Computer Basics: Image Formation & Management Systems

Image Formation & Management Systems

• Course code: 142-B14-DW
• Topic 1: Computer Basics

Specific Learning Objectives

• Understand the basic functions of a computer
• Define the basic functions of computer hardware components
• Identify primary computer tasks performed by technologists
• Distinguish between different types of image storage systems
• List the methods computers use to communicate
• Compare various network topologies
• Describe network risks and safeguards for medical imaging computer systems
• State the data storage and transmission requirements for PACS
• State the applications and advantages of telehealth and telemedicine
• Define and describe components of teleradiography

Information Videos

• Computer binary codes: [video links available]
• Computer hardware and software [video links available]
• Hard Disk Drive [video links available]
• RAID 0, 1, and 5 [video links available]
• Networking [video links available]
• DICOM [link available]
• Pixel definition [video links available]
• ADC [video links available]
• Image matrix size and bit depth [video links available]
• Radiologist job offer [link available]

A Computer

• Input, output, and data processing devices
• Processes data into information under a stored program control
• Data: unstructured facts
• Processes: changes to data
• Information: meaningful facts
• Stored program: a set of instructions

Important Dates in Computer History

• First electronic digital computer designed and built in 1939
• First general-purpose electronic computer developed in 1946 (cost $500,000; 18,000 vacuum tubes; one failed every 7 mins)
• Transistor invented in 1948; replaced vacuum tubes
• Transistor: an electronic switch that controls electronic signals

Computer Language

• The Binary Code: The foundation of computer programming/language uses 1s and 0s to process data from input devices
• Binary code processing is done by transistors that are on or off
• If the circuit is closed and current passes through, the value is 1; 0 if open
• Bit: single unit of data; byte: 8 bits storing alphanumeric characters
• Decimal to Binary codes of the alphabet are presented

Operating Systems

• Manage all computer resources; interface between software and hardware
• Examples: DOS, Windows 11, Mac OS X, Unix, Linux, iOS, Android
• Computer Hardware: Physical components (input/output devices)
• Software: Programs running on the hardware; Moodle & LEA are online learning platforms.

Hardware Components

• Box/Tower: Contains components in a cool, clean, and secure environment; prevents radio frequencies from spreading outside.
• Motherboard: A printed circuit board serving as the computer’s foundation; allocates power, enabling communication between hardware.
• Processor/CPU: Manages instructions from hardware and software using transistors to process data; examples include Intel Core i5-11600K.
• System Clock/Internal Clock: Regulates instruction execution rates and synchronizes computer components.
• RAM (Random Access Memory): Short-term data storage; contents are erased when the system is turned off.

Additional Hardware Components

• Ports/Connectors: Connecting peripherals to the computer.
• CMOS: Preserves hardware settings when the computer is off using a battery; stores system information and time.
• Network Interface Card (NIC): Enables communication with other computers (e.g., radiology workstations).
• Power Supply: Supplies electricity and cools the system.
• Hard Disk Drive (HDD): Stores programs and data; uses moving parts; RAID is widely used in radiology systems for long-term archiving.
• Solid State Drive (SSD): Stores data in microchips; faster than HDDs; suitable for both short-term and long-term storage in PACS.
• Cloud Storage: Remote server-based storage accessible via the internet; useful for backing up data and files.
• CD/DVD Disk Drives: Optical storage devices utilizing laser light to read and write data.
• Input/Output Devices: Various input devices (e.g., mouse, keyboard), and output devices(e.g., monitor, speakers)

Computer Applications in Radiology

• Computers control electronic devices (e.g., X-ray generators, control panels).
• Computed Tomography (CT), Magnetic Resonance Imaging (MRI), Ultrasound (US), and Nuclear Medicine (NM) are essential radiology applications.

Computer Networks

• A telecommunications network enabling information exchange between computers.
• Server: A computer providing services to other computers on the network, such as web servers, mail servers, and archive servers.
• Thin Client: Hardware without a hard drive requiring continuous server interaction.
• Thick Client (Fat Client): A workstation capable of functioning independently from the network.

Important Definitions

• Network Classification (LAN, WAN, Intranet, Internet)
• Network Protocols (e.g., TCP/IP)
• Transmission of data in packets; used for information sharing on private networks (intranet or extranet) and the internet
• OSI Model (Open Systems Interconnection) Model
• IP Address: Unique address for each computer on a network
• MAC Address: Unique physical address for hardware components
• Gateway: Networking node connecting two separate networks with different transmission protocols
• Hub and Switch: Network devices. A hub transmits every packet to all connected devices; a switch only transmits packets to the intended destination

Network Topologies

• Patterns defining how computers and network devices are connected in a network
• Star topology: Common in modern client-server networks with devices connecting to a central hub.
• Other examples include bus, ring, and mesh (point-to-point) topologies.

