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Stereotactic Radiosurgery/RadiotherapyStereotactic Radiosurgery/RadiotherapyStereotactic Radiosurgery/Radiotherapy

Almon S. Shiu, Ph.DAlmon S. Shiu, Ph.D

Radiation Physics DepartmentRadiation Physics DepartmentUniversity of Texas M. D. Anderson Cancer University of Texas M. D. Anderson Cancer

Center Houston, TexasCenter Houston, Texas

What is Stereotaxis?What is Stereotaxis?What is Stereotaxis?

A Method for locating A Method for locating points within the brain points within the brain

using an external, threeusing an external, three--dimensional frame of dimensional frame of

reference, usually based reference, usually based on the Cartesian on the Cartesian

coordinate systemcoordinate system

Available SystemsAvailable SystemsAvailable Systems

•• Gamma KnifeGamma Knife•• Tyco/Radionics XKnifeTyco/Radionics XKnife--RT/XplanRT/Xplan•• BrainLabBrainLab•• CyberKnifeCyberKnife•• Proton FacilitiesProton Facilities•• OthersOthers

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Delivery TechniquesDelivery TechniquesDelivery Techniques

•• 201 (192) intersecting beams (Gamma Knife) 201 (192) intersecting beams (Gamma Knife) -- Spherical dose distributionsSpherical dose distributions

•• Multiple arcs with circular collimators Multiple arcs with circular collimators (0.5 cm to 4.0 cm cone)(0.5 cm to 4.0 cm cone)-- ellipsoid or spherical dose distributionsellipsoid or spherical dose distributions

•• 1111--15 fields shaped with mMLC or dynamic15 fields shaped with mMLC or dynamicarcsarcs-- arbitrary dose distributions (conformal)arbitrary dose distributions (conformal)

•• 1 to 2 proton fields1 to 2 proton fields

IndicationsIndicationsIndications

•• Benign tumors (acoustic neuroma Benign tumors (acoustic neuroma …….).)•• AVMsAVMs•• MetsMets•• BoostsBoosts•• Salvage (e.g., recurrence after surgerySalvage (e.g., recurrence after surgery

and/or whole brain radiation)and/or whole brain radiation)

What is Linac-Based SRS?What is LinacWhat is Linac--Based SRS?Based SRS?

•• LinacLinac--Based SRSBased SRSdelivers a narrowlydelivers a narrowlycollimated xcollimated x--ray beamray beamwhile the gantry rotates while the gantry rotates around the target.around the target.

•• Target is positioned atTarget is positioned atthe center of gantry the center of gantry rotation.rotation.

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What is Linac-Based SRS?What is LinacWhat is Linac--Based SRS?Based SRS?

•• Process is repeated Process is repeated for a number offor a number oftreatment couch angles. treatment couch angles.

•• Target is caught in aTarget is caught in across fire of xcross fire of x--rayraybeams, Which deliversbeams, Which deliversa lethal dose to thea lethal dose to thetarget (red) and sparetarget (red) and sparethe surrounding tissues.the surrounding tissues.

Benefits Benefits Benefits

•• Large dose to small (1Large dose to small (1--4 cm diameter) lesion4 cm diameter) lesionwith minimum dose to surrounding tissue.with minimum dose to surrounding tissue.

•• Single fraction Single fraction -- good for outgood for out--ofof--town patients,town patients,patients in poor health, or other patients whopatients in poor health, or other patients whomight be burdened by six weeks of treatment.might be burdened by six weeks of treatment.

Prescription for SRSPrescription for SRSPrescription for SRS

•• RTOG 90RTOG 90--05 recommendations:05 recommendations:∗∗ 24 Gy for cones 1 24 Gy for cones 1 -- 2 cm2 cm∗∗ 18 Gy for cones 2.25 18 Gy for cones 2.25 -- 3 cm3 cm∗∗ 15 Gy for cones 3.25 15 Gy for cones 3.25 -- 4 cm4 cm

•• Modify depending on disease radiosensitivity,Modify depending on disease radiosensitivity,prognosis, and other factors.prognosis, and other factors.

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The first prototype of Leksell The first prototype of Leksell

Gamma Knife was installed in Gamma Knife was installed in

Stockholm, Sweden, 1968Stockholm, Sweden, 1968

Development of the Leksell Gamma KnifeDevelopment of the Leksell Gamma Knife

• SRS was first introduced by Leksell in 1951 SRS was first introduced by Leksell in 1951

•• The first gamma knife: in the late 1960sThe first gamma knife: in the late 1960s

•• The second unit: in 1975. The second unit: in 1975.

Initially Initially ----179 179 6060CO sources;CO sources;

Currently (Model C) Currently (Model C) –– 201 201 6060COCO sourcessources

Perfexion – 192 6060COCO sourcessources

•• Model: B, U, C, and Perfexion

Model UModel U19941994

Model CModel C20002000

New Features with New Features with LeksellLeksell Gamma Gamma Knife CKnife C

Operatorconsole

Color coded

collimators

Hand control

Automatic Positioning

System

Integrated helmet

changer

Leksell GammaPlan

Designed for:Designed for:• EaseEase--ofof--useuse

• SafetySafety

• SpeedSpeed

• SelectivitySelectivity

• EnhancementsEnhancements

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Advantages of Model CAdvantages of Model C

Link between computer planning Link between computer planning and treatment unit.and treatment unit.

