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The Tomotherapy Experience at Advocate Good Samaritan Hospital Mark Pankuch.

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Presentation on theme: "The Tomotherapy Experience at Advocate Good Samaritan Hospital Mark Pankuch."— Presentation transcript:

1 The Tomotherapy Experience at Advocate Good Samaritan Hospital Mark Pankuch

2 Today’s Discussion The History of Radiation at Good Samaritan The History of Radiation at Good Samaritan Quick Overview of the Tomotherapy Unit Quick Overview of the Tomotherapy Unit Treatment population and Statistics of our experience Treatment population and Statistics of our experience Results from Shielding Results from Shielding Comparison of plans Comparison of plans

3 Advocate Good Samaritan Treated first patient on May 13, 2002 Treated first patient on May 13, 2002 Single Linac Vault with a Seimens Primus Single Linac Vault with a Seimens Primus Hand me down GE CT scanner Hand me down GE CT scanner from radiology from radiology Paper-less / Film-less department Paper-less / Film-less department

4 Advocate Good Samaritan Within two years reached capacity for a single Linac department Within two years reached capacity for a single Linac department Began offering HDR treatments Began offering HDR treatments Strong administrative and physician support for expansion Strong administrative and physician support for expansion

5 Advocate Good Samaritan New Vault was needed New Vault was needed Doubling current patient volumes appeared as an over estimation for potential volume Doubling current patient volumes appeared as an over estimation for potential volume Present day IGRT with OBI not commonly available Present day IGRT with OBI not commonly available

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7 What did Tomotherapy Offer that Good Sam was missing? IGRT IGRT “Top End” IMRT “Top End” IMRT

8 The Answer For Good Sam?

9 Tomotherapy

10 Tomotherapy MLC

11 MLC’s Oriented in the Sagital Plane

12 The Treatment Process Patient is set up on table to moveable lasers (2 min) Patient is set up on table to moveable lasers (2 min) High energy CT scan performed in the Tx Position (3 Min) High energy CT scan performed in the Tx Position (3 Min) New images are fused with planning CT images (3 Min) New images are fused with planning CT images (3 Min) Adjustments are made for patient position (2 min) Adjustments are made for patient position (2 min) Treatment is delivered (10 Min) Treatment is delivered (10 Min)

13 Of Special Note on Hardware: No flattening filter No flattening filter Output ~ 900 MU / min Output ~ 900 MU / min Tx = 10,000 MU Tx = 10,000 MU MLC’s very, very fast (us) MLC’s very, very fast (us) Capable of MVCT export Capable of MVCT export MVCT ~ 2-3 cGy MVCT ~ 2-3 cGy

14 Planning System Single workstation for planning Single workstation for planning Cluster of 16 computers, w/ dual processors for computing. Cluster of 16 computers, w/ dual processors for computing. Optimizations done on “beamlets” that can be calculated overnight Optimizations done on “beamlets” that can be calculated overnight Very few contouring tools, need another system for contouring and fusions Very few contouring tools, need another system for contouring and fusions No planning review station, system not multitasking No planning review station, system not multitasking

15 What type of patients have we treated?

16 Tomotherapy Not optimal for all treatment sites Not optimal for all treatment sites Rotational / Helical Treatments Rotational / Helical Treatments Need the capability to give low doses to large areas of normal tissues Need the capability to give low doses to large areas of normal tissues Ability of “cave out” doses Ability of “cave out” doses Very conformal, with good dose drop off Very conformal, with good dose drop off

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20 Simultaneous Boost

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24 DQA Tomotherapy Supplied Phantoms Tomotherapy Supplied Phantoms Film and Point dose taken on every patient Film and Point dose taken on every patient Planning system has built-in QA tools Planning system has built-in QA tools Film analysis evaluated by calculating gamma index (Low et.al., Med Phys 25, 1998) Film analysis evaluated by calculating gamma index (Low et.al., Med Phys 25, 1998) 3% Dose 3% Dose 3mm DTA 3mm DTA

