1. Patient Dosimetry in Radiology, Management Center Europe, June 26 2010
DAP as a tool for analysis of effective dose and maximum skin dose: finalised and current projects
Klaus Bacher
Ghent University
Department of Basic Medical Sciences
Patient Dosimetry in Radiology, Management Center Europe, June

2. Dose area product (DAP)
Easy online measurement of patient radiation exposure
Quantity is directly used for:
Definition of diagnostic reference levels (DRLs)
Optimization
Possible use of DAP for further (risk) analysis:
Stochastic effects: correlation with effective dose
Deterministic effects: correlation with maximum skin dose
 not straightforward!

3. DAP and effective dose Effective dose
Weighted sum of equivalent organ doses HT
Risk-related quantity (not for individual risk assessment!)
Comparison of risks of different imaging modalities is possible
No in vivo measurement possible
To be calculated/simulated according to ICRP 103 publication (2007)

4. Effective dose for optimization?
DAP and effective dose
Effective dose for optimization?
Intercomparisons of different procedures:
same DAP in different X-ray procedures  same effective dose
Intercomparisons within a specific procedure:
lower DAP in specific X-ray procedure lower effective dose
From: L. Struelens, Optimisation of Patient Doses linked to Image Quality in Vascular Radiology, 2005

5. Project supported by FANC
DAP and effective dose
Project supported by FANC
Use of effective dose for further optimization, especially for interventional procedures
→ need for accurate conversion coefficients based on DAP
Project: DAP to effective dose conversion in cardiology and vascular/interventional radiology

6. Effective dose simulation
DAP and effective dose
Effective dose simulation
ICRP 103 publication (2007)
Taking into account the extended organ list (<-> ICRP 60)
New organ weighting factors
Use of reference voxelized computer model (<-> mathematical models)
From: M. Zankl et al., Organ dose conversion coefficients for external photon irradiation of male and female voxel models, 2002

7. Effective dose simulation
DAP and effective dose
Effective dose simulation
Male and female reference voxel phantoms (Zankl et al.)
X-ray Characteristics for Imaging and Radioprotection
Klaus Bacher

8. Effective dose simulation
DAP and effective dose
Effective dose simulation
ICRP 103 publication (2007)
Sex averaging of organ doses
From: ICRP Publication 103: The 2007 recommendations of the International Commission on Radiological Protection, 2007

9. Effective dose simulation
DAP and effective dose
Effective dose simulation
Simulations taking into account
12 projections for interventional cardiology procedures
20 projections for vascular/interventional radiology procedures
Different X-ray spectra (mm Al HVL)
→ 256 DAP to effective dose conversion coefficients
X-ray Characteristics for Imaging and Radioprotection
Klaus Bacher

10. DAP and effective dose Results
X-ray Characteristics for Imaging and Radioprotection
Klaus Bacher

11. DAP and effective dose Results
X-ray Characteristics for Imaging and Radioprotection
Klaus Bacher

12. DAP and effective dose Results
Final report available on: (section medische stralingsfysica/radiophysique médicale)

13. DAP and maximum skin dose
Belgian multi-centre study (2005)
Multicenter study on skin doses of patients, treated with prolonged cardiological interventions (supported by FANC):
Skin dose measurements in 318 adult patients in 8 Belgian hospitals
Investigation of correlation of maximum skin dose with DAP
From: E. Bogaert et al., Multicenter study on skin doses of patients, treated with prolonged cardiological interventions, 2005
X-ray Characteristics for Imaging and Radioprotection
Klaus Bacher

14. DAP and maximum skin dose
Belgian multi-centre study (2005)
Multicenter study on skin doses of patients, treated with prolonged cardiological interventions:
Identification maximum skin doses
From: E. Bogaert et al., Multicenter study on skin doses of patients, treated with prolonged cardiological interventions, 2005
X-ray Characteristics for Imaging and Radioprotection
Klaus Bacher

15. DAP and maximum skin dose
Belgian multi-centre study (2005)
Multicenter study on skin doses of patients, treated with prolonged cardiological interventions:
Investigation of correlation of maximum skin dose with DAP
→ establishing “trigger levels”
From: E. Bogaert et al., A large-scale multicentre study of patient skin doses in interventional cardiology: dose-area product action levels and dose reference levels, 2009
X-ray Characteristics for Imaging and Radioprotection
Klaus Bacher

16. DAP and maximum skin dose
Project supported by FANC
2005 project: DAP trigger levels for cardiological interventions
→ need for DAP trigger levels in other interventional procedures
Current project: Determination of trigger levels for patient doses for interventional procedures (TRIR)
DAP as a tool for risk analysis Klaus Bacher

17. DAP and maximum skin dose
Project supported by FANC
Measurements of skin dose distribution and maximum skin dose in 12 hosptitals and for different procedures:
Radiofrequency (RF) ablations
Transjugular Intrahepatic Portosystemic Shunt (TIPS)
Chemo embolizations of the liver
Cerebral embolizations
Embolizations of vena spermatica
Creation or treatment of AV fistula for hemodialysis
Endoscopic retrograde cholangiopancreaticography (ERCP)
Biliary drainages
End of measurements: june 2010
Final report by july 2010
X-ray Characteristics for Imaging and Radioprotection
Klaus Bacher