Coordinates are set by the computer Coordinates are set by the computer preventing human errorpreventing human errorCollimator helmet is checked by the Collimator helmet is checked by the computer and treatment is not allowed computer and treatment is not allowed unless the correct collimator is in unless the correct collimator is in place.place.

Advantages of Model CAdvantages of Model C

Treatment time is set by the software and can Treatment time is set by the software and can not be changed by operatornot be changed by operatorA completed treatment with detailed A completed treatment with detailed information is stored in a information is stored in a read onlyread only file for file for future referencefuture reference

Leksell Gamma KnifeLeksell Gamma Knife®®

PERFEXIONPERFEXION™™

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Leksell Gamma Knife® PERFEXION™

Leksell Gamma KnifeLeksell Gamma Knife®®

Treatable volumeTreatable volume

Leksell Gamma Knife® C

44--, 8, 8--, and 16, and 16--mmmm

Leksell Gamma KnifeLeksell Gamma Knife®®

Focus accessFocus accessLeksell Gamma Knife® C Leksell Gamma Knife® PERFEXION™

Dynamic shapingDynamic shaping

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Radiation protectionRadiation protectionBody doses up to 100 times less than from Body doses up to 100 times less than from alternative technologyalternative technologyLeakage levels low enough to allow for a Leakage levels low enough to allow for a window into the operating roomwindow into the operating roomRoom design can be optimized to space Room design can be optimized to space and costand cost

What is Linac-Based SRT?What is LinacWhat is Linac--Based SRT?Based SRT?

•• Conventional fractionated Conventional fractionated treatment with nontreatment with non--invasive, reproducibleinvasive, reproduciblestereotactic frame. stereotactic frame.

Prescription for SRTPrescription for SRTPrescription for SRT

•• MDACC recommendation:MDACC recommendation:∗∗ 30 Gy in 5 fractions, 6 Gy/fraction 30 Gy in 5 fractions, 6 Gy/fraction

•• Modify depending on previous treatment Modify depending on previous treatment history, dose tolerance of critical structures,history, dose tolerance of critical structures,and other factors.and other factors.

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Stereotactic Instrumentation(In-House)

Stereotactic InstrumentationStereotactic Instrumentation(In(In--House)House)

Stereotactic Instrumentation(Integra/Radionics)

Stereotactic InstrumentationStereotactic Instrumentation(Integra/(Integra/RadionicsRadionics))

Basic Requirements For SRSBasic Requirements For SRSBasic Requirements For SRS

•• Mechanical precisionMechanical precision•• Accurate localization Accurate localization •• Accurate and optimal dose calculationAccurate and optimal dose calculation•• Patient safetyPatient safety

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Mechanical PrecisionMechanical PrecisionMechanical Precision

•• Linac gantry, collimator and couchLinac gantry, collimator and couch•• LasersLasers•• Patient docking devicePatient docking device•• Frame systemFrame system•• Target verification deviceTarget verification device•• SRS system verification testSRS system verification test

Dose MeasurementsDose MeasurementsDose Measurements

•• Use AAPM TGUse AAPM TG--51 protocol51 protocol•• Output, CentralOutput, Central--axis %DD and TMR axis %DD and TMR

measurement measurement -- using PTW 0.1 c.c. using PTW 0.1 c.c. Chamber or Scanditronix diode (For Chamber or Scanditronix diode (For diameter diameter ≥≥ 10 mm)10 mm)..

•• Beam Profile Beam Profile -- using film or using film or stereotactic diode. stereotactic diode.

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Dose VerificationDose VerificationDose Verification

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Quality Assurance for ImageFusionQuality Assurance for ImageFusionQuality Assurance for ImageFusion

Measuring MRI Distortion with a Phantom HeadMeasuring MRI Distortion with a Phantom HeadDuring installation of the imageFusion system, a specially During installation of the imageFusion system, a specially designed Geometric Phantom will be used to measure the designed Geometric Phantom will be used to measure the spatial distortions inherent in the MRI scanner. These spatial distortions inherent in the MRI scanner. These distortions will give an idea as to the magnitude of the distortions will give an idea as to the magnitude of the errors to be expected. When scanning patients, use the errors to be expected. When scanning patients, use the same protocol that was used for the phantom, including same protocol that was used for the phantom, including slice spacing, slice thickness, field of view.slice spacing, slice thickness, field of view.Use the phantom to test distortion on a periodic basis, Use the phantom to test distortion on a periodic basis, particularly after a scanner system or software upgrade. particularly after a scanner system or software upgrade.

