In-beam PET measurement of 7Li3+ irradiation induced beta+-activity.
At present positron emission tomography (PET) is the only feasible method of an in situ and non-invasive monitoring of patient irradiation with ions. At the experimental carbon ion treatment facility of the Gesellschaft für Schwerionenforschung (GSI) Darmstadt an in-beam PET scanner has been integrated into the treatment site and lead to a considerable quality improvement of the therapy. Since ions other than carbon are expected to come into operation in future patient treatment facilities, it is highly desirable to extend in-beam PET also to other therapeutic relevant ions, e.g. (7)Li. Therefore, by means of the in-beam PET scanner at GSI the beta(+)-activity induced by (7)Li(3+) ions has been investigated for the first time. Targets of PMMA, water, graphite and polyethylene were irradiated with monoenergetic, pencil-like beams of (7)Li(3+) with energies between 129.1 A MeV and 205.3 A MeV and intensities ranging from 3.0 x 10(7) to 1.9 x 10(8) ions s(-1). This paper presents the measured beta(+)-activity profiles as well as depth dependent thick target yields which have been deduced from the experimental data. The beta(+)-activity induced by (7)Li ions was found to be a factor of 1.76 higher than the one induced by (12)C ions at the same physical dose and particle range.
Priegnitz
M
M
Division of Radiation Physics, Institute of Radiation Physics, Forschungszentrum Dresden-Rossendorf, Dresden, Germany. m.priegnitz@fzd.de
Möckel
D
D
Parodi
K
K
Sommerer
F
F
Fiedler
F
F
Enghardt
W
W
D001610:Beta Particles; D020450:Heavy Ions; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008094:Lithium / Q000032:analysis* / Q000528:radiation effects*; D049268:Positron-Emission Tomography / Q000379:methods*; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*
D008094:Lithium