Acronyms Flashcards
EHR
Electronic health record - a patients health record available anywhere in an organisation. Usually a limited subset focussed on a particular discipline and accessible locally
MPI
Master Patient Index - list of all patients known to an organisation and their demographics and ID numbers
PAS
Patient administration system - central admin system covering patient appointments, note taking etc often contains results and acts as a portal to other systems
RIS
Radiology information system - scheduling of imaging, resource management and inventory tracking, reporting and presentation, sign off and billing
PACS
Picture archive and communication system - storage of images and other data, visualisation of images, data transfer between systems
TPS
Treatment planning system - plan preparation and dose calculation
Dose checking system
Independent check of intended delivery e.g. Another TPS
RVS/VRS
Record and verify system - verifies treatment being delivered as intended. Permits parameter overrides and records what was actually delivered
OMS
Oncology management system - EHR and PAS for radiotherapy and chemotherapy. Incorporates RVS and TPS and also includes general patient info, prescriptions, imaging and scheduling
Four type of network application architecture
Client/Server
Standalone
Hybrid
Peer-to-peer
ISO
International standards organisation
OSI
Open systems interconnection
Layers of a network
Application, Presentation, Session, Transport, Network, Data Link, Physical
IP
Internet protocol - uniquely identifies a devices interface on a network to facilitate data transfer. IP address is a 32 bit number represented by 4 bytes.
Types of network connections
Direct Hub Switch Gateway Hub
Subnet
Local subdivision of an IP network. Subnet address common to all addresses in the subnet
Private subnet
Private IP address ranges that can be allocated at will and must not appear on the internet because they are not unique
NAT
Network address translation - mechanism by which traffic from host on a private subnet can be directed to the internet. Translated address is that of the internet access point.
Loopback address
127.0.0.1 - reserved address which directs traffic back to the local computer without reaching any real network interface.
TCP
Transmission Control Protocol - protocol for sending data packets over the internet. Built on top of IP. Operates at the data link layer. Data split into a series of sequential packets. Built in error detection/correction, packet receipt is aknowledged, data block reassembled at destination
UDP
Universal datagram protocol - simpler than TCP. No acknowledgement or info on sequence order or error checking, faster but more prone to error. Live broadcasts and online games
Port
Network location defined by IP address (device) and port (application communicating on that device). 16 bit integers
MAC address
Media access control address - physics address operating at data link layer. Represented by 6 bytes. Each network interface has a globally unique MAC address and each manufacturer has own unique prefix.
LAN
Local area network - small geographical area
WAN
Wider area network - large geographical area
MAN
Metropolitan area network - distributed over a city
N3
NHS WAN - private network linking NHS organisations. Prefixed nww.
DNS
Directory Name Service - links hostnames to IP address
DHCP
Dynamic host configuration protocol - allocates IP address to network device based on MAC address
AD
Active directory (AD) - superset of DNS that provides additional resources
VPN
Virtual private network - allows secure connection to network from external location. External resource appears to be on the private network with a local IP address
Network bandwidth
Rate at which data can be transferred in one direction - Mbps (bits)
Network latency
Delay between packet being sent by the sender and received by the receiver. Time taken for packet to travel from sender to receiver.
Ipconfig
Provides information about network interfaces - status, ip addresses, MAC addresses, DHCP information, DNS information,
Ping
Verifies that route between source and destination exists. Measures network latency. Resolves IP address from host name using DNS. Resolves hostname from IP address. Sends special ICMP packet (internet control message protocol) and waits for an ICMP echo reply.
Traceroute
Records routers through which packets travel on way to destination. Displays ping-type statistics
NS lookup
Name server lookup - interrogates DNS server for given hostname
Netstat
Reports status and statistics of network services
Sysinternal tools
TCPView
ProcMon
Wireshark
Monitors and reports on network traffic - reports on traffic intended for local computer only
Sources of standards
International Standards Organisations - ISO
National Standards Organisations - British Standards institution
Professional Standards - National Electrical Manufacturers Association (NEMA)
Corporate/Organisational Standards - NHS, Microsoft
HSCIC
Health and social care information centre
Open standards
Published and available to interested parties. Should be non-proprietary and freely available. Should allow parties to contribute to the Standards development.
DICOM
Digital imaging and communications in medicine - a standard covering digital images and associated data
DICOM scope
Transfer of data across a network Storage onto media - physical specifications and file format Conformance of systems Compression and security Image display and output
DICOM data element
Unit of information with defined data type and structure
Information object
Set of objects that describe a physical entity e.g. CT slice, plan
Service class
Action which can be performed on information objects e.g. Transferring, archiving, printing
SOP
Service object pair - defined action that can be performed on a particular object
DIMSE service classes
DICOM message service element service classes - implemented by application software. User - storageSCU, provider - storageSCP
DICOM organisation
Patient - study - series - instance
IHE profile
Integrating the health enterprise - define standard ways of communicating between different systems usually using DICOM and HL7.
HTTP
HyperText transfer protocol - structured text used to facilitate communication across the World Wide Web. Based on methods GET, POST, HEAD. Secured using SSL.
HTML
HyperText MarkUp Language - written in the form of HTML elements enclosed in angled brackets, web browsers read the HTML files, interpret the tags and turn them into web pages
Data encryption
Translation of data into a secret code. Used where there is a need to protect sensitive data in transit and at rest. Denies message content to interceptor.
