Informatics

1. Informatics Module 7 Part 3

2. Fundamental Knowledge • Basic Computer Terminology • Integrating Healthcare Enterprise (IHE) • PACS • Radiology Information System (RIS) • Hospital Information System (HIS) • Electronic Medical Record (EMR) • Health Level 7 (HL7) • Networks • Film Digitizers • Storage • DICOM • Data Compression • Security & Privacy

3. Inside the Computer

4. Bits, Bytes & Words • Computers can only understand electronic signals/impulses • Digital signals • Electric current is On/Off • Binary Numbers • Represented by 1’s or 0’s • Basic unit of info is called a bit • Byte • 8 bits grouped together • Represents • Numbers • Letters • Special characters • 256 different combinations (2N bits) • Word • Fixed sized group of bits that are handled as a unit by the processor • Typically 32 or 64 bits On Off OR = 1 bit 1 0 = 1 byte

5. Number Systems • Decimal Form • Base 10 • Digits 0 - 9 used to represent #’s • Value represented = digit x 10N • N = position in row, starting w/ 0 for right-most digit • e.g. 4,608 → (4x103) + (6x102) + (0x101) + (8x100) • Binary Form • Base 2 • Two digits of 0, 1 used to represent #’s • Value represented = digit x 2N • N = position in row, starting w/ 0 for right-most digit • Conversion between forms: • 101011 = (1x25) + (0x24) + (1x23) + (0x22) + (1x21) + (1x20) = 43

6. Units

7. Digital Radiological Images • Rectangular or square array of picture elements (pixels) • Each pixel represented by a single # • Converted to gray level on monitor • Image is stored as a matrix of these #s • ↑ Matrix size  ↑ Spatial resolution • Select image format such that pixel size ≤ size of smallest object • Largest # that can be stored in a single pixel determined by # of bits used / pixel • 2Nbits – 1 • 8 bits (1 byte) • 28 – 1 = 255 • 16 bits (2 bytes) • 216 – 1 = 65,535 • AKA ‘bit depth’

8. Example • 500 image CT study acquired @ 512 x 512 matrix size w/ a bit depth of 12 • How much storage will this study require? • The total # of bytes req’d to store an image • = (total # image pixels) x (# bytes/pixel) • (512 x 512 pixels) x (2 bytes/pixel) • = (262,144 pixels) x (2 bytes/pixel) • = 524,288 bytes /(1,000 bytes/kB) ≈ 525 kB • Total # of bytes req’d to store a study • = (# bytes /image) x (# of images) • (524,288 bytes/image) x 500 images • = 262,144,000 bytes/(1,000 bytes/kB) = 262,144 kB ≈ 262 MB Note that images often stored in integer # of bytes for bit depth So 12 bits > 1 byte  round up to 2 bytes

9. Typical Study Storage Requirements* *2009 Excludes CTA, 3-Tesla MR, MRA, fMRI, PET/CT, SPECT/CT and women’s imaging. 3 bytes for Doppler ultrasound and other color studies

10. Typical Storage Requirements/100K Studies* *2009 Excludes CTA, 3T MR, MRA, fMRI, PET/CT, SPECT/CT & Women’s Imaging

11. Storage Requirements for Digital Mammo • Based on: • 70% large cassette/paddle • 30% small cassette/paddle • 4 images for screening • 6 images for diagnostic studies

12. MU Total Exams - Last 12 Months • *Radiology Exams only • Does not include: • Cardiology • OB-GYN • Outside Images • Digitized Films MU typically uses ~ 1 TB / month

13. Computer Components • Motherboard • Central Processing Unit (CPU) • Main Memory • Connected Data Pathways (data buses) • System Clock • Chipset • Input / Output Devices • Power Supply • Cooling Fan • Drive Bays

14. Typical Computer Use Scenario • Turn computer on • Computer loads data from ROM & performs POST (Power-On Self-Test) • POST • Make sure all major components functioning • Memory controller checks all memory addresses for read/write errors • Loads BIOS (Basic Input / Output System) from ROM-i.e. loads most basic info about: • Storage devices • Boot sequence • Security • Plug & Play (auto device recognition) capability • Loads the OS (Operating System) from hard drive into RAM • Open an application • Any files opened for use are loaded into RAM • Save a file & close application • File written to specified storage device • File/application purged from RAM

