Control System for the Clinical
Operation in Proton Therapy
Center, NCC, Korea.
(Operation Experience)
Se Byeong Lee
Medical Physicist, Ph.D.
The 7nd International Workshop on Accelerator Operations
April 14, 2010

Proton Therapy Center

Outline• Introduction of NCC• Proton Therapy Facility• Proton Beam Modulation and Delivery• Safety System• Maintenance1. Introduction of NCC

Overview of NCC
Organization

323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769, Korea

Proton Therapy Facility in NCC
2005. 2.15

IBA Proteus 235 installation start

2005. 10.21

First Beam Production

2005. 9.~ 2006. 2. Beam tuning ( Cyclotron & Beam line )2006. 6.~ 2006.12. Passive mode beam calibration & acceptance test

( 1 Fixed Beam & 2 Gantry )2007. 1.~ 2007.2. GTR2 Commissioning & Beam data taking
2007. 3.19.

First Proton treatment start~ 2010.12. 519 patients treated in Proton Therapy Facility

Proton & Proton Therapy
Proton is a nucleus of Hydrogen atom with positive electron charge which has 2000 times heavy
mass than electron. Proton therapy is a radiation therapy using proton.

Characteristic of proton (Bragg Peak)Proton is quite different from x-ray in terms of energy transfer. As it enters a cancer patient’s
body through skin and tissue, it releases a relatively low dose of energy before it reaches the target. It,however, hits the targeted tumor by depositing the biggest dose of energy on it, then suddenly stopping
its activity afterwards. The point where the highest energy is released is called as the Bragg Peak.

CSI using 3D CRT, Tomotherapy,and Proton Therapy
99%
95%
90%
70%
80%
60%
50%

5~100% isodose line

Treatment sites with proton therapy at NCC

Meningioma, 3Extrahepatic, 1Abdomen, 5CSI, 2

Nasopharynx, 2Oropharynx, 1Sacrum, 7Orbit, 2Brain, 35

Breast, 30

Cervix, 3
Prostate, 111Liver, 28Lung, 25Pelvis, 4Pancreas, 13

Updated in Sept. 2008

2. Proton Therapy Facility

Layout of Proton beam facility- Cyclotron- Energy Selection System- Beam Transportation System- Treatment rooms(2-GTR, 1-FBRT, 1-Exp. room)Cyclotron

Proteus 235 Specification
Weight : 220 ton Height : 210 cm Diameter : 434 cm

Energy : 230MeV
Max. extracted beam current : 300nA
RF frequency :106 MHz

Energy Selection SystemBeam Transportation System

Gantry Treatment Room - 1

Gantry Treatment Room - 2

Fixed Beam Treatment Room

Experiment Room

Main Control Room : operation consoles

Main Control Room : ISEU, RF, Magnet E

Milling Machine Shop

3. Proton Beam modulation
and Delivery

MCR - Beam Production
Cooling
VacuumMagnetRF
Radial ProbeIon Source
ISEU
Deflector
Extraction Quads
Extraction Steering…

Clinical Beam Specifications
Item

Singles
Scattering

DoubleScattering

Range in Patient (g/cm2)

3.35-20.4

4.51-28.42

3.42-32.1

Range modulation (g/cm2)
adjustment & Size

0.4(R>6), 0.179.2

0.2
20.75

0.5
FullRange adjustment(g/cm2)

0.09(R>6),0.05

0.1

0.1

Average dose rate (Gy/min)

5.93

3

1.15

Max. Field Size (cm)4 (D)24.3 (D)40X30

Dose Uniformity (%)

1.25

1.05

1.5(R), 2.6(L)Effective SAD (m)

2.55

2.19

2.12

Distal Penumbra (g/cm2)

0.21

0.23

0.13

Lateral Penumbra(cm)

0.17

0.48

0.30(y), 0.22(x)H&N, RSGeneral

Large Size

Clinical Use

UniformScanning

Kinetic Energy(P) vs. Effective Range in Water

Transmission efficiency ESS

Transmission Efficiency

Transmission ESS

y = 0.000343e0.031319x
R2 = 0.995666

50%
45%
40%
35%
30%
25%
20%
15%
10%
5%0%
100 110 120 130 140 150 160 170 180 190 200 210 220 230
Beam Energy (MeV)Max Beam current in treatment room = 300 nA x Transmission ESS* transmission ESS to treatment room = ~100%* 300 nA = 4.8 x 1012 protons/sec.

