Digital Display Device

What is Quality Assurance (QA)?

Deals with patient and services

Examples of QA?

Patients experience from start to finish “customer service”

CQI?

Continuous Quality Improvment

CQI entail?

Focus is improving the process within which employees function as team members for patient care (how patients experience was from the beginning to the end of their hospital stay)

Who needs to be involved for CQI?

All employees must be involved in this improvement process

TJC

The Joint Commission

Who is the TJC?

Joint Commission on Accreditation of Health Organization (old term JCAHO)

Makes sure everyone is providing high-quality service and care

QC?

Quality Control

What is QC?

• Monitors radiology instrumentation, equip, and evolution of artifacts

• Ensures radiographic procedures are performed sagely on patients

• Designed to provide the highest quality images for interpretation

What needs to happen to each piece of equip before use?

Each new piece of equip should be tested prior to use

Required by law to maintain license for room and department

What is the process of QC programs?

1. Acceptance testing

2. Performance monitoring

3. Error maintenance

Annual evaluation are required

Acceptance Testing

Performed before machines is installed or any major repairs to current equipment (something big like replaced tube)

Why is Acceptance Testing done?

Completed to determine if equip is working properly

Performance Maintenance

Varies tests that must be performed daily, monthly, quarterly, and annually to assure equip is functioning properly to avoid equip failure

Error Maintenance

Occurs due to poor equip performance

Corrective action must be taken

QC Documentation

Important to keep consistent and accurate QC records

If unacceptable results (QC Doc)?

If any tests have unacceptable results, it must be documented and an action plan must be shown as to how it was corrected

Physicists Annual Testing (list)

1. Noise

2. Spatial Resolution

3. Contrast Resolution

4. Dose Response/Signal Dynamic Range

5. Detector Calibration

6. Dose Calibration

7. AEC testing

8. kVp Calibration

9. Plate Reader Calibration

10. Residual Signal Erase

11. Image Artifact

12. Repeat Analysis

13. Uniformity Test

14. Beam Filtration

15. Collimation

16. Monitor Display Function

17. Luminance and Reflection testing

Workstation

All work stations must have regular OC testing

Which work stations have higher quality?

The radiologists viewing stations are much higher quality than the technologists workstation

What document is completed by the Physicists and Tech regarding the workstation?

“Assessment for Display Performance for Medical Imaging System”

How often is the “Assessment for Display Performance for Medical Imaging System” completed?

daily, monthly/quarterly

Physicist complete test annually

SMPTE stands for

Society of Motion picture and Television Engineers

SMPTE test

Used to determine whether contrast / brightness settings of monitor are acceptable

what is the % of observation with SMPTE test?

Most common observation of 5% and 95% luminance patch

What does SMPTE help with?

Helps point out deviation in luminance adjustment

What is Workstation Calibration AAPM TG 18 test?

Pattern used to provide an overall assessment of a monitors adjustment and calibration

Test done most often (instead of SMPTE)

AAPM TG 18 aka

TG18-QC

What is Photometer?

Tool to measure light intensity at several areas of the illuminator on a workstation monitor (measures luminenscence)

Elements of a QC program

1. Filtration

2. Collimation

3. Focal Spot Size

4. Spatial Resolution

5. PSP imaging plate uniformity Test

6. PSP imaging plate erasure thoroughness

7. kVp Calibration

8. Exposure timer accuracy

9. Exposure linearity

10. Exposure Reproducibility

What does the state require regarding Filtraion?

• State required minimum total filtration of 2.5 mmAL

• Measured by checking HVL

• checked annually

Collimation / Beam Restricting Test

Beam alignment to check the perpendicularity of the beam to IR

What do most systems have today?

PBL Collimation

POSITIVE BEAM LIMITING/LIMITATION

Focal Spot

Important for good image quality

Small Focal Spot

Used when spatial resolution is needed

Large Focal Spot

is used when a short exposure time is priority plus more photons emitted

Spatial Resolution

is the ability to render small objects on an image

Smaller pixel size =

better spatial resolution

PSP Uniformity Test

Assess the overall uniformity of the recorded signal form an exposed IP

Assist in detecting artifacts

Must clean cassettes / IR regularly

PSP Imaging Plate Erasure Thorougness

Test ensures minimal residual Signal (ghosting)

White light is used to delete any trapped energy from IP

AEC

A method for setting exposure factors to ensure that a quality radiographic image is produced

Exposure time accuracy

Exposure Linearity

Ability of an x-ray unit to produce a constant radiation output for various combinations of mA and exposure time.

Example of Exposure Linearity

if 70 kVp and 50 mA, 1sec (50mAs) were produce 50 mR; then factors of 70 kVp and 100 mA, ½ sec (50mAs) should produce an exposure of 50mR

Protective Apparel Test

Includes: apron, gonadal shields, gloves checked for cracks, hole, or defects under fluoro

Recognition and Reporting

Responsibility is on the technologist to report all malfuctions

If equip failure, must be repaired and physicist will come and “recalibrate” system

Fluoro QC

Entrance Skin Exposure (ESE)

Fluoro exams = higher pt dose

What is the average fluoro exam time

3 to 5 rad/min

Exposure rate (state law)

State law: ESE shall not exceed 10mR/min = normal fluoro

20mR/min = IR procedures

What instrument should be used to ensure proper ambient light level in a reading room?

Luminescence meter

Digital image spatial resolution is determined by

pixel size

What is the purpose of the gray scale display function?

Maintain perceived brightness on any digital display device

Digital display device noise principally affects what image characteristic?

noise

Max non-uniformity for an individual digital device should be less than what value?

30%