Overview of Proton Beam Cancer Therapy with Basic Economic Considerations

Transcription

1 Overview of Proton Beam Cancer Therapy with Basic Economic Considerations Wayne Newhauser, Ph.D. Proton Therapy Project, Houston Cyclotron 235 MeV 300 na Extraction Channel Radial Probe Energy Degrader Wheel High-Precision Robotic Couch 1

2 Hitachi Gantry 13 m diameter 220 tons SAD 2.7 m Gantry Pit (Tsukuba University) Roller Bearings Rotating Mass ~200 T!!! ~12 m dia. NPTC First Patient Treatment on 8 November,

3 Proton Bldg Construction, NCC Korea Courtesy J Kim Hospital (existing) NCC, Korea Research complex (under construction) Proton therapy facility (under construction) Courtesy J Kim Ion beam laboratory RFQ injector 200 kv platform 5 MV van de Graaff Injector proton therapy beamline isochronous sector cyclotron 3

4 Cyclotron at HMI - Berlin Emerging Trends in Proton Therapy For-Profit Financial Model Reduce Time to Market (~ 3 y) Minimize Cost (< 100 M) Minimize Risk!!! Facility designs, planning software will continue to improve dramatically 4

5 New Ion Facilities About 10 new facilities will open in the next 3-4 years. INSTITUTION PLACE TYPE IMP, Lanzhou PR China C-Ar ion Wanjie, Zibo China p PSI Switzerland p Shizuoka Cancer Center Japan p Rinecker, Munich Germany p NCC, Seoul Korea p Heidelberg Germany p, ion FPTI, U. of Florida FL, USA p IThemba LABS, Somerset West South Africa p M. D. Anderson Cancer Center TX, USA p Chang An Information, Beijing China p CGMH, Northern Taiwan Taiwan p Bratislava Slovakia p, ion Erlangen Germany p CNAO, Milan & Pavia Italy p, ion Med-AUSTRON Austria p, ion Central Italy Italy p TOP project ISS Rome Italy p 3 projects in Moscow Russia p Krakow Poland p Proton Development N.A. Inc. IL USA p From Particles Newsletter Proton Therapy Center - Houston Facility Overview Treat approx pt/y (treating 12 h/d, 6 d/wk) Stand-alone facility (with CT, CT-sim, PET, MRI, ) 88,000 ft 2 of clinical space Beam Scanning Clinical Goals (IMPT) Treat 240 patients/y with scanned beams (8% of total) 30 min/patient (two fields) 24 patients/d 5

6 PTC-H Side View Accelerator Vault Gantry Rooms Fixed Beam Treatment Room Experimental Room PTC-H Treatment Level Experimental Scanning Large Field Ocular Passive Synchrotron 5 Passive Nozzles 1 Magnetically scanned nozzle Nozzle Snout X-ray Tube Couch Image Receptors Articulating Floor Univ. of Tsukuba 6

7 Linac Injector and Synchrotron HEBT Septum Magnet Electro Static Deflector MeV p/spill s rep Linac RF Cavity Bending Magnet LEBT Electro Static Inflector Univ. of Tsukuba s/spill Stable beam properties (no feedback) High reliability Rotational Gantry 13 m diameter 200 tons SAD 2.5 m 7

8 Results of 7 Measurements Displ [mm] Gantry Angle [degrees] Physics Review: Objectives Review basic proton interaction physics Understand how protons can be used to provide a clinical advantage Introduce equipment and technology 8

9 Energy Transfer Mechanisms Excitation Elastic scattering with nucleus Ionization Bremsstrahlung Most energy loss is via coulombic interactions with atomic electrons. Small deflections are caused by coulombic interactions with nucleus. Nuclear reactions play only a small role. Energy-Loss Rate, Proton Range Range Straggling Range straggling: σ = R

10 Range Straggling Smears out the Bragg Peak Enough Physics, now for some engineering Making a Spread-Out Bragg Peak 10

11 Bussiere and Adams, skull base sarcoma, TCRT 2003 Dynamic Beam Scanning Sweep small proton beam over a large tumor using magnetic beam deflection. Modulate beam range and fluence for each spot. A Some A full few proton set, more pencil with pencil beams a homogenous together. (spot)... dose conformed distally and proximally Images courtesy of Eros Pedroni, PSI (Switzerland) Scanning Nozzle: Preliminary Design Profile Monitor Vacuum chamber Y magnet (in plane) X magnet (crossplane) Beam (8 mm FWHM) Helium Chamber Scanning Magnets Scattering filters and retracting x-ray tube Spot Position Monitor Dose Monitors Fine Degrader Multi-leaf Collimator Nozzle range loss < 5 mm (Iso- Center) 11

12 Weber, Paraspinal sarcomas IJROBP 2004 Summary of Key Points 1) Proton beams stop - no exit dose 2) Laterally, proton beams have sharp penumbra 3) Proton beams provide uniform target dose distributions 4) Proton dose distributions can be made to conform tightly to irregular target shapes in all three dimensions 5) Lower integral dose with marked reduction of low-dose volume or dose-bath 4) Clinical radiobiology of proton beams is almost identical to that of photon beams 5) Hence, protons offer a significant clinical advantage and it is mainly due the ability sharpshoot with dose. 12