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28 QA cGy / MU cGy / MU cGy / min cGy / min Lasers coincidence Lasers coincidence Table Accuracy Table Accuracy Field Consistency Field Consistency MLC accuracy MLC accuracy

29 Clinical Outcomes Pelvis patients decreased side effects Pelvis patients decreased side effects Prostate patients no side effects (78Gy) Prostate patients no side effects (78Gy) Brain Patients get ring shape hair loss Brain Patients get ring shape hair loss Head / Neck patients Head / Neck patients Still have skin reactions Still have skin reactions Considerably reduces reaction in mouth Considerably reduces reaction in mouth Need more time for long term results Need more time for long term results

30 Skin Reactions

31 Shielding Considerations Large majority of shielding needed because of leakage Large majority of shielding needed because of leakage Scatter Radiation Scatter Radiation Primary beam Primary beam

32 Shielding Considerations X = W * U * T * ISF X = W * U * T * ISF Workload: Workload: 30 Patients/day 30 Patients/day 10 min Tx time 10 min Tx time 880MU/min 880MU/min 66,000,000 MU/year 66,000,000 MU/year Usage Factors = 1 Usage Factors = 1 Occupancy Factor as usual Occupancy Factor as usual Occupational areas kept to 10% of limits Occupational areas kept to 10% of limits ISF from 3 meters ISF from 3 meters

33 Shielding Considerations, Leakage Leakage levels obtained from chart like CT scanner Leakage levels obtained from chart like CT scanner Leakage was measured and plotted as a function of position around the gantry and radial distance Leakage was measured and plotted as a function of position around the gantry and radial distance All leaves closed for measurements All leaves closed for measurements Leakage fraction at 3 meters was used Leakage fraction at 3 meters was used ISF from 3 meters ISF from 3 meters

34 Shielding Considerations, Scatter Scatter levels a function of position around gantry Scatter levels a function of position around gantry Greatest at opening of couch Greatest at opening of couch With all leaves open, can be 186% of leakage exposure With all leaves open, can be 186% of leakage exposure Clinically, the exposure can be reduced by a factor of 16 Clinically, the exposure can be reduced by a factor of 16 Maximum % scatter increase = 12%, I used 15% Maximum % scatter increase = 12%, I used 15%

35 Shielding Considerations, Primary Unit has a built in Primary Beam Block, 13cm Pb Unit has a built in Primary Beam Block, 13cm Pb The primary beam was 6.3% of the overall radiation at 2.5 cm from the isocenter The primary beam was 6.3% of the overall radiation at 2.5 cm from the isocenter Clinically, the exposure can be reduced by a factor similar to scatter due to closed leaves Clinically, the exposure can be reduced by a factor similar to scatter due to closed leaves I ignored reduction factor, and increased exposure by 6.3%. I ignored reduction factor, and increased exposure by 6.3%.

36 Shielding Results North Wall South Wall West Wall East Wall CeilingDoor Calculated Exposure (mR/hr) Measured Exposure (mR/hr) Ratio of Measured / Calculated 141%22%26%117%17%54% Ratio of Measured / Required 58%12%5%3%12%38%

37 Plan Comparison Tomotherapy Tomotherapy CMS XIO, Step and Shoot CMS XIO, Step and Shoot Varian Eclipse, Sliding Window Varian Eclipse, Sliding Window

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44 Which is best?? Depends …….. Depends …….. Workload Workload Needs Needs Patient sites Patient sites Many systems now have IGRT Many systems now have IGRT Where is IGRT going? Where is IGRT going? No Breath Gateing on Tomotherapy No Breath Gateing on Tomotherapy Where is gateing doing? Where is gateing doing?

45 In the future for Tomotherapy Adaptive treatments Adaptive treatments Live time optimizations Live time optimizations Conductivity with IMPAC Conductivity with IMPAC Live time QC Live time QC Breath Coaching Methods Breath Coaching Methods

46 Questions ?? Thanks for your attention! Thanks for your attention! Free tour of the Cancer Center after lunch Free tour of the Cancer Center after lunch Questions ??? Questions ???


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