Speaker
Description
An important part of medical applications of ionizing radiation are included in nuclear medicine. This is based on the use of radioisotopes as radiation sources and allows the both medical diagnostic and treatment of the main diseases with the greatest social impact, such as cancer, cardiovascular problem and brain diseases [1]. The two main challenges to improve and develop new therapies include: the search for selective met-abolic radiotherapies that maximize the dose in the tumor tissue while minimizing the dose in the peripheral healthy tissues, and the development of new radioisotope pro-duction facilities to ensure a worldwide supply alongside existing nuclear reactors [2].
The future international facility IFMIF-DONES [3], which will have a high current linear accelerator capable of accelerating deuterons up to 40 MeV and 125 mA intensi-ty, will allow the study of radioisotope production for nuclear medicine among other purposes. Among others, to deal with the very high power densities is the main issue. However, the radioisotope production using deuteron beams at IFMIF-DONES facility is a topic of great interest for the complementary applications of the facility. In previ-ous ND2019, we showed the possibilities for the production with deuterons of several radioisotopes of interest in nuclear medicine in diagnostic and therapy [4]. Since then, we have studied a realistic setup for the production of radioisotopes in IFMIF-DONES with deuterons by means of SolidWorks simulations. Also, the production with neu-trons is being studied.
In this work we show the possibilities in Auger radioisotopes as 125I [5], 111In [6] and 195mPt [7], used both for the diagnostic and treatment of oncological diseases, and 161Ho [8], one of the most promising emerging radionuclides, are Auger electron- emitting radioisotope. These particles are characterized by having a nanometric range in the tissue and low energy, on the order of a few keV, exhibit a high linear energy transfer (LET). Therefore, if they are placed close to tumor cells the damage to DNA will be irreversible, allowing the destruction of the cells. In addition, side effects on the surrounding healthy tissues are considerably reduced.
In order to make an estimate of the radioisotope production rate [9] produced by deu-teron beams in a compact high-intensity accelerator, it is necessary to determine two parameters as a function of energy beforehand:
• Stopping power of the deuterons, defined as the amount of energy deposited per unit thickness of the medium traversed. Empirically, this variable is dependent with the charge and velocity of the particle, being independent of its mass. Through the expression of Andersen and Ziegler [10] for proton stopping power it is possible to establish equivalence for deuterons.
• Cross sections parameterization of the different nuclear reactions involved. For this case, it is necessary to make use of both experimental and evaluated in theoretical models, EXFOR [11] and TEDNL [12] respectively, databases.
The estimated production rates for 30 mA current intensity are the order of TBq. This referent value is illustrative of the current intensity achieved by the latest generation of high-intensity linear accelerator facilities. In view of these first calculations, the production rates that can be reached in the future IFMIF-DONES facility, where will operate at higher current, will be very high guaranteeing the possibility of large-scale production.
During irradiation, the production of isotopic impurities also takes place. By means of an estimated study of these, a percentage of the contamination level of the sample has been obtained. Finally, it will be discussed how isotopic impurities can be minimized [13].
References:
[1] https://www.who.int/es/news-room/fact-sheets/detail/the-top-10-causes-of-death
[2] Comunicación de la Comisión al Consejo y al Parlamento Europeo; Programa Indi-cativo Nuclear, COM (2010) 423; https://eur-lex.europa.eu/legal-content/ES/TXT/HTML/?uri=CELEX:52010DC0423&from=PL
[3] https://ifmifdones.org/es/inicio/
[4] J. Praena et al., Radioisotope production at the IFMIF-DONES facility, EPJ Web of Conferences 239, 23001(2020) ND2019; https://doi.org/10.1051/epjconf/202023923001
[5] H. Quan Ho et al., Feasibility study of large-scale production of iodine-125 at the high temperature engineering test reactor, Appl. Rad. and Iso. 140 (2018) 209-214
[6] A. Nikjou et al., Nuclear model calculations on the production of Auger electron emitter 111 In: As a teragnostic radionuclide, Appl. Rad. and Iso. 166 (2020) 109354
[7] M.U. Khandaker et al., Excitation functions of deuteron-induced nuclear reactions on natural platinum up to 24 MeV, Nucl. Inst. and Met. in Phys. Res. B 362, (2015) 151-162
[8] F. Tártányi et al., Investigation of production routes for the 161 Ho Auger-electron emitting radiolanthanide, a candidate for therapy, Journal of Radioanalytical Nuclear Chemistry 298 (2013) 277-286
[9] F. Arias de Saavedra et al., Routes for the production of isotopes for PET with high intensity deuteron accelerators, Nucl. Inst. and Met. in Phys. Res. A 887 (2018) 50-53
[10] H.H. Andersen et al., Hydrogen: Stopping Powers and Ranges in All Elements, Pergamon Press, New York (1985)
[11] Experimental Nuclear Reaction Data (EXFOR), March (2021), https://www-nds.iaea.org/exfor/
[12] TALYS-Based Evaluated Nuclear Data Library (TENDL), December (2019), https://tendl.web.psi.ch/tendl_2019/tendl2019.html
[13] S.M. Qaim et al., Charged-Particle cross sections database for medical radioiso-tope production, Journal of Nuclear Science and Technology, Supplement 2, august (2002) 1282-1285