Spatial localization QA phantomSpatial localization QA phantomSpatial localization QA phantom

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center of sphereAP LAT VERT25 20 20

3D distFusion-CT-0.4815 -0.0534 -0.0370 0.4859

Fusion-absolute-0.5654 -0.1601 -0.2357 0.6331

CT-absolute-0.0839 -0.1067 -0.1987 0.2407

tip of coneAP LAT VERT-35 -20 40

3D distFusion-CT-0.7117 -0.1668 0.0823 0.7356

Fusion-absolute-1.0747 -0.0964 -1.0305 1.4920

CT-absolute-0.3630 0.0704 -1.1128 1.1727

superior/anterior/left corner of cubeAP LAT VERT30 -27 40

3D distFusion-CT-0.7410 -0.6709 -0.0576 1.0012

Fusion-absolute-1.0319 -0.0419 0.1753 1.0475

CT-absolute-0.2909 0.6290 0.2329 0.7311

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SRS ProcedureFrame FixationSRS ProcedureSRS ProcedureFrame FixationFrame Fixation

Imaging ScanningImaging ScanningImaging Scanning

Auto Detecting RodsAuto Detecting Rods

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LT

Tem

pora

l Met

asta

sis

LT

Tem

pora

l Met

asta

sis

RT

Tem

pora

l Met

asta

sis

RT

Tem

pora

l Met

asta

sis

RT

Fro

ntal

Met

asta

sis

RT

Fro

ntal

Met

asta

sis

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LT TemporalLT Temporal RT TemporalRT Temporal

RT FrontalRT Frontal

Auto Plan

3D Display3D Display

LT TemporalLT Temporal RT TemporalRT Temporal

RT FrontalRT Frontal

Conformal ARCSConformal ARCS

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MU Calculation (for Arc)MU Calculation (for Arc)MU Calculation (for Arc)

Output @ isocenterOutput @ isocenterΨΨ = S.F. * TMR= S.F. * TMR

where S.F. = Scatter factorwhere S.F. = Scatter factorThen, MU = D * w/ Then, MU = D * w/ ΨΨ

where D = dose @ isocenterwhere D = dose @ isocenterw = beam weight w = beam weight ∝∝ arc lengtharc length

Pre-treatment QAPrePre--treatment QAtreatment QA

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Setup Patient for TreatmentSetup Patient for TreatmentSetup Patient for Treatment

Treatment DeliveryTreatment DeliveryTreatment Delivery

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TreatmentTreatmentTreatment

•• Typically 5 arcs, about 40Typically 5 arcs, about 40°° ∼∼ 6060°° eacheach•• 300 MU/min 300 MU/min ⇒⇒ 1 1 ∼∼ 2 min per arc 2 min per arc •• Total treatment is 5 to 10 min of beamTotal treatment is 5 to 10 min of beam

on time.on time.•• Room entries between arcs to moveRoom entries between arcs to move

couch and recouch and re--check patient alignment.check patient alignment.

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Computer-Controlled Miniature Multileaf Collimator (mMLC)

ComputerComputer--Controlled Miniature Controlled Miniature Multileaf Collimator (mMLC)Multileaf Collimator (mMLC)

TYCO/RADIONICSTYCO/RADIONICS

•• Maximum Field Size: Maximum Field Size: 13.5 cm x 11.3 cm @ 13.5 cm x 11.3 cm @ isocenterisocenter

•• Number of Leaves: Number of Leaves: 31 leaf pairs (62 leaves)31 leaf pairs (62 leaves)•• Projected Leaf Width: Projected Leaf Width: 4.35 mm @ 100 cm SAD4.35 mm @ 100 cm SAD•• Each Leaf Travel (@ isocenter): Each Leaf Travel (@ isocenter): --5 cm to 5 cm5 cm to 5 cm•• Leaf Transmit Time Rate: Leaf Transmit Time Rate: ~ 30 mm/sec~ 30 mm/sec•• Leaf Material: Leaf Material: Tungsten Alloy (7 cm thick)Tungsten Alloy (7 cm thick)•• Collimator to Isocenter Distance: Collimator to Isocenter Distance: ~ 37.5 cm~ 37.5 cm

Gantry

SF6

Interleaf Transmission

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mMLC inplane leakage

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

-10.0 -5.0 0.0 5.0 10.0 off-axis Position (cm)

% le

akag

e (n

orm

to 1

0x10

)

Leaf 1

Leaf 31

Leaf repositioning testLeaf repositioning test

mMLC Leaf PositioningmMLC Leaf PositioningmMLC Leaf Positioning

•• The reproducibility of each leaf is 0.2 The reproducibility of each leaf is 0.2 mmmm±± 0.070.07mm .mm .

•• Uncertainty for the multiple scans on Uncertainty for the multiple scans on each set of leaf positioning tests is each set of leaf positioning tests is within 0.1 mm.within 0.1 mm.

