RADSCI 338 Midterm

Computer

An electronic device that accepts data, processes it, produces output, and stores results.\

Input

Data or instructions entered into a computer.\

Processing

The stage in which a computer works on input data to perform calculations or complete tasks.\

Output

Information produced by a computer after processing data.\

Storage

The retention of data and information for future use.\

Algorithm

A finite, ordered set of instructions designed to complete a task.\

Number of Algorithms

There is no fixed number; computers can execute many algorithms depending on the programs and tasks involved.\

Microcomputer

A relatively small computer built around a microprocessor, such as a desktop or laptop.\

Minicomputer

A mid-sized computer system traditionally designed to support multiple users or applications.\

Supercomputer

A highly powerful computer that performs complex calculations using many processors, such as weather modeling.\

Hardware

The physical components of a computer.\

Software

Programs and instructions that tell computer hardware what to do.\

Operating System (OS)

System software that manages computer hardware and software and provides an interface for users.\

Input Devices

Devices used to enter data into a computer, such as a keyboard, mouse, microphone, or scanner.\

Output Devices

Devices that present computer results, such as a monitor, printer, or speakers.\

Input/Output Device

A device that both receives and sends information; a touchscreen is an example.\

Motherboard

The main circuit board that connects computer components and enables communication between them.\

Major Motherboard Components

CPU socket, RAM slots, BIOS or firmware, chipset, storage connections, expansion slots, and input/output ports.\

Central Processing Unit (CPU)

The main processor that executes computer instructions and processes data.\

Control Unit (CU)

The CPU component responsible for directing the flow of instructions and coordinating computer operations.\

Arithmetic/Logic Unit (ALU)

The CPU component responsible for arithmetic calculations and logical comparisons.\

Primary Memory

Memory directly accessible to the processor, primarily RAM and ROM in the terminology used in the lecture.\

Secondary Memory

Long-term storage used to retain programs, files, and data, such as HDDs and SSDs.\

Volatile Memory

Memory that loses its stored information when power is turned off; RAM is an example.\

Non-Volatile Memory

Memory that retains information when power is turned off; ROM, SSDs, and flash drives are examples.\

Hard Disk Drive (HDD)

A storage device that stores data magnetically on spinning disks.\

Solid-State Drive (SSD)

A storage device that uses flash memory and has no moving parts.\

Optical Disk

A storage medium read or written using a laser, such as a CD, DVD, or Blu-ray disc.\

Flash Drive

A portable storage device that uses flash memory and commonly connects through USB.\

Random Access Memory (RAM)

Temporary, volatile working memory that holds data and programs currently in use.\

Read-Only Memory (ROM)

Non-volatile memory used to retain instructions for basic computer operations, including startup.\

RAM vs. ROM

RAM is primarily temporary working memory that supports reading and writing; ROM retains stored instructions without power.\

Firmware

Software embedded in a device to control its basic operations.\

Basic Input/Output System (BIOS)

Firmware that initializes computer hardware and helps start the computer.\

Data Redundancy

The storage of the same data in multiple places.\

Data Redundancy in Medical Imaging

Duplicate patient images or studies can be reduced using patient identifiers, study identifiers, and duplicate-study checking in PACS; intentional redundancy can protect against data loss.\

Redundant Array of Independent Disks (RAID)

A storage method that combines multiple drives to improve data protection, performance, or both, depending on the configuration.\

Graphical User Interface (GUI)

A visual interface that lets users interact with a computer through elements such as windows, icons, menus, and buttons.\

System Software

Software that manages computer operations and provides a foundation for other programs.\

Application Software

Software designed to perform specific user tasks, such as image viewing, word processing, or spreadsheets.\

Operation Code (Opcode)

The part of a machine instruction that specifies which operation the processor should perform.\

Binary

A base-2 number system that uses only the digits 0 and 1.\

Denary (Decimal)

A base-10 number system that uses the digits 0 through 9.\

Binary vs. Denary

Binary uses base 2; denary uses base 10.\

Bit

The smallest unit of digital data, representing a binary digit of 0 or 1.\

Byte

A unit of digital data consisting of 8 bits.\

Word

In the lecture's terminology, a unit of data consisting of two bytes, or 16 bits.\

Kilobyte (KB)

Approximately 1,000 bytes using decimal measurement; commonly treated as 1,024 bytes under the binary convention used in the slides.\

Megabyte (MB)

Approximately 1 million bytes using decimal measurement; the slides use 1,024 KB under their binary convention.\

Gigabyte (GB)

Approximately 1 billion bytes using decimal measurement; the slides use 1,024 MB under their binary convention.\

Terabyte (TB)

Approximately 1 trillion bytes using decimal measurement; the slides use 1,024 GB under their binary convention.\

