The Tomotherapy The Tomotherapy Experience at Experience at Advocate Good Advocate Good

Samaritan HospitalSamaritan Hospital

Mark PankuchMark Pankuch

Today’s DiscussionToday’s Discussion The History of Radiation at Good SamaritanThe History of Radiation at Good Samaritan

Quick Overview of the Tomotherapy UnitQuick Overview of the Tomotherapy Unit

Treatment population and Statistics of our Treatment population and Statistics of our experienceexperience

Results from ShieldingResults from Shielding

Comparison of plansComparison of plans

Advocate Good Advocate Good SamaritanSamaritan

Treated first patient on May 13, 2002Treated first patient on May 13, 2002

Single Linac Vault with a Seimens PrimusSingle Linac Vault with a Seimens Primus

Hand me down GE CT scannerHand me down GE CT scanner from radiologyfrom radiology

Paper-less / Film-less department Paper-less / Film-less department

Advocate Good Advocate Good SamaritanSamaritan

Within two years reached capacity Within two years reached capacity for a single Linac departmentfor a single Linac department

Began offering HDR treatmentsBegan offering HDR treatments

Strong administrative and physician Strong administrative and physician support for expansionsupport for expansion

Advocate Good Advocate Good SamaritanSamaritan

New Vault was neededNew Vault was needed

Doubling current patient volumes Doubling current patient volumes appeared as an over estimation for appeared as an over estimation for potential volumepotential volume

Present day IGRT with OBI not Present day IGRT with OBI not commonly availablecommonly available

What did Tomotherapy What did Tomotherapy Offer that Good Sam was Offer that Good Sam was

missing?missing?

IGRTIGRT

““Top End” IMRTTop End” IMRT

The Answer For Good The Answer For Good Sam?Sam?

TomotherapyTomotherapy

tomotherapy_T1.mov

Tomotherapy MLCTomotherapy MLC

MLC’s Oriented in the MLC’s Oriented in the Sagital PlaneSagital Plane

The Treatment ProcessThe Treatment Process

Patient is set up on table to Patient is set up on table to moveable lasers (2 min)moveable lasers (2 min)

High energy CT scan performed in High energy CT scan performed in the Tx Position (3 Min)the Tx Position (3 Min)

New images are fused with planning New images are fused with planning CT images (3 Min)CT images (3 Min)

Adjustments are made for patient Adjustments are made for patient position (2 min)position (2 min)

Treatment is delivered (10 Min)Treatment is delivered (10 Min)

Of Special Note on Of Special Note on Hardware:Hardware:

No flattening filter No flattening filter

Output ~ 900 MU / minOutput ~ 900 MU / min

Tx = 10,000 MUTx = 10,000 MU

MLC’s very, very fast (MLC’s very, very fast (uus)s)

Capable of MVCT exportCapable of MVCT export

MVCT ~ 2-3 cGyMVCT ~ 2-3 cGy

Planning SystemPlanning System Single workstation for planningSingle workstation for planning Cluster of 16 computers, w/ dual Cluster of 16 computers, w/ dual

processors for computing.processors for computing. Optimizations done on “beamlets” Optimizations done on “beamlets”

that can be calculated overnightthat can be calculated overnight Very few contouring tools, need Very few contouring tools, need

another system for contouring and another system for contouring and fusionsfusions

No planning review station, system No planning review station, system not multitaskingnot multitasking

What type of patients have What type of patients have we treated?we treated?

Tomotherapy Patient Breakdown to Oct 2006

0 10 20 30 40 50 60

Male Pelvis

Brain

Head / Neck

Thorax

Female Pelvis

Spine

Abdomen

Number of Patients

TomotherapyTomotherapy Not optimal for all treatment sitesNot optimal for all treatment sites

Rotational / Helical TreatmentsRotational / Helical Treatments

Need the capability to give low doses Need the capability to give low doses to large areas of normal tissuesto large areas of normal tissues

Ability of “cave out” dosesAbility of “cave out” doses

Very conformal, with good dose drop Very conformal, with good dose drop offoff

Simultaneous BoostSimultaneous Boost

DQADQA Tomotherapy Supplied PhantomsTomotherapy Supplied Phantoms

Film and Point dose taken on every patientFilm and Point dose taken on every patient

Planning system has built-in QA toolsPlanning system has built-in QA tools

Film analysis evaluated by calculating Film analysis evaluated by calculating gamma index (Low et.al., Med Phys 25, gamma index (Low et.al., Med Phys 25, 1998)1998) 3% Dose3% Dose 3mm DTA3mm DTA

DQA Results For First 143 Procedures

0

10

20

30

40

4.0 to 3.5 3.5 to 2.5 2.5 to 1.5 1.5 to 0.5 0.5 to -0.5 -0.5 to -1.5 -1.5 to -2.5 -2.5 to -3.5 -3.5 to -4.0% Difference from Expected

QAQA

cGy / MUcGy / MU cGy / mincGy / min

Lasers coincidenceLasers coincidence Table AccuracyTable Accuracy Field ConsistencyField Consistency MLC accuracyMLC accuracy

