INTRODUCTION TO DIGITAL RADIOGRAPHY EXAM QUESTIONS SOLVED 100% LATEST VERSION 2025
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INTRODUCTION TO DIGITAL RADIOGRAPHY
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INTRODUCTION TO DIGITAL RADIOGRAPHY
INTRODUCTION TO DIGITAL RADIOGRAPHY EXAM QUESTIONS SOLVED 100% LATEST VERSION 2025
History: analog-to-digital converter (ADC) - Answers 1979: First application of digital technology in radiographic imaging when an analog-to-digital converter (ADC) was attached to the TV camera tube of a fluoroscop...
INTRODUCTION TO DIGITAL RADIOGRAPHY EXAM QUESTIONS SOLVED 100% LATEST VERSION 2025
History: analog-to-digital converter (ADC) - Answers 1979: First application of digital technology in
radiographic imaging when an analog-to-digital converter (ADC) was attached to the TV camera tube of
a fluoroscopy unit.
History: digital picture archiving and communication systems (PACS) - Answers 1982: Introduction of
digital picture archiving and communication systems (PACS) revolutionized the access, storage and
management of radiographic images. Coupled with teleradiology, the ability to send electronic images
anywhere in the world, the efficiency of medical imaging departments in providing patient care and
diagnoses was also revolutionized.
History: Computed radiography (CR) - Answers 1980s: Computed radiography (CR) became commercially
available but had a lot of technical issues early on.
CR systems utilize - Answers screens coated with certain fluorescent materials, similar to the screens
used to convert x-ray energy into light used with traditional x-ray films, that could be made to glow
when stimulated by laser beams. The stimulated light emission, using only the residual energy remaining
in the screen after an x-ray exposure, was dim but, after being captured by light sensitive diodes and
converted into an electrical current, could be electronically and digitally amplified before being
processed by a computer to produce a bright radiographic image on a display monitor.
CR systems were later refined and paved the way for the development of - Answers DR Digital
Radiography (1996)
active matrix array - Answers -A panel of electronic detector elements laid out in rows and columns,
used to convert incoming light or x-ray photons into an electrical signal
-Advanced miniaturization of electronics led to x-ray detectors that are smaller than can be perceived by
the human eye. Image receptor plates are constructed with thousands of these miniaturized detectors
laid out in an active matrix array
Direct Conversion DR - Answers A DR unit whose image receptor converts incoming x-rays directly into
electrical charge with no intermediate steps
-With the active matrix array it was possible to convert the latent image carried by the remnant x-ray
beam directly into electrical current, called direct-conversion DR.
Indirect-conversion DR - Answers A DR unit, whose image receptor first converts incoming x-rays directly
into light using phosphor layers, then converts the light into electrical charge.
Direct-conversion systems - Answers convert the x-ray energy directly into electricity without the
intermediate step of converting x-rays into light. Resolution is better than indirect-conversion systems.
Indirect-conversion systems - Answers have the advantage of saving patient radiation dose at the cost of
resolution.
, COMPUTED RADIOGRAPHY (CR) VS DIGITAL RADIOGRAPHY (DR) - Answers - Both CR and DR imaging
systems produce an electronic signal that represents the original image information
- This signal is sent to a computer for digital image processing and then displays the resultant image on
an electronic display monitor
- While both CR and DR systems may be in use at various facilities around the world, DR has emerged as
the state-of-the-art technology of choice for medical radiography in the US.
NATURE OF THE DIGITAL IMAGE - Answers - digital photography, and all other methods of acquiring a
digital image result in the creation of a matrix of numerical values that can be stored in computer
memory
- A matrix is a pattern of cells or locations laid out in rows and columns as shown in the image at right
- Each location or cell can be identified by its row and column designations, which the computer keeps
track of during processing.
- For radiographs, the pixel value represents the brightness (or darkness) assigned to the pixel's location
in the image
- This brightness level is taken from a range of values stored in the computer that represent different
shades from "pitch black" to "blank white" with hundreds of shades of gray in between
Pixel element - Answers Each location or cell in the matrix is referred to as a pixel
pixel value - Answers Each pixel in an image is assigned a single numerical value
Analog - Answers - Light enters through the lens of a camera in analog form as various intensities of light
that can have any value.
- x-rays from a radiographic projection enter the image receptor plate in analog form.
- All of the above forms of analog input must be converted into a digital form so that we can manipulate
the resulting images as we need to.
- An analog measurement can be as precise as we want because, by using a continuous scale, it is
infinitely divisible.
Digital - Answers - Digitizing data limits the degree to which measurements can be subdivided
- It also limits the scale from which measurements can be taken.
- In radiography, digitizing the pixel values limits the number of values that can exist between "pitch
black" and "blank white". This makes them manageable and puts a limit on file size because there is not
an infinite number of values to deal with.
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