CHAPTER 1,2,3 - PACS

Film and intensifying screens are primarily used in

conventional tomography

Intensifying screens

emit light

Which modality was the first to use the principle of digital imaging?

CT - computed tomography

Who was the first to incorporate digital imaging with the CT scanner?

Godfrey Hounsfield

Teleradiology, moving images via telephone lines to and from remote locations, was first

conceptualized by

Albert Jutras

The invention of CT is heralded as

One of the greatest milestones in medical imaging

Early reconstruction of raw CT data took a few ______ to form a recognizable image.

days

The first commercial CT scanners could image the

head only

In which decade was MRI first introduced?

1980s

Which two modalities could easily be converted to digital imaging properties?

ultrasonography and nuclear medicine

Early picture archival and communication systems were first developed

by the US military

Teleradiography incorporated ______ to produce radiographic images.

telephone lines

One of the early goals related to the development of PACS was to

allow radiologists to read stat films from a hospital while at home

CR acquires an image through

The use of a storage phosphor plate

Storage phosphor plates are similar to

intensifying screens

In a DR system, which of the following are needed to produce a radiographic image?

x ray absorber and a CCD

The two elements needed to convert light signals into an electrical signal while using indirect

capture DR are TFT and

photodiodes

The x-ray absorber typically used in direct capture DR is a

photoconductor

Technologist efficiency ratings are generally the same when comparing conventional

radiography with ______ radiography.

computed

Compared with a 90-second processing time found in conventional radiography, image

acquisition with DR has now been reduced to

3 - 5 seconds

The active element in a storage phosphor is

barium fluorohalide

In reference to PSP image capture, to release the latent image, which of the following devices

is scanned over the phosphor plate?

focused laser light

Which of the following best describes the sequence for PSP image capture?

Phosphor plate, focused laser light scanner, photomultiplier, analog-digital

converter, review station

X-ray energy related to direct capture DR will stimulate a ______, which eventually is

changed into an electrical signal.

scintillator

The ______ converts x-ray energy directly to a digital electrical signal.

photoconductor

Exposure latitude is to conventional radiography as _______ is to DR.

dynamic range

A look-up table maps

Image gray scale values

With conventional radiography, optical density is primarily controlled by

milliampere - seconds

Preset image annotation controls include all of the following except

date and time stamps

The first full-scale PACS was installed in 1993 in

Baltimore

All of the following are components of a PACS except

independent kilo voltage peak and milliampere - second stations

TRUE OR FALSE

Light exposing the film is in direct proportion to the amount and energy of the incident photon

upon the screen.

TRUE

TRUE OR FALSE

The earliest CT of the head took several hours to acquire a single slice of information.

TRUE

TRUE OR FALSE

When switching from a conventional diagnostic radiography room to one that incorporates

CR, major equipment changes are to be expected.

FALSE

TRUE OR FALSE

Similar to CR, DR can use the existing diagnostic equipment found in today's imaging

departments.

FALSE

TRUE OR FALSE

Indirect capture DR converts absorbed x-ray energy into visible light.

TRUE

TRUE OR FALSE

A Bucky apparatus is required for DR.

FALSE

TRUE OR FALSE

Many PACS reading stations also have image-processing capabilities.

TRUE

TRUE OR FALSE

DICOM is a standard that allows imaging modalities and PACS to communicate in the same

language.

TRUE

Multiple numeric values divided into an array of small elements capable of being processed is

the definition of _____ images.

digital

The continuous and varying levels of brightness and colors describe _____ images.

digital

Critical characteristics of a digital image include all of the following except

sample resolution

Which of the following statements is not true?

Changing the matrix and the FOV will not change the size of the pixel.

Each square in a matrix is called a

picture element

The number of bits per pixel is known as bit

depth

If a pixel has a bit depth of 29, the number of gray tones that pixel can produce is

512

The size of the pixel is determined by the

matrix

Which of the following statements is not true?

Exposure index refers to the amount of exposure to the patient.

