Download Monthly Quality Control Tests - BC Centre for Disease Control

Safety Code 35
John Aldrich PhD FCCPM
Regional Leader Clinical Physics
Kevin Hammerstrom RTNM
QC Coordinator
Department of Radiology
Vancouver Coastal Health
University of British Columbia
Medical X-ray Safety Codes
Safety Code 20A (1976)
Safety Code 35 (2008)
(two drafts in 2005 and 2007)
 Recommended safety
procedures for the installation,
use and control of x-ray
equipment. Mainly concerned
with the x-ray output
parameters of the equipment
 Only film processor QC defined
 Comprehensive safety
procedures for the installation,
use and control of x-ray
equipment.
 Includes all x-ray systems
 Increased emphasis on patient
dose
 25% of the Code is concerned
with QC of digital imaging
systems
Safety Code 35
A1. Responsibilities of owners and users (4)
A2. Procedures for minimizing staff dose (2)
A3. Procedures for minimizing patient dose (6)
B1. Facility shielding (3)
B 2-6. Equipment performance (15)
C 1-3. Quality Control (17)
Appendices (30)
Decoding the Code
Normal Font – Required Test (“must do”)
Italics - Recommended Test (“recommended”)
Required Tests currently recommended by RPS
 Handout includes all slides in our presentations
 Attached sheets have all the tables enlarged
 References are to details of the tests in the Code
eg D1 is the first daily test listed, W1 – weekly,
M1 - monthly, Q1 – quarterly, SY1 – semi-annually,
Y1 - Annual
Overview Session 1
Requirements for all systems
20
Radiation Protection
10
Questions
10
Radiography (Film/DR/CR)
20
Radioscopy (Fluoroscopy, Angio, DF)
20
Questions
10
LUNCH
Overview Session 2 After Lunch
CT
20
Equipment Purchase/ Acceptance Testing
15
Patient dose
15
Questions
10
Personnel qualifications
20
Education and training
10
Questions
20
Daily Quality Control Tests
Normal Font – Required Test (“must do”)
Italics - Recommended Test (“recommended”)
Required Tests currently recommended by RPS
Quality Control Procedures
Filmbased
All Systems
Daily Quality Control Tests
According to manufacturers instructions
Can include auto calibration eg CT
Equipment Warm-up (D1)
Meters Operation (D2)
Equipment Conditions (D3)
Darkroom Cleanliness (D5)
Film Processor Function (D6)
Overall Visual Assessment of Electronic
Display Devices (D7)
Meter, visible and audible indicators should function
Visual inspection for loose or broken components, ease of
movements
(M DAP)
(M DAP)
Display SMPTE or QC pattern for general image
quality of all Radiologists’ workstations
Check 5% and 95% areas visible
Weekly and Monthly Tests
Quality Control Procedures
All Systems
Weekly Quality Control Tests
Viewbox condition (W2)
Laser Film Printer Operation (W3)
Visual inspection for cleanliness, colour, illumination
Print pattern such as SMPTE or PQC
Check for 0/5% and 95/100% patch visibility
OD of 10% to 90% patches
No artifacts or geometrical distortion
Monthly Quality Control Tests
Darkroom Temperature and Humidity (M2)
Temp: 18-23C; Humidity 40-60%
Darkroom Light Conditions (M3)
Visual check for light tightness
Film Processor Operation (M4)
Temp ± 0.5C; Developer and fixer correct (M DAP)
Electronic Display Device Performance (M6)
Display pattern such as SMPTE or QC on all image
display devices
Laser Film Printer Operation (M7)
As W3 plus measurement of optical density of the 10% to
90% grey scale
Normal Font – Required Test (“must do”)
Italics - Recommended Test (“recommended”)
Required Tests currently recommended by RPS
Quarterly and Annual Tests
Quality Control Procedures
All Systems
Quarterly Quality Control Tests
Interlocks (Q2)
These are not usually used on diagnostic doors
Annual Quality Control Tests
Safelight Test (Y1)
Film/Screen Contact (Y2)
Viewboxes (Y26)
Expose film for 2 min
Image mesh and check
Check luminance, uniformity, homogeneity, ambient light
Electronic Display Device Performance (Y27)
All clinical workstations must be calibrated for luminance,
distortion, resolution and noise
Integrity of Protective Equipment (Y28)
Lead aprons, glasses, integral shields
General Preventive Maintenance (Y29)
As per manufacturer
Normal Font – Required Test (“must do”)
Italics - Recommended Test (“recommended”)
Required Tests currently recommended by RPS
Display QC
 Daily (D7) – for clinical interpretation

Radiologist at each login

Find suitable SMPTE test pattern
Make accessible on PACS
Test using various user logins/profiles
Alert radiologists of requirement, frequency, and
procedure



Problems with inconsistency
Left Display – 5% visible / 95 % not visible
Right Display – 5% not visible / 95 % visible
 Should see both 5% and 95% squares if calibrated properly
Display QC
 Monthly (M6)

