Nuclear Data for Radiation Therapy...NIRS / HIMAC 2 Résumé Introduction radiations used for radiotherapy what to estimate to carry out heavy ion therapy Macroscopic effect nuclear

NIRS / HIMACNIRS / HIMAC

Nuclear Datafor

Radiation Therapy

Naruhiro Matsufuji, Yuki Kase and Tatsuaki KanaiNational Institute of Radiological Sciences

Research Center for Charged Particle Therapy

~from macroscopic to microscopic~

Symposium on Nuclear Data 2004Nov. 12, 2004 @ JAERI, Tokai

22NIRS / HIMACNIRS / HIMAC

RésuméIntroduction

radiations used for radiotherapywhat to estimate to carry out heavy ion therapy

Macroscopic effectnuclear reaction

dose

Microscopic effectbeam quality

biological effectspatial distribution

advanced irradiationmicrodosimetry

nature of heavy ion radiotherapyneutrons

Summary


Radiations used for tumor therapy

“Heavy ion”

direct ionizing radiationelectronprotonhelium, carbon, neon, silicon, …：

indirect ionizing radiationphotonneutron：

44NIRS / HIMACNIRS / HIMACHIMAC (Heavy Ion Medical Accelerator in Chiba)•Established in 1994.•Aimed at finding optimal heavy ion therapy scheme.

0.3 / 0.5 Hzrepetition cycle

100～109 particles/pulsebeam intensity

800 MeV/n（ε=Z/A=1/2）maximum energy

H,He,C,Ne,Si,Ar,Fe,Kr,Xeion species


Clinical trials at HIMAC• Targets of carbon therapy

brain, scull baseeye head and neck

lung

liver pancreas

prostate, uterus rectum

bone, soft tissue

nasal passagecancer

Nov. 1, 2003: approved as a Highly Advanced Medical Technology¥3.14M / treatment


Basis of clinical dose prescription

radiation survival

＋ ⇒

loss of capacity for

multiplication (inactivation)• cell survival

0.01

0.1

1

0 2 4 6 8 10

Sur

vivi

ng F

ract

ion

Dose (Gy)

reference

test

effectsameradiationtest

radiationreference

DD

RBE __

_=

carbon: 2~3


Characteristic of heavy-ion therapyFragmentation of incident particles

projectile (carbon)

target

projectile fragmentparticipant

spectator

140-430MeV/n

Projectile fragments have almost

-…same velocity-…same direction

with those of primaries.

Therapeutic beam is

contaminated by fragments!


Why?

0

1

2

3

4

5

6

0 50 100 150 200

C290 MeV/n in Water

HIBRAGGsmeasurement

Rel

ativ

e D

ose

Depth in Water (mm)

Effect by fragmentationfrom clinical point of view

Production of fragment particles...…causes unwanted dose beyond the range…makes estimation of biological effect complex.…makes it possible to monitor beam range.

M. Scholz et al., Radiat. Environ. Biophys., 36, 59 (1997).T. Nishio (NCC-east), private comm.


Macroscopic effectDepth dose distribution


Depth-dose distributionDose……”quantity of radiation” ][/ GykgJDose =

the most fundamental factor to be controlled on radiotherapy

reaction cross sectionstopping power

multiple scattering and straggling:

physical factors

Disintegration of primariesloss of dominant dose carrier

Production of fragmentsdeliver dose but form ‘fragment tail’ beyond the range


Depth-dose distributionDepth-dose distribution in water measured at HIMAC

0

1

2

3

4

5

6

0 50 100 150 200

C290 MeV/n in Water

HIBRACmeasurement

Rel

ativ

e D

ose

Depth in Water (mm)

0

0.5

1

1.5

2

2.5

3

3.5

0 50 100 150 200 250 300 350

C400 MeV/n in Water

HIBRACmeasurement

Rel

ativ

e D

ose

Depth in Water (mm)

Dose can be controlled in clinically enough precision.

basis of ongoing carbon therapy


Macroscopic to Microscopic

What? – particle identification


Importance of P. I.LET and particle species dependency of RBE (CHO cell)

M. Scholz and G. Kraft, Rad. Prot. Dos., 52, 29 (1994)

How should we take into account this complexity?

