Yam Ada
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Transcript of Yam Ada
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Image Guided Intensity ModulatedPhoton Radiation Therapy With
Non-Invasive Immobilization forHigh Dose Treatment of Primary
Tumors of the Spinal Column
Yoshiya (Josh) Yamada MD FRCPC, Mark H. Bilsky MD,Michael Lovelock PhD, Joan Zatcky NP, Zvi Fuks MD
Departments of Radiation Oncology, Medical Physics and Surgery,
Memorial Sloan-Kettering Cancer CenterNew York, New York
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Why Paraspinal IMRT?
Vexing clinicalproblem:
Significant morbidity
Spinal cord toleranceissues
Primary tumors
Metastatic tumors
Prior treatment
Tumor control mayrequire radiationdose greater thancord tolerance
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Radioresistant and Radiation
Dose: Conventional XRT
Metastatic PrimaryMyeloma Ewings Sarcoma
Lymphoma Neuroblastoma
Breast Carcinoma
Colon Carcinoma Superior Sulcus Tumors
NSCLCa
Thyroid Carcinoma Osteogenic Sarcoma
Renal Cell Carcinoma Chondrosarcoma
Sarcoma Chordoma
Melanoma
Sensitive
ModeratelySensitive
Moderately
Resistant
HighlyResistant
SuboptimaltreatmentHigher doses may
result in spinalcordtoxicity
Effectivetreatment
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Dose Matters: XRTFailure Analysis
141 patients with chordoma and chondrosarcoma of theskull base/cervical spine
Mixed proton beams 69 Co Gy (67 72)
26 failures
23% failed in prescribed dose region
58% failed in regions constrained by normal tissuetolerance
10% in surgical pathway 10% marginal miss
75% of failures occurred in areas with less than
prescribed dose
JP Austin et al. Int J Rad Oncol Biol Phys 1993; 25: 439 - 444
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Image-Guided Photon IMRT
Irradiating tumors tohigh doses beyondSC tolerance:
Accurate identificationof target and normalstructures
Treatment planning
Immobilization
Verification
Delivery
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IMRT: An Alternative to Proton
Beams ? Ideally suited for concave dose distributionsaround the spinal cord
Inverse treatment planning with constraints
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Cord Sparing Dose Intensity Map
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Primary Tumors (N=20)
PrescribedDose
7000 cGy 5940-7000 cGy
PTV (cc) 153 cc 86-316 cc
% PTV 90% 83-100%
Cord Max 68% 14-75%
Cord Ave (%) 31% 7-66%
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Immobilization
Non invasive image guided cradle immobilization Thoracic and pelvic pressure plates
Aquaplast mask
Alpha cradle support
MRI/CT compatible
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Set up Reproducibility
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Immobilization Performance
Immobilization determined by computing patient shift from start toend of treatment
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Image Guided Verification:EPID
Digital portal imageverification
Surgical Hardwareas Fiducial Markers
Calculatenecessary shiftwith imageoverlay
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Image Guided Verification
Fiducials
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2 D Image Guided Verification
Gold seed fiducials
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2 D Image Guided Verification
Fiducial
3 mm lateral shiftcorrection
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2 D Image Guided Verification
Fiducial Match
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3D Verification:Cone Beam CT
3-D to 3-D image matchingData for treatment plan modificationImplanted fiducial markers not necessaryLess than one minute to acquire imagesAutomated registration and set up correction calculationsRetrofit to existing LINACs
C B Fl i
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Cone Beam vs. FluroscopicImages
CT CT Verification (OBI):
Direct 3D to 3D comparison
Direct soft tissue visualization
On table simulation: 3D data
for treatment plan modification(weight loss, tumor responsesetc)
Fluroscopic 3D Verification
Indirect (2D to 3D) comparisonRelies on bony landmarks or radioopaque markers
Requires CT simulation for replan
I G id d V ifi ti
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Image Guided Verification3D to 3D Matching
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OBI Paraspinal Cone Beam Scan
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Other Advantages of Cone
Beam Less radiation for position verification
Cone beam CT 4-6 cGy
MV port film 2 cGy
Faster verification vs. portal imaging
Cone beam acquisition ~ 1 minute vs. multiple
port films Automated correction algorithms
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The Future with Cone Beam CT
Unleash the full potentialof IMRT
Reduce geometric uncertainties
Accuracy: Redefine PTV Increase Biologic Effective Dose
Hypofractionation/Single fraction radiotherapy
Real time treatment planning/modification True 4 D Conformal Therapy
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The Paradigm To DeliverAdequate Dose Safely
IMRT to spare the cord
Immobilization to reduce motion
uncertainties: Radiation is given as intended to tumor
and normal tissues
Verify isocenter position:Radiographic/Cone Beam CT
Correct for any set up errors
+/- 1 mm treatment accuracy
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Clinical Outcomes
N=20 Chondrosarcoma (5)
Other Sarcoma (9)
Chordoma (5)
Desmoid (1)
Median age=60 years (29-79)
Median follow up= 21 months (3-45) FU with MRI every 3 months
All patients followed until death
L l C t l P i
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Local Control PrimaryLesions
Local Control
0
10
2030
40
50
60
70
80
90
100
0 10 20 30 40 50
Months
Proportion Surviving
80%
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Overall Survival
Survival
0
10
20
30
40
50
60
7080
90
100
0 10 20 30 40 50
Months
Proportion Survivin
84%
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IMRT Complications
No significant toxicity
Grade 2 mucositis in 2 patients No Clinical or Radiographic Evidence of
Myelopathy/Radiculopathy/Plexopathy
80% of patients durable palliation of
symptoms
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IMRT Chondrosarcoma
1975:Chondroblastoma
12/00:ChondrosarcomaSevere biologic andradicular pain
2/7/01:OperationGross total resection
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IMRT Chondrosarcoma
6/02: Recurrence withleft hand intrinsics andbiceps 2-3/5
7/12/02: IMRTTumor: 7080 cGy/38SC: 5320 cGy
8/12/02: Completemotor recovery
4/24/03: Tumorshrinkage on MRI
9/24/04:Radiographically stable
6/02
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Conclusions
High dose photon radiotherapy sparing thespinal cord is feasible with IG IMRT
Radioresistant or inadequate doses?
Highly accurate and reliable non invasiveimmobilization is possible for multiple fractions
Preliminary clinical outcomes are favorable:
Palliation of symptoms Radiologic control
No significant toxicity