Naslov
Absorbed fraction estimates for beta and electron emitting radionuclides in spherical sources

Autori
Bokulić, Tomislav ; Lacić, Miodrag ; Kusić, Zvonko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
European Journal of Nuclear Medicine / - , 1996

Skup
Radioactive Isotopes in Clinical Medicine and Research, 22nd International Symposium

Mjesto i datum
Bad Gastein, Austrija, 09.01.1996. - 12.01.1996

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
absorbed dose fractions; S-values; electron emitters

Sažetak
The radiation dose to small structures and organs containing beta and electron emitting radionuclides may differ significantly from traditional macroscopic models in which it is assumed that all of the electron energy emitted in the source region is absorbed in that region too. The purpose of this stndy was to estimate absorbed fractions for several common (e.g. 1-131, Y-90) and less common (Pm-147, Rh-106, Ag- 111, Sc-47) radionuclides for radioimmunotherapy (RAIT) in spherical source geometry and aqueous medium. Compiled results based on multiple scattering calculation for scaled absorbed dose distributions F(x, xpo), and scaled distances x90 for point sources were used. Absorbed fraetions of energy in the souree region were calculated by means of a "spline" interpolation of F(x, xpo) distributions, employing Gaussian quadrature integration thereafter. Calculations were done for sphere masses ranging from 10^(-5) to 10^(-1) kg. With the results for absorbed fractions, "S-values" were calculated and compared with these which do not take into account the correction for beta (electron) energy loss. For beta particle emitters, considerable decrease of the absorbed fraction values starts above approximately 0.4 MeV average energy and masses smaller than 2x10^(-2) kg, and in the case of electron emitters this limit is at 0.7 MeV and for masses under the 2x10^(-2) kg. Uncorected "S- values" are significantly overestimated for high energy beta emitters and small masses (<10^(-2) kg), while for most masses in the case of low energy emitters corrrection is small. Although dealing with the idealised geometry and several approximations this result could serve as a good starting point in many applications involving beta (electron) emitters, and could be extended to more complex and realistic systems.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kliničke medicinske znanosti

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