15. CPU • Contains circuitry necessary to manipulate data & execute instructions • 1st commercially available microprocessor introduced in 1971 • Modern CPU has millions & millions of transistors (switches) in its circuitry • Major Components • Arithmetic Logic Unit (ALU) • Carries out arithmetic functions (+, -, x, /) etc. • Control unit • Receives, decodes, stores results & manages execution of data flow through CPU • Registers • Very small memory locations responsible for holding data that is to be processed • Stores most frequently used instructions & data

16. CPU Performance Factors • Data Bus Width • # of pathways w/in CPU that transfer data • Word Size • Max. # of bits of data the CPU can process at a time • Operations per cycle (clock speed) • # of clock cycles per second

18. CoProcessors • Sound Card • Internal expansion card that facilitates input output of audio signals • Can also be integrated onto motherboard • Video Card • Expansion card which generates output image feed to a display • Has its own video RAM • High end may have additional cooling features (heat sink/fans) • Can also be integrated onto motherboard • Includes functions such as: • Accelerated rendering of 3D scenes &2D graphics • MPEG-2/MPEG-4 decoding • TV output • Connect multiple monitors • Outputs • VGA, HDMI, DVI, S-video, etc. • Acquisition Boards • Internal expansion card specifically designed in conjunction w/ some external data acquisition device • e.g. Film digitizer

19. Memory • Primary Memory • Often (but not always) associated w/ addressable semiconductor memory • i.e. Integrated circuits consisting of silicon-based transistors • Fast access, no moving parts, relatively expensive, small storage capacity • Secondary Memory (AKA Storage) • Physical devices for program & data storage • Slower access, but ↑memory capacity • 2 main types: • Volatile • Requires power to maintain stored info • Temp. storage area where CPU can access needed info more quickly • Random Access Memory (RAM) • DRAM (Dynamic RAM) • Nonvolatile • No power req’d to retain the stored info • Types • Read-Only Memory (ROM) • Used for firmware such as boot programs • Flash • Magnetic storage devices • Hard disk • Optical Disks CPU memory access hierarchy CPU Register Cache Level 1 Level 2 RAM Temporary Storage Areas Physical RAM Virtual memory Storage Device Types Network/ Internet Storage ROM/ BIOS Removable Drives Hard Drive Permanent Storage Areas Input Sources Scanner Camera Mic Video Remov-able Media Remote Source Other Sources Keyboard Mouse

20. Input Devices • Keyboard • Mouse • Touchpad • Touchscreen • Light pen • Microphone • Webcam • Scanner • Joystick • Gamepad

21. Output Devices • Monitor • Speakers • Headphones • Printer • Storage Devices

22. Networks • Hardware • Bandwidth • Communication Protocols

23. Hardware Cabling • Twisted Pair (Copper) Wire • 2insulated copper wires twisted around each other • To ↓crosstalk /electromagnetic induction between pairs of wires • Each connection on twisted pair requires both wires • RJ45 connector • Similar to phone jack (RJ11) • Coaxial Cable • Inner conductor surrounded by flexible, tubular insulating layer, surrounded by a tubular conducting shield • Greater throughput/bandwidth • Greater noise immunity • Optical Fiber • Transparent core surrounded by a transparent cladding material w/ lower index of refraction • Light kept in core by total internal reflection • Permits transmission over longer distances & @ higher bandwidths (data rates) • Signals: • travel w/ less loss • immune to electromagnetic interference

24. Network Interface Cards • AKA “NIC” • Provides physical connection between the network & computer • Major factor in determining speed of network • 2 Types: • Ethernet • Usually included with a computer • Contain connections for either coaxial or twisted pair cables (or both) • Wireless Adapter • Found in most portable devices, (laptops, smart phones, & tablets) • External wireless adapters can be installed on most computers having USB port or unused expansion slot

25. Wireless Networks • AKA “Wi-Fi” • Wireless Fidelity • Uses high frequency radio signals, infrared light beams, or lasers to communicate • Each device on a wireless network has some sort of transceiver/antenna to send & receive data • For longer distances: cellular telephone technology, microwave transmission, or satellite

26. Advantages & Disadvantages of Wireless Advantages • Mobility • Fast setup • Cost • Expandability Disadvantages • Security • Interference • Inconsistent connections • Speed

