Digital QC

A more detailed QC program for DR systems has been
developed by the

AAPM

acceptance testing is performed by a

medical physicist

daily testing is performed by a

technologist

weekly testing is performed by a

technologist

monthly testing is performed by a

technologist

semiannual/annual testing is performed by a

medical physicist

system adjustments are made by the

vendor or service personnel

dropped pixels

Areas of no data (usually appearing as black dots or lines) caused by damage to the active matrix array

electronic noise

Each detector element has a certain
amount of electronic noise associated with it (also known as
dark noise)

incomplete charge transfer

Caused by the collection element not sufficiently sending all data to the computer for processing, resulting in incomplete image formation

electronic memory artifact

Exposures are taken in too rapid a sequence, resulting in not enough time for each previous exposure to transfer the entire signal, creating an
artifact known as “ghosting.”

uneven amplification

In large detector arrays, several amplifiers are used that can vary in gain from one to the next. Flat-fielding or equalization is a software correction that is performed to equalize the response of each pixel to a
nonuniform X-ray beam.

backscatter

Scattering through the back of the cassette that can either create noise in the image or may create an image of the internal circuitry found in the back of the cassette

high capital cost

DR image receptors are very expensive; therefore, they must be rugged to handle the workload during radiographic examinations.

three levels of Quality Control and System Maintenance required for digital radiographic systems

routine, full inspection, system adjustment

there is no standard QC process that can

be used by all systems due to variety

since there is no standard QC process, QC techs must rely on the

manufacturer’s guidelines for specific QC procedures

There are some basic QC procedures that are

common to all manufacturer's systems

common QC procedure for portables

exposure switch cord should be a minimum of 6ft

basic QC common to all systems

DR AMA inspection and cleaning, display monitor inspection and cleaning, phantom image testing, wireless transmission inegrity

main components of a DR system include

image receptor, computer and software, workstation (display monitor)

image receptor

consists of an active-matrix array (AMA) or flat panel (FP)

computer or software

used for processing the image

workstation (display monitor)

used to display image and carry out post processing functions

The image receptors used must be kept clean and free of dirt, debris, blood, contrast media, etc. to

ensure they remain effective and provide accurate and quality images

The internal batteries on wireless DR cassettes should be inspected to ensure that they

are fully charged

wireless transmission integrity should be evaluated

daily (basically done without realizing)

An exposure of a phantom can be made on a wireless DR cassette and then viewed on the monitor to ensure that

the wireless signal was received uncorrupted

computer processor

Determines how fast the computer works (Should be at least an I7 or I9 (preferred) processor)

computer RAM

16-32 GB (preferred)

hard drive

solid state device (SSD), preferably swappable

software

program that allow the computer to process the image

software should contain productivity aids

positioning guides, image communication tools/web viewers/email/DICOM, technique/x-ray exposure setting assistance during image acquisition, auto report generation for radiologist

how often should you check display monitor peformance

at least monthly (recommended by ACR)

A high resolution monitor is used as the

primary display monitor for viewing of digital radiographic images

standard computer monitors are used for

secondary displays (clinical displays)

Cathode Ray Tube Displays (CRT)

They are no longer manufactured, but many are still in use today

Liquid Crystal Displays (LCD)

flat panel monitors that are the most used monitor for general computer
use as well as viewing diagnostic images

Plasma Screen

also a flat panel monitor, this displays a brighter image than the first two types but is more expensive

AAPM QC Acceptance Testing says to check

inventory, installation, function, clinical use

inventory check

did you get what you ordered (features, accessories)

installation check

is it correctly placed in the room

function check

does it work as advertised

clinical use check

are the images acceptable

Phantom images are obtained from

special test tools that can either be supplied by the digital system manufacturer, or a multipurpose test phantom that can evaluate any digital system can be purchased

Phantom image testing should be performed on

all digital systems

PACS are used to

store, archive, and retrieve digital images

PACS should be tested

quarterly

Two methods for performing digital fluoroscopy

image intensifier tube (digital fluoro), flat panel (digital fluoro)

digital fluoroscopy components

oX-ray Generator
oImage Intensifier – tube type or flat-panel
oCamera – only with tube-type II
oAnalog to Digital Converter
oComputer – creates image using a matrix
oWorkstation with high resolution monitors allows for post-processing

Nondigital components should be tested using

same
procedures as standard fluoroscopy

Digital imaging components are tested using

special test tools according to system manufacturer

All of the following types of QC tests can be done by technologist EXCEPT
a) Daily tests
b) Acceptance tests
c) Monthly tests
d) Weekly tests

Acceptance tests

All of the following are potential DR imaging problems EXCEPT
a) Electronic Noise
b) Back Scatter
c) Decreased Capital Costs
d) Electronic Memory Artifacts

Decreased Capital Costs

The primary monitor is the monitor that we view images on as technologist.
a) True
b) False

False

When performing Acceptance testing, the AAPM says to check which of the following?
a) Inventory
b) Installation
c) Clinical Use
d) All the above

All the above

As a technologist, you can perform which of the following daily QC tests?
a) Verify that the wireless DR systems are communicating without any interference
b) Phantom image testing and analysis
c) Image processing evaluation
d) Evaluate exposure indicator accuracy

Verify that the wireless DR systems are communicating without any interference