*Chien-Yi Yeh, Ji-Hong Hong * 葉健一洪志宏

Transcription

1 林口 Proton Therapy in Ti Taiwan *Chien-Yi Yeh, Ji-Hong Hong * 葉健一洪志宏 Chang Gung Memorial Hospital at Lin-Kou, Taiwan 林口長庚紀念醫院 OCPA2010 at Beijing, China Aug. 5, 2010

2 Outline 1. The principle of proton radiotherapy 2. Introduction ti of the current medical environment in Taiwan 3. Preview of radiotherapy in Taiwan 4. The proton project at CGMH in Taiwan 5. Conclusion

3 The principle of proton radiotherapy

4 Clinical i l Rationale for Advanced d Beam Modalities for Radiation Therapy To improve local-regional control through dose escalation to improve overall survival To reduce normal tissue complications to improve quality of life To reduce treatment time/cost

5 Particles used in radiotherapy Photon Electron Neutron Proton Heavy charged particles

6 Type of radiation Direct ionization radiation electron beam *proton beam helium carbon neon Silicon Charged particle Indirect ionization radiation photon beam neutron beam Uncharged particle

7 Interaction with matter in physics Linear Energy Transfer (LET) Related to mass, energy and charge of particle

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9 2 nm interaction with cell in biology Indirect action (2/3) HO - H 2 O Direct action (1/3)

10 Relative Biological effect (RBE) RBE t = D 250 /D t (same biological end-point of 250KV X-ray) *RBE value related to the type of radiation, energy and cell type.

11 Oxygen enhancement ratio (OER) Oxygen is a powerful oxidizing agent and therefore acts as a radiosensitizer if it is present at the time of irradiation (within μsecs). Its effects are measured as the oxygen enhancement ratio (O.E.R.) OER O.E.R. =the ratio of doses needed to obtain a given level of biological effect under anoxic and oxic conditions. O.E.R. = D(anox)/D(ox) 1.0 For low LET the O.E.R. is For neutrons, O.E.R is about S.F. oxic hypoxic O.E.R.= Dose (Gy)

12 RBE and OER as a function of LET RBE (for cell kill) OER Co-60 Diagnostic gamma rays X-rays Proton Fast Alpha Neutrons Particles OER 2 RBE Linear Energy Transfer (LET kev/μm)) OER is the inverse of RBE because it depends on the indirect action of ionizing radiation

13 RBE and OER for different beam modalities

14 Biological Characteristics of Proton Beam Averaging RBE for proton =1.11

15 Physical Characteristics of Proton Beam Modulated proton beam Spread-out Bragg peak Bragg peak target X-ray Dos se Unmodulated proton beam Depth Tumor

16 Why use proton? No biological advantage: RBE: Mainly physical advantages: Bragg Peak and Spread of Bragg peak

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18 How about the heavy ion? RBE significantly varied with depth. Use physical dose to compensate the biological variation. Biological dose as the prescribed dose

19 Why uses heavy ion? 1. Bragg peak & Spread of Bragg Peak (SOBP) 2. High RBE 3. Biological as well as physical advantage But: 1. Tail dose very high RBE 2. RBE varies with energy and depth 3. Limited facility experimental 4. Expensive

20 History of heavy ions

21 235MeV Cyclotron

22 Cyclotron 1. Fix time/per cycle, with increasing i diameter to comply with the increasing speed of particle. 2. Continuous beam, not pulse. High output and dose rate. 3. Beam at the outlet: fixed energy. 4. Adjust energy by beam degrader. 5. Relatively more radioactivity of contamination. 6. Stable output, more suitable for pencil beam scanning.

23 Synchrotron 1. Fix diameter, with increasing the speed of changes of magnetic field to comply with the increasing speed of particle. 2. Pulse beam, not continuous. lower output and dose rate. 3. Beam at the outlet: variable energy. 4. Relatively more radioactivity of contamination. 5. Relatively not stable within a pulse, more difficult in pencil beam scan.

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26 Basic systems for particle facility Accelerator system Beam transport system Beam delivery system Patient positioning system Treatment planning system

27 The Cost of a Proton Facility The building/shielding US$ 40million The accelerator US$ 10-30million The gantries/others - US$ 30million The cost of a Carbon facility will be 2-3 times more!

