the safety of high-frequency surgical equipment. IEC 60601-2-3:1991Medical electrical equipmentPart 2-3: Particular requirements for the safety of short-wave therapy equipment; Amendment 1:1998. IEC 60601-2-4:2002Medical electrical equipmentPart 2-4: Particular requirements for the safety of cardiac defibrillators and cardiac defibrillator monitors. IEC 60601-2-5:2000Medical electrical equipmentPart 2-5: Particular requirements for the safety of ultrasonic physiotherapy equipment. Product Safety Standards IEC 60601
IEC 60601-2-25:1993Medical electrical equipmentPart 2-25: Particular requirements for the safety of electrocardiographs; Amendment 1: 1999. IEC 60601-2-26:2002Medical electrical equipmentPart 2-26: Particular requirements for the safety of electroencephalographs. IEC 60601-2-27:2005Medical electrical equipmentPart 2-27: Particular requirements for the safety of electrocardiographic monitoring equipment. IEC 60601-2-28:1993Medical electrical equipmentPart 2-28: Particular requirements for the safety of x-ray source assemblies and x-ray tube assemblies for medical diagnosis. IEC 60601-2-29:1999Medical electrical equipmentPart 2-29: Particular requirements for the safety of radiotherapy simulators.
IEC 60601-2-30:1999Medical electrical equipmentPart 2-30: Particular requirements for the safety, including essential performance, of automatic cycling noninvasive blood pressure monitoring equipment. IEC 60601-2-31:1994Medical electrical equipmentPart 2-31: Particular requirements for the safety of external cardiac pacemakers with internal power source; Amendment 1:1998. Product Safety Standards others ISO 11197:2004Medical electrical equipmentParticular requirements for safety of medical supply units ISO/TR 16142:2006Medical devicesGuidance on the selection of standards in support of recognized essential principles of safety and performance of medical devices
ISO/IEC Guide 63:1999Guide to the development and inclusion of safety aspects in international standards for medical devices IEC 60513:1994Fundamental aspects of safety standards for medical electrical equipment. EN 793:1998Particular requirements for safety of medical supply units. EN 45502-1:1998Active implantable medical devicesPart 1: General requirements for safety, marking, and information to be provided by the manufacturer EN 50061Medical electrical equipmentSafety of implantable cardiac pacemakers EN 61204:1995Low-voltage power-supply devices, dc outputPerformance characteristics and safety requirements; Amendment 1:2002 EN 60950:2000Safety of information technology equipment; Corrigendum: 2002
CISPR 11 - Industrial, Scientific and Medical (ISM) Radio-Frequency Equipment -- Electromagnetic Disturbance Characteristics -- Limits and Methods of Measurement. Product Safety Standards IEC 60601 Summary of first and Second edition Software as a medical product Control algorithms for medical hardware
CT, pacemaker, Data evaluation, visualisation Expert systems, databases Computer aided surgery, Tele-medical applications Risk Management Processes became essential adapted from IEC 60601-1-4 CDRH Center for Devices and Radiological Health Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices
What does this all mean for our EEG device ? Steps to get an EN-60601 CE certification: improvement of ESD protection for all inputs +15kV, especially for the amplifier input pins (IEC 1000-4-2) improvement of isolation barrier (DC/DC converter and optocouplers) to withstand 3kV permanently calibration procedurces in software, impedance checking certification by notified bodies: sterreichisches Normeninstitut, TV last but not least: some money
(do not try this at home without 20000 at hands ) Electrostatic Discharge Protection ESD: One root cause of equipment failure Can happen during production and in field Errors often difficult to track, degrading performance Example: RS232 interface chip after exposure to an ESD event of 15kV
ESD: Origin of electrostatic chargeing - triboelectric effect: materials with opposite surface charges come together transfer of electrons from one material the other seperation leaves a net-negative and a net-positive charge ESD: low humidity prevents localized charges from moving Interaction of people with their surrounding can produce
