Seminare de DPNC
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Mercredi, 5 Mai 1999

17.00 - Auditoire Stuckelberg

Universite de Geneve
Departement de physique
nucleaire et corpusculaire
24, quai Ernest-Ansermet
1211 Geneva 4

Tel. 022 702 6273
Fax 022 781 2192

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Sujet:	Tumortherapy with Relativistic Ion Beams

Par: Prof. Dr. G. Kraft, GSI, Darmstadt


Resume:	
Beams of heavy-charged particles like protons or carbon ions represent the 
optimum tool for the treatment of deep-seated inoperable tumors: in contrast to 
the conventionally used photons the dose increases along with the penetration 
depth through the body, culminating in a sharp maximum at the end of the 
particle range. In order to achieve a precisely conform irradiation of the 
selected target volume, this maximum can be shifted in depth by energy 
variation  and distributed laterally through magnetic deflection of the 
particle beam. Since carbon ions have a lateral scattering of only about 1 
millimeter they offer the most conform irradiation.
In addition to this excellent physical selectivity the biological efficiency 
concerning cell killing increases towards the end of the carbon ions' range. 
Therefore, the increase in dose is potentiated by an increase in biological 
efficiency. 
Finally, the stopping of the carbon ions can be monitored by tracing a small 
amount of beta+active 10C and 11C ions which are produced in nuclear 
reactions 
with atoms in the target volume. This beta+ distribution can be visualized by 
applying PET-techniques, thus allowing a good control of the beam range. 
At GSI Darmstadt a heavy-ion therapy unit has been designed and constructed in
collaboration with the Radiological Clinic and the DKFZ Heidelberg and 
the FRZ Dresden. The layout of this facility as well as the treatment of 
now more than 
30 patients will be reported on. The proposal for the layout of a dedicated 
medical facilty at Heidelberg will be presented.