achieving low-gradient field matching with...
TRANSCRIPT
![Page 1: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/1.jpg)
©2016 MFMER | slide-1
Achieving Low-Gradient Field Matching with VMATCraniospinal and Beyond
Pam Lemish, CMD, RTTMayo Clinic Arizona
AAMD 41st Annual Meeting, Atlanta, GeorgiaJune 12, 2016
![Page 2: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/2.jpg)
©2016 MFMER | slide-2
Mayo Clinic Arizona Department of Radiation Oncology
• Two Campus Locations –Scottsdale and Phoenix
• 5 linear accelerators• 2 CT Simulators • IORT• Brachytherapy HDR• 6 photon dosimetrists• 8 medical physicists
![Page 3: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/3.jpg)
©2016 MFMER | slide-3
Pediatric Radiation Oncology Program at Mayo Clinic Arizona
Joint collaboration to provide radiation oncology services for Phoenix Children's Hospital
![Page 4: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/4.jpg)
©2016 MFMER | slide-4
History of Pediatric Radiation Oncology Treatments
• Radiation Oncology Department in Arizona opened in 1988
• No pediatric department at Mayo Arizona • First patient January of 2014• First patient CSI with Posterior Fossa and Spine
Boost• Three staff pediatric radiation oncologists• Currently treat approximately 4-6 pediatric
patients per day
![Page 5: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/5.jpg)
©2016 MFMER | slide-5
Objective
Demonstrate a versatile and adaptable method for planning craniospinal treatments utilizing Volumetric Modulated Arc Therapy (VMAT) therefore eliminating the need for match line shifts.
![Page 6: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/6.jpg)
©2016 MFMER | slide-6
Outline
• Describe the planning process of low gradient field matching with VMAT for CSI
• Apply the VMAT low dose gradient method to other cases requiring matching fields
• Case DescriptionsCSIHodgkin’s LymphomaHead and NeckMetastatic Lumbar SpineWhole Thorax and Abdomen
![Page 7: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/7.jpg)
©2016 MFMER | slide-7
Dangerous Gradients
• What is a low gradient field junction ?
• Why is a low-gradient field junction better than conventionally matched fields ?
![Page 8: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/8.jpg)
©2016 MFMER | slide-8
High Gradient Profile
![Page 9: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/9.jpg)
©2016 MFMER | slide-9
Junction Gradients
![Page 10: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/10.jpg)
©2016 MFMER | slide-10
Low Gradient Profiles
![Page 11: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/11.jpg)
©2016 MFMER | slide-11
CSI Treatment : Goals• Streamlined, reproducible setup• Efficient method of imaging• Straightforward and timely delivery to reduce
time under anesthesia• Class solution method of treatment planning for
dosimetry• No match line shifts
![Page 12: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/12.jpg)
©2016 MFMER | slide-12
Comparison of Methods for planning CSI• Hybrid Forward and Inverse Planned IMRT
• 3 field method and Single Posterior Field
• VMAT – Forward Planning for BrainVMAT Planning for Spine
![Page 13: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/13.jpg)
©2016 MFMER | slide-13
CSI Technique Comparison
Single spine field Post LPO-RPO VMAT
![Page 14: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/14.jpg)
©2016 MFMER | slide-14
CSI Technique Comparison
Plan HeartMean < 1100 cGy
Lung TotalMean < 1000 cGy
R Kidney Mean <1000 cGy
L Kidney Mean<1000 cGy
140 SSDSingle spine
1793 cGy 702 cGy 603 cGy 764 cGy
3 Field IMRT 896 cGy 1108 cGy 987 cGy 993 cGy
VMAT 844 cGy 1062 cGy 811 cGy 832 cGy
![Page 15: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/15.jpg)
©2016 MFMER | slide-15
CSI - Workflow• Standard simulation procedure• Planning method must have good quality
dosimetrically and be practical to deliver and with the possibility for quick turn around
• Clearly define for the therapists anatomic landmarks and tolerances for setup
• At what point is the spine straight enough?• Imaging – Use of “bounding box”
![Page 16: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/16.jpg)
©2016 MFMER | slide-16
• Impact of head tilt (5º); 3mm PTV
CSI: Treatment Tolerances (Lateral FinF Brain)
lenses
PTV
cochlea
![Page 17: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/17.jpg)
©2016 MFMER | slide-17
CSI : Treatment TolerancesWhen is the spine “straight enough”
PTVCTV
2 mm L/R setup error
4 mm L/R setup error(1% reduction of CTV D95%)
PTVCTV
![Page 18: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/18.jpg)
©2016 MFMER | slide-18
Bounding Box for KV Imaging
![Page 19: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/19.jpg)
©2016 MFMER | slide-19
It all begins with the immobilization ……..