28 Dose comparison between photon and proton 6MV X-rays Protons

29 Dose comparison between photon and proton

30 Intensity Modulation Proton Thearpy (IMPT)

31 Medulloblastoma of Child Photon Photon 100 Proton Proton

32 History: 1954-now Patients: > 77,000 patients

33 Proton Therapy Pre-PBT Post-76 GyE PBT 67y F, Hepatocellular Carcinoma

34 Proton Therapy Non-coplanar beam Pre-PBT Isodose Curve Post-65 GyE PBT 48y F, Ethmoid Sinus Cancer No visual weakness, no brain damage

35 Proton Therapy

36 Does Taiwan need particle facility? If need, how many is necessary?

37 Geography of Taiwan Area~ 36,000 sq meter Population~ 23,000,000 37

38 Preview of radiotherapy in Taiwan

39 Leading Causes of Death in Taiwan, 2009 Rank Cause of Death No of Death rate per 100, death population 1 Malignant neoplasms 39, Heart disease 15, Cerebrovascular disease 10, Pneumonia 8, Diabetes mellitus 8, Accidents and adverse effects 7, Chronic respiratory disease 4, Chronic liver disease and cirrhosis 4, Suicide 4, Nephritis, nephrotic syndrome and nephrosis 3, Ttl Total 107,

40 Leading Causes of Cancer Death in Taiwan, 2009 Rank Cause of Death No of death Death rate per 100, population 1 lung cancer 7, liver cancer 7, colorectal cancer 4, female breast cancer 1, stomach cancer 2, oral cavity cancer 2, prostate cancer esophageal cancer 1, pancreatic cancer 1, cervical cancer All other causes 9, Total 39,

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42 International Comparison of Standardized Mortality Rates Per 100,000 people Due to Cancer Taiwan South Korea Japan Singapore UK USA Australia By 1976 W.H.O. World Standard Population as the Standard

43 Cancer prevention and control in Taiwan

44 Why need more radiotherapy facilities? The cancer incidence id is predicted d by WHO(1995) to increase to approximately 15 million new cases by the year About 50% of cancer patients still require radiation treatment, either curative or palliative. The need for rapid worldwide expansion of radiation treatment technology demands adequate resources, including the creation of new treatment t t facilities, new technology, well trained medical personnel.

45 Preview of radiotherapy in Taiwan No of linear accelerator in Taiwan sets Linear accelerator 5 sets Cyber knife 8sets Gamma knife 10 sets Tomotherapy

46 Radiotherapy facility in Taiwan Northern area 35% Southern area 19 31% Eastern area 5 8% Northern area 22 35% Central area 26% Estern area 8% Total: 62 Central area 16 26% Southern area 31%

47 Preview of radiotherapy in Taiwan Radiation oncology attending physicians Medical physicists 60 Resident doctors

48 The first proton project in Taiwan 台灣的第一步 ( 部 )

49 New Proton Center of Chang Gung Memorial Hospital Linkou area, Taoyuan county PTS Operation will start in km from the Taoyuan International Airport Existing hospital complex

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51 Proton Therapy in Taiwan Chang Gung Memorial Hospital

52 Proton Therapy System (PTS) for CGMH Experimental Beam Port Wobbling Nozzle with Fine Pitch Multi Leaf Collimator Pencil Beam Scanning Dedicated Nozzle Contracted in June, cyclotron, 4 rotating gantries, and 1 experimental port system 2 wobbling systems and 2 pencil beam scanning dedicated systems Advanced equipment: Robotic couch, DR systems, respiration gating systems, and Multi-leaf leaf collimators 230 MeV Cyclotron with Oil-Free Cryopump

53 49M 13M Cyclotron Gantry X 4 Experiment 91.2M

54 18M Cyclotron Gantry X 4 Experiment

55 Max. Field Size Max. Range (Energy) Min. Range (Energy) Energy Steps Clinical Specifications of Proton therapy at CGMH in Taiwan Item Wobbling Nozzle Pencil Beam Scanning Nozzle Range Modulation 25 cm x 25 cm (w/o MLC) 20 cm x 20 cm (with MLC) 32 g/cm 2 (230 MeV) without scatterer 4 g/cm2 (70 MeV) Continuous from 230 MeV to70 MeV Steps of 1g/cm2 by ridge filters 40 cm x 30 cm (L x W) 32 g/cm 2 (230 MeV) Steps of 0.2 g/cm2 Dose Uniformity it ± 2.5% over 80% of field ± 25% 2.5% over 40 cm x 30 size cm (comformity) Average Dose Rate 1 Gy/min/liter (regardless of depth and field size)

