Search Results (139)

Background/Objectives: The increasing use of radiopharmaceuticals in clinical practice has raised concerns regarding potential radiation exposure for healthcare personnel handling biological samples from treated patients. The objective of this study was to assess the radioactivity levels in clinically necessary blood samples taken from patients treated with radioactive iodine-131 (I-131) or lutetium-177 (Lu-177) in a real-world setting. Methods: Prospective, tertiary care single-center study. Blood samples, at the clinically necessary time points, from 220 consecutive targeted radionuclide therapies (TRTs) used to treat 151 distinct patients between October 2021 and January 2025 were included. The influences of the eGFR and the time interval between tracer administration and blood sampling on radioactivity concentration were investigated by linear regression models. The applied amount of radioactivity was excluded as a confounder by adjusting all cases to 1 GBq. Statistical programming language R was utilized and p < 0.05 was considered significant. Results: The mean age of the patients was 62 years and 52% were male. Mean radioactivity concentrations of 6 vs. 60 kBq/mL were measured at 52 vs. 13 h after application of 1.9 vs. 6.7 GBq I-131 vs. Lu-177, respectively. Better renal function and later blood sampling were both associated with lower radioactivity concentration in blood samples (each p < 0.001). Total radioactivity levels in all samples were well below the upper limits for the disposal of biological samples (1 MBq for I-131 and 10 MBq for Lu-177). Conclusions: There was only a low exposure risk for nuclear medicine personnel and laboratory staff. These findings emphasize that handling blood samples from patients treated with I-131 and Lu-177 in clinical routine is minimal. Full article

[^99mTc]sestamibi ([^99mTc][Tc(MIBI)₆]⁺; MIBI = 2-methoxybutylisonitrile) is a clinically established myocardial perfusion SPECT tracer. Its one-pot kit-based synthesis from [^99mTc]pertechnetate ([^99mTc][TcO₄]⁻) is complex, involving a 6-oxidation state transition (Tc(VII) to Tc(I)) and complete ligand replacement. We aimed to unravel this complex reaction, to inform rational quality control and identify new technetium synthons for molecular imaging. Generator-produced [^99mTc]pertechnetate was added to commercial or bespoke clinically used kits, varying the reaction time, temperature, and concentrations of reagents (individually and collectively) and carrier technetium-99. Radioactive products were analysed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) with optical, radiometric, and mass spectrometric (MS-ESI+) detection. At least 11 radioactive intermediates were detected by radio-HPLC. Technetium(V) and technetium(I) intermediates were identified or imputed by radio-HPLC-MS, including [Tc^VO(cysteinate)₂]⁺, [Tc^I(MIBI)₄L₂]⁺, and [Tc^I(MIBI)₅L₁]⁺ (L = labile monodentate ligand, e.g., H₂O). Tc(III) intermediates [Tc^III(cysteinate)₂(MIBI)]⁺ and [Tc^III(cysteinate)₂(MIBI)₂]⁺ were indicated by weak MS-ESI+ ions. We conclude that the reaction proceeds via reduction from [Tc^VIIO₄]⁻ via unknown intermediates to [Tc^VO(cysteinate)₂]⁺, then via Tc(III) intermediates containing both cysteinate and MIBI ligands (e.g., [Tc^III(cysteinate)₂(MIBI)₂]⁺), to form Tc(I) without cysteine and with <6 MIBI ligands, followed by further ligand displacement by MIBI to form [Tc(MIBI)₆]⁺. Once formed, [Tc(MIBI)₆]⁺ undergoes no further reaction. Full article

Radionuclide-based molecular imaging modalities are active and developing areas of functional and molecular diagnosis. Among the radionuclides used for SPECT imaging in oncology, ^99mTc is a leading candidate for radiolabeling. At present, a sufficient number of complexons for ^99mTc have been described; however, the development of effective delivery systems for this isotope to the area of interest is a complex research task. The use of tumor-targeting molecules as carriers for radioactive tracers is an effective strategy that has enabled the development of many novel radiopharmaceuticals for cancer imaging. Background: To date, a number of studies have shown tumorotropicity of tetrapyrrole compounds to tumor tissues, in particular derivatives of natural chlorophyll A. Methods: Purification was performed using solid-phase extraction. Assessment of radiochemical yield and purity was performed via radio-ITLC. The in vitro tumor cell accumulation was assessed using SKOV-3 and A-431 cell lines. Dose-dependent biodistribution was evaluated in Nu/J mice bearing epidermoid carcinoma (A-431) xenografts. Results: In this work, we obtained complexes with ^99mTc based on water-soluble carboxylate chlorin e₆ derivatives in order to evaluate their potential for use as SPECT radiopharmaceuticals. We performed radiolabelling optimization of a series of the novel chlorins and primary preclinical studies, including an assessment of the effect of their lipophilicity and charge on tumor uptake. Conclusions: Modification of the periphery of the chlorin macrocycle with chelating groups allows for complexing a wide range of metals, including ^99mTc, which can be used for targeted delivery of the radionuclide to the area of interest. Full article

