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In this work, innovatory production of three radioisotopes 117mSn, 186Re AND 188Rewhich can be used in nuclear medicine, is described. The natural tin and rhenium targets were irradiated by a high-energy 20 MV X-ray therapeutic beam from a medical linear accelerator. Additionally, the targets were in the photoneutron field. The radioisotopes were obtained in photonuclear and neutron reactions. A special lead-PMMA system was used to increase the slowed-down neutron flux in the target volume. The specific activities of 117mSn, 186Re AND 188Re are 11 kBq/g, 2.6 MBq/g and 0.26 MBq/g in the saturation state, respectively. The produced amounts of the radioisotopes of tin and rhenium are sufficient for various laboratory tests in nuclear medicine. [ABSTRACT FROM AUTHOR]

The test of production of the 198Au radioisotope by means of Varian medical linear accelerators used in teleradiotherapy was carried out. The targets made of the natural gold (100% of the 197Au isotope) were irradiated with high-energy therapeutic 20 MV X-ray beam. 198Au was produced in the simple capture reaction 197Au(n;)198Au. 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 198Au radioisotope produced by medical linear accelerators makes this technique not suitable for a massive production of 198Au for nuclear medicine, but the produced amount of 198Au is sufficient for laboratory tests of new drugs for possible clinical applications. [ABSTRACT FROM AUTHOR]

The test of production of the 99Mo/99mTc complex by means of Varian medical linear accelerators used in teleradiotherapy was performed. The targets made of the natural molybdenum were irradiated by high-energy therapeutic 20 MV X-ray beam. 99Mo was produced mainly in the photonuclear reaction of 110Mo(γ , n)99Mo. The obtained specific activities are relatively small in the saturation state (from 155.4 kBq/g to 163.2 kBq/g) because only the high-energetic part of the spectrum of 20 MV X-ray beam covers the energy range of the 110Mo(γ , n)99Mo reaction cross section. The new application of the 99Mo/99mTc complex of the low activity was suggested using the molybdenum nanoparticle technology. [ABSTRACT FROM AUTHOR]

Emission of high-energy X-ray and electron therapeutic beams from medical linear accelerators is related to undesirable neutron production and to induction of radioactivity. In this work, measurements of thermal and resonance neutron fluence and induced radioactivity were performed inside two bunkers with medical linacs - Elekta in the Center of Oncology in Opole (Poland). The bunkers differ with a construction of their walls. The neutron measurements were performed by means of the induced activity method during emission of the 18 MV X-ray beam. The investigation of radioactivity induced by neutrons was based on the method of off-line gammaray spectroscopy measurements. This work has shown that the differences in the considered construction of bunkers do not influence significantly on the thermal and resonance neutron fluence as well as on the induced radioactivity. The greatest thermal neutron fluence (1.4 × 104 cm-2 MU-1) as well as the resonance one (0:7 × 104 cm-2 MU-1) was measured at the isocenter of a rotation of the accelerator head. The radioisotopes of 187W, 56Mn, 24Na and 82Br originating from the (n, γ) reactions were identified in the spectral measurements. [ABSTRACT FROM AUTHOR]

Ionizing radiation has become widely used in medicine, with application in diagnostic techniques, such as computed tomography (CT) and radiation therapy (RT), where X-rays are used to diagnose and treat tumors. The X-rays used in CT and, in particular, in RT can have harmful side effects; hence, an accurate determination of the delivered radiation dose is of utmost importance to minimize any damage to healthy tissues. For this, medical specialists mostly rely on theoretical predictions of the delivered dose or external measurements of the dose. To extend the practical use of ionizing radiation-based medical techniques, such as magnetic resonance imaging (MRI)-guided RT, a more precise measurement of the internal radiation dose internally is required. In this work, a novel approach is presented to measure dose in liquids for potential future in vivo applications. The strategy relies on MRI contrast agents (CAs) that provide a dose-sensitive signal. The demonstrated materials are (citrate-capped) CaF 2 nanoparticles (NPs) doped with Eu 3+ or Fe 2+ /Fe 3+ ions. Free electrons generated by ionizing radiation allow the reduction of Eu 3+ , which produces a very small contrast in MRI, to Eu 2+ , which induces a strong contrast. Oxidative species generated by high-energy X-rays can be measured indirectly using Fe 2+ because it oxidizes to Fe 3+ , increasing the contrast in MRI. Notably, in the results, a strong increase in the proton relaxation rates is observed for the Eu 3+ -doped NPs at 40 kV. At 6 MV, a significant increase in proton relaxation rates is observed using CaF 2 NPs doped with Fe 2+ /Fe 3+ after irradiation. The presented concept shows great promise for use in the clinic to measure in vivo local ionizing radiation dose, as these CAs can be intravenously injected in a saline solution.