1. Dosimetry Audit in Radiotherapy, in Greece Costas J. Hourdakis, A. Boziari & V. Kamenopoulou Greek Atomic Energy Commission, EEAE Athens, 12 September 2014

2. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Regulatory Inspections (Greek Atomic Energy Commission) Management System Audits – Accreditation Audits Clinical Audits Dosimetry Audits (Greek Atomic Energy Commission) Quality Control Quality Assurance (QC-QA) Internal Audits Tools for Quality

3. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Competent national regulatory authority in the fields of radiological protection and nuclear safety. Greek Atomic Energy Commission (ΕΕΑΕ) independent public service It is an independent public service, supervised by the General Secretariat for Research and Technology under the Ministry of Education & Religious Affairs. Regulatory and legal duties Inspection duties Services (personnel dos., calibrations, environmental controls, etc) Education and research duties Radiological emergency ISO 9001 Integrated Management System : ISO 9001 (TUV Hellas) ISO 17020 ISO 17025 Quality Management Systems : ISO 17020 and ISO 17025 (Hellenic Accreditation System - ESYD)

4. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr 31 : Hospitals – Clinics (Aug 2014) RT & BT in Greece TotalPublicPrivate ≥ 3 systems (Linac or Co60)422 2 systems (Linac or Co60)1394 1 Linac or Co60981 Only BT (HDR or I125 seeds)55

5. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr ≈ 60 photon beams (6–23 MV) 7 60 Co beams 7 60 Co beams ≈ 130 electron beams (4-21 MeV) IMRT at 5 RT centers for ≈ 12 systems 4 linacs / 1 M population - 250,000 inhabitants / Linac Tendency to growth : Replacement of old systems & new centers RT & BT in Greece

6. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr EEAE inspections and dosimetry audits in RT and BT, in Greece Scope : Assessment of radiation protection of workers – patients – public Assessment of safe performance of radiological equipment Assessment of applied patient dosimetry Assessment of applied clinical and dosimetry procedures and practices Identification of errors and mal-practices / Investigation / Recommendations Harmonization of dosimetry protocols at national level Comparison of dosimetry results with other studies worldwide

7. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Dosimetry Audits, ΕΕΑΕ On site visits Ionization chambers - detectors EEAE dosimetry & QC equipment (independent from users’) Calibration in IRCL/EEAE-EIM SSDL QC-QA and dosimetry protocols (IAEA TRS 398) Applied to all RT & BT centers and systems Rounds 1 st round : 2002 - 2006 2 nd round : 2006 - 2011 3 rd round : 2011 -...

8. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Dosimetry equipment ABSOLUTE DOSIMETRY Photons in water : Waterproof Farmer type 0.6 cc - IBA FC65 P IC-69 Photons in Solid Water Phantom : Flexible IC 0.3 cc - PTW 31003 Electrons in water : Parallel plate - PTW MARCUS (since 2011) Electrons in water : Parallel plate - PTW ADVANCE (after 2011) Electrometer : PTW UNIDOS 10001 RELATIVE DOSIMETRY IBA solid state / diodes for photons and electrons Dosimetry Audits, EEAE

9. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr IBA RFA 200, 2D water phantom OmniPro-Accept software Solid state diodes Solid state diodes Farmer IC Farmer IC P-P electron IC P-P electron IC Solid Water Phantom Insert for PTW flexible IC Insert for PTW flexible IC Dosimetry Audits, EEAE Basic Phantoms

10. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Dosimetry Audits, EEAE 1.Assessment of Mechanical and Functional equipment performance 2.Relative (PDD, profiles, etc) and Absolute dosimetry in water (Gy/MU) 3.Assessment of TPS output 4.Assessment of the overall radiotherapy procedure, for dosimetry Dosimetry Audit performed in 4 levels [ performed in sequence : from basic to complex ]

11. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Basic parameters : Field size Accuracy of gantry and collimator rotation Accuracy of table movement and rotation Stability of the isocentre (ISO) during rotations Laser accuracy 1. Assessment of Mechanical and Functional equipment performance

12. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Deviations |δ| classified in three categories : |δ| < 2 mm : Accepted Investigation 2 < |δ| < 4 mm : Investigation |δ| > 4 mm : Non-accepted 1. Assessment of Mechanical and Functional equipment performance

13. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr > 4 mm 235 tests for Linacs & 81 for Co-60 1. Assessment of Mechanical and Functional equipment performance

14. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr 2. Relative and Absolute dosimetry

15. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr EEAE measures in water phantom TPR 20,10, for photons R 50 for electrons percent depth dose, PDD beam profiles Dose at reference point, Dw ΕΕΑΕ measurements, D M, are compared with the center’s stated values, D S r = D S /D M relative deviation, d r = [(D S /D M ) – 1] ×100% 2. Relative and Absolute dosimetry

16. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Uncertainties of EEAE measurements Measurement of Dose to Water Type AType B % Calibration coefficient, ND,w, of IC + electrometer 0.90 Long term stability of ND,w0.10 Scale reading / resolution 0.00 Stability of measurements0.10 Temperature & Pressure0.170.08 Temperature difference (thermometer & maes. point) 0.00 Uniformity of radiation beam 0.06 Depth - IC positioning0.29 Field size, SSD, angle 0.50 Leakage current 0.00 Recombination loss 0.10 Polarity effct 0.10 Beam quality correction, kQ 1.00 QUADRATIC SUM0.221.47 Combined Standard Uncertainty, k=11.49% EXPANDED UNCERTAINTY, k=22.98% 2. Relative and Absolute dosimetry

17. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Comparison - Acceptance d ≤ 3 % : Accepted 3% < d < 5% : Investigation d ≥ 5% : Non-accepted 1 st round2 nd round3 rd round │d r │≤ 3% 79.2%96.9%93.5% 3% <│d r │< 5% 16.7%3.1%6.5% │d r │≥ 5% 3.1%0.0%0.0% 2. Absolute dosimetry at reference point (Gy/MU) : Photons Standard uncertainty of D M : ~ 1.5 %

18. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr 2. Absolute dosimetry at reference point (Gy/MU) : Electrons 1 st round2 nd round3 rd round │d r │≤ 3% 82.1%71.1%95.7% 3% <│d r │< 5% 5.0%28.9%4.3% │d r │≥ 5% 12.9%0.0% Standard uncertainty ~ 2.0 %

19. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr 2. Absolute dosimetry : BT Reference Air Kerma Rate (Gy h -1 @ 1m) Standard uncertainty ~ 0.8 %

20. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Various clinical irradiation conditions are predefined in random, e.g. 18MV, field 12 x 7, depth 8.5 cm, SAD/SSD, Wedge 45 o, etc. [Gantry=0 o ] TPS calculates the MU (or min), in order to deliver 1 Gy at the predefined depth and irradiation conditions The irradiation conditions are reproduced at Linac (or Cο60) in a water phantom & the irradiation performed for the calculated MU (or min) EEAE measures the Dw & deviations from 1 Gy are derived Tests are performed for many & different irradiation conditions (> 15). 3. TPS output

21. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr data > 2011 3. TPS output d ≤ 3 % : Accepted 3% < d < 5% : Investigation d ≥ 5% : Non-accepted Standard uncertainty of D M : ~ 1.5 %

22. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr data > 2011 3. TPS output d ≤ 3 % : Accepted 3% < d < 5% : Investigation d ≥ 5% : Non-accepted Standard uncertainty of D M : ~ 1.5 % “We do not complete the audit until we investigate & resolve all deviations (d > 3%)”

23. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr 4. Assessment of overall RT procedure Simulation of all RT steps, with a solid water phantom : CT scan Simulation Treatment Planning Positioning - Verification Irradiation Hospital’s procedures are followed All steps are performed by the hospital’s staff

24. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr 4. Assessment of overall RT procedure Flexible IC IC’s reference point is at the geometrical center of the phantom (cross marking).

25. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Initial preparation Marking, with bee-bees, a hypothetical original (anatomical) isocentre (ISO)

26. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr CT scan Images are transfered to TPS

27. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Treatment Isocenter determination Anatomical ISO defined by the bee-bees Treatment ISO is determined from the respective CT slice & it corresponds to the geometrical centre of phantom

28. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Therapy simulation – Offset determination Deviation of treatment isocentre from phantom geometrical centre d ≤ 2 mm Followed TPS data : Offset from Original – Anatomical Isocentre to Treatment Isocentre (should be at the phantom center)

29. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Treatment planning CUBE : BOX technique (4 diametrically fields) OBLIQUE : 1 vertical (0 o ) with wedge and 2 lateral (sideways, e.g. 105 o and 255 o ) MU calculation, in order to deliver total dose to treatment isocentre (from all fields) 2 Gy

30. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Phantom irradiation Phantom positioning : Cards from TPS are followed EEAE measures the dose from each field, D M,i and the total dose, D M,T Comparison of D M,I and D M,T with the dose values as stated by the RT staff, according to TPS output data.

31. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr 4. Assessment of overall RT procedure d ≤ 5 % 5 % < d < 7 % d ≥ 7 % Standard uncertainty ~ 3.0 % data > 2011

32. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr 4. Assessment of overall RT procedure d ≤ 5 % 5 % < d < 7 % d ≥ 7 % Standard uncertainty ~ 3.0 % data > 2011 “We do not complete the audit until we investigate & resolve all deviations (d > 3%)”

33. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.grCONCLUSION Patient Dosimetry and Radiation Protection is at high level in Greece. EEAE applies system inspections and dosimetry audits in RT and BT (and elsewhere) over 14 years, continuously and systematically. The experience gained is important. Benefits: Improved dosimetry - harmonization - dissemination of information - strengthening the confidence of hospitals’ staff. Hospitals welcome and seek inspections and audits of EEAE.

34. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr Challenges and Future work Small field dosimetry Dosimetry in “New technologies” (Tomotherapy, Cyber-Knife Gamma-Knife) Reporting of accidents Clinical Audit Enhancement of “Safety culture” and “Security culture” “Quantity” vs “Quality” to be balanced in a few cases

35. EFOMP Symposium,Athens -12 Sept 2014, ΕΕΑΕ, costas.hourdakis@eeae.gr I thank you for your attention