![Page 20: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/20.jpg)
©2016 MFMER | slide-20
CSI : Simulation• Managing multiple-isocenter delivery
• Head tilt reproducibility• Stretching of neck• Spine straightness• Smooth workflow to reduce anesthesia time
![Page 21: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/21.jpg)
©2016 MFMER | slide-21
Planning Targets
• CTV spine – Spinal cord and nerve roots• CTV brain - brain• PTV brain – 3 mm expansion of CTV brain• PTV spine – 5 mm expansion of CTV spine
![Page 22: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/22.jpg)
©2016 MFMER | slide-22
OAR Structures
• Cribiform plate• Lenses• Eyes • Cochlea• Lungs • Heart• Kidneys
![Page 23: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/23.jpg)
©2016 MFMER | slide-23
CSI: Set Field IsocentersBrain and Lower Spine
Brain iso10.0 cm Superior to shoulder
Lower spine iso40 cm length field2.0 cm inferior to PTV
![Page 24: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/24.jpg)
©2016 MFMER | slide-24
CSI: All Field Isocenters
![Page 25: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/25.jpg)
©2016 MFMER | slide-25
Create PTV Segments
1:Jxn01
1:Jxn10
Midspine opt
Low spine opt
![Page 26: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/26.jpg)
©2016 MFMER | slide-26
Whole Brain FiF to Create Low Gradient Junction
![Page 27: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/27.jpg)
©2016 MFMER | slide-27
Whole Brain FiF to Create Low Gradient Junction
![Page 28: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/28.jpg)
©2016 MFMER | slide-28
Whole Brain FiF to Create Low Gradient Junction
![Page 29: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/29.jpg)
©2016 MFMER | slide-29
Dose profile of Forward Planned Brain
![Page 30: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/30.jpg)
©2016 MFMER | slide-30
Field in Field Gradient with MLC
Incorrect Taper Correct Taper
![Page 31: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/31.jpg)
©2016 MFMER | slide-31
Lower Spine - Optimization
![Page 32: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/32.jpg)
©2016 MFMER | slide-32
Dose profile Lower Spine
![Page 33: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/33.jpg)
©2016 MFMER | slide-33
Dose profile Lower Spine – Adjust
![Page 34: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/34.jpg)
©2016 MFMER | slide-34
Reoptimize
![Page 35: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/35.jpg)
©2016 MFMER | slide-35
Sum PlanBrain and Lower Spine
Use as base plan for Upper Spine Optimization
![Page 36: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/36.jpg)
©2016 MFMER | slide-36
Final optimization – Mid Spine
![Page 37: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/37.jpg)
©2016 MFMER | slide-37
Final CSI Plan
HeartMean < 1100 cGy
Lung TotalMean < 1000 cGy
R Kidney Mean <1000 cGy
L Kidney Mean<1000 Gy
1076 cGy 631 cGy 826 cGy 626cGy
PTV Coverage = 97.7%
Sum Plan of Brain , Upper and Lower Spine
![Page 38: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/38.jpg)
©2016 MFMER | slide-38
And Beyond …….
![Page 39: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/39.jpg)
©2016 MFMER | slide-39
Case 2 • 15 year old male• Hodgkin’s Lymphoma Stage IIB• Neck, and intra-thoracic nodal involvement• Chemotherapy prior to radiation
![Page 40: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/40.jpg)
©2016 MFMER | slide-40
Target DVH Objectives• PTV – 21 Gy• Heart – Mean dose < 11Gy• Total Lung – Mean dose < 8 Gy
V13Gy <20%V18Gy <15%
Larynx - < 10 GyCord – Max < 22 GyLeft Ventricle - < 8 Gy
![Page 41: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/41.jpg)
©2016 MFMER | slide-41
PTV Volume
![Page 42: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/42.jpg)
©2016 MFMER | slide-42
Treatment Planning : VMAT Only
![Page 43: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/43.jpg)
©2016 MFMER | slide-43
Issues with VMAT Only Treatment Plan
• PTV Coverage Low • Decrease larynx, esophagus lung and thyroid
dose
![Page 44: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/44.jpg)
©2016 MFMER | slide-44
Create a Low Dose Gradiant Plan• Split PTV Volume into Upper and Lower• Create 5.0 cm or more gradient between upper
and lower fields with FiF segments• Create a VMAT plan for the inferior portion of
the PTV volume using the Upper plan as a base dose plan
![Page 45: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/45.jpg)
©2016 MFMER | slide-45
Create a dose taper at the inferior edge of field with Forward planning Field in Field
