Introduction to Digital Imaging

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Questions and Answers

What is one advantage of digital imaging over analog film images?

Greater image storage capacity (correct)

Longer image processing times

Higher maintenance costs

Increased physical space requirements

Which parameter is NOT considered an aspect of image quality in digital imaging?

Image contrast

Automatic file saving (correct)

Line Spread Function (LSF)

Modulation Transfer Function (MTF)

What type of software programs make it easier for users to operate a computer effectively?

Firmware

Application programs

System software (correct)

Driver software

What does Detective Quantum Efficiency (DQE) measure in digital imaging?

The efficiency of image capturing systems Signup and view all the answers

Which of the following is NOT an example of an application program?

MAC-OS Signup and view all the answers

In the context of digital imaging, what does 'FOV' stand for?

Field of View Signup and view all the answers

What does RAM primarily store?

Temporary data Signup and view all the answers

Which type of digital radiography detector directly captures images without the use of cassettes?

Direct Digital Radiography (DR) Signup and view all the answers

Which component of the computer allows it to manipulate data and execute software instructions?

Central Processing Unit Signup and view all the answers

What is an important consideration when manipulating digital images in radiology?

Controlling exposure parameters Signup and view all the answers

Which of the following is NOT a function of CR cassettes in digital imaging?

Direct image viewing Signup and view all the answers

What is the maximum capacity unit typically used to express RAM?

Megabytes (MB) Signup and view all the answers

What technology controls high-voltage x-ray generators in modern medical imaging?

Computerized systems Signup and view all the answers

Which of the following statements about Read-only Memory (ROM) is accurate?

It holds firmware instructions that cannot be erased. Signup and view all the answers

How is CPU performance measured?

In megahertz (MHz) Signup and view all the answers

Which of the following components is responsible for input in a computer system?

Input hardware Signup and view all the answers

What is the significance of a 16 bit dynamic range in digital mammography?

It provides 65,536 shades of gray. Signup and view all the answers

Which of the following correctly describes the relationship between bits and bytes?

1 byte equals 8 bits. Signup and view all the answers

How much storage space does a 16 bit image with a resolution of 2000 × 2500 pixels approximately require in megabytes?

9.5 MB Signup and view all the answers

What does the term 'stored program' in a computer refer to?

Instructions and data are stored in the computer's memory. Signup and view all the answers

Which of the following accurately describes the capacity of 1 terabyte (TB)?

1,024 GB Signup and view all the answers

What is the purpose of using the Power of 2 notation in radiologic imaging?

To describe image size, dynamic range, and storage capacity. Signup and view all the answers

Which of these statements is true about a computer's hardware?

It encompasses everything about the computer that is visible. Signup and view all the answers

How many bytes are there in 1 megabyte (MB)?

1,048,576 bytes Signup and view all the answers

What is the purpose of filtering light before photodetection?

To prevent long-wavelength light from reaching the photodetector Signup and view all the answers

Which of the following is NOT one of the four principal characteristics of any medical image?

Color resolution Signup and view all the answers

What happens during the digitization of an analog signal?

It undergoes compression, sampling, and quantization Signup and view all the answers

How many gray levels can a typical screen-film image display?

30 Signup and view all the answers

What distinguishes CR imaging from S/F imaging regarding radiation exposure?

CR imaging does not critically depend on radiographic technique Signup and view all the answers

Which statement is true regarding the image receptor response function?

It extends through an optical density range from 0 to 3 Signup and view all the answers

What is the primary drawback of image noise in CR imaging?

It is only bothersome at low radiation exposure Signup and view all the answers

Which principle about exposure control is specific to CR imaging?

mAs does not affect contrast over multiple decades Signup and view all the answers

What is a key feature of CR systems compared to S/F systems regarding patient radiation dose?

CR systems have lower noise levels, allowing for lower patient radiation doses. Signup and view all the answers

What effect does increased kVp and decreased mAs have in CR systems?

