Type Of Radioisotope Research Articles

Determination of the type of radioactive nuclei and gamma spectrometry analysis for radioactive sources

Determining the type of radioactive nuclei is the second activity after the inventory of radioactive waste in Kosovo, their location and the number of radioactive sources. Before starting any type of radioactive waste action, it is necessary to determine the content of their activity, the type of radioisotope, physical and chemical form and the risks associated with their management. The realization of this is achieved as a combination of quality assurance processes, the inventory of the radioisotope and its activity that is present in the waste, the composition of the waste material and direct measurements. This serious activity was carried out entirely in the field and was undertaken due to the lack of source certification or any other indication of their classification and activity. The process of determining the type of radioactive nuclei helps to realize a more effective characterization of them as well as to determine the path of waste management. The probability that a gamma radiation detector interacts with it to produce a pulse represents the effectiveness of the detector.

Radioligand Therapy with [177Lu]Lu-DOTA-TATE or [177Lu]Lu-DOTA-TATE and [90Y]Y-DOTA-TATE in Patients with Neuroendocrine Neoplasms of Unknown Locations, or Locations Other Than the Midgut and Pancreas as Primaries in a G1, G2 and G3 Grade.

Neuroendocrine neoplasms (NENs) are a rare group of tumors with a different clinical course, prognosis and location. Radioligand therapy (RLT) can be used as a first or second line of treatment. It is registered in gastroenteropancreatic NENs (GEP-NENs) as grades G1 and G2. Tumors with an unknown point of origin, diagnosed outside the gastrointestinal tract and pancreas (non-GEP) or at the G3 grade, remain in the "grey area" of treatment. Analysis of 51 patients with NENs who underwent RLT in a single highest reference center from 2018 to 2023 was performed. Treatment was administrated to the patients with neoplasms of unknown origin, non-GEP-NENs, and ones with G3 grade. In total, 35 patients received 177-Lutetium (7.4 GBq), while 16 received 177-Lutetium and 90-Yttrium with equal activities (1.85 + 1.85 GBq). The progression-free survival (PFS) before RLT qualification was 34.39 ± 35.88 months for the whole study group. In subgroups of patients with an unknown tumor location (n = 25), the median PFS was 19 months (IQR = 23), with "other" locations (n = 21) at 31 months (IQR = 28), and with NEN G3 (n = 7) at 18 months (IQR = 40). After RLT, disease stabilization or regression was observed in 42 (87.5% of) patients. RLT did not cause statistical changes in creatinine or GFR values. Hematological parameters (RBC, WBC, PLT, HGB) as well as chromogranin A concentration decreased significantly. There were no statistical differences between both subgroups regarding the type of radioisotope (177-Lutetium vs. 177-Lutetium and 90-Yttrium). After RLT in long-term observation, the median observation time (OT) was 14 months (IQR = 18 months). In patients with progression (n = 8), the median PFS was 20 months (IQR = 16 months), while in patients with confirmed death (n = 9), the median overall survival (OS) was 8 months (IQR = 14 months). Our study showed that 87.5% of NEN patients with unknown origin, non-GEP-NENs, and those with GEP-NEN G3 grade had benefited from the radioligand therapy. There were no significantly negative impacts on renal parameters. The decrease of bone marrow parameters was acceptable in relation to beneficial disease course. The decrease of chromogranin concentration was confirmed as a predictive factor for disease stabilization or regression.

Investigation of Radioisotopes Produced in the Core of a Navy Nuclear Reactor with Low- and High-Enriched Uranium Flues During One Cycle

ABSTRACT Today, nuclear reactors, especially small reactors, have been significantly welcomed in different countries and have various applications, including use as desalination plants, naval propulsions, etc. During the operation of the reactor, different types of radioisotopes are produced, some of which have very high activity and half-life. The type and amount of radioisotopes produced depends on the type of fuel used, the level of enrichment and the operating time of the reactor. The atomic density and activity of the most important radioisotopes for a typical reactor with two types of high and low enrichment fuel have been calculated in terms of time using MCNPX and CINDER codes. The activity of some of these radioisotopes is high and it is necessary to pay attention to possible environmental hazards. In this research, using the MCNPX Monte Carlo code, the core of a small nuclear reactor proposed as a Virginia class submarine propulsion with a power of 150 MWth was modeled. Using the BURN and KCODE cards in this code as well as the CINDER code, the fuel burnup calculations of the core of this naval reactor have been performed. For this reactor, there are two types of metal alloy fuels, including the high-enrichment UO2-Zr fuel and the low-enrichment U-10Mo fuel, and fuel burnup calculations have been performed for both fuels. After calculations, different types of radioisotopes were identified and changes in atomic density and activity quantities were calculated for the most important of these radioisotopes with high half-life during cycle and compared.

Long-Term Complications of Radioligand Therapy with Lutetium-177 and Yttrium-90 in Patients with Neuroendocrine Neoplasms

Neuroendocrine neoplasms are a group of tumors deriving from neural crest. They can be located in every tissue, but most commonly in gastrointestinal tract. Targeted therapy with use of radionuclides is an available and acceptable way of treatment, but its long-term safety is still to be determined, especially with sensitive methods. Study was performed on a group of 42 patients. They underwent full cycle (4 courses; 8-12 weekly intervals) of radioligand therapy with [177Lu]Lu-DOTATATE alone or tandem therapy with [177Lu]Lu-DOTATATE+[90Y]Y-DOTATATE. Late and long-term marrow and renal complications were assessed. Analysis focused on comparing data before first, fourth, and one year after the last course of RLT. Study showed decreasing of all blood parameters in long-term observation, especially in lymphocytes line. Type of radioisotope, other diseases, primary tumor location, BMI, gender or age did not affect results. The only factor that had influence on hemoglobin and erythrocytes was decreased renal filtration. In long-term observation almost 10% decrease of renal filtration was observed. Type of isotope, gender, age, BMI did not affect these results. Moreover, reduction of urine IL-18, KIM-1, and albumin concentration has been observed. Though low-grade complications of radioligand therapy are possible, it stay a safe method of NEN treatment where benefits outweigh the risk.