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aa--Si FlatpanelSi Flatpanelaa--Si FlatpanelSi Flatpanel

X-ray sourceX-ray source

NovalisNovalis®® Hardware ComponentsHardware Components

Clinical ApplicationsClinical ApplicationsClinical Applications

•• SRS and SRT for intracranial tumors SRS and SRT for intracranial tumors and metastasesand metastases

•• SRT for head and neck lesionsSRT for head and neck lesions•• SRT for the small tumors in the thorax SRT for the small tumors in the thorax

and abdomenand abdomen

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Case PresentationCase PresentationCase Presentation

•• Primary Site and HistopathologyPrimary Site and Histopathology:: Recurrent Recurrent posterior fossa ependymomaposterior fossa ependymoma

•• Stage:Stage: RecurrentRecurrent•• History:History: A 40A 40--yearyear--old gentleman who was old gentleman who was

initially see in 1972 at the age of 15. He initially see in 1972 at the age of 15. He underwent a resection of his posterior fossa underwent a resection of his posterior fossa ependymoma and was treated with 36 ependymoma and was treated with 36 fractions of external beam radiation therapy. fractions of external beam radiation therapy. He was without disease recurrence until He was without disease recurrence until 1998 when he noticed the onset of left facial 1998 when he noticed the onset of left facial paresis.paresis.

•• History (continued):History (continued): He had a repeat He had a repeat surgical resection at MDACC and the tumor surgical resection at MDACC and the tumor was removed in the pontine and prepontine was removed in the pontine and prepontine areas. Approximately two years later, areas. Approximately two years later, regrowth was identified in 1993, and the regrowth was identified in 1993, and the patient underwent chemotherapy treatment patient underwent chemotherapy treatment over 12over 12--month time and since that time slow month time and since that time slow progression of tumor has been noted. In progression of tumor has been noted. In early 1998, he had the onset of occipital pain early 1998, he had the onset of occipital pain and also also decreased function in the left and also also decreased function in the left hand.hand.

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•• History (continued):History (continued): Although his tumor was Although his tumor was relatively indolent but it had been increasing since relatively indolent but it had been increasing since 1993. Surgery and stereotactic radiotherapy (SRT) 1993. Surgery and stereotactic radiotherapy (SRT) were presented to the patient at that time. Patient were presented to the patient at that time. Patient underwent serious injuries with his two previous underwent serious injuries with his two previous surgeries and has expressed his desiresurgeries and has expressed his desire for SRT.for SRT.

•• MRI Finding:MRI Finding: an MRI of the brain with & without an MRI of the brain with & without contrast on 4/28/98, it showed a large nodular contrast on 4/28/98, it showed a large nodular enhancing tumor in the prepontine cistern and the enhancing tumor in the prepontine cistern and the cerebral pontine angle predominantly on the left side. cerebral pontine angle predominantly on the left side.

•• Basic Treatment Plan:Basic Treatment Plan: The recurrent tumor The recurrent tumor was treated to a total dose of 25 Gy in 5 was treated to a total dose of 25 Gy in 5 fraction (twice per week). The dose was fraction (twice per week). The dose was prescribed at the 90prescribed at the 90thth percentile.percentile.

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Case PresentationCase PresentationCase Presentation

•• Primary Site and Histopathology:Primary Site and Histopathology: Carcinoma Carcinoma of the nasopharynxof the nasopharynx

•• Stage:Stage: Recurrent (a recurrent mass filling Recurrent (a recurrent mass filling the sphenoid sinus mostly on the left with the sphenoid sinus mostly on the left with possible invasion into left cavernous sinus.)possible invasion into left cavernous sinus.)

•• History:History: A 47A 47--yearyear--old gentleman who had a old gentleman who had a history of T2, N1 carcinoma of the history of T2, N1 carcinoma of the nasopharynx. nasopharynx.

•• Previous Treatment: (1997)Previous Treatment: (1997)Radiotherapy Radiotherapy -- 70 Gy/35 fractions70 Gy/35 fractionsChemoradiotherapy Chemoradiotherapy -- ciscis--platimum and 5platimum and 5--FUFU

•• Risk of Radiation Therapy:Risk of Radiation Therapy: Significant risk Significant risk of left optic neuropathy and the optic of left optic neuropathy and the optic chiasm has a low probability but real risk for chiasm has a low probability but real risk for neuropathy.neuropathy.

•• Basic Treatment Plan:Basic Treatment Plan: Treated with salvage Treated with salvage radiotherapy to a dose of 70 Gy in 35 radiotherapy to a dose of 70 Gy in 35 fractions. fractions.

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MeningiomaMeningioma

Diagnosis: Diagnosis: MeningiomaMeningioma of the right cavernous sinusof the right cavernous sinusStage: Locally recurrent Stage: Locally recurrent History: A male patient is now 12 years out from a History: A male patient is now 12 years out from a previous surgery for a right cavernous sinus previous surgery for a right cavernous sinus hemangiomahemangioma. Serial evaluation by MRI for this process . Serial evaluation by MRI for this process has revealed a slight interval growth in residual disease has revealed a slight interval growth in residual disease within this region in comparison to MRI that was within this region in comparison to MRI that was performed in 2001. Although he remains performed in 2001. Although he remains asymtomaticasymtomatic, , he will receive a course of definitive radiation in this he will receive a course of definitive radiation in this setting to prevent further growth which could setting to prevent further growth which could conceivably result in conceivably result in neurologicneurologic compromise.compromise.