56 230 MeV Sumitomo Cyclotron Dia.: 4.3m dia. Weight: 220 tons Energy: 230 MeV Beam Current: 300 na 230 MeV Cyclotron for NCCH PTS in Japan

57 Energy Selection System (ESS) Beam from Cyclotron Beam Energy Range: MeV 1.2 Stepwise Energy Absorber Collimator Bending (Analyze) magnet Defining Slit Rela ative Dose Low Energy High Energy to Gantry Depth (mm)

58 Beam Transport System Quadrupole Magnet Requirement for beam delivery room switching time < 2 sec Changed Block Magnets to Laminated Magnets Magnet Shop in SHI

59 Rotating Gantry Dipole Magnet Rotating Gantry Beam Nozzle Treatment Room Proton Beam Patient Bed

60 1st and 2nd Treatment Room: Wobbling Nozzle Multi Leaf Collimator Patient Snout Wobbling Nozzle

61 Radiation Field Formation by Collimator and Compensator Compensator (Polyethylene) Collimator (Brass) Proton Beam Ridge Filter Compensator Collimator Tumor Scatter Fine Degrader Block Collimator Proton Radiation Beam by Scattering Method

62 3 rd and 4 th Treatment Room: Pencil Beam Scanning Nozzle For Pencil Beam Scanning Quadrupoles Scanning magnets Dose monitor 2D monitor

63 Continuous Line Scanning Continuous line scanning is realized by two X-Y scanning magnets. The power supplies of scanning magnets can generate output current with fast time response. - scanning speed : 10mm/ms - response of velocity change : < 1ms Scanning pattern for uniform field Scanned field measured with a fluorescent plane + CCD camera

64 Maximum Field Size Maximum field of 30cm(X) 40cm(Y) 28cm(SOBP) Field uniformity of ±2.5% was confirmed at 230 MeV Depth dose with SOBP=28cm (at beam center) Dose at the center of SOBP (X-direction) Dose at the center of Depth dose with SOBP SOBP=28cm (Y-direction) (at beam center)

65 Field Evaluation by Gamma Index Gamma index evaluation at 3%/3mm has been done for the uniform and intensity-modulated 2D fields, which were measured at the Bragg peak using 230MeV beam. 1) Uniform field

66 Field Evaluation by Gamma Index 1) Uniform field 100% of evaluation points have passed the criterion of gamma index < Gamma index map Dose Dose Uniform field / X-direction Measurement Simulation Gamma index Distance [mm] Uniform field / Y-drection 120 Measurement Simulation Gamma index Distance [mm] Gamma index Gamma index

67 Intensity Modulation by Scanning Speed Intensity modulation is done by changing the scanning speed (high speed for low dose) keeping the beam current constant in each layer low dose region (high scanning speed) high dose region (low scanning speed) Dose simulation of two steps pattern

68 Field Evaluation by Gamma Index 2) Intensity modulation field

69 Field Evaluation by Gamma Index 2) Intensity modulation field

70 Patient Positioning Verification System

71 DR System with Cone Beam CT Function for Easy and Accurate Patient Positioning X-ray Generator DR System Flat Panel Detector1 DR system and Patient Positioning Verification System (PPVS) make Cone Beam CT (CBCT) image. PPVS also provides high speed and high accuracy 3D-3D image matching to correct the error of patient set-up. Positioning Accuracy: < 0.5 mm

72 Accurate Irradiation for Moving Tumor by Respiration Gating System Respiratory-gated irradiation can be made by Respiration Gating System with laser sensor and DR system. Respiratory signal Laser sensor OFF ON Gating signal Example of gating display on PC

73 Project Schedule TFDA QSD Product Registration Site Test Human Test AEC Building construction Manufacturing Installation Commissioning Radiation Shielding Site Test

74 Manufacturing at Niihama Factory in Japan 230 MeV Cyclotron manufactured at Sumitomo Niihama Factory Major and critical components are designed and manufactured in Sumitomo s own factory to maintain high quality, high reliability, high performance, low cost, and short delivery time.

75 Conclusion The therapeuticti effects of proton therapy in many cancers have been well established. In Taiwan, liver tumors and head and neck tumors will be the tumors having greatest benefit. The indication covers different type of tumors, but main issue is the cost and cost/effectiveness. If one proton therapy treated around 1500 patients per year, Taiwan needs 2 or more proton therapy centers.

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