MANUFACTURING OF RADIOPHARMACEUTICAL ISOTOPES THROUGH THE LINAC 7 ACCELERATOR FOR BIOMEDICAL APPLICATIONS

Linac 7 consists of a new generation linear proton accelerator completely designed and built at the Beam Laboratory (IZPILab-Beam Laboratory) of the University of the Basque Country UPV/EHU. One of the most important health applications conceived within the Linac 7 project is the production of pharmaceuticals of various species, locally around large clinical centers. Currently, medical radioisotopes are manufactured externally to hospitals and involve the use of distant, expensive and complex infrastructures. This results in long transports, production of large doses of radioisotopes that decay rapidly over the several hours of transport, and also usually only elements with sufficient half-life for use as appropriate pharmaceuticals can be used, with no other options. Our compact Linac 7 linear accelerator allows the manufacture of multiple types of radioisotopes locally and tailored to the corresponding biomedical needs, including specific doses of pharmaceuticals for patients, on demand of the medical staff in our hospitals. Keywords: Particle accelerators, radiopharmacy, nuclear medicine

Clinical efficacy of first and second series of peptide receptor radionuclide therapy in patients with neuroendocrine neoplasm: a cohort study

Objectives Peptide receptor radionuclide therapy (PRRT) is an established treatment for metastatic neuroendocrine neoplasms (NEN). However, only limited data exists for the effect of multiple series of PRRT. The aim of this study was to investigate PFS and OS inNEN patients treated with multiple series of PRRT conforming to the ENETS treatment protocol. Methods We included all patients with gastrointestinal (GI), pancreatic and bronchopulmonary (BP) NEN treated with PRRT from 2008 to 2018. We used Kaplan-Meier estimation to evaluate PFS and OS with subgroup analysis of primary tumor, Ki67-index, type of radioisotope and number of PRRT series. Results 133 patients (female/male 61/72) were included, median age 70 (interquartile range 64–76) years. GI-NEN comprised 62%, pancreatic 23% and BP 11%. Median Ki67-index was 5%. After first PRRTG1- and G2-tumors had PFS of 25 and 22 months, compared to 11 months in G3-NENs (p < .05) and PFS was longer in G1/G2 GI-NENs than BP-NEN (30vs. 12 months, p < .05). After retreatment with a second series of PRRT, the overall PFS (G1–G3) was 19 months, with G1- and G2-tumors having the highest PFS of 19 and 22 months, respectively. Overall, the GI and BP tumors had an OS of 54 and 51 months. Conclusions PRRT is an effective therapy with long-term PFS and OS, especially in G1 and G2 NENs, and with better prognosis in GI-NEN compared with BP-NENs. OS and PFS was shorter after the second series of PRRT compared with the first, however results were still encouraging.

EVALUATION OF RADIONUCLIDE CONCENTRATION IN THE BOTTOM GROUND OF WATER RESERVOIRS AND WATERSIDE SOIL

The paper covers evaluation of concentration of natural and artificial radionuclides found in the soil and the bottom ground of water reservoirs. It was measured that radionuclide concentration in the soil is bigger than that in the bottom ground of water reservoirs (40K concentration in the ground equals 500 Bq/kg, in the bottom ground ‐ about 200 Bq/kg). Positive correlation was set among all types of radioisotopes. Correlation quotient between artificial radionuclide 137Cs and natural radionuclides amounts to zero.

Nuclear Terrorism

Recent events have heightened awareness of the potential for terrorist attacks employing nonconventional weaponry such as biological agents and radiation. Historically, the philosophy of nuclear risk has focused on global or strategic nuclear exchanges and the resulting damage from large-scale releases. Currently, nuclear accidents or terrorist attacks involving low-level or regional release of radiation are considered the most likely events. Thus far, there have been several regional radiation incidents exposing hundreds of thousands of people to radiation, but there have been only a limited number of significant contaminations resulting in death. There are several different types of radioactive particles that differ in mass, extent of radiation emitted, and the degree to which tissue penetration occurs. Radiation affects its toxicity on biological systems by ionization, which creates tissue damage by the generation of free radicals, disruption of chemical bonds, and directly damaging cellular DNA and enzymes. The extent of damage depends on the type of radioisotope and the radiation dose. Radiation doses exceeding 2 to 10 Gy are considered lethal. Optimal management of radiation casualties requires knowledge of the type and dose of radiation received, a recognition of the manifestations of radiation sickness, and the use of standard medical care, decontamination, and decorporation techniques.

Chemical and biological consequences of?-decay

In Part 1 of this article physical and chemical effects of beta-decay in labelled molecules were reviewed and their potential importance for breaking predetermined and specific bonds were pointed out. After incorporation of labelled biomolecules in living systems, such as viruses, phages or cells, the radioactive decay of the label alters the biological behaviour of the system, in the extreme case causing loss of the ability to reproduce, the extent of these consequences depending strongly on the type of radioisotope. Now Part 2 includes a brief discussion of biological effects associated with beta-decay emphasizing the relative importance of local transmutation and internal radiation effects from the decay of 3H, 14C, 32P, 33P, 35S and 125I. Attempt is also made, whenever possible at the present stage of understanding, to correlate biological effects with chemical processes on a molecular level.