Maintains image contrast while reducing radiation dose. Signup and view all the answers

Which of the following characterizes the transition from S/F radiography to CR?

Improved contrast resolution and reduced patient radiation dose. Signup and view all the answers

What phenomenon is CR technology based on?

Photostimulable luminescence (PSL). Signup and view all the answers

How does the CR reader make the latent image visible?

Using a stimulating laser light beam to release excited electrons. Signup and view all the answers

What aspect of CR allows for wider latitude in radiation exposure?

The predictable behavior of CR pixel values over varying exposures. Signup and view all the answers

Which characteristic of CR systems contributes to fewer repeat examinations?

Improved contrast resolution and wide exposure latitude. Signup and view all the answers

What is indicated by the characteristic curve of CR pixel values?

A linear relationship over five decades of exposure. Signup and view all the answers

Study Notes

Computer Fundamentals

Stored program concept allows a computer to have instructions and data stored in memory.
Powered by electrical components, making them electronic.
Data represented in discrete values defines computers as digital.

The Power of 2 Notation

Used in radiologic imaging to outline image size, dynamic range, and storage capacity.
Common digital image sizes:
- MRI and CT resolution: 256×256 (28) to 1024×1024 (210).
- Digital fluoroscopy: 1024×1024 (210).
- Digital radiography: 2048×2048 (211).
- Digital mammography: 4096×4096 (212).

Data Measurement Units

Bit: A binary digit (0 or 1); 8 bits form a byte.
Memory conversions:
- 1 byte (B) = 8 bits
- 1 kilobyte (kB) = 1,024 bytes (210)
- 1 megabyte (MB) = 1,048,576 bytes (220)
- 1 gigabyte (GB) = 1,073,741,824 bytes (230)
- 1 terabyte (TB) = 1,099,511,627,776 bytes (240)

Digital Imaging and Storage

Each pixel in digital x-ray images is represented by bits defining grayscale.
Example: A digital mammogram has a dynamic range of 16 bits, allowing display of 65,536 shades of gray.
Radiology department computers typically have storage capacities measured in GB or TB.

Computer Components

Two principal parts: hardware (physical components) and software (instructions/processes).
Central Processing Unit (CPU): The core for data manipulation and instruction execution; examples include Intel Core i9 and AMD Ryzen.
RAM (Random Access Memory): Temporary storage for data; critical for efficient processing; measured in MB, GB, or TB.
ROM (Read-Only Memory): Contains firmware; non-volatile storage that loads initial system instructions.

Medical Imaging Characteristics

Four key imaging characteristics: spatial resolution, contrast resolution, noise, and artifacts.
Digital imaging utilizes various metrics to ensure quality: Line Spread Function (LSF), Detective Quantum Efficiency (DQE), and image histograms.

Computed Radiography (CR) and Direct Digital Radiography (DR)

CR uses photostimulable phosphors to capture latent images, which are processed with lasers to produce visible images.
DR provides immediate image acquisition and typically improved exposure latitude, resulting in reduced patient radiation doses and necessitating fewer repeat exams.

Patient Radiation Dose

CR allows for lower radiation exposure while maintaining image quality.
Standard exposure factors for S/F (screen-film) imaging may represent maximum safe levels for CR.

Workload and Efficiency in Imaging

Transitioning to CR from S/F results in fewer repeat examinations and improved workload efficiency due to continuous operation and enhanced contrast resolution.

Summary of Digital Radiography (DR) Evolution

DR began in the 1980s and was developed from CR technologies.
Utilizes X-ray interaction with phosphors to create latent images, visible through digital processing, enabling wide grayscale representation and improved patient safety regarding radiation exposure.

Abbreviations for Reference

Familiarize with common abbreviations relevant to this field for studies and practical applications.

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Description

This quiz covers key concepts in digital imaging, including the significance of stored programs, the electronic components of computers, and the role of digital values in image representation. It also touches upon the Power of 2 notation used in radiologic imaging for describing image size and storage capacity.