27. Network Hardware: Switches • Provides central connection point for cables from networked devices • Receives message from any device connected to it & then transmits message only to device for which message was meant • More intelligent than hub • Receives message & then transmits it to all other devices on its network • Usually installed in a standardized rack

28. Network Hardware: Routers • Forwards data packets between computer networks • Connected to 2+ data lines from different networks • Data packet comes in one line • Router reads address info in packet to determine its ultimate destination • Using info in its routing table, directs packet to next network on its journey • Routers perform the "traffic directing" functions on the Internet • Select best path to route message, based on destination address of packet • Direct traffic to prevent head-on collisions • Smart enough to know when to direct traffic along back roads &shortcuts

29. LAN/WAN & VPN • Local Area Network • In contrast to WANs usually: • higher data-transfer rate • smaller geographic area • lack need for leased telecommunication lines • Ethernet over twisted pair cabling& Wi-Fi are 2 most common technologies • Wide Area Network • Transmit data over long distances & between different LANs, MANs etc. • Often, but not always use leased lines • Internet is type of WAN • Virtual Private Network • Uses Internet/intermediate network to connect computers to isolated remote networks that would otherwise be inaccessible • Provides some level of security • Traffic isolated from other computers on intermediate network: • Use dedicated connection from one "end" of VPN to the other, or • Through encryption • Connect individual users to remote network or connect multiple networks together

30. Bandwidth: Max. throughput of network

31. Communication Protocols • Set of rules that governs communications between networked computers • i.e. must be speaking the same language • Protocols: • TCP/IP (Transmission Control Protocol/Internet Protocol) • Basic communication language of internet/LAN’s etc. • 2-layer program • Higher layer, TCP, manages assembling of message/file into smaller packets • Transmitted & received by TCP layer that reassembles packets into original message • Lower layer, IP, handles address part of each packet so that it gets to the right destination • FTP (File Transfer Protocol) • Allows you to request specific files from remote computers • SMTP (Simple Mail Transfer Protocol) • Used for sending/receiving e-mails • Often used in conjunction w/ other protocols like POP3 • Let’s user save messages in a server mailbox & download them periodically from the server • HTTP (Hypertext Transfer Protocol) • Set of rules for transferring files on WWW • Includes idea that files can contain references to other files whose selection will elicit additional transfer requests • Telnet • Protocol for accessing remote computers • Log on as a regular user w/ whatever privileges you may have been granted

32. Storage • Hardware • Storage Requirements • Disaster Recovery

33. Mass Storage Devices Nonvolatile storage • Most have mechanical components • Magnetic disk drives • Magnetic tape drives • Optical disks • Some entirely electronic • Flash memory • Solid state drives • Data Read/Write • Data sent to mass storage device  Writing data • Data requested from mass storage device  Reading data • WORM: write-once, read-many-times • Rewritable • Data access • Random Access • Locations of data may be read/written in any order • Solid-state, magnetic disks, optical disks • Sequential Access • Data storage locations may only be accessed in serial manner • Magnetic tape

34. Magnetic Disks Common hard drive technology • Spinning disk(s) coated w/ easily-magnetized material • Magnetization can be easily erased/rewritten • Info stored in concentric rings (tracks) • Read-write head(s) placed close to surface • Read: senses magnetization of individual locations • Write: changes direction of magnetization of individual locations • Up to 2 TB each as of 2012 • Access time • Head seek time • Time req’d for head to reach proper track • Rotational latency • Time req’d for spinning disk to bring info to the head • Data transfer rate • Rate @ which data read-written once head & disk properly oriented • Depends on: • Rotational speed of disk • Typically 5,400 – 15,000 rpm • Density of info stored in track • Very slow compared to solid-state drives, very fast compared to magnetic tape Hard drive “crash”

35. Magnetic Tape • Plastic tape coated w/ magnetizable substance • NOT random access • Data must be read serially from beginning • Very slow access • Relatively large capacity • Up to 1.5 TB per cartridge/cassette • Most often used for deep archive • Back up copy 10.5” reel

36. Optical Disks • Removable disk that rotates during data access • Data read/written using laser • Write • High intensity laser changes reflective property of disk • Read • Low intensity laser shines on a point in spinning disk • Photodetector senses intensity of reflected light • Categories • Rewritable • WORM • CD (compact disk) • Up to 650 MB capacity • DVD (digital video disk) • Laser focused to a smaller spot on disk • Up to 4.5 GB • Higher capacity Optical disks • 405 nm wavelength blue-violet laser • Up to 50 – 60 GB per disk