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Case (Continued)Case (Continued)

Basic Radiation Treatment Plan: The plan at Basic Radiation Treatment Plan: The plan at this time will be to treat the area of recurrent this time will be to treat the area of recurrent meningomameningoma within the right cavernous sinus. within the right cavernous sinus. We will likely utilize We will likely utilize stereotacticstereotactic SRT to treat SRT to treat this region to a dose of 50 this region to a dose of 50 GyGy in 25 fractions, in 25 fractions, precise aiming the lesion and sparing the optic precise aiming the lesion and sparing the optic nerves and optic chiasm.nerves and optic chiasm.

Fused ImagesFused Images

GT

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A0_0A0_0 B0_310B0_310 C110_270C110_270

D290_305D290_305 E270_260E270_260

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Central Axes Plan Central Axes Plan IsodoseIsodose distributionsdistributions

IsodoseIsodose DistributionsDistributions

DVHDVH

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Heaven meet EarthHeaven meet Earth

ImageImage--Guided NonGuided Non--Invasive SRS/SRTInvasive SRS/SRT

Almon Shiu, Ph.D.Almon Shiu, Ph.D.Radiation Physics DepartmentRadiation Physics Department

UTMDACCUTMDACCHouston, TX 77030Houston, TX 77030

ObjectiveObjective

Develop a nonDevelop a non--invasive intracranial invasive intracranial stereotactic radiosurgery technique with the stereotactic radiosurgery technique with the same high degree of accuracy as that of the same high degree of accuracy as that of the current invasive headcurrent invasive head--ring SRS Technique.ring SRS Technique.

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Planning CTPlanning CT

Planning MRIPlanning MRI

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DailyDaily

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--18.118.1--23.723.7--1.01.03/8/20063/8/2006

--18.118.1--23.723.7--1.01.03/1/20063/1/2006

--17.717.7--23.723.7--1.01.02/21/20062/21/2006

--18.218.2--23.223.2--1.21.22/13/20062/13/2006

--17.617.6--24.124.1--0.80.82/3/20062/3/2006

--17.917.9--23.423.4--0.90.92/2/20062/2/2006

--18.118.1--23.423.4--1.61.62/1/20062/1/2006

--18.118.1--23.523.5--1.01.01/31/20061/31/2006

--18.118.1--23.923.9--1.51.51/30/20061/30/2006

--17.317.3--23.923.9--1.31.31/27/2006 (planning)1/27/2006 (planning)

VERT(mm)VERT(mm)LAT (mm)LAT (mm)AP (mm)AP (mm)DateDate

--0.10.10.20.20.10.1STDSTD

--0.10.10.30.30.20.2meanmean--RefRef

--17.917.9--23.923.9--1.31.3Ref Ref

0.60.60.20.20.10.1STDSTD

--0.10.1--0.40.40.20.2mean mean -- PlanningPlanning

--18.018.0--23.623.6--1.11.1meanmean

--17.317.3--23.923.9--1.31.31/27/2006 (planning)1/27/2006 (planning)

VERT(mm)VERT(mm)LAT (mm)LAT (mm)AP (mm)AP (mm)DateDate

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APAP RT LATRT LAT

Planned DRRPlanned DRR

PortalPortal

ConclusionsConclusionsThe imageThe image--guided nonguided non--invasive stereotactic invasive stereotactic radiosurgery has the capability of delivering radiosurgery has the capability of delivering high level accuracy of dose to the lesion without high level accuracy of dose to the lesion without the pain and discomfort due to the pins fixed to the pain and discomfort due to the pins fixed to the patientthe patient’’s skull. s skull. Revise the fractionated SRT procedures by Revise the fractionated SRT procedures by using image registration for the initial five using image registration for the initial five treatments. Based on the variations of the treatments. Based on the variations of the isocenter, use the Ref isocenter for the isocenter, use the Ref isocenter for the remaining SRT treatments without performing remaining SRT treatments without performing the image registrationthe image registration process daily. process daily.

Thank youThank you

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ImageImage--Guided Guided StereotacticStereotactic Body RadiotherapyBody Radiotherapy(Featuring a 6D Robotic Couch(Featuring a 6D Robotic Couch--TopTop ))

Almon S. Shiu, Ph.DAlmon S. Shiu, Ph.D..Radiation Physics DepartmentRadiation Physics Department

The University of Texas M.D. Anderson Cancer Ctr.The University of Texas M.D. Anderson Cancer Ctr.Houston, Texas Houston, Texas

Research Team (2002)Research Team (2002)

AlmonAlmon Shiu, Ph.D.Shiu, Ph.D.Eric Chang, M.D.Eric Chang, M.D.JinJin--Song Ye, M.S.Song Ye, M.S.

Jim Lii, M.S.Jim Lii, M.S.

IntroductionIntroductionSpinal metastases are a common component of Spinal metastases are a common component of metastaticmetastatic disease afflicting 40% of all cancer disease afflicting 40% of all cancer patients which can cause severe pain, and patients which can cause severe pain, and neurologicneurologicsequelaesequelaeConventional radiation therapy widely used but is Conventional radiation therapy widely used but is inherently limited by spinal cord tolerance leaving inherently limited by spinal cord tolerance leaving little possibility for relittle possibility for re--irradiation in case of irradiation in case of recurrencerecurrenceStereotacticStereotactic body radiotherapy (SBRT) is an body radiotherapy (SBRT) is an emerging technology designed to precisely deliver emerging technology designed to precisely deliver higher doses, improve tumor control, and permit rehigher doses, improve tumor control, and permit re--irradiation of the spineirradiation of the spine

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IntroductionIntroduction

Research workshop on 4/3/02 to propose the Research workshop on 4/3/02 to propose the development of imagedevelopment of image--guided guided stereotacticstereotacticbody radiotherapybody radiotherapyPhase I development finished in August, Phase I development finished in August, 2002.2002.

