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ACR Phantom Phantom Images

ACR Phantom Phantom Images. Overview Session 2. Patient Dose (A 3.0). It is recommended that Diagnostic Reference Levels (DRLs) be used as guidance in the optimization of patient dose DRLs are values related to patient dose using Dose Indicators which can be easily measured

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ACR Phantom Phantom Images

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  1. ACR Phantom Phantom Images

  2. Overview Session 2

  3. Patient Dose (A 3.0) • It is recommended that Diagnostic Reference Levels (DRLs) be used as guidance in the optimization of patient dose • DRLs are values related to patient dose using Dose Indicators which can be easily measured • dose-linear product (DLP) for CT or • dose-are product (DAP) for radiography/radioscopy. • Conversion factors are available to convert from Dose Indicator values to Effective Dose (E)

  4. Diagnostic Reference Levels • It is very difficult to ‘optimize’ patient dose • However, it is relatively easy to decide those doses which are clearly too high and unacceptable • DRLs are derived from large surveys of examinations in a region or country; usually the DRL is set at the 75% level of the distribution

  5. BC CT Dose Survey 2004 • Hospitals around BC were asked to provide data on routine head, chest, abdomen, pelvis CT • Data collected from 18 hospitals

  6. BC Patient Dose - Head DRL

  7. BC Patient Dose - Chest

  8. BC Patient Dose – Abdomen

  9. Reference Doses BC * 75 percentile

  10. Reference Doses • For other imaging systems the dose-area product (DAP) is the most convenient to use to evaluate patient dose • Should be a requirement on all new radiographic and radioscopic systems

  11. Dose Area Product Meter Collimator X-ray field Dose Area Product detector after collimator intercepts all radiation used both for radiography and radioscopy X-ray Tube 5.2 Gy.cm2 PACS DAP meter

  12. Patient Dose Monitoring It is now technically possible to estimate patient dose from most x-ray systems Both DLP and DAP values are directly related to patient dose

  13. CT Patient Dose Monitoring

  14. Diagnostic Reference Levels

  15. Diagnostic Reference Levels

  16. Diagnostic Reference Levels

  17. Diagnostic Reference Levels *diagnostic + angioplasty

  18. Overview Session 2

  19. Acceptance Testing (C 1.0) • “The following steps must be included for the establishment of QC procedures • Clear performance specifications • Baseline performance • Reference images • QC Action Levels”

  20. Acceptance testing Baseline value determination Device use period Next constancy testing Data evaluation Within the established criteria PASS FAIL Remedy Quality Control • Acceptance testing • New equipment • Conformance to manufacturer’s specifications/RFP • Baseline performance

  21. Acceptance testing

  22. Acceptance testing

  23. Acceptance testing

  24. Equipment Purchase This new Code has implications for new equipment • Code 20A was usually a condition for RFPs • With Code 35 much more is involved • Performance of the x-ray system • At acceptance • In routine operation • Performance of the image receptor • At acceptance • In routine operation • Ability to determine patient dose indicators • At control • For transfer to PACS

  25. Equipment Purchase • Will service contracts cover the increased testing? • For new units • For existing equipment • At the moment radiation doses such as CTDI are not measured by any of the companies as part of QC • What about equipment not on service contract?

  26. Overview Session 2

  27. Personnel Qualifications • Responsible User • X-ray equipment Operator • RSO

  28. Responsible User • Possess qualifications required by applicable province or statute eg RCPSC, CAMRT • Acquire refresher training according to similar standard • Ensure equipment functions correctly • Ensure equipment is used correctly • Establish safe operating procedures • Promulgate radiation safety for staff • Ensure radiation levels are within regulatory limits

  29. X-ray Equipment Operator • Possess qualifications required by applicable province or statute eg RCPSC, CAMRT • Acquire refresher training according to similar standard • Have documented training • Ensure equipment is used correctly • Establish safe operating procedures • Promulgate radiation safety for staff • Ensure radiation levels are within regulatory limits

  30. Overview Session 2

  31. Education and Training - Standards • Collation of Standards/Action Levels • Although frequency of tests is well covered in SC 35 not all Action Levels are defined.

  32. Education and Training - QC • PACS and image display systems QC • Visual • Measurements • Image receptor quality tests and calibration • CR • DR • DF • CT

  33. Education and Training - Dose • Patient dose measurement • Dose- area product (DAP) in radiography and radioscopy. Calibration of meters. • CTDI in computed tomography

  34. The Future The only perfect science ishindsight

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