Clinical OutcomesClinical Outcomes Pelvis patients decreased side effectsPelvis patients decreased side effects

Prostate patients no side effects Prostate patients no side effects (78Gy)(78Gy)

Brain Patients get ring shape hair lossBrain Patients get ring shape hair loss

Head / Neck patientsHead / Neck patients Still have skin reactionsStill have skin reactions Considerably reduces reaction in mouthConsiderably reduces reaction in mouth Need more time for long term resultsNeed more time for long term results

Skin ReactionsSkin Reactions

Shielding ConsiderationsShielding Considerations

Large majority of shielding needed Large majority of shielding needed because of leakagebecause of leakage

Scatter RadiationScatter Radiation

Primary beamPrimary beam

Shielding ConsiderationsShielding Considerations X = W * U * T * ISFX = W * U * T * ISF Workload:Workload:

30 Patients/day30 Patients/day 10 min Tx time10 min Tx time 880MU/min880MU/min 66,000,000 MU/year 66,000,000 MU/year

Usage Factors = 1Usage Factors = 1 Occupancy Factor as usualOccupancy Factor as usual Occupational areas kept to 10% of Occupational areas kept to 10% of

limitslimits ISF from 3 metersISF from 3 meters

Shielding Considerations, Shielding Considerations, LeakageLeakage

Leakage levels obtained from chart like CT Leakage levels obtained from chart like CT scanner scanner

Leakage was measured and plotted as a Leakage was measured and plotted as a function of position around the gantry and function of position around the gantry and radial distanceradial distance

All leaves closed for measurementsAll leaves closed for measurements

Leakage fraction at 3 meters was usedLeakage fraction at 3 meters was used

ISF from 3 metersISF from 3 meters

Shielding Shielding Considerations, ScatterConsiderations, Scatter

Scatter levels a function of position around gantry Scatter levels a function of position around gantry

Greatest at opening of couchGreatest at opening of couch

With all leaves open, can be 186% of leakage With all leaves open, can be 186% of leakage exposureexposure

Clinically, the exposure can be reduced by a Clinically, the exposure can be reduced by a factor of 16 factor of 16

Maximum % scatter increase = 12%, I used 15%Maximum % scatter increase = 12%, I used 15%

Shielding Considerations, Shielding Considerations, PrimaryPrimary

Unit has a built in Primary Beam Block, Unit has a built in Primary Beam Block, 13cm Pb 13cm Pb

The primary beam was 6.3% of the overall The primary beam was 6.3% of the overall radiation at 2.5 cm from the isocenterradiation at 2.5 cm from the isocenter

Clinically, the exposure can be reduced by a Clinically, the exposure can be reduced by a factor similar to scatter due to closed leaves factor similar to scatter due to closed leaves

I ignored reduction factor, and increased I ignored reduction factor, and increased exposure by 6.3%.exposure by 6.3%.

Shielding ResultsShielding Results

North Wall

South Wall

West Wall

East Wall

Ceiling Door

Calculated Exposure (mR/hr)

0.163 0.042 0.017 0.009 0.058 0.278

Measured Exposure (mR/hr)

0.288 0.012 0.005 0.013 0.012 0.188

Ratio of Measured / Calculated

141% 22% 26% 117% 17% 54%

Ratio of Measured / Required

58% 12% 5% 3% 12% 38%

Plan ComparisonPlan Comparison

TomotherapyTomotherapy

CMS XIO, Step and ShootCMS XIO, Step and Shoot

Varian Eclipse, Sliding WindowVarian Eclipse, Sliding Window

Rt Parotid

0%

10%

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30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60

Dose (Gy)

Vo

lum

e

Tomotherapy

XIO

Eclipse

Lt Parotid

0%

10%

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30%

40%

50%

60%

70%

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90%

100%

0 10 20 30 40 50 60

Dose (Gy)

Vo

lum

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Tomotherapy

XIO

Eclipse

Spinal Cord

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60

Dose (Gy)

Vo

lum

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Tomotherapy

XIO

Eclipse

Brain Stem

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60

Dose (Gy)

Vo

lum

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Tomotherapy

XIO

Eclipse

PTV

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60

Dose (Gy)

Vo

lum

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Tomotherapy

XIO

Eclipse

Which is best??Which is best??

Depends ……..Depends …….. WorkloadWorkload NeedsNeeds Patient sitesPatient sites

Many systems now have IGRTMany systems now have IGRT Where is IGRT going?Where is IGRT going?

No Breath Gateing on TomotherapyNo Breath Gateing on Tomotherapy Where is gateing doing?Where is gateing doing?

In the future for In the future for TomotherapyTomotherapy

Adaptive treatmentsAdaptive treatments

Live time optimizationsLive time optimizations

Conductivity with IMPACConductivity with IMPAC

Live time QCLive time QC

Breath Coaching MethodsBreath Coaching Methods

Questions ??Questions ??

Thanks for your attention!Thanks for your attention!

Free tour of the Cancer Center after Free tour of the Cancer Center after lunchlunch

Questions ???Questions ???