Ongoing ID02Ongoing ID02--446 Clinical Trial446 Clinical TrialNov 2002 Nov 2002 –– SBRT first introduced to MDACC SBRT first introduced to MDACC through Phase I/II clinical trial for patients through Phase I/II clinical trial for patients with spinal or with spinal or paraspinalparaspinal metastases as a joint metastases as a joint collaboration between Radiation Oncology, collaboration between Radiation Oncology, Neurosurgery, and Radiation PhysicsNeurosurgery, and Radiation Physics

Primary objective to establish safety, Primary objective to establish safety, feasibility, and efficacy using CTfeasibility, and efficacy using CT--onon--Rails Rails based SBRT to treat spinal and based SBRT to treat spinal and paraspinalparaspinalmetastasesmetastases

Patient populationPatient populationProtocol intended for patients with spinal Protocol intended for patients with spinal metastases occurring in a variety of situations metastases occurring in a variety of situations felt to be candidates after discussion in multifelt to be candidates after discussion in multi--disciplinary tumor boarddisciplinary tumor board

GENERAL INDICATIONSGENERAL INDICATIONSPRIMARYPRIMARY -- Newly diagnosed solitary or Newly diagnosed solitary or oligooligo--spinal metastases. spinal metastases. ““RadioresistantRadioresistant”” subtypessubtypesPOSTPOST--OPOP –– adjuvant or elective treatmentadjuvant or elective treatmentSALVAGESALVAGE -- surgical or RT recurrencessurgical or RT recurrences

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LINAC/CTLINAC/CT--onon--Rails ImageRails Image--guided guided StereotacticStereotactic Body RadiotherapyBody Radiotherapy

Immobilization: Tyco/Radionics Body Immobilization: Tyco/Radionics Body SystemSystem™™ consisting of a carbon base consisting of a carbon base plate, vacuum cushions, a vacuum plate, vacuum cushions, a vacuum system and Fixation sheets.system and Fixation sheets.A Varian ExactCT targeting system A Varian ExactCT targeting system ––A GE CT scanner and a Varian Clinic A GE CT scanner and a Varian Clinic 21 EX LINAC, shared the same couch 21 EX LINAC, shared the same couch between CT and LINAC.between CT and LINAC.Treatment planning Treatment planning –– IMRT IMRT Linkage between patient anatomy and Linkage between patient anatomy and stereotactic body frame and update stereotactic body frame and update daily isocenter based on 3D image daily isocenter based on 3D image fusion. fusion.

A. Shiu, et al. IJROBP 57(3): 605-613,2003

Spinal IMRT RadiotherapySpinal IMRT RadiotherapyTreating PlanningTreating Planning

•• Prescription: Prescription: 30 Gy/5 TX, 27 Gy/3 TX, or 30 Gy/5 TX, 27 Gy/3 TX, or 18 18 GyGy to 26 Gy/1 TXto 26 Gy/1 TX

•• Beam Arrangement: Beam Arrangement: 66-- and 18and 18--MV PhotonsMV Photons

280280ºº

8080°°180180°°240240°°

210210°° 150150°° 120120°°

Isodose DistributionIsodose DistributionAxial and sagittal views of Axial and sagittal views of isodose distributions isodose distributions ––normalized to GTV mean dosenormalized to GTV mean doseTypical prescribed dose to the Typical prescribed dose to the volume included by the 90% volume included by the 90% isodose lineisodose lineThe ultimate prescription dose The ultimate prescription dose was constrained by our IRB was constrained by our IRB requirement for protocol requirement for protocol approval that the dose to the approval that the dose to the spinal cord could not exceed a spinal cord could not exceed a total of 10 Gy over five total of 10 Gy over five TxTx (9 (9 Gy over three Gy over three TxTx, 8 , 8 GyGy over 1 over 1 TxTx ).).Dose volume histogram Dose volume histogram --another way to evaluate the another way to evaluate the treatment plantreatment plan

L1 (CTV)L1 (CTV)

Dose (cGy)Dose (cGy)

RT KidneyRT Kidney

LT KidneyLT Kidney

Cord+2mmCord+2mmCordCord

Dose Volume HistogramDose Volume Histogram

Nor

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ume

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L1 (CTV)L1 (CTV)

Dose (cGy)Dose (cGy)

RT KidneyRT Kidney

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Dose Volume HistogramDose Volume Histogram

Nor

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IGSBRT IGSBRT –– Treatment Process Flow ChartTreatment Process Flow ChartPlanning CT Scan

