Radiography Technology Quiz

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Questions and Answers

What is the primary function of intensifying screens in conventional film/screen radiography?

To emit light when struck by x-rays, thereby exposing the film. (correct)

To filter out low-energy x-rays.

To directly expose the film to x-rays.

To absorb scattered radiation.

What is the fundamental characteristic of digital imaging?

It uses film and intensifying screens to develop images.

It involves an image acquisition process that results in an electronic image. (correct)

It uses light boxes to view diagnostic images.

It produces a latent image that requires chemical processing.

Which of the following best describes teleradiology?

The electronic transmission of images between locations. (correct)

The manipulation of digital images on a computer.

The use of film-screen radiography in remote locations.

The storage of images in a picture archiving system.

When was the term 'digital imaging' first used, coinciding with the development of which technology?

1970s, with the development of computed tomography (CT) (C) Signup and view all the answers

In the context of early PACS development, which entity provided major support for its implementation, especially for military and VA hospitals?

The U.S. government (A) Signup and view all the answers

What is a key feature of Photostimulable Phosphor (PSP) systems that differentiates them from traditional film/screen systems?

They capture an electronic image, which can be viewed on a computer. (C) Signup and view all the answers

What was the primary reason for the slow initial acceptance of PSP systems by radiologists?

There was a general resistance to new technologies. (D) Signup and view all the answers

In traditional film/screen radiography, where is the manifest image viewed after processing?

On a light box. (C) Signup and view all the answers

In conventional film/screen radiography, what primarily controls radiographic contrast?

kVp (A) Signup and view all the answers

What attracts silver ions to the sensitivity speck in conventional film/screen radiography?

A negative charge on the speck (B) Signup and view all the answers

What type of material is commonly used in PSP imaging plates?

Barium fluorohalide with europium activator (B) Signup and view all the answers

In PSP systems, what is the role of the laser scan?

To stimulate the release of trapped electrons, emitting light (C) Signup and view all the answers

In an FPD system utilizing indirect capture, what is the function of the scintillator?

To absorb x-ray energy and emit light (B) Signup and view all the answers

What is the primary function of the storage phosphor in PSP imaging?

To absorb and store x-ray energy. (D) Signup and view all the answers

How is the latent image formed in a conventional film/screen system?

By the collection of electrons at sensitivity specks (D) Signup and view all the answers

What type of device is coupled with the x-ray absorber material in a flat panel detector (FPD)?

A thin-film transistor (TFT), CMOS, or CCD. (B) Signup and view all the answers

In direct capture FPD systems, what is the function of the photoconductor?

To convert x-ray energy directly into a digital electrical signal (C) Signup and view all the answers

Where does image processing take place in a FPD system?

In a computer often integrated with the x-ray console (A) Signup and view all the answers

In indirect capture DR, what is the first step after the x-rays are absorbed by the detector?

Conversion of x-rays to light. (D) Signup and view all the answers

In direct capture DR, what material absorbs x-rays?

A photoconductor. (A) Signup and view all the answers

What is the role of the analog-to-digital converter (ADC) in both indirect and direct capture DR systems?

To convert electrical signals to digital data. (A) Signup and view all the answers

Which imaging system typically provides more immediate image availability?

Flat panel detectors (FPD). (C) Signup and view all the answers

What is the initial interaction, following exposure to x-rays, in a conventional film/screen system?

X-rays interacting with the intensifying screen. (C) Signup and view all the answers

How does the efficiency of FPDs compare to conventional film/screen and PSP systems?

FPDs are much more efficient. (A) Signup and view all the answers

Which of the following best describes a Digital Imaging system?

Any image acquisition process that results in an electronic image viewable on a computer. (C) Signup and view all the answers

An indirect capture flat panel detector (FPD) involves which sequence of conversions?

X-rays to light, then to an electrical signal. (B) Signup and view all the answers

What is a key function of a Picture Archiving and Communication System (PACS)?

To manage and archive digital images using a network of computers, servers, and archives. (D) Signup and view all the answers

What is the primary purpose of DICOM in medical imaging?

To provide a standard language for communication between imaging modalities and PACS. (B) Signup and view all the answers

Which of the following is NOT a component of a Medical Image Management and Processing System (MIMPS)?

Analog film processing equipment. (C) Signup and view all the answers

What primary factor controls optical density on film?

mAs (D) Signup and view all the answers

What replaces exposure latitude in digital imaging systems?

