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ELEKTA LUNCH and LEARN

VMAT and SBRT with Monaco

Lori SlackManager Medical Dosimetry

Radiation OncologyAllegheny Health Network

Acknowledgements

This presentation would not have been possible without the help of:

Ellen Day, PhDSenior Physicist, Allegheny Health Network-

Physicist, co-worker and friend.

A special thank you to Elekta for inviting me to speak today

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Disclosures

• No conflict of interest to disclose

• Elekta has partially funded my trip

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Allegheny Health Network Department of Radiation Oncology

ICCC

Somerset

Armstrong

Allegheny Valley

Trinity

West Penn

Peters

Wexford HWP

Clarion

Jefferson

AGH

What are we talking about?

• Monaco 5.1

• SBRT

• VMAT

• Monaco 5.11

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Monaco Planning

Utilizes Monte Carlo and Collapsed Cone algorithmsBiological modelingMulti-Criterial goalsConstrained optimizationSensitivity AnalysisBias Dose PlanningMultiple PrescriptionsForward planningDicom recalculation from any RTPFrozen Dose

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Monaco = True Monte Carlo Planning

• Continuous arc calculation (not limited to dose approximations)

• Sharper dose gradients in SRS targets

• Better sparing of critical structures

• Highly conformal dose distribution

• Allows more modulation where required

Monaco 5.1

• Upgraded to 5.1 March 2016

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Monaco 5.1 Benefits of new features

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• Ability to import plans from 3rd party TPS systems for recalculation with Monte Carlo AlgorithmImport of MLC Segmented Plans

• Ability to import/export templates within Monaco systems for sharing, reduce learning curve and speed up the planning timeTemplate Manager

• Improved Step and Shoot SSO routine for better plan qualitySequencer Improvements

• Ability to manually create, edit, and delete segments for static beamsForward Planning Tool

• Ability to create multi-modality, composite and integrated bias dose plans from within the same plan file.Multiple Rx

• Ability to plan on MR images using bulk density overridesMR Planning

• Ability to recall, edit and retain existing dose and plan integrity when making changes that invalidate dose.Frozen Dose

• Ability to create structure templates for import into patientsAnatomical Groups

• Ability to save and apply isodose templatesIsodose Templates

• New registration algorithm for image fusionPoint to Point Registration

• Ability to create MIPs, MinIPs and AVG images from 4D image sets4D Specialty Images

• Monaco 5.1 allows 3 concurrent sessions per userConcurrent Sessions

Import of MLC Segmented Plans

Ability to import plans from 3rd party TPS systems for recalculation with Monte Carlo Algorithm.

This allows the system to acknowledge any dose that was previously given to an OAR or Target and include that dose in the new plan when calculating.

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Template Manager (Import/Export)

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Forward Planning

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Multiple Rx

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Multiple Rx

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Frozen Dose

• Dose no longer deleted when adding/editing/deleting structure that doesn’t affect dose calculation

The following conditions cause plans to be frozen:• CT to ED file replaced

• External structure is modified

• Internal Structure with ED is modified

• Assigned bolus or couch structure is modified or assigned/unassigned

• MLCGeometry, MLCDynamics or MLCLeakage are modified (Settings, Physics)

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Frozen Dose

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User can choose what to do when loading plan with Frozen Dose:

Frozen Dose

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Frozen Dose Warning in T/S/C views and reports

SBRT

(Stereotactic Body Radiation Therapy )

SBRT

• Why so much SBRT• Because your clinic and your Physicians want to do it

• Because you did SBRT lung so you can treat anything SBRT

• Because we want to keep the Physicians happy!

SBRT Monte Carlo

• Provides an accurate dose representation in the periphery of the tumor• Most algorithms underestimate in this specific area especially in the lung

• Uses XVMC for accurate dose calculation

• Shows the true point maximum doses• Important for serial OARS

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History of SBRT at Allegheny Health Network

• Started treating SBRT in 2007 @ AGH then moved out to the other sites • Siemens Machine

• Treat with the Artiste and Primus

– Artiste 6X only

• Elekta machines• Resubmitted beam data for small field modelling (September 2015)

– During validation it was noticed that the small fields needed to be remodeled

• Received new beams from Elekta and starting to validate (November 2015)

– Created one model for all three Elekta machines

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SBRT at Allegheny Health Network

• Sites treated with SBRT• Lung

• Liver

• Spine

• Pancreas

• Prostate (Occasionally)