With Frame

Plan IsoOn Frame

Plan DRRs

Daily CT Scan

Daily Iso

Daily DRRs

Patient Positioning

Portal Images

Treatment

ImageRegistration

DRRRegistration

DRR & PortalRegistration

AnatomyRegistration

FrameRegistration

Daily Treatment SetupDaily Treatment SetupImageImage--guided stereotactic Target alignmentguided stereotactic Target alignment

CT imaging prior CT imaging prior treatmenttreatment

Fuse the planning images Fuse the planning images with the current CT with the current CT images to calculate the images to calculate the shift and the rotation shift and the rotation from the planning from the planning isocenter to the daily isocenter to the daily isocenterisocenter

Automatic OnAutomatic On--Line Image RegistrationLine Image RegistrationBased on Mutual InformationBased on Mutual Information

Automation of Image Registration And VerificationAutomation of Image Registration And Verificationfor Imagefor Image--Guided Stereotactic Body RadiotherapyGuided Stereotactic Body Radiotherapy

52

DRR DRR ComparisonComparisonConvention method: sideConvention method: side--byby--side comparisonside comparison

DRR Comparison DRR Comparison –– Split ScreenSplit Screen

By displaying two corresponding By displaying two corresponding DRRsDRRs in in one frame in a split screen format, subone frame in a split screen format, sub--

millimeter shifts can be readily detected.millimeter shifts can be readily detected.

• Apply the shift from the planning isoccenterApply the shift from the planning isoccenter andandalign the updated isocenter with lasersalign the updated isocenter with lasers

Daily Treatment SetupDaily Treatment SetupImageImage--guided stereotactic alignmentguided stereotactic alignment

RTRT ANTANT LTLT

53

-5

-4

-3

-2

-1

0

1

2

3

0 10 20 30 40

LATAPSI

Daily Frame Center Deviated from Ref Daily Frame Center Deviated from Ref CT Frame CenterCT Frame Center

Number ofNumber of Daily CT Daily CT

Dev

iatio

n (m

m)

Dev

iatio

n (m

m)

HexaPOD Robotically Controlled 6D Couch TopHexaPOD Robotically Controlled 6D Couch Top

•• Verify the target isocenter coincided with theVerify the target isocenter coincided with theLINAC radiation isocenter (Portal films)LINAC radiation isocenter (Portal films)

APAP RT LATRT LAT

Portal FilmPortal Film

Planning Planning DRRDRR

Daily Treatment SetupDaily Treatment SetupImageImage--guided stereotactic alignmentguided stereotactic alignment

54

Portal EPID Image Registration with DRRPortal EPID Image Registration with DRR

•• Deliver the IMRT treatmentDeliver the IMRT treatment

210° 240° 280° 080°

120° 150° 180°

•• Repeat CT scan after treatment to confirm Repeat CT scan after treatment to confirm setup accuracysetup accuracy

Planning IsoPlanning Iso

PostPost--Iso 1/27/03Iso 1/27/03

Post Post --Iso 2/5/03Iso 2/5/03

55

Deviation from Planned Isocenter Using Daily Pre-treatment CT

-10.00

-5.00

0.00

5.00

10.00

0 20 40 60 80 100

Treatment Number

Dev

iatio

n (m

m)

LATAPSI

Assessment of Setup Accuracy Using Immediate Post-Treatment CT

-10.00

-5.00

0.00

5.00

10.00

0 20 40 60 80 100Treatment Number

Dev

iatio

n (m

m)

LATAPSI

Phantom Study for Phantom Study for HexaPODHexaPOD Setup AccuracySetup Accuracy

56

Portal Image Verification with DRR Portal Image Verification with DRR

57

00000066

00110055

00220044

00000033

00000022

11001111

SI (Z) mmSI (Z) mmAP (Y) mmAP (Y) mmLat (x) mmLat (x) mmFractionFraction

Positioning Accuracy of HexapodPositioning Accuracy of HexapodAfter the automatic position of Hexapod, After the automatic position of Hexapod, additional shifts needed for a perfect alignment additional shifts needed for a perfect alignment (rounded to the nearest mm)(rounded to the nearest mm)

L 3L 3

Case1: 46 M previously irradiatedCase1: 46 M previously irradiated (40 (40 GyGy in 16 in 16 fxsfxs))Lung cancer T12 metastasis progressed (biopsy proven)Lung cancer T12 metastasis progressed (biopsy proven)

July2004

July 2005

58

Case2: 52 M solitary renal cell carcinoma Case2: 52 M solitary renal cell carcinoma metastasis centered on cervical vertebrae 2metastasis centered on cervical vertebrae 2

59

Case3: 20 F Case3: 20 F plasmacytomaplasmacytoma causing back pain causing back pain

•• ExtraduralExtradural extension causing cord compression at T10extension causing cord compression at T10•• Needle Needle bxbx revealed revealed plasmacytomaplasmacytoma•• 45 45 GyGy in 25 fractions to T9in 25 fractions to T9--11 previous irradiated11 previous irradiated•• 3 3 mosmos later MRI later MRI -- recurred below: Epidural recurred below: Epidural dzdz T11T11--12. 12.

