Book/Report

FZJ-2019-01813

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Aktivierungsquerschnitte von (p,x)-Prozessen an biologisch relevanten Elementen im Energiebereich von 50 bis 350 MeV für medizinisch-therapeutische Anwendungen

Faßbender, M. (Corresponding author)FZJ*

1997
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/21814

Report No.: Juel-3348

Abstract: For developing a cross section data base for estimating the activation of human tissue and beam collimator material during proton therapy, several (p,x) processes were investigated in the energy range of 50 to 360 MeV using the stacked-foil activation method, radiochemical separations and high resolution y-ray spectrometry. Irradiations were done with medium-energy protons from the cyclotrons TSL Uppsala (Sweden) and LNS Saturne (France). The subsequent radiochemical work was done at Jülich. A cation exchange-HPLC method was developed to obtain the low-yield products $^{7}$Be and $^{22}$Na in a radiochemically pure form. Cross sections of (p, $^{7}$Be) reactions could be measured for the first time on the elements P, S, Cl, Ca, Zn and brass alloy. Over the investigated energy range of 80 to 360 MeV the cross section amounts to 0.1- 2.0 mb. New information was also obtained on (p,$^{7}$Be) reactions on C, N, 0, F, Na, Al, Si, Fe and Cu in various energy regions. Cross sections for the formation of the sodium radioisotopes $^{22}$Na and $^{24}$Na were obtained for the elements Si, P, S, Cl, Na, Ca and Cu for proton energies from 100 up to 260 MeV. In most of the cases very little information was available in the literature, so that gaps could be filled. The formation of the short-lived $\beta^{+}$ emitters $^{11}$C (T$_{1/2}$=20.0 min) and $^{15}$O (T$_{1/2}$=2.0 min) in the interaction of protons with C,N and O was investigated over the energy range of 50 to 70 MeV and at 180 MeV. More detailed studies were perfomed on the formation of activation products in irradiations of Ca, Cu, Zn and brass with 80-360 MeV protons. Cross sections for the formation of $^{55,56,57,58}$Co, $^{52g,54}$Mn, $^{51}$Cr, $^{48}$V, $^{44m.48}$Sc, $^{47}$Ca and $^{43,42}$K were determined experimentally. For an interpretation of the data nuclear model calculations using the code ALICE-IPPE 96 were perfomed. The experimental data agree with the results of model calculations, especially for product nuclides in the vicinity of the target nuclide, and for energies < 120 MeV. Considerable deviatlons were obseived for higher energies and for product nuclides far from the $\beta$-stability line. Activation and dose estimates were perfomed for the formation of $^{11}$C, $^{15}$O and $^{7}$Be in muscle and $^{22}$Na and $^{44m}$Sc in bone tissue. Activation estimates were also done for the production of $^{62}$Zn, $^{67}$Ga and $^{54}$Mn in the beam collimator material: While $^{62}$Zn decays completely between two therapy runs, the $^{67}$Ga residual activity oscillates between 4 and 20 MBq (for a 200 MeV p-beam of 400 nA). Due to its long half-life, $^{54}$Mn is accumulated to activity levels of about $^{55}$ MBq ($\sim$ 2 mCi) yearly. The total radionuclide dose generated in the treated tissue volume amounts to about 25% of the irradiation dose (assumed as 2 Sv p-radiation dose/ application).

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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