• Anything else the Physician wants

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SBRT Dose Prescriptions

• Lung• 1200 x 4 • Central lesion (800 X 5) OR (900 X 5)

• Liver• 1200 x 4

• Spine• 800 x 3

• 1350 x1

• Pancreas• 500-600 x 5

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SBRT - like it a bit better

• SBRT at Allegheny General.• XiO

• SBRT on Monaco• Prior to Monaco 5.1 planning SBRT was so slow

• Put your beams on

• Set your prescription

• Make sure the calculation properties are correct

• Run the calculation

• Modify one leaf, loose the dose

• Run the calculation, modify one leaf

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SBRT Monaco 5.1

• Move a leaf and the dose stays • This is huge

• Grid Spacing• 2mm grid for small lesions

• Calculation Properties• Per Control point

• Per Calculation

– Which one do I use

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SBRT XiO vs Monaco

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MonacoXiO

SBRT IMRT Spine (L Spinal Neuroma)1350cGy in 1 Fx -planned in Monaco due to the bone-tissue interface and the fact that the tumor was so small.

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Elekta 10X Artiste 6X

IMRT Constraints

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HWP Elekta

AGH Artiste

SBRT IMRT Spine DVH

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Questions

VMAT

(Volumetric Modulated Arc Therapy)

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History VMAT

January 2011

Monaco was used to treat a VMAT plan at St. James University Hospital in the UKAfter fully understanding Monaco, a head and neck VMAT can be completed in two to three hours after contouring,

“Monaco has transformed our IMRT service” Dr. Cosgrove

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VMAT at Allegheny Health Network

• Went live with VMAT March 2016• Biggest hold up

• 14 Physicists..

– DO they know when to stop

• Created a single beam for all three Elekta LINACS they are matched• Prior to go live

– Test plans (~ 25) were created and delivered to a solid water phantom (Cheese) that has different plug locations and a chamber measurement recorded.

– The test plans were delivered to the ArcCheck device and chamber measurements recorded.

• Use the ArcCheck device from Sun-nuclear with the multiplug for QA of the VMAT plans.

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3DVH (Chamber position locator)

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ArcCheck

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Verification of VMAT

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Arc Check ArcCheck Chamber2% 2mm 3% 3mm

L4 L5 95.8 99.5 -1.60%Prostate 96.7 99.3 -0.70%Prostate 99 100 -0.50%Brain 92.6 99.3 -1.70%

What is VMAT

• VMAT = Volumetric Modulated Arc Therapy

• Monaco VMAT allows for full or partial arcs and creates the desired radiation field by modulating the gantry speed, MLC speed and direction and dose rate

• Beam is broken into Arc segments that are specified at time of planning

• All initial arc segments will contain the full number of degrees while the last arc segment will use up the remainder. (100 degrees/20 = 3 full segments of 30 degrees + 1 partial segment which moves 10 degrees)

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Monaco VMAT Algorithm Stage 1

• Optimized fluence maps are produced at a series of discrete beam angles

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Monaco VMAT Algorithm Stage 2

• These optimized fluence are then converted into deliverable VMAT arcs with segments

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Spot the difference

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MLC’s cause a lot of problems but they are a fact of life

VMAT vs IMRT XiO

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VMAT vs IMRT

Prostate

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Constraints

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Acts like a Max Acts like a Mean

Beam Sequencing

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IMRT vs VMAT

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VMAT non vs VMAT

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DVH Orbit

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VMAT and SBRT combined

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DVH

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Calculation considerations

• IMRT Parameters

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Treatment Time Comparison

Average VMAT plan vs. Average IMRT plan

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MU Segments Treatment TimeHead and Neck VMAT 2 Arcs 664.56 169 3 minutes

IMRT 9 Fields 588.43 132 8 minutesProstate VMAT 1 Arc 611.2 78 2 minutes

IMRT 7 Fields 423.7 117 6 minutesProstate VMAT 1 Arc 533.2 96 2 minutes

IMRT 7 Fields 428.1 104 6 minutesProstate and Nodes VMAT 2 Arcs 683.1 154 4 minutes

IMRT 7 Fields 457.5 126 5 minutes

Monaco 5.1 Summary

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Speed Comparison

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Monaco – Speed Improvements

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In Conclusion:

As we expand our department and increase our ease with Monaco planning, I am looking forward to using this system exclusively.

Our SBRT and VMAT programs continue to expand rapidly and our dosimetrists are embracing the challenge of learning and perfecting the plans that they are producing.

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Questions?

Thank You