Current tumor diagnostics rely on fluorodeoxyglucose (FDG)-PET imaging, but FDG’s short half-life and high cost limit its widespread use. Infrared (IR) probes are emerging as non-radioactive alternatives to conventional tracers for tissue section and other in vitro imaging applications. Because cells and tissues are relatively free of absorption peaks between 1800 and 2200 cm⁻¹, metal-carbonyl complexes, especially cyclopentadienylrhenium(I) tricarbonyl (Cp[Re(CO)₃]) derivatives, absorb strongly in this window and provide robust platforms for bioconjugation. Furthermore, Cp[Re(CO)₃] fragments can be introduced into organic substrates via an elegant three-component reaction that simultaneously forges the cyclopentadienyl-metal and cyclopentadienyl-substituent bonds. As a result, the functionalized half-sandwich complex is obtained in a single step without any special handling issues. We have therefore properly modified a glucose molecule with that complex and developed a novel glucoconjugated Cp[Re(CO)₃] probe that enables IR-based visualization of diseased cells at 2100 cm⁻¹, offering a non-invasive, non-radioactive histological tool and a promising basis for future medical imaging devices. Full article

Sedimentary dynamics in the Palamós Canyon are influenced by river inputs and storm resuspension, as well as by bottom trawling on the canyon flanks. In this study, we estimate recent sediment deposition patterns along the canyon axis using the excess activity concentration of the short-lived radiotracer ²³⁴Th (half-life of 24.1 days). Sediment cores were obtained at various locations along the canyon axis from a depth of approximately 800 m to 2100 m in June 2023 and August 2024. Excess ²³⁴Th (²³⁴Th_xs) was detected in all sampled sites with variable penetration depths (0.5–3.5 cm). ²³⁴Th_xs-derived estimations of mixing rates decreased downcanyon from up to 15.6 cm² y⁻¹ at the canyon head (~800 m) to negligible mixing at the canyon mouth (~2100 m). ²³⁴Th_xs inventories, a proxy of recent sediment deposition, were high (1800–3490 Bq m⁻²) at the canyon head and at the upper canyon (~1400 m) close to fishing grounds and decreased downcanyon (82–694 Bq m⁻²) at the lower canyon (~1800 m) and canyon mouth. Inventories varied 2-fold across years presumably attributed to enhanced riverine and bottom trawling sediment fluxes. Similar ²³⁴Th-derived sediment deposition patterns can be found in submarine canyons worldwide, highlighting the value of this radiotracer for sedimentary dynamics studies in such complex environments. Full article

Numerical simulation of groundwater level dynamics plays a crucial role in the safety assessment of near-surface radioactive waste disposal facilities. Such disposal sites are typically located in regions characterized by extensive bedrock outcrops. However, accurately characterizing the permeability of fractured media is challenging, and the scarcity of groundwater level data poses significant difficulties for constructing reliable numerical models. This study focuses on a near-surface disposal site in northwestern China. By integrating field packer tests with hydraulic conductivity tensors computed from borehole televiewer data, we quantitatively evaluated the permeability of fractured rocks of different lithologies to provide accurate parameters for numerical modeling. The constructed groundwater flow model was further calibrated and validated using long-term groundwater level monitoring data and field tracer-based groundwater flow direction tests, ensuring high model reliability. Using the calibrated model, groundwater level variations were simulated under various rainfall and pumping scenarios. The results show that pumping intensity in the downstream farmland area exerts a limited influence on groundwater levels beneath the disposal site, while rainfall intensity plays a dominant role. Under the heavy rainfall scenario, the groundwater level at the disposal site rises by approximately 5.2 m after 50 years, leaving a 6 m gap above the base of the disposal unit. Under prolonged heavy rainfall conditions, implementing drainage measures may be necessary to ensure the repository’s long-term safety. Full article