The measurement for radiation that was incident on the image receptor for a particular

exposure is known as

KIND

Deviation index is the difference between _____ and _____ expressed in logarithmic fashion.

actual exposure (KIND) ; target exposure (KTGT)

Factors that can adversely affect the pixel values expressed in the deviation index include all

of the following except

failure of the system to recognize the exposure indicator

How dark or light a digital image appears on a display monitor is known as

brightness

The ability of a digital system to display subtle changes in shades of gray is called

contrast resolution

The ability of an imaging system to demonstrate small details of an object is known as

spatial resolution

A system's ability to respond to varying levels of exposure, resulting in more detail, is

referred to as

dynamic range

"The sum of the components in a recording system cannot be greater than the system as a

whole" is a definition of

modulation transfer function (MTF)

A perfect image processing system would have an MTF of

100%

The more light spread, the ______ the MTF.

lower

The range of exposure values the image detector is able to produce is known as

latitude

The efficiency of a system to convert x-ray input signal into a useful output image is known as

detective quantum efficiency

TRUE OR FALSE

Air kerma is the measurement of radiation energy absorbed in a unit of air.

TRUE

TRUE OR FALSE

The reflection of ambient light can be problematic with monochromatic monitors.

TRUE

TRUE OR FALSE

MTF is a way to quantify the contribution of each system component and the component's

overall efficiency.

FALSE

TRUE OR FALSE

It is possible to achieve an MTF of 100%.

FALSE

Failure of the reader to find the collimation edges of an image

may cause the image to be too bright or too dark

If the entire range of exposure were digitized, pixel values representing ______ would be

digitized.

all values

Data collected within the collimator are represented by a

histogram

A histogram displays the useful signal by locating

Maximum and minimum signal

The higher the kilovoltage peak, the

narrower the histogram

The Nyquist theorem states that the

sampling frequency must be twice the input signal bandwidth

If too few pixels are sampled, the result will be

low resolution

Raw data used to form the image histogram are compared with

a normal histogram referenced by the computer

Loss of detail in a digitally processed image

occurs because of the number of conversions

The longer an image is stored in the computed radiography (CR) cassette, the

more energy is lost by the electrons

A wraparound image or image aliasing occurs when

sampling occurs less than twice per cycle

In an effort to display the pixels for the area of interest when exposure is greater or less than

what is needed to produce an image, ______ occurs.

automatic rescaling

Automatic rescaling means that images are produced, regardless of the amount of exposure,

with

uniform contrast and density

A look-up table is not used as a reference to

set appropriate kilovoltage peak and milliampere-seconds values.

Changing the slope of the look-up table graph will increase or decrease

contrast

If all of the shades were left in an image after processing, the contrast would be

too low

Changing the steepness of the exposure gradient

controls image contrast

Focal spot and OID affect image sharpness _____ imaging.

in both film / screen and digital

The improper algorithm application may result in

degradation of the image

The more manipulation of the image, the greater the

loss of information

Amplification of the frequencies of the areas of interest is known as

edge enhancement

Suppressing frequencies in the areas of interest is known as

masking

Low-pass filtering is also known as

Smoothing

High-pass filtering is useful for enhancing

organs and soft tissue

Averaging the frequency of each pixel with surrounding pixel values to remove

high-frequency noise is called

low pass filtering

Image level parameters control image

brightness

Window width controls the ratio of black and white, also known as

contrast

Excessive light entering the eye when viewing an image is known as ______ glare.

veil

An image manipulation process that fills in the background so that it is darkened is known as

shuttering

The image reader scans and reads the image from the

leading edge of the imaging plate to the opposite end

The process of joining two or more images into one continuous image is known as image

stitching

The workstation function that allows selection of preset terms or manual text input is termed

image

annotation

Input of annotation for identification of the patient's left or right side

should be used in conjunction with the technologists markers

Magnification of the entire image at the workstation is termed

zoom

Proper patient demographic input ensures

Linking of all the patient's files

The ability to send images to local network stations can be accomplished using the

manual send function