Binary Place Values

Powers of two, beginning with 1 and continuing as 2, 4, 8, 16, 32, 64, 128, and so on.\

Binary-to-Denary Conversion

Add the place values corresponding to each binary digit that equals 1.\

ASCII (American Standard Code for Information Interchange)

A character-encoding system that assigns numerical codes to letters, numbers, and symbols.\

Purpose of ASCII

To represent and exchange text using numerical character codes.\

Hexadecimal

A base-16 number system that uses digits 0 through 9 and letters A through F, with A representing 10 and F representing 15.\

Purpose of Hexadecimal

To represent binary values in a more compact and readable form.\

Binary-to-Hexadecimal Relationship

One hexadecimal digit corresponds to four binary bits.\

Software Program

A set of instructions that tells a computer how to perform a task.\

Display Monitor

A device that visually presents computer information and images.\

Importance of Medical Displays

Accurate image presentation is necessary for detecting subtle differences that may indicate disease.\

Hard Copy

A physical copy of an image, such as a printed radiograph or film.\

Soft Copy

A digital image viewed on an electronic display.\

Cathode Ray Tube (CRT)

An older display technology that produces images by directing an electron beam onto a phosphor-coated screen.\

CRT Disadvantages

Large size, heavy weight, high power consumption, heat generation, possible uneven brightness, and brightness deterioration over time.\

Veil Glare

Reflected or scattered light that creates a hazy appearance over an image and reduces contrast.\

Flicker

A noticeable fluctuation in screen brightness, often associated with a low refresh rate.\

Flat Panel Display

A thin, lightweight display technology that includes LCDs, LED-backlit LCDs, and OLEDs.\

Liquid Crystal Display (LCD)

A display technology that uses liquid crystals to control light transmission.\

How LCDs Work

A backlight produces light, polarizing filters control its direction, liquid crystals regulate transmission, and color filters produce colors.\

LCD vs. CRT

LCD monitors are thinner, lighter, and generally use less power than CRT monitors.\

Active Matrix LCD (AMLCD)

An LCD that uses active electronic components, typically thin-film transistors, to control individual pixels.\

AMLCD Benefits

Improved pixel control, sharper images, and faster response than older passive-matrix LCD technology.\

LED Monitor

A typical monitor that uses an LCD panel illuminated by light-emitting diodes as its backlight.\

Organic Light-Emitting Diode (OLED)

A display technology in which individual pixels produce their own light without a separate backlight.\

OLED Advantages

Deep blacks, high contrast, thin displays, and wide viewing angles.\

Display Matrix

The arrangement of rows and columns of pixels that form a digital display image.\

Matrix Size

The horizontal and vertical pixel dimensions of a display, such as 1920 by 1080.\

Resolution

The amount of image detail a display can show; higher pixel counts generally allow more detail.\

Pixel

The smallest addressable picture element of a digital display.\

Subpixel

A colored component within a pixel.\

RGB

Red, green, and blue, the three standard subpixel colors used to produce colors on many displays.\

Typical Color LCD Pixel

Typically contains red, green, and blue subpixels.\

Pixel Pitch

The distance from the center of one pixel to the center of an adjacent pixel.\

Pixel Pitch and Resolution

Smaller pixel pitch places pixels closer together and generally improves spatial resolution when other display characteristics are comparable.\

Ambient Light

Light from the surrounding environment that falls on or reflects off a display.\

Effect of Ambient Light on Medical Images

Excessive ambient light can cause reflections and reduce perceived contrast, making subtle grayscale differences harder to see.\

Backlight

The light source behind an LCD panel that illuminates its pixels; OLED displays do not require one.\

Diagnostic Display

A monitor used for primary interpretation of medical images by radiologists and subject to the strictest performance requirements.\

Modality Display

A monitor used by technologists to review images at acquisition workstations during or after image acquisition.\

Clinical Specialist Display

A monitor used by clinicians to review images for patient care.\

Electronic Health Record (EHR) Display

A monitor used for general clinical image review within the electronic health record.\

Bit Depth

The number of bits used to represent a pixel's intensity or color information; greater bit depth permits more shades or color values.\

8-Bit Display

The display bit-depth standard identified in the lecture for medical imaging displays.\

Quality Control (QC)

Testing and monitoring display performance to ensure medical images are presented consistently and accurately.\

FDA

The Food and Drug Administration, which regulates medical devices, including certain medical display devices.\

ACR

The American College of Radiology, which publishes professional guidance and standards related to medical imaging.\

AAPM

The American Association of Physicists in Medicine, which develops technical recommendations for medical imaging and display performance.\

When to Perform Monitor QC

At installation, periodically according to the quality assurance program, after repairs, and when performance problems are identified.\

Consistent Presentation of Images (CPI)

The goal of making medical images appear consistently to technologists, radiologists, and other physicians throughout the imaging process.\