All displays
Technologist
 PACS administrator
 Biomed


SMPTE test pattern / test
pattern generator / vendor
Display QC
 Annually (Y27)

Clinical interpretation and
interventional use




QC Coordinator
PACS administrator
Biomed
SMPTE test pattern / test pattern
generator / vendor QC software
and photometer
Viewbox QC
 Weekly visual inspection (W2)
 Cleanliness
 Viewing area discolouration
 Improper luminance
 Clean, replace plastic or bulb if necessary
 Technologists / Biomed / Plant services
Viewbox QC
 Yearly inspection (Y26)
 Technologist / physicist
 Maintain logsheet
Luminance
> 2500 cd/m2
Should
Light output uniformity
+/- 10%
Should
Light output homogeneity
+/- 20%
Should
Ambient light control
< 50 lux (50 cd/m2)
5-10 lux recommended (5-10 cd/m2)
Must
Viewbox QC
Laser Film Printer QC
 Weekly (W3)
 Use same viewbox panel
 Print SMPTE from PACS workstation or from printer menu
 View 5% and 95% grayscale squares
 Maintain logsheet
Laser Film Printer QC
Laser Film Printer QC
 Monthly (M7)
 Use same viewbox panel
 Print SMPTE from PACS
workstation or from printer menu
 Measure optical density of
grayscale gradient squares,
geometrical distortions, artifacts
 View 5% and 95% squares and
compare densitometer readings
 Maintain logsheet
Laser Film Printer QC
Overview Session 1
Requirements for all systems
20
Radiation Protection
10
Questions
10
Radiography DR/CR
20
Radioscopy (Fluoroscopy, Angio), DF
20
Questions
10
LUNCH
Radiation Protection
 Radiation Safety Officer (1.4)
 Room Shielding (5.0)
 Lead aprons (4.1)
Radiation Safety Officer
 There must be a Medical Physicist or
Radiation Safety Officer to advise on all
aspects of Radiation Safety




Planning, registration, inspection
Working conditions, procedures
Classification of personnel, dosimetry
Record keeping, investigations
Radiation Protection - Shielding
 Design of Shielding


Recommend NCRP 147
(2004) methods which are
based on empirical data
(although Appendix is NCRP
49 (1976) which will tend to
overshield rooms)
 Surveys of rooms must be
done for new or altered
rooms (equipment, use or
vicinity Sec A5)
Design shielding
Check lead installation
Measure radiation in
surrounding areas
Lead Aprons
Lead equivalence of aprons
 SC 20A

<150 kVp
0.5 mm
 SC 35



< 100 kVp:
100< kVp <150:
>150 kVp:
0.25 mm
0.35 mm
0.5 mm
Lead apron QC
 Annually (Y28)



Radiographic / radioscopic
Rejection if total defective area > 670 mm2
Thyroid and reproductive areas < 5 mm diameter equivalent total
Overview Session 1
Requirements for all systems
20
Radiation Protection
10
Questions
10
Radiography DR/CR
20
Radioscopy (Fluoroscopy, Angio), DF
20
Questions
10
LUNCH
Overview Session 1
Requirements for all systems
20
Radiation Protection
10
Questions
10
Radiography DR/CR
20
Radioscopy (Fluoroscopy, Angio), DF
20
Questions
10
LUNCH
Equipment Life Cycle
 Acceptance testing



Acceptance testing
New equipment
Conformance to manufacturer’s
specifications/RFP
Baseline performance
Baseline value determination
Device use period
 Routine performance
evaluations

Next constancy testing
Data evaluation
Specific tests performed at
regular intervals
 Consistency checks

Evaluate malfunctioning or outof-spec equipment
Within the
PASS
established criteria
FAIL
Remedy
Imaging QC Principles
Proactive QC rather than Reactive QC
 Test
tool/phantom
 Patient
the rated
System
performance rated
Systemreplaces
performance
phantom
BEFOREimaging
clinical imaging
AFTER clinical imaging.
 Standard
parameters/conditions
 Non-standard imaging
parameters/conditions
 Scheduled testing (Daily/Weekly)
Frequent
 Defined and objective
Which approach would
youtesting (every patient)
acceptance/rejection
 aIll-defined
prefer if you were
patient??and subjective
criteria
acceptance/rejection
criteria
Radiographic Systems
 Projection radiography

Film

Digital detectors (DR)

