Heavy Ion Tumor Therapy

Michael Scholz

GSI Darmstadt

Introduction

Advantage of ion beams for therapy:

Physical aspects:• Inverted depth dose profile• Defined penetration depth• Reduced lateral scattering

Biological aspects:• Increased effectiveness• Reduced oxygen effect

Increased effectiveness depends on many parameters like e.g.dose, Z, LET, or depth, which have to be taken into account fortreatment planning

Depth Dose Profile

Penetration Depth [cm]Relative Dose

Die höhere Wirkung schwerer Ionen

Die RBE hängt ab von:

• Dosis

• Strahlenergie

• Ionensorte

• Reparaturvermögen

der Zelle

Depth Dose Profile

Survival: Dependence of RBE on Cell Type

Biological Verification of Treatment Plans

“Head Phantom”

Biological Verification of Treatment Plans II

Local Effect Model

NucleusNucleus

Xlethal dV

V

zyxdSN

)),,((ln

Comparison of LEM with Exp. Data

Heavy ion induced foci

Cell Nucleus

CDKN1A/p21: greenDNA: red

Tracks in CR39

p21 response

Pb-ions, 3.1 MeV/u, 3x106/cm2

Ca-ions, 10.1 MeV/u, 2x106/cm2

Visualization of tracks

sample holdersample holder

Rasterscan

Heavy Ion Therapy

• Carbon: advantage of RBE• 3 Blocks / 4 weeks per year• 10…15 Patients / Block• 140 Patients total since Dec. 1997

2/3 carbon alone

1/3 photons + carbon boost

• Tumors: head and neck, few pelvic• chordoma, chondrosarcoma, ACC, meningeoma

Therapy Online Monitor

Treatment Room

Heavy Ion Therapy: Technical Aspects

• Horizontal fixed beam• Active magnetic scanning + energy variation

– 250 energies, 7 focus steps, 15 intensity steps

• 2-4 fields per patient and treatment day• Typical treatment time: 45 min• Typical irradiation time/field: 5…10min• Verification of distal field edge by PET using 11C

Current Activities

• Moving targets

• Installation of patient chair

• PET with protons (FZ Rossendorf, W. Enghardt et al.)

• Preparation of the dedicated clinical facility at Heidelberg

Schedule for Heidelberg Facility

2002 Call for tenderRefine specificationsPrepare Component manufacturingBuilding construction documentation

2003 Component manufacturingConstruction work

2004 Component manufacturingComponent acceptance trials

Begin 2005 SystemtestsMid 2005 CommissioningMid 2006 Pre-clinical operationsEnd 2006 Clinical operation

The Biophysics Group