Dynamic range (C) Signup and view all the answers

Which of these does not directly influence image noise?

Subject contrast (D) Signup and view all the answers

What is the primary function of a Look-up table (LUT) in digital imaging?

Control image display quality (C) Signup and view all the answers

Which image capture system is most sensitive to scatter radiation?

PSP and FPD (A) Signup and view all the answers

What type of image format must a MIMPS accept?

DICOM (D) Signup and view all the answers

What is a key function of a Medical Image Communications Device?

Image manipulation and transfer between devices (C) Signup and view all the answers

What is the most critical reason patient identification is essential in digital imaging?

To ensure correct retrieval of images (D) Signup and view all the answers

Study Notes

Chapter 1: Introduction to Digital Radiography and Picture Archiving and Communication System

This chapter introduces digital radiography and Picture Archiving and Communication Systems (PACS)
Digital imaging is an image acquisition method that produces electronic images.
The term digital imaging was first used in the 1970s with the development of computed tomography (CT).
Digital images can be viewed and manipulated on computers.
Digital images can be networked to various locations.
Teleradiology is the movement of images via telephone lines to remote locations.
The concept of teleradiology began with Albert Jutras in Canada in the 1950s.
Early PACS systems were developed in the 1980s with U.S. government support for the U.S. military to transfer images between battlefields and VA hospitals.

Objectives

Define digital imaging.
Explain latent image formation for film/screen (F/S) radiography.
Compare and contrast latent image formation for storage phosphor, flat panel with thin-film transistor (TFT), and charge-coupled device (CCD) digital imaging systems.
Explain what a picture archiving and communication system (PACS) is and how it is used.
Define digital imaging and communications in medicine (DICOM).

Key Terms

Digital imaging
Direct capture digital radiography
Flat panel detector (FPD)
Indirect capture digital radiography
Photostimulable phosphor (PSP) image capture
Teleradiology

Conventional Film/Screen Radiography

Uses film and intensifying screens (F/S) in image production.
Film is placed on one or between two intensifying screens.
Screens emit light when struck by x-rays.
Light and x-rays expose the film.
The film is processed chemically.
The manifest image on the film is viewed on a lightbox.

Digital Imaging

Defined as any image acquisition process that produces an electronic image.
The term was first used in the 1970s with the development of computed tomography (CT).
Images can be viewed and manipulated on a computer.
Images can be networked to various locations.

Photostimulable Phosphor (PSP)

Previously known as computed radiography (CR).
More accurate than computed radiography and avoids confusion.
Newer systems may not be cassette-based.
First introduced in the U.S. by Fuji Medical Systems of Japan in 1983.
Slow acceptance by radiologists.
Installation increased in the early 1990s.
A 1996 law that reduces Medicare reimbursements.
2018 will drive a decrease in PSP use.

PSP Image Capture

Equipment includes existing radiographic equipment, PSP storage plates, PSP reader, technologist QC workstation, viewing station (a printer, or both).
Storage phosphor plates are similar to intensifying screens.
Store x-ray energy for an extended time.

CR Detector

Photostimulable Storage Phosphor (PSP)
BaFBr compound, Eu activated
Phosphor plate or imaging plate ("IP")

Flat Panel Detectors (FPDs)

Uses an x-ray absorber material coupled to a TFT, CMOS, or CCD to form the image.
May retrofit existing rooms or use portable detectors in existing equipment.
Two types of FPD: indirect capture and direct capture.

Flat Panel Detectors (1 of 2): Indirect Capture

Device absorbs x-rays and converts them to light.
Light is collected by an area-CCD, CMOS, or TFT.
Converted into electrical signals.
Electronic signal is sent to ADC.
Computer processes electrical signals to images.
Images are viewed on a monitor.

Flat Panel Detectors (2 of 2): Direct Capture

Photoconductor absorbs x-rays and converts them to electrical signals.
TFT collects and sends the signal to the analog-to-digital converter (ADC).
Computer turns digital data into an image.
The digital image is processed and viewed on a monitor.

Comparison of Film/Screen to Digital Imaging

Equipment efficiency ratings.
Conventional F/S and PSP are about the same efficiency.
FPD is much more efficient as images are available immediately.

