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Safety Code 35 John Aldrich PhD FCCPM Regional Leader Clinical Physics Kevin Hammerstrom RTNM QC Coordinator Department of Radiology Vancouver Coastal.

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Presentation on theme: "Safety Code 35 John Aldrich PhD FCCPM Regional Leader Clinical Physics Kevin Hammerstrom RTNM QC Coordinator Department of Radiology Vancouver Coastal."— Presentation transcript:

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 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

5 Overview Session 1 Requirements for all systems20 Radiation Protection10 Questions10 Radiography (Film/DR/CR)20 Radioscopy (Fluoroscopy, Angio, DF)20 Questions10 LUNCH

6 Overview Session 2 After Lunch CT20 Equipment Purchase/ Acceptance Testing 15 Patient dose15 Questions10 Personnel qualifications20 Education and training10 Questions20

7 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

8 Weekly and Monthly Tests Quality Control ProceduresAll 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 ProceduresAll 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 Should see both 5% and 95% squares if calibrated properly Problems with inconsistency Left Display – 5% visible / 95 % not visible Right Display – 5% not visible / 95 % visible

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> 2500 cd/m 2 Should Light output uniformity+/- 10%Should Light output homogeneity+/- 20%Should Ambient light control< 50 lux (50 cd/m 2 ) 5-10 lux recommended (5-10 cd/m 2 ) 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 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 systems20 Radiation Protection10 Questions10 Radiography DR/CR20 Radioscopy (Fluoroscopy, Angio), DF20 Questions10 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 <150 kVp0.5 mm SC 35 < 100 kVp: 0.25 mm 100< kVp <150: 0.35 mm >150 kVp: 0.5 mm

26 Lead apron QC Annually (Y28) Radiographic / radioscopic Rejection if total defective area > 670 mm 2 Thyroid and reproductive areas < 5 mm diameter equivalent total

27 Overview Session 1 Requirements for all systems20 Radiation Protection10 Questions10 Radiography DR/CR20 Radioscopy (Fluoroscopy, Angio), DF20 Questions10 LUNCH

28 Overview Session 1 Requirements for all systems20 Radiation Protection10 Questions10 Radiography DR/CR20 Radioscopy (Fluoroscopy, Angio), DF20 Questions10 LUNCH

29 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 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 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??

31 Radiographic Systems Projection radiography Film Digital detectors (DR) Computed radiography (CR)

32 Weekly Radiographic Tests Quality Control ProceduresFilmCRDRComments Weekly Quality Control Tests Visual Inspection of Imaging SystemsW1 Inspect screens/CR plates/DR housing Viewboxes ConditionW2 Cleanliness, luminance Laser Film Printer OperationW3 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 ProceduresFilmCRDRComments Monthly Quality Control Tests Cassette, Screen, and Imaging Plate Cleaning M1 Clean screens/CR plates/DR housing Darkroom Temperature and Humidity Conditions (DAP) M2Temp: 18-23C; Humidity 40-60% Darkroom Light ConditionsM3Visual check for light tightness Film Processor OperationM4 Temp ± 0.5C; Developer and fixer correct Retake AnalysisM5 For film, CR and DR Electronic Display Device PerformanceM6 Display pattern such as SMPTE on all image display stations Laser Film Printer OperationM7 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 ProceduresFilmCRDRComments Annual QC Tests Safelight TestY1Expose film for 2 mins in room Film/Screen ContactY2Image mesh and check Accuracy of Loading FactorsY3 mAs Linearity Radiation Output ReproducibilityY4 Reproducibility Radiation Output LinearityY5 Output with mAs X-ray Beam FiltrationY6 HVL Automatic Exposure ControlY7 Check AEC for all kVps and thicknesses X-ray Field and Light Field Alignment Y8 Congruency of x-ray beam and light field edges X-ray Beam CollimationY9 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 ProceduresFilmCRDRComments Image Quality Grid PerformanceY10 Check uniformity and movement of grid Exposure IndexY12 Exposure Index versus Dose 1 to 50 Gy Noise, Uniformity and Image Artifacts Y14 For above range of dose measure noise in center and each quadrant Check for artifacts Spatial ResolutionY15 Line-pair or Leeds phantom Contrast DetectabilityY16 Leeds phantom Digital Detector Residual ImagesY17 Take image at 50 Gy then zero; check for artifacts Phantom Dose MeasurementsY18 Measure dose at surface of standard phantom eg 20 cm PMMA DAP MeterCalibrate 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 DetectorReading 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 Dose Calibration Spatial Resolution Spatial Resolution Low Contrast Low Contrast Uniformity Uniformity Artifacts 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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