Radiation quality (fluence and energy)


depth

LET

fragment simulation

How? - NIRS scheme

survival

Biological dataHSG cell

depth

∑= iimix f αα

∑= iimix f ββ

Biol. dose

LQ model:S= exp(-αD-βD2)

dose

dose

1515NIRS / HIMACNIRS / HIMACHow many? - fluence

12C-290MeV/n Calculation: hibrac (old)

Z=6,2,1 Z=5,4,3

0

0.2

0.4

0.6

0.8

1

0 50 100 150

Z=6Z=2Z=1

Z=6Z=2Z=1

Z=6 (CR39)

Nor

mal

ized

Flu

ence

PMMA Thickness (mm)

0

0.02

0.04

0.06

0.08

0.1

0 50 100 150

Z=5Z=4Z=3

Z=5Z=4Z=3

Z=5 (CR39)Z=4 (CR39)

Nor

mal

ized

Flu

ence

PMMA Thickness (mm)

Need improvement on simulation modelN. Matsufuji et al Phys. Med. Biol., 48, 1605 (2003)

1616NIRS / HIMACNIRS / HIMACComparison with PHITS

Z=6,2,1 Z=5,4,312C-290MeV/n Calculation: PHITS 1.80

0

0.5

1

1.5

0 20 40 60 80 100 120 140 160

Z=6Z=2Z=1

Z=6Z=2Z=1

Nor

mal

ized

Flu

ence

BF Thickness (mm)

0

0.02

0.04

0.06

0.08

0.1

0 20 40 60 80 100 120 140 160

Z=5Z=4Z=3

Z=5Z=4Z=3

Nor

mal

ized

Flu

ence

BF Thickness (mm)


Z=6Z=5Z=4Z=3Z=2Z=1

0

1

2

3

4

5

6

0 50 100 150 200

Rel

ativ

e D

ose

Depth in Water (mm)

102

103

104

101 102

Dos

e (A

rbitr

ary

Uni

t)

LET (keV/µm)

PMMA = 0 mmH2O

102

103

104

101 102

Dos

e (A

rbitr

ary

Uni

t)

LET (keV/µm)

PMMA = 90 mmH2O

102

103

104

101 102

Dos

e (A

rbitr

ary

Uni

t)

LET (keV/µm)

PMMA = 130 mmH2O

LET spectra12C-290MeV/n

100% 81% 77%


Heavy-ion therapy sites

LBL NIRSHyogo

GSI

1977~1991

1997~

2002~1994~


Where? – spatial distribution


Importance of the spatial distributionScanning irradiation with pencil beam

Not fully understood both experimentally / theoretically

(picture from SIEMENS)

lateral nonuniformity

stopping powermultiple scattering

production cross sectionreaction cross sectionmomentum transfer

:


More microscopic!- microdosimetric approach


Microdosimetric problem• Random energy deposition

in cell nucleus

•amorphous (averaged) track •actual (sparse) track


What? – neutrons


Neutrons in therapy room12C-290MeV/n 10000 particles （simulation with PHITS）

carbon

neutronscatterer ridge filter collimator patient

Geometry: from Nose (IHI)


Neutrons in therapy room12C-290MeV/n 10000 particles （simulation with PHITS）

Neutron dose distribution

scatterer ridge filter collimator patient

•Risk estimation for the induction of the secondary cancer

•Dependency to irradiation scheme

•Optimal treatment method


SummaryMacroscopic effect

Charge-changing cross section

Depth-dose distribution is given in good precision

Dose is delivered to tumor accurately

Need further investigation for heavier elements

2727NIRS / HIMACNIRS / HIMACSummary

Microscopic effectsFluence and LET distribution (broad beam)

Feedback to biology (ex. survival simulation)

Spatial distribution (pencil beam)

Input data for RTP of scanning irradiation

Angular distribution, double differential production cross section, momentum transfer, …

Development of simulation code including spatial information, advanced RTP (inhomogeneous structure)

Microdosimetric approach

Understanding of the nature of heavy ion therapy


Thank you for your attention.Thank you for your attention.

Mt. Fuji from Chiba city

A part of this work was carried out as the Research Project with Heavy Ions at HIMAC.

Documents

Nuclear Data for Radiation Therapy...NIRS / HIMAC 2 Résumé Introduction radiations used for radiotherapy what to estimate to carry out heavy ion therapy Macroscopic effect nuclear