hippocampal sparing whole brain rt
TRANSCRIPT
1 | VARIAN ONCOLOGY SYSTEMS | VARIAN CONFIDENTIAL/PROPRIETARY: DISCLOSED SOLELY FOR IMMEDIATE RECIPIENT ONLY
• Anthony Magliari
Hippocampal sparing whole brain RT
2 | VARIAN ONCOLOGY SYSTEMS | VARIAN CONFIDENTIAL/PROPRIETARY: DISCLOSED SOLELY FOR IMMEDIATE RECIPIENT ONLY
Conflict of Interest disclosure
• Anthony Magliari
• Employed by Varian Medical Systems
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Overview
• What is HCSWB-RT?
• Why do it?
• What protocols exist?
• Beam arrangements
• Optimization strategies
• Additional resources
• 2015 AAMD / Sun Nuclear Plan Challenge
• 2016 AAMD Hippocampal Sparing presentation by Timothy Oh
• Knowledge Based Planning solution (RapidPlan) on Oncopeer
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What is Hippocampal Sparing WBRT?
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Why HCSWB-RT?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2997490/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3462659/
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Protocols: RTOG 0933 / NRG-CC001
• RTOG 0933 superseded by…
• NRG-CC001 (30Gy in 10Fx)
“treatment-planning
priorities should be
followed:
1. OpticChiasm
2. OpticNerve_L
OpticNerve_R
3. Hippocampus
4. PTV_3000
5. Lens_L or
Lens_R”
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Other Protocols / planning guides
• NRG-CC003 (Prophylactic Cranial Irradiation) • 25Gy in 10 Fx
• Scaled down version of NRG-CC001
• Prokic V, et al (Whole Brain Irradiation With Hippocampal
Sparing and Dose Escalation on Multiple Brain Metastases:
A Planning Study on Treatment Concepts) • 30Gy in 12Fx with SIB for metastasis to 51Gy
• http://www.redjournal.org/article/S0360-3016(12)00302-1/pdf
• 2015 AAMD / Sun Nuclear Plan Challenge • Combined Rx from Prokic V with RTOG 0933 contraints, and more
• http://planchallenge.sunnuclear.com/
• Oncopeer Rapidplan Solution and Description Document • 30Gy in 10 Fx with 7Gy HCS goal and constraints from all the above
• Posted by Rob Foster http://www.oncopeer.com • menu > my groups > RapidPlan – Model Sharing > activity
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Beam arrangements
• Preferred: 3 or 4 arcs (6X or 6X FFF) • 2 non-coplanar arcs 315*/45* collimator and 1 or 2 vertex ½ arcs
• Vertex ½ arc 90* couch and MLCs parallel to arc direction (0*) or
• Vertex ½ arcs 90* couch and 315*/45* collimator
• Check jaws to ensure arcs open to entire brain throughout rotations
• 2 non coplanar arcs, same as above no vertex
• Non coplanar partial arcs with “sub PTVs” • Shen J, et al Medical Dosimetry journal
• Referenced in Timothy Oh’s 2016 AAMD presentation
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Beam arrangements
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Optimization
• General tips
• Ask for reasonable goals (don’t drastically overshoot)
• Never create conflicts in the optimizer
• Use and tune with NTO (“rings” normally unnecessary in Eclipse)
• Let the total cost function line get completely flat
• Pause VMAT optimizer at each step
• Increase max seconds for static field IMRT
• Specific tips
• Understand the lower you push dose to the Hippocampus the more
heterogeneous (hot spots), 115-120% Dmax not abnormal and OK
• Use a “PTVopt” with an expansion from the hippocampus of 7-8mm
when shooting for ~7Gy min dose
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Optimization
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Other resources: 2015 plan challenge
• Includes video interviews with top performers from all TPS • http://planchallenge.sunnuclear.com/webinars
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Other resources: 2016 AAMD meeting http://atlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Wednesday/Oh.pdf
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Other resources: RapidPlan on Oncopeer
https://varian.app.box.com/v/HCSWB
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Questions?
• Anthony Magliari