M5 - QC for CR, DR, PACS

Quality for CR, DR, and PACS

Define quality assurance

a plan for the systematic assessment of the equipment or department

Define quality control

a comprehensive set of activities that help to monitor and maintain equipment

Define acceptance testing

tests performed when equipment is first installed

Define routine maintenance

tests done periodically to ensure equipment is performing optimally

Define error maintenance

tests done when equipment malfunctions and needs to be repaired

Define continuous quality improvement (CQI)

focuses to improve the process that people follow as a team to complete work

• all level of people involved to improve the process

Define total quality management (TQM)

evaluates the overall effectiveness of imaging systems

• equipment maintenance

• image acquisition

• processing standards

What are the 4 things PACS should be evaluated for?

• image display quality (on the monitor and for film)

• processing speed

• network transfer speed

• integrity of compressed data called back from archives

What is “electronic display device performance” test?

the performance of all display devices

• checked using a test pattern monthly

What is this?

SMPTE test pattern

What does SMPTE stand for?

Society of Motion Picture and Television Engineers

What is this?

AAPM test pattern

What does AAPM stand for?

American Association of Physicists in Medicine

What qualities are to be observed using the SMPTE pattern?

• color and sharpness of lines

• optimal luminance

• minimal noise

• image/monitor resolution using line pairs

• geometric distortion at the edges

What instrument is used to measure luminance, reflection, noise, and glare?

photometer

How is workstation speed evaluated?

• study for test is chosen

• record time it takes for study to open and download images

• record time it takes to perform a (post) processing function

How is image transfer speed evaluated?

• study for test is chosen

• record speed from modality to PACS

• record speed from archive to workstation

• retrieve study and note the time it takes for entire study to arrive at the workstation

How is quality of images tested?

• save images of test tool using

  • no compression

  • lossless compression (2:! ratio)

  • lossy compression

• recall all images and compare to the original

How often should IP’s be erased?

daily

What is the relative sensitivity test?

ensures that the CR reader system sensitivity calibration or DR system sensitivity are consistent with the baseline

• can also be used to evaluate generator output and consistency

• EI number should be the same when the same dose is used

What is the uniformity test?

evaluates uniformity of image brightness across the scanning width (CR) or DR plate

• if laser is not uniform light and dark bands may appear across the image

What are the steps for the uniformity test?

1. 180 cm SID, 80 kVP, enough mAs to produce 10 mR of radiation

2. process IR and examine for uniformity

3. can use region of interest to check brightness at various points on the image

4. readings should be within 10% of each other

What is flat-fielding?

a software correction that can equalize each pixel to make the image look more uniform

What is the erasure test?

confirms that CR plate has been completely erased, or that all previous charges are removed in DR

What are the steps for the erasure test?

• use knee or other phantom to take an image on CR plate

  • use extreme exposure

  • process

  • ensure plate has been properly erased

    • otherwise ghosting artifact may result

similar process is used for DR but uses a lead blocker instead of a phantom

What are some tests that should be done annually?

• response function

• exposure index

• dynamic range

• etc.

What are some of a technologists daily duties?

• clean and erase CR plates

• general check of test pattern

What are some of a technologists weekly duties?

• inspect CR plates for damage

• clean monitor, keyboard, and mouse

What are some of a technologists monthly duties?

• repeat/reject analysis

• clean imaging plates

• problem reporting

What are some of a technologists annual duties?

• light field congruency test

• AEC test

What is MANQAP?

Manitoba Quality Assurance Program

• under the College of Physicians and Surgeons

• establishes standards for all DI departments