ICARO Vienna April Implementing 3D conformal radiotherapy and IMRT in clinical practice: Recommendations of IAEA- TECDOC-1588

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1 ICARO Vienna April Implementing 3D conformal radiotherapy and IMRT in clinical practice: Recommendations of IAEA- TECDOC-1588 M. Saiful Huq, Ph.D., Professor and Director, Dept. of Radiation Oncology University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, USA M. Saiful Huq Transition from 2D to 3DCRT & IMRT 1 IAEA-CN-170/013

2 Goal of radiation therapy Conformity of dose distribution to a 3D target volume at the same time minimizing the dose to an acceptable level to the surrounding healthy structures Achieve local (or regional) control with limited risk of normal tissue complications M. Saiful Huq Transition from 2D to 3DCRT & IMRT 2 IAEA-CN-170/013

3 Conventional radiation therapy Shaped field defined from planar radiograph M. Saiful Huq Transition from 2D to 3DCRT & IMRT 3 IAEA-CN-170/013

4 3D conformal radiation therapy Full 3D CT dataset; ICRU 50,62 definition of target and OAR volumes M. Saiful Huq Transition from 2D to 3DCRT & IMRT 4 IAEA-CN-170/013

5 IMRT Full 3D CT dataset; ICRU 50,62 definition of target and OAR volumes; co-registration of PET and CT images M. Saiful Huq Transition from 2D to 3DCRT & IMRT 5 IAEA-CN-170/013

6 IMRT (3DCRT) planning and delivery process Position verification File transfer and management Positioning and immobilization Image acquisition Structure segmentation Treatment planning and evaluation Treatment delivery and verification Plan validation as necessary Adapted from an illustration presented by Webb, 1996 M. Saiful Huq Transition from 2D to 3DCRT & IMRT 6 IAEA-CN-170/013

7 IMRT Requires knowledge and understanding of patient immobilization/organ motion volumetric imaging 3D heterogeneous dose calculations large-scale optimization dynamic beam delivery of non-uniform beam fluences M. Saiful Huq Transition from 2D to 3DCRT & IMRT 7 IAEA-CN-170/013

8 IMRT - advantages Highly conformal, even concave dose distributions Large dose gradient near the perimeter of both the target volume and healthy structures Potentially allows for AHARA [as high (dose) as reasonably achievable] Decreased dose to normal tissue Improvement of therapeutic ratio M. Saiful Huq Transition from 2D to 3DCRT & IMRT 8 IAEA-CN-170/013

9 However Increased conformity of IMRT may lead to geographical miss of the tumor due to inadequate target delineation, organ motion, patient positioning inaccuracies A larger margin may lead to unacceptable high dose to adjacent normal critical structures M. Saiful Huq Transition from 2D to 3DCRT & IMRT 9 IAEA-CN-170/013

10 Clinical implementation of IMRT Equipment and space requirements Staff training and patient education Time and personnel requirements including their responsibilities Changes in treatment planning & delivery practices QA of equipment and individual patient treatments Changes in scheduling & overall integration See also: IAEA TECDOC 1588 AAPM Guidance document: Med Phys 30, (2003) M. Saiful Huq Transition from 2D to 3DCRT & IMRT 10 IAEA-CN-170/013

11 Clinical implementation of IMRT: Highlights Equipment Linac MLC OBI/CBCT Gating Shielding Imaging CT Sim (MRI, PET/CT) EPID, port films 4D CT (optional) TPS Inverse planning R&V 2 nd check software Immobilization QA/Dosimetry Chamber/diode array or film/epid dosimetry MLC QA (film/epid) M. Saiful Huq Transition from 2D to 3DCRT & IMRT 11 IAEA-CN-170/013

12 Clinical implementation of IMRT: Highlights Physicians Training Cross-sectional anatomy Inverse planning concepts, dose constraints Margins, effects of organ motion DVH based planning and analysis Plan evaluation-dose conformality/heterogeneity Dose prescription Limitations of IMRT See also: IAEA TECDOC 1588 AAPM Guidance document: Med Phys 30, (2003) M. Saiful Huq Transition from 2D to 3DCRT & IMRT 12 IAEA-CN-170/013

13 Clinical implementation of IMRT: Highlights Training In addition to the previous ones Medical physicists Understanding of optimization methods Characteristics of IMRT dose distributions, plan QA Beam modeling and delivery for IMRT See also: IAEA TECDOC 1588 AAPM Guidance document: Med Phys 30, (2003) M. Saiful Huq Transition from 2D to 3DCRT & IMRT 13 IAEA-CN-170/013

14 Clinical implementation of IMRT: Highlights Training Medical oncologist IMRT/SRS/SBRT Radiologists PET Additional Staffing Increased time for planning and delineation of target volume (Physician, planner) Image guidance Increased treatment time/delivery/qa TUMOUR STAGING WITH PET ( 18 F-FDG) FDG) M. Saiful Huq Transition from 2D to 3DCRT & IMRT 14 IAEA-CN-170/013

15 Self questions to be asked!! What can be achieved with IMRT? What specific dose goals should be given to specific treatment sites? What are the dose/dose-volume tolerances of organs at risk? How is this affected by fractionation? How are achievable results affected by marginsimmobilization, localization, treatment delivery method, TPS and dose calculation method? M. Saiful Huq Transition from 2D to 3DCRT & IMRT 15 IAEA-CN-170/013

16 Modern radiotherapy is complex Hardware breaks, software always has bugs, and people make mistakes! Every clinic is susceptible to these kinds of errors (i.e., BIG ones)! M. Saiful Huq Transition from 2D to 3DCRT & IMRT 16 IAEA-CN-170/013

17 Reported accidental exposures with new technologies Keeping equipment in calibration is essential Few events resulted from machine errors Micro-multileaf collimator VARiS IMRT/MLC However, each had a strong human failure The vast majority of events begin with a staff error ROSIS database; ICRP Draft 2009 M. Saiful Huq Transition from 2D to 3DCRT & IMRT 17 IAEA-CN-170/013

18 Assessment of dose M. Saiful Huq Transition from 2D to 3DCRT & IMRT 18 Josef Novotny IAEA-CN-170/013

19 ICRP draft 2009 Risk-informed and cost-effective approaches for prioritizing tests and checks by means of prospective methods of risk assessment, to be performed in cooperation with manufacturers M. Saiful Huq Transition from 2D to 3DCRT & IMRT 19 IAEA-CN-170/013

20 What is Risk? A term which frequently embodies probability of an event occurring and severity should such an event occur Need to quantitate probability and severity New tools Process tree FMEA Fault tree Risk assessment AAPM TG100: A new paradigm for QA in radiation therapy M. Saiful Huq Transition from 2D to 3DCRT & IMRT 20 IAEA-CN-170/013

21 Conclusions Human factors Training Miscommunication within and between departments Lack of attention by people performing task Lack of consistent procedural guidelines People as well as linacs, need to be commissioned Lack of comprehensive QA, QC & QM programs AAPM TG100: A new paradigm for QA in radiation therapy M. Saiful Huq Transition from 2D to 3DCRT & IMRT 21 IAEA-CN-170/013

22 Our job is not to prevent errors, but to keep the errors from injuring the patients. Lucian Leape It is useful to report all accidents before consequences appear It is impossible to make anything foolproof because fools are so ingenious. Artur Bloch, Murphy s law Courtesy: Josef Novotny M. Saiful Huq Transition from 2D to 3DCRT & IMRT 22 IAEA-CN-170/013