Computed radiography (CR)
Weekly Radiographic Tests
Quality Control Procedures
Film
CR
DR
Comments
Visual Inspection of Imaging Systems
W1
W1
W1
Inspect screens/CR plates/DR housing
Viewboxes Condition
W2
W2
W2
Cleanliness, luminance
W3
W3
Print pattern such as SMPTE
Weekly Quality Control Tests
Laser Film Printer Operation
Normal Font – Required Test (“must do”)
Italics - Recommended Test (“recommended”)
Required Tests currently recommended by RPS
Monthly Radiographic Tests
Quality Control Procedures
Film
CR
DR
Comments
Cassette, Screen, and Imaging Plate
Cleaning
M1
M1
Darkroom Temperature and Humidity
Conditions (DAP)
M2
Temp: 18-23C; Humidity 40-60%
Darkroom Light Conditions
M3
Visual check for light tightness
Film Processor Operation
M4
Temp ± 0.5C; Developer and fixer
correct
Retake Analysis
M5
Monthly Quality Control Tests
Electronic Display Device Performance
Laser Film Printer Operation
Clean screens/CR plates/DR housing
M5
M5
For film, CR and DR
M6
M6
Display pattern such as SMPTE on
all image display stations
M7
Print pattern such as SMPTE
Check for 0/5% and 95/100% patch
visibility
OD of 10% to 90% patches
No artifacts or geometrical distortion
M7
Normal Font – Required Test (“must do”)
Italics - Recommended Test (“recommended”)
Required Tests currently recommended by RPS
Annual Radiographic Tests (1)
Quality Control Procedures
Film
CR
DR
Comments
Annual QC Tests
Safelight Test
Y1
Expose film for 2 mins in room
Film/Screen Contact
Y2
Image mesh and check
Accuracy of Loading Factors
Y3
Y3
Y3
mAs Linearity
Radiation Output Reproducibility
Y4
Y4
Y4
Reproducibility
Radiation Output Linearity
Y5
Y5
Y5
Output with mAs
X-ray Beam Filtration
Y6
Y6
Y6
HVL
Automatic Exposure Control
Y7
Y7
Y7
Check AEC for all kVps and thicknesses
X-ray Field and Light Field
Alignment
Y8
Y8
Y8
Congruency of x-ray beam and light field
edges
X-ray Beam Collimation
Y9
Y9
Y9
Congruency of x-ray beam and light field
centres
Normal Font – Required Test (“must do”)
Italics - Recommended Test (“recommended”)
Required Tests currently recommended by RPS
Annual Radiographic Tests (2)
Quality Control Procedures
Film
CR
DR
Comments
Y10
Y10
Y10
Check uniformity and movement of grid
Exposure Index
Y12
Y12
Exposure Index versus Dose 1 to 50 mGy
Noise, Uniformity and Image
Artifacts
Y14
Y14
For above range of dose measure noise in
center and each quadrant
Check for artifacts
Image Quality
Grid Performance
Spatial Resolution
Y15
Y15
Y15
Line-pair or Leeds phantom
Contrast Detectability
Y16
Y16
Y16
Leeds phantom
Y17
Y17
Take image at 50 mGy then zero;
check for artifacts
Y18
Y18
Measure dose at surface of standard
phantom eg 20 cm PMMA
Digital Detector Residual Images
Phantom Dose Measurements
Y18
DAP Meter
Calibrate
Normal Font – Required Test (“must do”)
Italics - Recommended Test (“recommended”)
Required Tests currently recommended by RPS
Digital Imaging
Any sufficiently advanced
technology is indistinguishable
from magic… Arthur C Clarke 1961
Digital X-ray Systems
 Direct Radiography DR

Formation of image without a secondary
read-out device
 Computed Radiography CR

Use of storage phosphor plate usually in a
cassette-based system
Digital System QC
Film
Developed
And
Fixed
Detector
Reading
Digital
Processing
Stored
PACS
Viewed
Display
QC of the digital systems is an additional requirement
– in addition to the usual x-ray performance tests
- it is not performed magically
DR, CR and DF – Extra QC





Dose Calibration
Spatial Resolution
Low Contrast
Uniformity
Artifacts
Dose Calibration
 Each system should be calibrated
according to the manufacturers protocol,
as they are all slightly different
 General set-up



Arrange for defined dose at surface of cassette at
80 kVp
Expose and read image
Record Exposure Index
 The image can also be used to check for
uniformity, linearity and artifacts
Image Quality
 All CR and some DR/DF manufacturers have
custom Image Quality phantoms and
automatic software to analyze image quality
Resolution and Contrast
 Any high contrast resolution phantom
can be used to provide comparative
information
 Low contrast resolution is one of the
most difficult parameters to measure.
There are several phantoms and
measurement is subjective, so
consistent technique is essential
 Image Noise is usually be a good
indicator of consistency
Digital Radiography QC
 Many DR systems require more frequent
calibration of the uniformity eg every month

Flat field measurement (uniform Cu orAl plate)
Uniformity correction
 Noise
 Artifacts


Contrast-detail and resolution phantom
CR & DR QC
• Weekly visual inspection (W1)
•
Dust / dirt
•
Clean if necessary
•
Technologist
• Monthly inspection / cleaning (M1)
•
Dust / dirt / damage
•
Clean each IP. Replace damaged IPs.
•
Technologist
•
Maintain logsheet
CR QC