Web-Based Systems

• Client uses internet connection to access a network's web server to remotely access data (e.g., images in a PACS).
• Advantage: Less powerful hardware required; potential for access from anywhere, faster retrieval
• Disadvantages: Slower data download; often limited software functionality. Typically, images are saved as JPEG files only.

Internet and Intranet

• Internet: An international network of networks using TCP/IP protocols.
• Intranet: A local network using TCP/IP protocols for sharing information within an organization.

Telehealth and Telemedicine

• Telehealth and telemedicine: Telecommunication applications providing community medical information and services (e.g., Info-Sante 811).
• Telehealth: More broad, general, and may include prevention measures.
• Telemedicine: Focuses on diagnosis and treatment.
• Applications include diagnosis, education, research, phone and video conferencing, teleradiology, telepathology, and telesurgery

Teleradiology

• Remote transmission of medical images for interpretation and/or consultation.
• Accessed through various internet, WAN, LAN, satellite, and phone lines.
• Increased use due to COVID-19.

RUISSS (Réseau Universitaire Intègre de la Santé et des Services Sociaux)

• Coordinates tertiary healthcare services in remote areas of the province through associated teaching hospitals.
• Supports healthcare professional training and development.
• Tertiary Care: Specialized consultative care usually by referral from primary or secondary care personnel.

Network Security

• Potential risks: Viruses; ethical issues, human errors, confidentiality issues; defective hardware/software; issues with data integrity and reliability (data loss, corruption).
• Techniques to enhance security include anti-virus programs, anti-spyware software, firewalls, pop-up blockers, and encryption.

Calculating Image File Size and Storage Capacity

• Image file size calculation formula: Matrix size x Bit Depth.
• Calculations to determine the bytes of storage needed for digital image data based on a given matrix size and bit depth, along with calculations to determine how many images can be stored in a given storage space (e.g., 700MB or 1GB)
• Image file size calculations shown for 2-D and 3-D datasets.

Raw Data & Image Data

• Raw data: Unprocessed image data; acquired by the digital imaging unit.
• Image data: Processed raw data, adjusted and without non-essential background data; typically, smaller size than raw data file.

Analog & Digital Signals

• Analog signal: Continuous varying information (e.g., watch hands, analog X-ray film).
• Digital signal: Discrete data units (e.g., digital watch, image acquisition systems such as CT, MRI, CR or DR).
• Analog-to-digital converter (ADC): Translates analog signals into digital form.

Sampling and Quantization

• Sampling: Specific points in time selected for conversion.
• Quantization/Digitization: Analog level approximates to the closest digital level; assigned binary code.

Additional Information about Bit Depth

• Bit depth method: Number of shades of gray in an image; e.g., 8 bits (256 shades); 16 bits (65,536 shades); 24 bits or more (many shades).

The Digital Image

• Advantages: Image manipulation and reprocessing; lower storage and floor space requirements
• Disadvantages: Lower spatial resolution compared to analog (film) images.

Image Matrix Sizes in Radiology

• Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) have matrix dimensions from 256x256 up to 1024x1024.
• Other imaging modalities like radioscopy, radiography, and mammography have different matrix sizes.

Calculation of Pixel Size

• Pixel size calculation formula: Image area divided by matrix size.

Other Important Concepts

• Exposure: Defined as the quantity of X-ray photons reaching the image receptor.
• Factors affecting exposure: kVp, mAs, SID, SOD, OID, patient body habitus, part thickness, and other items.
• kVp (Kilovoltage peak): Controls the energy of the X-ray beam, and thus its penetrating power; directly relates to exposure.
• mAs (milliampere-seconds): Controls the quantity of X-rays generated; directly relates to exposure.
• SID (Source to Image Distance): Controls exposure and magnification. Longer distance means less exposure.
• SOD (Source to Object Distance): Controls exposure and magnification.
• OID (Object to Image Distance): Affects magnification and shape distortion.
• Inverse Square Law (ISL): Demonstrates the relationship between the distance from the source and exposure intensity.
• Grid Ratio: The height of the lead strips in a grid divided by the distance between the strips; determines how a grid removes scatter.