SMART Stereotactic MR-guided adaptive radiotherapy Department of Radiation Oncology Marloes Jeulink Omar Bohoudi
First clinical treatment May 4th 2016 First clinical treatment May 4 th 2016
MR-guided RT system: MRIdian MRI 0.35 T 70 cm bore 50 cm FOV Real-time imaging 4 FPS RT 3 Co-60 sources 550cGy/min Full divergent MLCs Tx =27cmx27cm TPS Monte Carlo Very fast Online ART SOURCE: VIEWRAY.COM
SOURCE: VIEWRAY.COM MR-guided RT system: MRIdian
SOURCE: VIEWRAY.COM The MRIdian Linac System
The MRIdian Linac System MRI 0.35 T 70 cm bore 50 cm FOV Real-time imaging 8 FPS SOURCE: VIEWRAY.COM RT 6 MV FFF >600cGy/min Double-Focused Double Stacked Tx =27cmx24cm Tx = 0.4x0.2cm TPS Monte Carlo Very fast Online ART
The MRIdian Linac RAYZR MLC DOUBLE FOCUSSED SOURCE: VIEWRAY.COM
Clinically available sequences Siemens 0.35T TrueFISP (Fast Imaging Steady-state Precession) T2/T1 ratio image contrast, fluids high signal 1.5 2 X 1.5 mm = 172 sec (~ 3 min) 1.5 2 X 3.0 mm = 25 sec Fast acquisition, less sensitive to motion 1.5 2 X 1.5 mm = 172 sec (~ 3 min) SOURCE: VIEWRAY.COM 8
Image quality on the MRIdian
Image quality on the MRIdian Cranial Bladder wall Vesicles Fibromuscular zone Middle Apex Marginal zone Peripheral zone Neurovasc bundle Ischiorectal fossa
MRI safety 11
SMART patients Stereotactic MR guided Adaptive Radiation Therapy
Pre-treatment workflow Patient information Patient Positioning (Breathhold) CT+ MR Delineation GTV and OAR Adaptive Treatment plan generation QA
Patient immobilization
Classic workflow MR+CT Contouring Treatment planning QA treatment
SMART basis treatment plan Not an end product Point of departure for adaptive setting Basisplan MR Match Deformatie Recontouring Electron Density check Plan prediction Reoptimisation QA Treatment treatm
Treatment plan adaptive setting What doesn t change online: Physicians intent - prescription Beam angles Optimization objectives
Treatment plan adaptive setting What does change online: Anatomy MRI imaging Electron density Treatment planning structures Segments (amount, duration, shape) Dose distribution
Electron density
Electron density Deformable Fusion
Electron density
Electron Density online adaptive
Case study: electron density Simulation MRI
Case study: electron density MRI first fraction
Case study: electron density Elektron Density
Would you correct the electron density? Uncorrected electron density Corrected electron density
Case study: dose on electron Density
Contouring
Contouring
Contouring
Contouring
Contouring
Contouring
Contouring
Contouring
Contouring
Contouring
Isocenter location Limited by MR bore
Effects isocenter location
Imaging duringtracking
41 Beam group
Mridian IMRT optimalisatie
Robust plan objectives
SMART delivery workflow Patient positioning Pilot scan HR scan (breath-hold) Setup on GTV (rigid match) Project and deform OAR Independent QA Adapt plan Predict dose Electron density check Adjust deformed contours (within 3cm) Verificate positioning Set gating window (3mm) Treatment delivery (breathhold)
SMART delivery workflow 1. Patient positioning with coils 2. Perform pilot scan (23 sec) 3. Rough alignment with planning MRI 4. Select appropriate FOV 5. Perform high-resolution MRI ( 3 min) 6. Deform (and adapt) skin contour 7. Perform couch shift
Online adaptive strategy: contouring High-dose region matters most for toxicity (certainly in SBRT) Deformation is an aid, but not perfect Fast: patient is on table in treatment position Accurate: dealing with the relevant high dose region Manual adjustment of deformed OAR contours in area 3 cm outside the PTV
Improved sparing duodenum/ stomach Improved coverage GTV/PTV
Delivery video feedback system
Video feedback system
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Smart components Positioning Scan & match Re-contouring* Re-planning* QA check* Treatment time 2 min 16 min * 5 min * * 8 min 9 min 7 min
PRO-Q responses first 150 patients Was it difficult to control the target by holding your breath? Was it confronting to see your tumor during the treatment? Did you like having an active role during treatment? Not at all A bit Moderate Considerable Did you worry about your contribution to the treatment? 0% 20% 40% 60% 80% 100%
PRO-Q responses first 150 patients Anxiety Noise Cold yes considerable Paresthesia Heat Dizziness Metallic taste Light sensations 0% 20% 40% 60% 80% 100%
Thank you Chair: Ben Slotman Clinicians: Anna Bruynzeel Suresh Senan Niels Haasbeek Swie Swat Oei Shyama Tetar Frank Lagerwaard Clinical Physicists: Miguel Palacios Tezontl Rosario Marjan Admiraal Johan Cuijpers Technicians: Daan Hoffmans Karel de Jong Frank de Geest Dosimetrists: Omar Bohoudi Jessica Oudeboon Robin Botman Roosje Bakker Emile Koper Paul Duijvenvoorde Ruud de Moes Marloes Jeulink Lisanne Labee