![Page 46: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/46.jpg)
©2016 MFMER | slide-46
Dose Taper
![Page 47: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/47.jpg)
©2016 MFMER | slide-47
Approved vs. Rejected Plan: Spot the difference
![Page 48: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/48.jpg)
©2016 MFMER | slide-48
Approved vs. Rejected Plan: Spot the difference
![Page 49: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/49.jpg)
©2016 MFMER | slide-49
Approved vs. Rejected Plan: Spot the difference
![Page 50: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/50.jpg)
©2016 MFMER | slide-50
Case 3• 72 year old male• Newly diagnosed Merkel Cell of Left Eyebrow• S/P wide excision and sentinel node biopsy• Treated with adjuvant radiation therapy
![Page 51: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/51.jpg)
©2016 MFMER | slide-51
Left Eyebrow and ScalpNeck Nodes
![Page 52: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/52.jpg)
©2016 MFMER | slide-52
Initial Plan – No Change in Electron Cutout
![Page 53: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/53.jpg)
©2016 MFMER | slide-53
Dose ProfileNo Electron Cutout Change
![Page 54: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/54.jpg)
©2016 MFMER | slide-54
Left Eyebrow and Scalp
![Page 55: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/55.jpg)
©2016 MFMER | slide-55
![Page 56: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/56.jpg)
©2016 MFMER | slide-56
Combined Dose Profile
![Page 57: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/57.jpg)
©2016 MFMER | slide-57
Case 4
• 76 year old male with Stage T3N1 Esophagus Ca• Underwent neo adjuvant Chemo / RT • 4500 cGy / 5000 cGy / 25 fractions• Surgical Resection with IORT 1000 cGy / 1 Fraction• Subsequently presents with metastatic disease in the
region of L1 and surrounding soft tissue
![Page 58: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/58.jpg)
©2016 MFMER | slide-58
Target DVH Objectives• PTV – 28 Gy / 3.5 Gy per Fraction• Cord dose –
• Prior dose to cord in adjacent region ranging from 26 Gy to 40 Gy
• Duodenum, colon, kidneys skin and caudaequina
![Page 59: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/59.jpg)
©2016 MFMER | slide-59
Previous Dose from Esophagus Treatment
![Page 60: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/60.jpg)
©2016 MFMER | slide-60
Approved vs. Rejected Plan
![Page 61: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/61.jpg)
©2016 MFMER | slide-61
Case 5• 31 yo male with Anaplastic Ependymoma• CSI to 3600 cGy in 2011• Areas of disease to 4500 cGy• Recurrent disease in 2015• Re-treat symptomatic lumbar area in 2015
![Page 62: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/62.jpg)
©2016 MFMER | slide-62
CSI Treatment 2011
![Page 63: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/63.jpg)
©2016 MFMER | slide-63
Low Gradient Plan T11-L2
![Page 64: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/64.jpg)
©2016 MFMER | slide-64
Mayo Clinic Proton Beam Therapy
![Page 65: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/65.jpg)
©2016 MFMER | slide-65
Proton Plan- Retreat CSI Low Gradient Junction in Boost Area
![Page 66: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/66.jpg)
©2016 MFMER | slide-66
Proton Plan- Retreat CSI Low Gradient Junction in Boost Area
![Page 67: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/67.jpg)
©2016 MFMER | slide-67
Conclusion• TPS generated junctions may not provide as
much control over the gradient as manual methods.
• Manually creating low gradient junctions and maintaining a sufficient overlap distance allows more control within the region of the field junction while maintaining uniform dose distributions
![Page 68: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/68.jpg)
©2016 MFMER | slide-68
Thank you• Josh Stoker, PhD• Thomas Daniels, MD• Sameer Keole, MD• Samir Patel, MD• William Rule, MD• Sujay Vora, MD
![Page 69: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/69.jpg)
©2016 MFMER | slide-69
Thank you• Denise Mead, CMD• Katie O’Leary, CMD• Christie Schulz, CMD• Marsha Buzan, CMD• Gabriel Lee, CMD• Pedro Lara, CMD
![Page 70: Achieving Low-Gradient Field Matching with VMATatlanta2016.medicaldosimetry.org/2016AnnualConference/assets/File/Sunday/Lemish.pdf©2016 MFMER | slide-1 Achieving Low-Gradient Field](https://reader030.vdocument.in/reader030/viewer/2022040907/5e7e965821bc5139c052abe1/html5/thumbnails/70.jpg)
©2016 MFMER | slide-70
Questions ?