significant charge: Human body model: 100pF capacitance charged upt to 15kV 1500 Ohm series resistance When discharged, this setup produces a very fast rise time with peak current of 15kV/1500Ohm = 10 A ESD Testing standards Chip package pins
are tested against other groups of pins I/O pins should be tested seperately ESD Testing standards Four Levels of ESD compliance in the IEC 100-4-2 standard: Contact and Air Gap discharge
ESD Testing Example ESD waveform: rise time, peak current, amplitude at 30 an 60 ns Electron Microscope View of a Fused Metallization Site, as a Result of Electrical Overstress ESD protection strategies / guidelines
Capacitor protection / Resistor Protection to limit voltage / current Layout and design compatibility needed Metal oxide varistors / silicon avalanche suppressor (TransZorb) Place bypass and charge-pump capacitors close to IC or I/O-port Include a ground plane on the PCB Use protection ICs (e.g. NUP 4201) and/or ESD protected ICs Proper grounding of persons and facility Suitable power up strategy for the circuit, consider maximum ratings Further reading: Maxim Application Note 639 on ESD
Sources / Links Dr. Wolfgang Ecker: Skriptum Medizinproduktegesetz: http://cis.technikum-wien.at/documents/bbe/5/srk/download/ Articles by EisnerSafety http://www.eisnersafety.com sterr. Verband fr Elektrotechnik (www.ove.at) sterr. Normungsinstitut (www.on.at) International Electrotechnical Commission (www.iec.ch) European directives http://ec.europa.eu/enterprise/medical_devices/index_en.htm http://ec.europa.eu/enterprise/electr_equipment/emc/
http://ec.europa.eu/enterprise/newapproach/legislation/guide/index.htm US Food and Drug Administration / Center for Devices and Radiological Health (www.fda.gov/cdrh) Standards for Communication and Modelling DICOM Digital Imaging and Communications in Medicine developed by ACR (American College of Radiology) and NEMA (National Electrical Manufacturers Association ) main purpose: transfer of image data (CT images)
overcomes file format incompatibilities allows creation of distributed databases (TCP/IP) specifies semantics of commands and associated data Information Objects for images, waveforms, reports, printing specifies levels of conformance, not implementation details DICOM General Communication Model Upper Layer service provides independence from physical
networking Basic File Service provides storage media access DICOM Parts and Application Profile Example configuration of an application, corresponding DICOM Parts HL7 - Health Level Seven Non-Profit organisation, developing standards for exchange of clinical and administrative data
HL7 Reference Information Model (RIM) representation of clinical data domains Special Interest Groups develop vocabulary, XML-integration, Messaging Standards Objectives: Messaging/Protocols, Query Sturctures, Medical Records Patient Administration / Financial Management, Clinical Order Entry, Laboratory Automation, Application Management, Personnel Management Security in Data Exchange (in respect to HIPAA, the Health Insurance
Portability and Accountability Act, 1996) HL7 - Reference Information Model (RIM) CDISC - Clinical Data Interchange Standards Consortium CDISC develops industry standards for electronic acquisition, exchange, submission and archiving of clinical trials data Study Data Tabulation Model (SDTM): Metadata Variable definitions: name, type, origin, role Observation Classes: Interventions (medication etc.), Events, Findings
Relationships among Datasets and Records Trial Design Model File Formats for physiological data File Formats: Proprietary EEG recording formats Alpha-Trace DigitalEEG EEG, PAT, EVT ASA (ANT Software B.V.) EEG Axon Instruments EEG, PAT Bio-logic CEEGraph1 EEG, PAT
Cadwell EEG, PAT, EVT Cleveland Clinic Vangard EEG, PAT, EVT EBNeuro Galileo DOS EEG, PAT, EVT EBNeuro Galileo NT EEG, PAT, EVT EEProbe AVR (ANT Software B.V.) EEG, EVT Electrical Geodesics (EGI) EEG, PAT EMS Pegasus 1 and 2 EEG, PAT European Data Format EEG, PAT, EVT Excel Tech NeuroWorks EEG, PAT, EVT Micromed BrainQuick EEG, PAT, EVT, VIDEO