SSL
Secure sockets layer - encrypted link between web browser and web server
ISMS
Information security management systems
NHS principles of Information Security
Confidentiality - data secured against unauthorised access
Integrity - safeguarded against unauthorised modification
Availability - accessible to authorised users when needed
Information governance
Ensures the necessary safeguards for the appropriate use of patient and personal information
Key IG legislation
DPA 1998 Caldecott principles Computer Misuse Act 1990 FOIA 2000 HSCA 2012
Data protection act 1998
Processed fairly and lawfully Processed only for specified purposes Adequate, relevant and not excessive Accurate and up to date Not kept for longer than necessary Processed in accordance with rights of data subject Appropriate security Not transferred out of EU without protection
Caldicott principles
Justify the purpose of every proposed used or transfer
Don’t use unless absolutely necessary
Use the minimum necessary
Access to it should be in a strict need to know basis
Everyone with access to it should be aware of their responsibilities
Understand and comply with the law
Duty to share information can be as important as duty to protect patient
Computer Misuse Act 1990
Unauthorised access to computer material
Unauthorised access to a computer system with intent to commit or facilitate the commissioning of a serious crime
Unauthorised modification of computer material
Problem definition
Defines what the problem is without any reference to possible solutions
Requirements
Describe in detail what a software system is supposed to do and they are the first step to a solution
Software architecture
High-level part of software design, the frame that holds the more detailed parts of the design
Software design
Conception of a scheme for turning a specification for a computer program into an operational program
Characteristics of a design
Minimal complexity Ease of maintenance Loose coupling Extensibility Reusability High fan-in - a large number of software objects use a given software object Low to medium fan out - given software object uses a low to medium number of other objects High cohesion Portability Leanness Stratification Standard techniques
UML
Unified modelling language - a set of formalised graphical representations for design entities and relationships
Pseudocode
Informal, natural language-like notation for describing how an algorithm or program will work
Real-time system
Any information processing system which has to respond to externally generated input stimuli within a finite and specified period
Hard real time
Imperative responses occur within a required deadline e.g. Flight control
Soft real time
Systems where deadlines are important but system will still function correctly if sometimes missed
Firm real time
Soft real time but in which there is no benefit for late delivery
Time-aware
makes explicit reference to time
Reactive
System must produce output within deadline
Time-triggered
Computation triggered by passage of time
Event-triggered
Computation is triggered by an external or internal event
Characteristics of a real time system
Guaranteed response time
Concurrent control of separate system components
Facilities to interact with specific hardware
Support for numerical computation
Extreme reliability and safety
Safety
Freedom from conditions that can cause death, harm or injury
Reliability
A measure of the success with which a system conforms to some authoritative specification of its behaviour
Failure
When the behaviour of a system deviates from that which is specified for
Fault types
Transient - fault starts at a particular time, remains in the system and then disappears
Permanent - fault remains in the system until repaired
Intermittent - transient faults that occur from time to time
Fault prevention
Attempts to eliminate any possibility of faults creeping into a system before it goes operational
Fault tolerance
Enables a system to continue functioning even in the presence of faults
Fault avoidance
Limits the introduction of faults during system construction
Three types of fault tolerance
Full fault tolerance - system continues to operate in presence of faults for a limited time with no loss of performance
Graceful degradation - system continues to operate accepting a partial degredation
Fail safe - system maintains integrity while accepting a temp hault
Protective redundancy
Extra elements in the system for detection and recovery of faults
Exception handling
Error recovery mechanism - control passed to handler so recovery procedure can be initiated
Benefits of exception handling
Cope with abnormal conditions arising to the environment
Enable program design faults to be tolerated
Provide a general purpose error detection and recovery facility
Medical image
Representation of the human body that can be interpreted by an observer
Image fusion
Bringing images together into same geometrical context on same screen
FBP
Filtered back projection
Image
Array of imaging device output numbers mapped onto pixels of the output device
Windowing
Select a range of data values and stretch these across available pixel values of the display device
Signal
Function of one or more variables which conveys information on the nature of a physical phenomenon
Aliasing
Effect that causes different signals to become indistinguishable when sampled
Fourier transform
Mathematical transformation employed to transform signals between time domain and frequency domain
Medical device
Any instrument, apparatus, appliance, material or other article, whether used alone or in combination including the software necessary for its proper application intended by the manufacturer to be used for human beings for the purpose of:
Diagnosis, prevention, monitoring, treatment or alleviation of a disease
Diagnosis, monitoring, treatment, alleviation or compensation for an injury or handicap
Investigation, replacement, or modification of the anatomy or of a physiological process
Control of conception
And which does not achieve its principal intended action on the human body by pharmacological, immunological, or metabolic means, but which may be assisted in its function by such means
Placing on the market
Making available in return of payment or free of charge of a device other than a device intended for clinical investigation with a view of distribution and or use on the community market regardless of whether it is new or fully refurbished
Custom-made device
Any device specifically made in accordance with a duly qualified medical practitioners written prescription which gives under his responsibility specific design characteristics and is intended for the sole use of a particular patient
Medical device essential requirements
Relevant standards
Appropriate validation
Risk management
Technical file
Verification
To determine whether the software is doing what it is claiming to do correctly
Validation
Determine that it meets the requirement and is fit for purpose