Objectives. Image-Guided RT: Process. kv CBCT Novel Clinical Applications and Future Directions. Standard Clinical Uses. Novel Applications.

Transcription

1 kv Novel Clinical Applications and Future Directions Douglas J. Moseley PhD, DABR Department of Radiation Oncology University of Toronto Radiation Medicine Program Princess Margaret Hospital Objectives Standard Clinical Uses Incident Reduction Residual Error OAR avoidance Novel Applications On-line Palliative Summary Image-Guided RT: Process! Initial Setup Image Image transfer Target Shift Adjust Adjust Within tolerance Begin Tx Commissioning Commissioning Upgrades Re-try Verify Verify Within tolerance 1

2 Process and Workflow Automatic couch New units, New Tx sites Localization Incidents per Tx Course JP Bissonnette, PMH Start of 3D IGRT 0.5% 0.5% 0.4% 0.4% 0.3% 0.3% 0.2% 0.2% Cut in half 0.1% 0.1% 0.0% Year 2

3 IGRT Rx: The Prescription kv Anatomical Sites Imaging Technique kvp, ma, ms FOV, half vs. full Scan Imaging Dose Targeting ROI (clip-box) Manual vs. Automatic Bone vs. Soft-tissue Action Levels Online vs. Offline Shifts/Rotations Verification/Monitoring Residual Error Intra-Fraction Motion Evidence based margins Head and Neck - Bony Liver - Soft-Tissue Prostate - FM s & Soft-tissue CNS - Bony Breast - Chest wall Lung - Bony or Soft-tissue Anal Canal - Bony Sarcoma - Bony IMRT Lung 35 Gy in 20 fractions V20 for both lungs <20% First tx Soft Tissue Monitoring Image guidance protocol Matched to bone Weekly cone beam Daily MV port films 3 mm action level shift couch Monitor soft tissue changes 3

4 Mid tx Soft Tissue Monitoring Last tx Soft tissue Monitoring Avoid Organs at Risk Avoid Organs at Risk Heart Heart (OAR) 30 in 3 ITV PTV 60 Gy in 3 ITV PTV Planning CT Target Localized Heart Outside High Dose (OAR) Region Planning CT - Target Localized - Heart Outside High Dose (OAR) Region 4

5 Avoid Organs at Risk Heart Avoid Organs at Risk Patient Re-Positioned ITV PTV Planning CT - Target Localized - Heart Inside Planning CT - Target Localized - Heart Inside - Target Re-Localized - Heart Outside information: T2N2c Postcricoid region Sept Reference Scan scan Residual Error Various Anatomical Sites May Problem: Significant tissue discrepancy between reference scan and at 3 rd fraction Reason: Tumour progression, acute swelling(?) Result: RO notified, pt sent for emergency tracheotomy. Pt rescanned with new mask. Princess Margaret Hospital Pelvis + Thorax Pelvis - Bone fiducials 4 sites (fiducials, thorax, pelvis, skull) 3 modalities (2D MV, 2D kv, 3D kv) 5 Random setups + IG Evaluate residual error (120 image sets!!!) Skull McNiven et al

6 Results: Residual Error Prostate Fiducial Markers MV kv Prostate Residual Error Letourneau, IJROBP 2008 On-line Palliation Population: 50% of all RT patients. Bone metastases: 25% of all RT patients. (Möller et al, Acta Oncol. 2003, Mackillop et al, IJROBP, 1999 and Huang et al, JCO, 2001) Palliative Intent: Quality of Life Symptom Control (pain, neurological deficits, etc) Semin Radiat Oncol, 17:2007 Effective Treatment : 8 Gy in 1 fx Probability of pain relief: > 70% Probability of re-treatment: 20% (Chow et al, Meta-analysis, JCO 2007) 6

7 On-line technique workflow Online Palliative On-line Session Summary of the Online Technique Same staffing than conventional technique Timing comparison Task Simulation Planning Treatment Online Technique 37.4 ± 6.0 min Conventional Technique 30 min 90 min min First treatment: 30 min time slot Incentive for single fraction treatment Summary widely available Low residual error Automated match and shift tools Paradigm shift Soft-tissue OAR avoidance as well as target coverage On-line planning and delivery 7

8 Acknowledgements PMH Daniel Letourneau, Graham Wilson, Mike Sharpe, Tim Craig, Amin Nurul, Hina Akmal, Dave Lewis, Terry Michaelson, Steve Ansell, Bern Norrlinger, Jason Smale, Noor Mail, Jean-Pierre Bissonnette, Tom Purdie, David Jaffray Laura Dawson, Cynthia Menard, Winnie Li, Sophie Foxcroft Andrea McNiven, Lee Chin, Aaron vandermeer, Xia Wu, Claire McCann Elekta/Impac Kevin Brown, Jill Stief, Andrew Long, Lindsay Watt, Tony Manfredi, Leon Tomzyck Varian Keith Stinson, Peter Munro, Bob Tonks, Mika Miettinen, Corey Zankowski Image courtesy of michael.trauttmansdorff.ca 8