MPI Nijmegen (MPIData) EEG, PAT Neuroscan AVG, CNT and EEG EEG, PAT, EVT Nervus/Profile EEG, PAT, EVT, VIDEO Nicolet AllianceWorks Intuition EEG, PAT, EVT Nicolet BMSI 5000 EEG, PAT, EVT, VIDEO Nicolet BMSI 6000 EEG, PAT, EVT, VIDEO Nicolet Bravo Intuition EEG, PAT, EVT, VIDEO Nicolet EEG Vue EEG, PAT, EVT Nicolet UltraSom NT EEG, PAT, EVT
Nicolet Voyageur EEG, PAT NCI Uniquant EEG, PAT, EVT, VIDEO Nihon Kohden 2100 EEG, PAT, EVT Persyst Layout (Exported Data) EEG Schwarzer/OSG EEG, PAT, EVT Stellate Harmonie EEG, PAT, EVT Telefactor TUFF EEG, PAT TMSI SMP EEG, PAT Walter Graphtek EEG, PAT, EVT
EEG: EEG Data , PAT: Patient Information, EVT: Event Data, MNT: Montage Information, VIDEO: Digital Video Data Source: http://www.eemagine.com/fileformats.htm File Formats: European Data Format - EDF and EDF+ Simple format for exchange and storage of multichannel biological signals Defacto standard for EEG recordings EDF was published in 1992, EDF+ in 2003 EDF+ suports annotations and events -> EP, sleep stages etc.
Hundreds of EDF+ files and several EDF+ viewers available on the internet format description and demo applications: http://www.edfpuls.info File Formats: EDF - structure HEADER RECORD 8 ascii : version of this data format (0) 80 ascii : local patient identification 80 ascii : local recording identification
8 ascii : startdate of recording (dd.mm.yy) 8 ascii : starttime of recording (hh.mm.ss) 8 ascii : number of bytes in header record 44 ascii : reserved 8 ascii : number of data records (-1 if unknown) 8 ascii : duration of a data record, in seconds 4 ascii : number of signals (ns) in data record ns * 16 ascii : ns * label (e.g. EEG Fpz-Cz or Body temp) ns * 80 ascii : ns * transducer type (e.g. AgAgCl electrode) ns * 8 ascii : ns * physical dimension (e.g. uV or degreeC)
ns * 8 ascii : ns * physical minimum (e.g. -500 or 34) ns * 8 ascii : ns * physical maximum (e.g. 500 or 40) ns * 8 ascii : ns * digital minimum (e.g. -2048) ns * 8 ascii : ns * digital maximum (e.g. 2047) ns * 80 ascii : ns * prefiltering (e.g. HP:0.1Hz LP:75Hz) ns * 8 ascii : ns * nr of samples in each data record ns * 32 ascii : ns * reserved DATA RECORDS nr of samples * integer : first signal in
the data record nr of samples * integer : second signal .. nr of samples[ns] * integer : last signal File Formats: Physionet and the WFDB tools WFDB: Waveform Database a set of tools to read, annotate and convert physiological data from the physiobank archive WFDB toolset includes c-libraries, signal viewers,
data and file conversion tools supported formats: AHA, HEA, MIT/BHI, Netfiles (remote on the web) header-, signal-, annotation- and calibration files Link to physionet and the physiobank archives: http://www.physionet.org BIOSIG Toolbox, other file formats: Biosig Toolbox by Alois Schlgl (TU-Graz) : accessible from C / Python / Matlab / Octave more than 30 import filters for common file formats signal analysis tools
BDF : a 24 bit extension of EDF, developed by BIOSEMI GDF/BKR : defined by TU-Graz DDB/DDF : Daisylab Data Files MFER: medical waveform encoding rules CEN/FEF: file exchange format for vital signs DAT: brain atlas EEG data file structure SIGIF: signal interchage format Further information about file formats and the biosig toolbox: http://hci.tugraz.at/schloegl/matlab/eeg
http://biosig.sourceforge.net/ The IEEE 11073 family of standards : Personal Telehealth Devices Point of Care medical device communication IEEE 11073 The Scenario: E-Health Integration Telecare Technology Vision: E-Health Interaction and Integration Origins: IEEE 1073 MIB: Medical Information Bus
IEEE 1157 MEDIX : Medical Data Exchange IEEE 11073 family of standards device standards for controlling information exchange to and from personal telehealth devices and cell phones, personal computers, personal health appliances and other compute engines codes, formats and behaviors in a telehealth environment to favor plug-and-play interoperability Capture and integration of medical instrumentation data generated