RT was not an option at the timeRT was not an option at the time•• LaminectomyLaminectomy, , facetectomyfacetectomy, resection tumor, resection tumor•• 4 mo later recurred above: 4 mo later recurred above: RtRt T7T7--8 8 neuroforamenneuroforamen•• Received Received stereotacticstereotactic radiation to epidural diseaseradiation to epidural disease•• Attending college and remains diseaseAttending college and remains disease--free 3 years free 3 years

laterlater

NeuroforaminalNeuroforaminal and Epidural Diseaseand Epidural Disease

Case4: 48 F breast cancerCase4: 48 F breast cancer

Feb 03 Feb 03 -- Metastasis at T9 Metastasis at T9 previously irradiatedpreviously irradiatedat outside institution to 40 Gy/16fx/2.5Gyat outside institution to 40 Gy/16fx/2.5Gy

Feb 04 Feb 04 ––MR progressive MR progressive dzdz at T9, metastasis at at T9, metastasis at posterior elements of T6. Worst pain 5/10posterior elements of T6. Worst pain 5/10

Mar 04Mar 04--PrePre--treatment PET/CT showed T9 treatment PET/CT showed T9 SUV 6.2, T6 SUV 14.1SUV 6.2, T6 SUV 14.1

Apr 04 Apr 04 --SBRT 20 Gy/5 SBRT 20 Gy/5 fxfx given to T6 given to T6 spinousspinousprocess and T9 vertebra with pain reliefprocess and T9 vertebra with pain relief

60

T6 T6 SpinousSpinous ProcessProcess

T9 Vertebral BodyT9 Vertebral BodySagittalSagittal T6 + T9T6 + T9

Pre/Post treatment MRIPre/Post treatment MRI

Feb 2004Feb 2004 May 2004May 2004

T6 SUV14.1

T9 SUV 6.2

T6 SUV3

T9 SUV 0

F-18 FDG CT-PET

March 2004 May 2004

61

00

2525

5050

7575

100100

MonthsMonths

Prop

ortio

nPr

opor

tion

00 66 1212 1818 2424 3030

ACTUARIAL TUMOR CONTROLACTUARIAL TUMOR CONTROL

85%85%

StereotacticStereotactic LungLungPrescription: Prescription: 50Gy in 5 fractions50Gy in 5 fractions

62

Isocenter Plane, Bone Window

Isocenter Plane, Lung Window

PTV

PTV Display

63

7.5mm Inferior, Bone Window

7.5mm Inferior, Lung Window

7.5mm Superior, Bone Window

64

7.5mm Superior, Lung Window

ConclusionsConclusionsNearNear--simultaneous CT imagesimultaneous CT image--guided verification guided verification technique can be used as a new platform technique can be used as a new platform technology for extratechnology for extra--cranial applications of cranial applications of stereotactic radiotherapy to spine and paraspinal stereotactic radiotherapy to spine and paraspinal tumors. tumors. –– Treatment is totally nonTreatment is totally non--invasive.invasive.The use of SBFS only can not achieve the setup The use of SBFS only can not achieve the setup accuracy comparable to that of intracranial SRS.accuracy comparable to that of intracranial SRS.The isocenter setup accuracy of imageThe isocenter setup accuracy of image--guided guided stereotactic spine treatment is within 1 mm and stereotactic spine treatment is within 1 mm and comparable to the setup accuracycomparable to the setup accuracy of intracranial of intracranial SRS. SRS.

ConclusionsConclusions

•• The 3D navigation guided 6D robotic couchThe 3D navigation guided 6D robotic couch--top demonstrated that it could enhance the top demonstrated that it could enhance the isocenter setup accuracy of imageisocenter setup accuracy of image--guided body guided body radiotherapy and improve the treatmentradiotherapy and improve the treatment--process efficiency. process efficiency.

•• the automatic repositioning process could the automatic repositioning process could remove the possibility of the human errors for remove the possibility of the human errors for updating the target updating the target isocenterisocenter incorrectlyincorrectly..

65

ConclusionsConclusions

Combine with 4Combine with 4--D CT to generate ITV and D CT to generate ITV and PTV, the imagePTV, the image--guided Radiotherapy guided Radiotherapy technique can be used to treat small lesions, technique can be used to treat small lesions, e.g., lung, liver, kidney, etce.g., lung, liver, kidney, etc..

AcknowledgementsAcknowledgementsRadiation OncologyEric Chang, M.D.Chester Wang, Ph.DJim Lii, M.S.Ram Sadogopan MSNarayan Sahoo, Ph.DAnita Mahajan, MDShiao Woo, M.D.Moshe Maor, MDHaihong Cai, APN

ResearchBarry Brown, Ph.DLeni Mathews, RNPamela Allen, MPH

NeurosurgeryLaurence Rhines, M.D.Ehud Mendel, M.D.Jeff Weinberg, M.D.Symptom ResearchCharles Cleeland, Ph.DShelley Wang, M.D.Ibraham GningAdministrationJames Cox, MDRay Sawaya, MDRadhe Mohan, PhDMike Gillin, PhDMitch LatinkicPaul OrtizCharles Washington

M.D. Anderson Medical

Oncologists

Thank YouThank You