Proton Beam Nozzle – Beam Modulation

Schematic Plot of Beam Nozzle

1stand 2ndScatterors

Range Modulation wheels

Parameters for Beam Range, SOBP
Clinical BeamCondition

PT MachineParameters

Accurate beam intensity modulation, up to 2.5 kHz.
Command-Feedback

2.5

2signal (V)

1.5

1

0.5

0-0.06

-0.04

-0.02

0-0.5

-1t (sec)

0.02

0.04

0.06

Simulation of Proton beam Delivery
Geant4 version: 8.2.p01- EM model : G4hIonization with ICRU49 parameterized table- Hadronic : LHEP_PRECO_HP ( precompound model )MC Simulation

NCC Proton Beam Delivery MC Simulation

Patient dedicated Devices :Aperture & Compensator
Tumor
Normal Organ

ApertureCompensatorBeam Scanning Magnets

Demonstration of Pencil Beam ScanningClinical input

PBS irradiation result

PBS System

Modulation of the beam current (ISEU)
Concretely at+the ISOCENTER
Control of the scanning trajectory (SMPS)
100200300

400500

600

700

800

900

1000

1100
100

Curtesy of IBA

200300

400

500

600

700

800

900

Proton Beam Specifications

Momentum spread, 1 sigma
0.60

dP/P, %%

0.50
0.40
0.30
y = -4E-08x2 - 0.0031x + 0.7999
R² = 0.9536

0.20
0.10
0.00
0Beam sigma at the isocenter

50100

150

200

250

E, MevBeam Momentum Spread at Nozzle entrance

Curtesy of IBA

Proton Beam modulation methodsPassive mode

Dynamic mode

SOBP on Scattering mode
1. BCM file pickup

3. Beamgeneration

2.Beam gatingsignal(10Hz)

6. SOBP5. RM wheel synchronizing

4. Maximum Energy in Patient(600 rpm)

Proton Beam time Schedule (11shift/week)
time
6
7

Mon

Tue

WedThuFri

Morning QA work for daily Patient Treatment

891011

Patient Treatment

1213141516
17181920
2122

Patient QA &Beam data
Measurement

Patient QA &Beam data
Measurement

Patient QA &Beam data
Measuremen

Patient QA &Beam data
Measuremen

Patient QA &Beam data
Measurement

SatPatientTreatment(Reserved)

Sun
Beam data
Measurement,
Machine QA& Research4. Safety system

Building Interlock…

System Monitoring & Safety System Interlock

Detailed TroubleshootingStructure of the relay circuitry

TSSRelaybox

TSS RELAY BOX

INTERLOCKS
SCU
Programmable
logic controller

INPUT LAYERLOGIC LAYEROUTPUT LAYER

DEVICESSCUMain Control Room : TSS relay racks

CCD camera system

CCD camera system

Radiation level monitor with Area detectors

Radiation level monitor with Area detectors

Layout of Cyclotron and ESS(Energy selection system)ESS (Energy selection system) transmission loss (%)
100

Transmission Loss (%)

9080706050403020
100130140150160170180190

Beam Energy (MeV)

200210220230

Radiation level after beam stop

A level of radiation around cyclotron and energy selection system area
through random measurements after accelerator operation.

A level of radiation attenuation by operationcondition

Working under radiation exposureRadiation Exposure statistics for workers
CategoryExposure Dose in 2009

Therapists< 1 mSv

Medical Physicists< 1 mSvMCR Operators

0.7 ~ 2.5 mSv

Maintenance Engineers

4.5 ~ 7.0 mSv

5. Maintenance Issues

NCC PT Maintenance manpower• Biomedical Engineers : 2.5 man/year- 1 RF & PT system Engineer : 100%
- 1 Electronics Engineer : 100 %- 1 Mechanics Engineer : 30 %- 1 Software Engineer : 20%• MCR Operators(PTC) : 1.2 man/year- 4 Engineers of IBA certification for Cyclotron OP- Operation 70% + Maintenance support 30%* IBA’s technical supports (Regular + Emergency visit from Belgium)

All PM Tasks for PT in NCC

320 items per day, week, month, year

PPSCU

PPS

PCU

MFC

MCRVUEMain Coil

Magnet

LLRF

Light FieldISEU

Ion Source

IMPA

ICEU

ICCycloIC

Harmonic Coil

Hand pendant

H2Group3

Gradient corrector

Gantry

FSEU

FPMEU

FPA

First Scatter

ECUBTCU

Door Interlock

DIPS

DID

DegraderDeflector

Cyclotron

Couchcooling

BPM

BLPSCUBeamStop

Beam LineBCM

All Power Failure

ACU

Statistics of trouble parts

80706050403020100

Statistics of trouble parts
The Number Of Problems In KNCC
600500400300
The Number Of Problems
2001000
Beam Line

Cyclotron(MCR)

PowerServer

Treatment

Water

RoomCoolingSummary• Proton Therapy facility in NCC is successfully
operating since Mar. 2007.
• We are lack in manpower for PTS maintenance.
( ~ 94% operation rate, Potential radiation risks,etc.) So, we are going to strengthen the support forcyclotron maintenance to improve operation rate.

Thank you!