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ACR Phantom Phantom Images. Overview Session 2 CT20 Patient dose15 Equipment Purchase/ Acceptance Testing 15 Questions10 Personnel qualifications20 Education.

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Presentation on theme: "ACR Phantom Phantom Images. Overview Session 2 CT20 Patient dose15 Equipment Purchase/ Acceptance Testing 15 Questions10 Personnel qualifications20 Education."— Presentation transcript:

1 ACR Phantom Phantom Images

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

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 ExamReference DLP Reference Dose mSv mGy.cm Head13003 Chest Abdomen Pelvis Abdomen-Pelvis

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 Dose Area Product detector after collimator intercepts all radiation used both for radiography and radioscopy X-ray Tube Collimator X-ray field 5.2 Gy.cm 2 DAP meter PACS

12 Patient Dose Monitoring It is now technically possible to estimate patient dose from most x-ray systems EquipmentDose IndicatorStatus CT  Dose-length product DLP Available on all CTs Radiographic/ Fluoroscopic/ Angiographic  Dose-area product DAP Available on all new units- can be retrofitted CR  Exposure Index (EI) of detector All CR Both DLP and DAP values are directly related to patient dose

13 CT Patient Dose Monitoring Patient ID:Exam No: Exam Description: CABD2PCTDate: Dose Report SeriesTypeScan Range (mm) CTDIvol (mGy) DLP (mGy.cm) Phantom cm 1Scout---- 2HelicalS111-I Body 32 1/1

14 Diagnostic Reference Levels Radiographic Exam ViewDRL Generalized Conversion Coefficients DAP to Effective Dose Gy.cm 2 mSv per Gy.cm 2 SkullPA20.03 Lat ChestPA Lat T SpineLat70.1 AP40.2 L SpineLat110.1 AP50.2 AbdomenPA40.1 AP40.2 PelvisAP40.3

15 Diagnostic Reference Levels Complete ExamsDRLDAP to E Fluoroscopy Time Gy.cm 2 mSv per Gy.cm 2 minutes Barium Swallow Barium Meal Ba follow thru Barium enema IVP140.2 MCU Nephrostography Retro Pyelogram T tube cholangiogram Sinography9 2.1 Small bowel enema Venography leg7 2.2 Coronary angiography

16 Diagnostic Reference Levels Complete ExamDRLDAP to E Fluoroscopy Time Gy.cm 2 mSv per Gy.cm 2 minutes Biliary Drainage Facet joint injection Hickman line Nephrostomy Esophageal stent Esophageal dilation Pacemaker PTCA single stent

17 Diagnostic Reference Levels Exam EU DRL Dose Area Product Gy cm 2 VGH DR Ave Dose Area Product Gy cm 2 DAP to E Conversion Factor mSv/Gy cm 2 Skull AP Chest PA Abdomen AP Pelvis AP Barium enema300.2 IVP140.1 Coronary Angiography *0.15 *diagnostic + angioplasty

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

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 Quality Control 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

21 Acceptance testing Items for Acceptance TestingFilmCRDRRadioscopicCT 1.0 Identification 1.1 Initial Inspection and InventoryXXXXX 1.2 Inspection of DocumentationXXXXX 2.0 Visual and Functional Tests 2.1 Mechanical PropertiesXXXXX 2.2 Safety SystemsXXXXX

22 Acceptance testing Items for Acceptance TestingFilmCRDRRadioscopicCT 3.0 Performance Evaluation (X-ray Generator) 3.1 X-ray Tube VoltageXXXXX 3.2 Current Time ProductXXX 3.3 Loading TimeXXX 3.4 Radioscopic Timer and ChronometerX 3.5 Beam Limitation and IndicationXXXXX 3.6 X-ray Beam FiltrationXXXX 3.7 Automatic Exposure ControlXXX 3.8 Automatic Intensity ControlX X 3.9 Radiation OutputXXXX X 3.10 Maximum Air Kerma RateX 3.11 Phantom (Entrance) Dose (Rate)XXXXX

23 Acceptance testing Items for Acceptance TestingFilmCRDRRadioscopicCT 4.0 Performance Evaluation (Image Receptor) 4.1 Exposure IndexXX 4.2 Dynamic RangeXX X 4.3 Spatial ResolutionXXXXX 4.4 Contrast DetectabilityXXXXX 4.5 UniformityXXX 4.6 ArtifactsXXXXX 4.7 Digital Detector Residual ImageXX 4.8 NoiseXXX 4.9 Modulation Transfer FunctionXX 4.10 Mean CT Numbers (calibration and linearity)X 4.11 Tomographic Section ThicknessX 4.12 Axial Patient Positioning AccuracyX 4.13 Positioning of Patient SupportX

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 CT20 Patient dose15 Equipment Purchase/ Acceptance Testing 15 Questions20 Personnel qualifications20 Education and training10 Questions20

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 CT20 Equipment Purchase/ Acceptance Testing 15 Patient dose15 Questions20 Personnel qualifications20 Education and training10 Questions20

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 is hindsight


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