at the point of patient care to achieve a better understanding of the condition of the patient CEN, ISO and IEEE cooperate to solve to the problem of proprietary device- and communication standards could provide a link between device-level data and HL-7 long term health records IEEE 11073 family of standards IEEE P11073-00103: Technical Overview: data exchange, data representation and terminology for communication
between personal telehealth devices and computers IEEE P11073-10400: Common Framework of communication, managing devices and allow vendors to access non-standard features. IEEE P11073-10404: Pulse Oximeters IEEE P11073-10406: Heart Rate Monitors IEEE P11073-10407: Blood Pressure Monitors IEEE P11073-10408: Thermometers IEEE P11073-10415: Weighing Scales IEEE P11073-10417: Glucose Meters
IEEE P11073-20401: Point-of-Care Medical Device Communication Application Profile Common Networking Infrastructure, IEEE P11073-20601: Device Communication Application Profile Optimized Ex-change Protocol, which will define a common framework for creating an abstract model of personal health data IEEE 11073 family of standards Goal: interoperability
with existing medical information systems Method: object-oriented modelling of functionality and areas of application (Domain Information Model) Sources: Thomas Norgall - ECG Data Interchange Formats and Protocols: http://www.openecg.net/WS2_proceedings/Session05/S5.2_PR.pdf Care Services Improvemnt Partnership: www.icn.csip.org.uk/telecare
IEEE 11073 communication framework The manager agent framework IEEE 11073 some essential definitions Agent: The embedded measurement device Manager: The computing unit or data logger to which the Agent is connected MDIB: Medical Data Information Base supplies an abstract object-oriented data model representing the information and services provided by the medical device.
The objects include the Medical Device System (MDS), channels, numerics, real-time sample arrays, alerts, and others ACSE: Association Control Service Element provides services including association request and response, association release, association abort CMDISE: Common Medical Device Information Service Element, and CMIP: Common Management Information Protocol: provide basic services for managed objects, including the performance of GET, SET, CREATE, DELETE, ACTION, and EVENT REPORT functions
IEEE 11073 some essential definitions A Scanner is a tool that collects information of various kinds from the device's MDIB and sends it to the Manager in event-report messages. A periodic scanner will examine a set of data items and send an update at regular intervals. A context scanner is used to report the object-model containment tree to the Manager system. This way, the Manager can "discover" the data that are supported by a given device during the Association State. Once the containment tree has been sent to the Manager system and the Agent has received a confirmation reply, the state model passes to the Operation State, ready to begin regular data communications
PDUs (protocol data units) are the messages of the Common Medical Device Information Service Element (CMDISE) IEEE 11073 communication framework Step 1: Local Agent Initialisation IEEE 11073 communication framework Step 1: Local Agent Initialisation
IEEE 11073 communication framework Step 2: Start of the Association Procedure IEEE 11073 communication framework Step 3: Start Configuration: Agent MDS reports itself to the Manager IEEE 11073 communication framework
Step 4: Manager Application creates Context Scanner in Agent MDIB IEEE 11073 communication framework Step 5: Configuration : Agent sends Event reports, Manager creates mirrored MDIB IEEE 11073 communication framework
Step 6: Manager reads attribute from agent using the GET service IEEE 11073 communication framework Manager creates a scanner for automated attribute access IEEE 11073 communication framework Scanner sends automated event reports
Further information on IEEE 11073 : http://www.ieee1073.org/standards/1073standards.html http://www.ieee1073.org/overview/ISO-IEEE11073-10201Annex.pdf Thanks for your attention !
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