Comparison: Latent Image Formation (Film/Screen)

Film placed inside a cassette containing an intensifying screen.
X-rays strike the intensifying screen, producing light.
Light and x-ray photons interact with silver halide grains in the film emulsion.
An electron is ejected from the halide.
The ejected electron is attracted to the sensitivity speck.
The speck now has a negative charge.
Silver ions are attracted to equal out the charge.
This process happens many times within the emulsion to form a latent image.
After chemical processing, the sensitivity specks are processed into black metallic silver, and the manifest image is formed.

Comparison: Latent Image Formation (PSP)

Most are made of a barium fluorohalide with europium activator.
Housed inside a cassette, some light is emitted when x-rays strike the PSP.
Some photon energy is deposited within the phosphor particles, creating a latent image.
Plate is then fed through the PSP reader.
A focused laser scans the plate.
Electrons return to their original state, emitting light in the process.
The light is picked up by a photomultiplier tube and converted into an electrical signal.
The electrical signal is sent through an ADC to produce a digital image.

Comparison: Latent Image Formation (FPD)

No cassettes are required.
Image acquisition device is built into the table or wall stand or is enclosed in a portable device.
Processing time is 3-5 seconds.
Two image acquisition methods: indirect capture and direct capture.
Indirect capture is like PSP in that x-ray energy stimulates a scintillator, which gives off light detected and turned into an electrical signal.
Direct capture - x-ray energy is detected by a photoconductor that converts it directly to a digital electrical signal.

Comparison: Latent Image Formation (Film/Screen -continued)

Image is determined by the shape of the film's response curve and processing chemicals.

Comparison: Latent Image Formation (PSP and FPD)

Image processing takes place in a computer.
For PSP, the computer is located near the readers.
For FPD, the computer is located next to x-ray console, or integrated within the console, and image is processed before the next exposure.

Comparison: Exposure Response and Image Characteristics (Film/Screen)

Radiographic contrast is primarily controlled by kVp.
Optical density on film is primarily controlled by mAs.
Exposure latitude is narrow.

Comparison: Exposure Response and Image Characteristics (PSP and FPD)

Exposure latitude is replaced with dynamic range and is now wide.
Every detector is sensitive to a wide range of exposures.
Subject contrast is influenced by kVp.
Image noise is influenced by mAs.
Look-up table (LUT), an image processing algorithm, controls quality of image display.

Comparison: Scatter Sensitivity and Noise

All three image capture systems are sensitive to scatter.
PSP and FPD can be more sensitive to scatter than screen/film.
Quantum mottle resulting from low mAs values is seen on all three image capture systems.

Medical Image Management and Processing Systems (MIMPS)

Formerly PACS (Picture Archival and Communication System).
Can accept any image that is in DICOM format.
FDA changed the name to take storage and archiving out.
Ability to be manipulated for interpretation by physicians, allowing it to fall into the category of medical devices (2021).

Medical Storage Device

Physical hardware provides electronic storage and retrieval.
Provides image access to multiple users at the same time, on-demand images.

Medical Image Communications Device

Electronic transfer of medical images between devices.
Uses simple image manipulation tools (window/level, pan/zoom, measurements).

MIMPS Uses

Image manipulation tools.
Radiologist reading stations.
Complex image processing.
Enhancements.
Reconstruction.

Transitioning from Film/Screen to Digital Imaging

Patient demographics are more important with digital imaging.
Incorrect or incomplete data can make retrieval impossible.
The correct image must be placed into the correct data file.
Technologist markers and post-processing are important for correct image capture.
Every effort should be made to appropriately mark the side of the patient.
Post-processing labels should annotate patient position and timing.
Images are sent to MIMPS for interpretation after viewing and processing.

Summary (1 of 2)

Digital imaging is an image acquisition process that results in an electronic image viewable and manipulatable on a computer.
PSP systems are a digital acquisition modality using photostimulable phosphor plates to produce digital images.
FPDs are divided into indirect and direct capture.
Indirect capture detectors receive x-rays that are converted to light, captured, and converted to an electrical signal.

Summary (2 of 2)

Direct capture converts x-ray energy directly into an electrical signal.
PACS are networked groups of computers, servers, and archives used to manage digital images.
DICOM is a standard that allows imaging modalities and PACSs to communicate.
MIMPS consists of many parts, such as radiologist reading stations, physician review stations, web access, technologists QC stations, administrative stations, archive systems, and various interfaces for hospitals and radiology systems.

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Description

Test your knowledge on the essential concepts of radiography technology, focusing on topics such as film/screen radiography, digital imaging, and PACS development. This quiz covers key features, historical contexts, and functional characteristics of the imaging systems used in radiology.