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The test of production of the Au-198 radioisotope by means of Varian medical linear accelerators used in teleradiotherapy was carried out. The targets made of the natural gold (100% of the Au-197 isotope) were irradiated with high-energy therapeutic 20 MV X-ray beam. Au-198 was produced in the simple capture reaction Au-197(n, gamma) Au-198. The obtained specific activities in the saturation state are relatively low, not exceeding the value of 510.4 kBq/g, because only the high-energy part of the spectrum of 20 MV X-ray beam covers the energy range of the neutron production cross section. Low activity of the Au-198 radioisotope produced by medical linear accelerators makes this technique not suitable for a massive production of Au-198 for nuclear medicine, but the produced amount of Au-198 is sufficient for laboratory tests of new drugs for possible clinical applications.

Radioisotopes play an important role in nuclear medicine, both in medical diagnostics and in the development of isotope - targeted therapy. At present, there is a crisis in world radioisotope production mainly because of the exploitation of nuclear research reactors which global production of radioisotopes is based on. The answer to this situation is the search for alternative ways of making radionuclides for nuclear medicine. Within this work the possibilities of the use of the medical linear accelerators for the aforementioned purposes was checked. The high-energy photons generated in such medical linac cause photonuclear reactions (γ,n) and (γ,2n) which except of radioactve isotopes, neutrons are also produced in. These neutrons with the broad energy spectrum are the contamination of the therapeutic beam. The secondary neutron radiation can also be a source of nuclear reactions leading to the production of radioisotopes. The main aim of the thesis was to test a possibility of production of medical isotopes such as: 99Mo/99mTc, 198Au, 186Re and 188Re. The targets made of the natural elements were irradiated with the use of high-energy therapeutic 20 MV X-ray beam generated by the Varian medical linacs (Clinac 2300 and TrueBeam). The irradiations were performed at the Maria Skłodowska-Curie Memorial Cancer Centre and Institute of Oncology in Gliwice. The produced activity was determined on the base of the gamma energy spectra measured during decay of specific radioisotopes. The spectral measurements were carried out by means of the germanium detector. The research is completely innovative, there are no scientific reports with similar experiments. In this thesis the research associated with therapeutic dose enhancement was also described. The dose enhancement is obtained when the high atomic number metal nanoparticles are introduced to a target volume. This dose enhancement is caused by the increase of the photoelectric effect due to irradiation with the therapeutic megavoltage X-rays. The additional increase of a dose can be reached by means of the nanoparticles with radioactive gold atoms. Simulations were carried out using GEANT4 in version 4.9.2 installed on the Linux platform. The first part of the thesis is based on literature and available scientific publications. In the introduction the most important problems that make it possible to understand the research presented in this work were discussed. The literature section presents possible applications of radionuclides. I tested methods of their production, and briefly discribed their basic physical properties. What is more, this section describes important issues related to knowledge of current methods of production of radioisotopes and techniques of nanoparticle synthesis including gold nanoparticles. The methodology of measurements and calculations is described in the second part of the thesis. This section presents an innovative radionuclide production technique using medical linear accelerators available in each oncology center. Moreover, this chapter summarizes qualitative data analysis methods in a brief manner, including computational methods. The experimental part presents the spectra of gamma radiation emitted by radioactive isotopes recorded by means of semiconductor detectors, decay schemes of radionuclide, and cross sections for typical reactions occurring in target materials during the emission of high energy therapeutic beams. The rest of this chapter includes the results of experiments based on well known production methods. A discussion of the results of experiments taken from the specialist literature has the advantage that in the following part of this thesis facilitates the interpretation of the obtained results. It allows to estimate the effectiveness of the proposed method of production of radioactive isotopes used in nuclear medicine. The six chapter presents the structure of simulation programs based on the Monte Carlo techniques. A separate chapter (the chapter seven) presents the results of experiments and calculations. The obtained results were compared with literature data and summarized in the chapter eight.

W wielu miejscowościach znajdują się pozostałości po zakładach przemysłowych. Nawet jeśli taki teren został zrekultywowany, często obszary położone nieco dalej nie zostały przywrócone do pierwotnego stanu. Na takich terenach można spodziewać się istnienia podwyższonych stężeń różnych pierwiastków, w tym izotopów promieniotwórczych. Do badań pobrano próbki gleby na obszarze byłej cementowni „Piast”, znajdującej się w granicach miasta Opola oraz na obszarze pobliskich ogródków działkowych. W badanych próbkach stwierdzono obecność naturalnych izotopów promieniotwórczych oraz 137Cs. Największe aktywności wykazywały 40K oraz 137Cs. Aktywności naturalnych izotopów promieniotwórczych były znacznie niższe i porównywalne względem siebie. Nie stwierdzono istotnych różnic aktywności radionuklidów w próbkach gleby zebranych na obszarze byłych terenów przemysłowych oraz tych, które zebrano w ogrodach działkowych., In many cities the abandoned industrial estates can be found. Even if such area has been recultivated and prepared the regions located further from the historical source of pollution could not have been restored. In such areas some unwanted substances, originated from former industry, still remain in soil. Among others, the radioactive isotopes in significant concentrations could appear in processing of mineral materials as well as in branches of production where coal combustion is utilized. Soil samples were collected in the area of the former cement plant “Piast”, situated within Opole city borders and in the area of nearby allotment gardens. A number of naturally occurring radioisotopes were found as well as artificial 137Cs. The biggest radioactivity concentration was produced by 40K and 137Cs. Concentration of activities of the remaining radioisotopes was lower and similar to each other. No significant differences in activities of radionuclides in soil samples collected in former industrial estate and in allotment gardens were found.