Comparison of Clinical Parameters for Proton Therapy in the United States

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Comparison of Clinical Parameters for Proton
Therapy in the United States
Paige Summers, MS
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Disclosure

• This project is supported by the Federal Share of
  program income earned by Massachusetts General
  Hospital on C06 CA059267, Proton Therapy Research
  and Treatment Center and by grants CA10953 and
  CA81647 (NCI, DHHS).

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RPC Background

• Funded by the NCI, tasked with ensuring that
  radiotherapy institutions participating in
  clinical trials deliver clinically comparable and
  consistent doses
• Asked to develop monitoring program for proton
  therapy facilities too

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Proton Therapy Facilities

• Monitored by RPC
• 10 clinical sites
• 1 international site in Japan
• Forecast 20 new centers
• Will likely see increase in clinical trials with
  proton therapy, making comparability important

NJ 2012
Shizuoka 2003
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Proton Approval Steps

• Proton facility questionnaire
• Annual monitoring of beam calibrations by the RPC
  
• Ability to electronically transfer treatment
  plans
• Irradiation of RPCs baseline proton phantoms
• On-site dosimetry review visit

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Information Collected by the RPC

• Typical review components
• Dosimetry equipment calibration
• CT scanner, CTN/RSP conversion
• Patient immobilization
• Treatment planning procedures
• QA documentation

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Patient Simulation Parameters
Institution Scanner kVp mAs Slice Thickness Acquisition Mode Pitch SFOV cm
1 GE LightSpeed RT 16 140 600 1.25 mm Axial N/A 50
2 GE LightSpeed RT 16 120 300 2.5 mm Helical 0.94 50
3 Philips PET / Big Bore 120 / 140 500 / 400 1.25 mm Helical 0.51 / 0.56 65 / 85
4 GE VCT 120 350 2.5 mm Axial/Helical N/A / 0.94 50
5 Siemens Biograph 16 PET 120 / 140 150 1 mm Helical 0.55 50
6 Siemens Sensation 120 300 1.5 mm Helical 0.75 50
7 GE LightSpeed RT 16 140 250 1.25 mm Helical 0.94 50
8 GE LightSpeed RT 16 120 300 1.25 mm Helical 0.98 50

• Values obtained during on-site audit
• Can institutions improve simulation imaging
  parameters? Lower CT dose?

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Treatment Margins

• Described by institution in facility questionnaire

Site-Specific Lateral Margins mm Site-Specific Lateral Margins mm Site-Specific Lateral Margins mm Site-Specific Lateral Margins mm Site-Specific Lateral Margins mm
Brain HN Abdomen Pelvis
Institution 1 2.5 3 5 5
Institution 2 3 3 5 5
Institution 3 3 3 5 5 - 8
Institution 4 5 7 7 - 9 7
Institution 5 2 2 2 2
Institution 6 3 3 5 - 7 5 - 10
Institution 7 5 5 5 5
Institution 8 3 3 - 5 5 - 10 3 - 5
Institution 9 2 2 5 5
Institution 10 3 5 5 5
Institution 11 5 5 10 10
Penetration Uncertainty Margins Penetration Uncertainty Margins

Institution 1 3
Institution 2 3.5 3mm
Institution 3 1.50
Institution 4 3.5 3mm
Institution 5 2 mm
Institution 6 3.5 3mm
Institution 7 1 1mm
Institution 8 1.5 1.5mm
Institution 9 -
Institution 10 1 1mm
Institution 11 3.5 3mm
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Prescribing Dose
Prescription Levels Prescription Levels Prescription Levels Prescription Levels Prescription Levels Prescription Levels Prescription Levels
Brain HN Thorax Abdomen Pelvis Extremities
Institution 1 95 - 98 95 - 98 95 - 98 95 - 98 95 - 98 95 - 98
Institution 2 95 - 98 - 95 - 98 95 - 98 97.5 -
Institution 3 95 92 95 95 95 95
Institution 4 100 100 100 100 100 100
Institution 5 100 100 100 100 100 100
Institution 6 98 98 98 98 98 98
Institution 7 95 95 95 95 95 95
Institution 8 98 98 98 98 98 98
Institution 9 95 95 95 95 95 95
Institution 10 95 95 95 95 95 95
Institution 11 95 95 95 95 95 95

• Institutions normalizing in different ways, to
  different levels

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Significance

• Differences exits across centers
• Task groups focusing on QA, papers on outcomes
  not many recommendations about clinical
  parameters - could use more recommendations from
  experienced proton centers
• Important to consider variation of dosimetric
  parameters in planning clinical trials proton
  alone or mixed modality

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Questions?
??
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Proton Approval Steps

• Proton facility questionnaire
• Annual monitoring of beam calibrations by the RPC
  
• Ability to electronically transfer treatment
  plans
• Successful irradiation of RPCs baseline proton
  phantoms
• Successful completion of on-site dosimetry review
  visit

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Facility Questionnaire

• AAPM Proton Advisory group aids RPC QARC in
  updating proton facility questionnaire
• Submitted to QARC via email or paper copy sent
  to RPC
• Questions covered
• Experiences in the clinic
• Dose calibration verification
• Proton beam production delivery
• Treatment Planning
• Immobilization
• Patient Alignment
• QA

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RPC Proton Site Visits

• Typical site visit measurements
• Beam calibration comparison RPC/Inst
• CAX lateral and depth dose profiles for reference
  and patient fields
• Scanning beam less fields tested, more profiles
  obtained
• X-ray system measurements
• TLD measurements