37. Solid State (Flash) • Stores digital information as small electrical changes • Non volatile • No moving parts • Advantages • Less susceptible to physical shock • Silent • Require less power • Less susceptible to magnetic forces • Lower access time & latency • More expensive than spinning disk • Uses • Replace spinning disk hard drives on some laptops • Flash drives, AKA Thumb drives • Connect to USB ports • Replaced floppy drives • Rapidly replacing CDs

38. Large Archives • Massive amounts of imaging data being generated → • Technologies developed to permit automated data • storage • retrieval • back up • RAID: Redundant Array of Independent/Inexpensive Disks • Several small magnetic disk drives linked together • Functions as single large hard drive • Several levels of configurations available w/ varying levels of fault tolerance • Jukeboxes (Magnetic tape cartridges or optical disks) • Media stored in large racks • Robotic arm load/remove media into one or more drives

39. Storage Capacity If you plot the storage req’s for radiology modalities, curves parallel one another! Capacity (GB) 1980 1985 1990 1995 2000 2005 2010 Year

40. Cost/TB Projected $/TB Cost ($) Year

41. RAID Terminology • Striping • Dividing data into blocks & spreading blocks over several hard disks • Parity • Additional stripe containing parity info is stored on its own hard disk • Parity checks whether data has been transferred correctly • Disk Striping used w/ or w/out parity • Mirroring • Replication of data onto a separate hard disk

42. RAID Levels *Industry standard for years **Becoming industry standard

43. Jukebox

44. NAS & SAN • DAS: Direct Attached Storage • Server directly attached to storage device is only server that can directly use that storage • NAS: Network Attached Storage • Dedicated computer that provides file/disk sharing • AKA NAS head • Shared/Accessed across same network as institution's e-mail & business applications • Underlying storage infrastructure behind NAS head may be DAS, SAN • SAN: Storage Area Network • High-speed dedicated (usually fiber-optic) network of shared storage devices

45. Disaster Recovery • Back-up Procedure • Digital Modalities Downtime • Infrastructure Downtime Procedures • PACS Disaster Recovery Procedure • PACS Downtime Procedures • Scheduled Downtime • Unscheduled Downtime

46. IHE - Integrating the Healthcare Enterprise • Initiative by RSNA & HIMSS to improve the way computer systems in healthcare share information • Anatomic Pathology • Ophthalmology • IT Infrastructure • Laboratory • Patient Care Coordination • Patient Care Devices • Quality, Research & Public Health • Radiation Oncology • Radiology • Promotes coordinated use of established standards such as DICOM & HL7 to address specific clinical need in support of optimal patient care • Systems developed in accordance w/ IHE: • communicate w/ one another better • are easier to implement • enable care providers to use information more effectively

47. IHE Process

48. Radiology Information System (RIS) • Computerized database used by radiology departments to store, manipulate, & distribute patient radiological data & imagery • Basic Functions • Generating clinical reports associated w/ radiological images • Interface w/ modalities via worklist • Exam order details sent to modality devices • Negates need for manual order entry by technologist • Patient management • Track patient’s entire workflow w/in radiology department • Scheduling • Appointments can be made for both in- & out-patients w/ specific radiology staff • Patient tracking • Patient’s entire radiology history can be tracked from admission to discharge • History can be coordinated w/ past, present & future appointments • Results reporting • Generate statistical reports for a single patient, group of patients or particular procedure • Film tracking • Track individual films & their associate data • Billing • Facilitates detailed financial record-keeping, electronic payments & automated claims submission

49. Hospital Information System (HIS) Comprehensive, integrated information system designed to manage: medical administrative financial legal aspects of a hospital & its service processing • Components consist of one or more of the following: • Clinical Information System • Financial Information System • Laboratory Information System • Nursing Information Systems • Pharmacy Information System • Picture Archiving Communication System • Radiology Information System

50. Electronic Medical Record (EMR) • Designed for collecting, storing, manipulating & making available clinical information important to the healthcare delivery process • Clinical data repository that stores clinical data such as the patient’s history of illness & the interactions w/ care providers • Helps physicians decide about the patient’s • condition • treatment options • wellness activities • status of decisions • actions undertaken • other relevant information that could help in performing those actions