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Palliative Radiotherapy Using Cone Beam Ct
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Palliative Radiotherapy Using Cone Beam Ct

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  • 1. A One Step Model for Online Planning and Treatment for Palliative Radiotherapy using Cone Beam CT David Fitzpatrick, Anita Vloet, Daniel Letourneau, Rebecca Wong, Mary Gospodarowicz, David A Jaffray 5th Annual Toronto Radiation Medicine Conference Kingbridge Sunday 27 April 2008
  • 2. Background • Palliative radiation should be effective yet fast • Uses simple Techniques – Ant/Post opposed fields – A Direct field • Conventional CT planning – a multistep process – can take a few hours to 1-2 days • 2D planning – Quicker than CT planning – But lacks dosimetric information
  • 3. Cone Beam CT (CBCT) • CBCT scan images can be rapidly acquired on an RT treatment unit • CBCT established for Image Guided RT Jaffray, Kupelian at al Expert Rev Anticancer Therapy 2007 • CBCT recently developed to permit image quality sufficient for treatment planning Letourneau, Wong et al IJROBP 2007. Sharpe, Moseley et al Med Physics 2006.
  • 4. Conventional CT Simulation (PCT) Planning and RT Time: Many Hours to 1-2 Days Volumetric Imaging Planning QA and IGRT 3
  • 5. Conventional Planning Process PLANNING CT PT WAITS FOR RT EXPORT IMAGES TO TPS CONTOURING PLANNING + DR APPROVAL PHYSICS QA QA ROOM WEB PUBLISHING EXPORT PLAN TO RT UNIT TREATMENT UNIT PT SET UP + IGRT PT HAS RT TREATMENT DELIVERY
  • 6. Study Objective To Replace a multistep PCT process by a 1 step 30 min appointment at the treatment unit. A CBCT enabled Online Treatment Strategy Volumetric Imaging Online Planning QA Delivery and IGRT 3
  • 7. Methods • Phase A – Is the image quality adequate for planning? • Spine, Mediastinum, Abdomen/Pelvis • Suitable for CT planning • n = 3x3 • Phase B – Trial on-line planning within the clinical environment – n = 45 (15 spine, 15 thoracic, 15 abdomen/pelvis) • Phase C – Testing the efficacy of the established on-line planning system to treat patients. – n = 60 (15 spine + 15 bone, 15 thoracic, 15 abdomen/pelvis)
  • 8. Methods • Outcomes – Agreement between CBCT and PCT defined GTV – Adequacy of coverage of PCT generated PTV by CBCT plan 90% isodose – Time – Patient satisfaction rates
  • 9. Phase A OVERCOVERAGE by CBCT v PCT Spine or mediastinum or abdominal disease CBCT For palliative RT Overlap Conventional Planning CT (PCT) Cone beam capable treatment unit PCT DRR UNDERCOVERAGE by CBCT v PCT
  • 10. Phase A GEOGRAPHIC AREA COMPARISON CBCT/PCT CBCT/DRR PCT/DRR Mean ±SD% Mean ±SD% Mean ±SD% 46 ± 61 42 ± 47 11 % UC 31 ± 34 29 ± 34 11 % OC 57 ±17 57 ±16 80 % Overlap
  • 11. Phase B Spine Mediastinum For Pall RT Abdomen/Pelvis PCT plan used to treat patient During 1 fraction of treatment a CBCTscan acquired images and CBCT study plan generated
  • 12. CBCT Plan vs PCT Plan Spine Mediastinum/ Abdomen pelvis lung Field Area Field Area Field Area mean (SD) mean (SD) mean (SD) n = 13* n = 15 n = 16 % UC 12 (13) 18 (16) 20 (15) % OC 15 (21) 21 (24) 10 (13) % OL 89 (13) 82 (15) 80 (15)
  • 13. Phase B • Adequacy of CBCT plan CBCT plan 90% isodose line 90% isodose coverage of PCT generated PTV - Spine - 93 + 11 % PTVPCT - Mediast – 89 + 15% - Abd/Pelvis – 92 + 5%
  • 14. Phase B - Timing results CBCT Planning CT Patient or Planning CT Institution's Institution's perspective Patient's Perspective Perspective Total Time 28+/- 8 min 30 +/- 12 min 149 +/- 78 min
  • 15. Phase B C Phase Bone only to date 1 Step Process Mediastinum Patient Set Up Abdomen/Pelvis PCT CBCT Image Acquisition Process: Exported to TPS Images Define PTV Cone beam scan GTV PCT Fields PCT Planning acquired on treatment unit and CBCT Time PCT Plan Published generated plan used to Pt satisfaction PCTPlan to RT unit Export treat patient Dr. Approval + QA IGRT CBCT Conventional Planning CT Treatment Delivery for Retrospective validation
  • 16. Phase C Elapsed Time (10 spine patients) Task Time (min) Professional Patient Walk in and Setup 8.3 ± 2.2 MRT(T) CBCT Acquisition and Export 6.3 ± 2.1 MRT(T) and Planner Dr Contouring 3.4 ± 1.3 RO Planning / Export / WebPub 9.9 ± 3.0 Planner QA_Phys, RO and QA, Approval and CBCT #2 8.7 ± 2.6 MRT(T) Treatment Delivery 2.5 ± 0.5 MRT(T) Patient Walk out 2.3 ± 1.0 MRT(T) Total ------ 39.3 ± 6.8 MRT(T): Therapist, RO: Radiation oncologist and QA_Phys: QA physicist
  • 17. Phase C Total Elapsed Time (10 patients)
  • 18. Satisfaction data 1= strongly agree, 2 = agree, 3 neither agree/disagree, 4 disagree, 5 strongly disagree Median (Range) Previous XRT 4 Yes 3 no (3 NA) Planning and treatment process uncomfortable 4 (3-5) Inconvenient 4 (2-5) Process difficult 4 (4-5) Difficulty lying in position 3.5 (1-5) Took a long time 3.5 (2-5) Efficient 2 (1-5) Satisfied with care 1 (1-2)
  • 19. Clinical Advantages of 1 Step Online Planning and Treatment • 1 step (less handoffs) • Time efficiency from Institutional perspective • Weekend on call – Minimize pt transfer between units when staff minimal – Do not require staff trained to operate both CT Simulator and RT treatment unit • Same day Sim + Treatment start • Minimize delays due to sequencing between systems • Could potentially be used in developing countries for 3D simulation and Planning
  • 20. Thank You for Your Attention

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