Safety Code 35 John Aldrich PhD FCCPM Regional Leader Clinical Physics Kevin Hammerstrom RTNM QC...
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Transcript of Safety Code 35 John Aldrich PhD FCCPM Regional Leader Clinical Physics Kevin Hammerstrom RTNM QC...
Safety Code 35
John Aldrich PhD FCCPMRegional Leader Clinical Physics
Kevin Hammerstrom RTNMQC Coordinator
Department of RadiologyVancouver Coastal Health
University of British Columbia
Medical X-ray Safety Codes
Safety Code 20A (1976)
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
Safety Code 35 (2008)(two drafts in 2005 and 2007)
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
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
Normal Font – Required Test (“must do”)Italics - Recommended Test (“recommended”)Required Tests currently recommended by RPS
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
Quality Control Procedures Film-
based All Systems
Daily Quality Control Tests
Equipment Warm-up (D1)According to manufacturers instructions
Can include auto calibration eg CT
Meters Operation (D2) Meter, visible and audible indicators should function
Equipment Conditions (D3)Visual inspection for loose or broken components, ease of
movements
Darkroom Cleanliness (D5) (M DAP)
Film Processor Function (D6) (M DAP)
Overall Visual Assessment of Electronic Display Devices (D7)
Display SMPTE or QC pattern for general image quality of all Radiologists’ workstations
Check 5% and 95% areas visible
Normal Font – Required Test (“must do”)Italics - Recommended Test (“recommended”)Required Tests currently recommended by RPS
Weekly and Monthly Tests
Quality Control Procedures All Systems
Weekly Quality Control Tests
Viewbox condition (W2) Visual inspection for cleanliness, colour, illumination
Laser Film Printer Operation (W3)
Print pattern such as SMPTE or PQCCheck for 0/5% and 95/100% patch visibility
OD of 10% to 90% patchesNo 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) Expose film for 2 min
Film/Screen Contact (Y2) Image mesh and check
Viewboxes (Y26) 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
Should see both 5% and 95% squares if calibrated properly
Problems with inconsistencyLeft Display – 5% visible / 95 % not visible Right Display – 5% not visible / 95 % visible
Display QC
Monthly (M6) All displays
TechnologistPACS administratorBiomed
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: 0.25 mm 100< kVp <150: 0.35 mm >150 kVp: 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
Baseline value determination
Device use period
Next constancy testing
Data evaluation
Within the
established criteria
Remedy
Acceptance testing
FAIL
PASS
Acceptance testing New equipment Conformance to manufacturer’s
specifications/RFP Baseline performance
Routine performance evaluations
Specific tests performed at regular intervals
Consistency checks Evaluate malfunctioning or out-
of-spec equipment
Imaging QC Principles
Proactive QC rather than Reactive QC
Test tool/phantom Standard imaging
parameters/conditions Scheduled testing (Daily/Weekly)
Defined and objective acceptance/rejection criteria
Patient replaces the phantom
Non-standard imaging parameters/conditions
Frequent testing (every patient)
Ill-defined and subjective acceptance/rejection criteria
System performance rated BEFORE clinical imaging
System performance rated AFTER clinical imaging.
Which approach would you prefer if you were a patient??
Radiographic Systems
Projection radiography Film
Digital detectors (DR)
Computed radiography (CR)
Weekly Radiographic Tests
Quality Control Procedures Film CR DR Comments
Weekly Quality Control Tests
Visual Inspection of Imaging Systems W1 W1 W1 Inspect screens/CR plates/DR housing
Viewboxes Condition W2 W2 W2 Cleanliness, luminance
Laser Film Printer Operation W3 W3 Print pattern such as SMPTE
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
Monthly Quality Control Tests
Cassette, Screen, and Imaging Plate Cleaning
M1 M1 Clean screens/CR plates/DR housing
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 M5 M5 For film, CR and DR
Electronic Display Device Performance M6 M6 Display pattern such as SMPTE on
all image display stations
Laser Film Printer Operation M7 M7
Print pattern such as SMPTECheck for 0/5% and 95/100% patch
visibilityOD of 10% to 90% patches
No artifacts or geometrical distortion
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
Image Quality
Grid Performance Y10 Y10 Y10 Check uniformity and movement of grid
Exposure Index Y12 Y12 Exposure Index versus Dose 1 to 50 Gy
Noise, Uniformity and Image Artifacts
Y14 Y14 For above range of dose measure noise in center and each quadrant
Check for artifacts
Spatial Resolution Y15 Y15 Y15 Line-pair or Leeds phantom
Contrast Detectability Y16 Y16 Y16 Leeds phantom
Digital Detector Residual Images Y17 Y17 Take image at 50 Gy then zero; check for artifacts
Phantom Dose Measurements Y18 Y18 Y18 Measure dose at surface of standard phantom eg 20 cm PMMA
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
FilmDeveloped
AndFixed
Detector ReadingViewedDisplay
DigitalProcessing
StoredPACS
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 CalibrationDose Calibration Spatial ResolutionSpatial Resolution Low ContrastLow Contrast UniformityUniformity ArtifactsArtifacts
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 correctionNoiseArtifacts
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