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Safety Code 35

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Title: QC in a Digital World Author: John Aldrich Last modified by: terrys Created Date: 4/16/2008 8:44:14 PM Document presentation format: On-screen Show – PowerPoint PPT presentation

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Title: Safety Code 35


1
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

2
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

3
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)

4
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

5
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
6
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
7
Daily Quality Control Tests
Normal Font Required Test (must do) Italics
- Recommended Test (recommended) Required
Tests currently recommended by RPS
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 According to manufacturers instructions Can include auto calibration eg CT
Meters Operation (D2) Meter, visible and audible indicators should function Meter, visible and audible indicators should function
Equipment Conditions (D3) Visual inspection for loose or broken components, ease of movements 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
8
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 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
9
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
10
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

11
Problems with inconsistency
Right Display 5 not visible / 95 visible
Left Display 5 visible / 95 not visible
  • Should see both 5 and 95 squares if calibrated
    properly

12
Display QC
  • Monthly (M6)
  • All displays
  • Technologist
  • PACS administrator
  • Biomed
  • SMPTE test pattern / test
  • pattern generator / vendor

13
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

14
Viewbox QC
  • Weekly visual inspection (W2)
  • Cleanliness
  • Viewing area discolouration
  • Improper luminance
  • Clean, replace plastic or bulb if necessary
  • Technologists / Biomed / Plant services

15
Viewbox QC
  • Yearly inspection (Y26)
  • Technologist / physicist
  • Maintain logsheet

Luminance gt 2500 cd/m2 Should
Light output uniformity /- 10 Should
Light output homogeneity /- 20 Should
Ambient light control lt 50 lux (50 cd/m2) 5-10 lux recommended (5-10 cd/m2) Must
16
Viewbox QC
17
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

18
Laser Film Printer QC
19
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

20
Laser Film Printer QC
21
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
22
Radiation Protection
  • Radiation Safety Officer (1.4)
  • Room Shielding (5.0)
  • Lead aprons (4.1)

23
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

24
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

25
Lead Aprons
  • Lead equivalence of aprons
  • SC 20A
  • lt150 kVp 0.5 mm
  • SC 35
  • lt 100 kVp 0.25 mm
  • 100lt kVp lt150 0.35 mm
  • gt150 kVp 0.5 mm

26
Lead apron QC
  • Annually (Y28)
  • Radiographic / radioscopic
  • Rejection if total defective area gt 670 mm2
  • Thyroid and reproductive areas lt 5 mm diameter
    equivalent total

27
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
28
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
29
Equipment Life Cycle
  • Acceptance testing
  • New equipment
  • Conformance to manufacturers specifications/RFP
  • Baseline performance
  • Routine performance evaluations
  • Specific tests performed at regular intervals
  • Consistency checks
  • Evaluate malfunctioning or out-of-spec equipment

30
Imaging QC Principles
  • Proactive QC rather than Reactive QC
  • System performance rated BEFORE clinical imaging
  • System performance rated AFTER clinical imaging.

Which approach would you prefer if you were a
patient??
31
Radiographic Systems
  • Projection radiography
  • Film
  • Digital detectors (DR)
  • Computed radiography (CR)

32
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
33
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 SMPTE Check for 0/5 and 95/100 patch visibility OD 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
34
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
35
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 mGy
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 mGy 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
36
Digital Imaging
  • Any sufficiently advanced technology is
    indistinguishable from magic Arthur C Clarke 1961

37
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

38
Digital System QC

Film
Developed And Fixed
Detector
Reading
Viewed Display
Digital Processing
Stored PACS
QC of the digital systems is an additional
requirement in addition to the usual x-ray
performance tests
- it is not performed magically
39
DR, CR and DF Extra QC
  • Dose Calibration
  • Spatial Resolution
  • Low Contrast
  • Uniformity
  • Artifacts

40
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

41
Image Quality
  • All CR and some DR/DF manufacturers have custom
    Image Quality phantoms and automatic software to
    analyze image quality

42
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

43
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

44
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

45
CR QC
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