Background: Radioactive colloids are considered the standard of care for sentinel lymph node (SLN) detection. An alternative detection method using superparamagnetic iron oxide (SPIO) nanoparticles is well documented in breast cancer but poorly studied for gynecological tumors, including vulvar cancer (VC). Objective: Our aim was to evaluate the feasibility, accuracy, and safety of SPIO nanoparticles for SLN mapping in patients with VC as a stand-alone technique compared with the combination of two methods: the standard of care using a radioactive isotope (technetium-99; Tc-99) and SPIO as a new tracer. Methods: We conducted a prospective and observational study of SLN mapping in patients with stage IB VC and tumor size ≤ 4 cm. We calculated detection and malignancy rates per patient and per groin in both study groups. During the 36-month follow-up, the groin recurrence rate was estimated for positive and negative SLNs. Kaplan–Meyer curves were used to analyze the probability of survival, depending on disease-free survival. Results: A total of 110 groins assessed by SLN in 60 patients included in this study were analyzed (70 groins from 40 patients in the group with a single tracer and 40 groins from 20 patients in the group of combined tracers). At least one sentinel lymph node was detected in every patient while the bilateral detection rate was 92.3% for the SPIO group and 88.2% for the Tc-99 and SPIO group. The groin detection rate was 94.3% and 90%, respectively. SLN mapping failure was similar in both groups (2.8% and 2.5%, respectively). During a 3-year follow-up, the isolated groin recurrence rate was 2.1% for negative groins and for disease-free survival it was 28.9 months in the combined tracer group versus 32.8 months in the SPIO group. The Kaplan–Meyer curves showed the increased probability of survival for the SPIO group (87.5%); however, it was insignificant. Conclusions: SLN mapping using the SPIO technique in patients with VC is non-inferior to the combined SPIO and Tc-99 method. Full article

Background: Nuclear medicine is a highly specialized field that combines advanced technology and multidisciplinary collaboration. Despite its complexity, the role of nurses in this context remains underexplored, especially regarding their clinical and administrative activities. Methods: This is a scoping review protocol developed according to the Joanna Briggs Institute (JBI) methodology and reported in accordance with the PRISMA-ScR guidelines, as recommended by the EQUATOR Network. The research question was structured using the PCC mnemonic (Population, Concept, and Context): What are the clinical and administrative activities performed by nurses in nuclear medicine services? A comprehensive search will be conducted in Web of Science, PubMed, Embase, Cochrane, SciELO, LILACS, Scopus, and CINAHL, complemented by grey literature sources such as Google Scholar and ProQuest Dissertations & Theses Global. No restrictions on language or publication date will be applied. Study selection and data extraction will be performed independently by two reviewers. This protocol is registered on the Open Science Framework (OSF) and is publicly accessible. The selection process will be detailed in a PRISMA-ScR flow diagram. A descriptive table will summarize the characteristics of the included studies, including the authors, year, country, study type, objectives, population, main nursing activities, and key findings. Expected Outcomes: The anticipated results are expected to clarify nurses’ contributions to patient safety and service quality in nuclear medicine. Conclusions: This review may also support the development of an assessment tool for nursing activities, guide professional training, and inform policies to strengthen nursing practice in this specialized field. Full article

The investigation of complex karst systems has always been a difficult task for hydrogeologists, especially related to the spatial position of karst channels. The city of Pirot, which is located in southeastern Serbia, taps karst water for water supply from three karstic springs (Kavak, Krupac and Gradište), which are characterized by extremely good and stable groundwater regime and quality. According to the general water regime, it can be concluded that in addition to the development of shallow and large karst conduits (as proven by tracer tests), there are also deeper karst channels, in which water circulates very slowly and remains for much longer. In order to understand the genesis and characteristics of karst springs used for water supply, multi-parameter research was conducted, which, in addition to monitoring the yield on a daily basis, also included detailed hydrochemical research together with an analysis of microelements and stable and radioactive isotopes. Water from springs has a stable hydrochemical composition highlighting prolonged contact with the host rock. Isotopic analysis showed that the water is a mixture of young waters (residing in the system for a few days, as determined by tracer tests); semi-young waters that, based on the radioactive isotopes ³T and ³He, have resided in the system for 53 years; and very old waters that have spent more than 3000 years in the system. Finally, such new data on significant dynamic as well as static reserves of quality drinking water are of particular importance for long-term sustainable water utilization. Full article

A vital step for any hydrochemical assessment is properly carrying out quality assurance and quality control (QA/QC) techniques to evaluate data confidence before performing the assessment. Understanding the processes governing groundwater evolution in coastal aquifers is critical for managing freshwater resources under increasing anthropogenic and climatic pressures. This study reassesses the hydrochemical and isotopic data from the Deep Confined Aquifer System (DCAS) in the Jiangsu Coastal Plain, China, by firstly applying QA/QC protocols. Anomalously high Fe and Mn concentrations in several samples were identified and excluded, yielding a refined dataset that enabled a more accurate interpretation of hydrogeochemical processes. Using hierarchical cluster analysis (HCA), principal component analysis (PCA), and stable and radioactive isotope data (δ²H, δ¹⁸O, ³H, and ¹⁴C), we identify three dominant drivers of groundwater evolution: water–rock interaction, evaporation, and seawater intrusion. In contrast to earlier interpretations, we present clear evidence of active seawater intrusion into the DCAS, supported by salinity patterns, isotopic signatures, and local hydrodynamics. Furthermore, inconsistencies between tritium- and radiocarbon-derived residence times—modern recharge indicated by ³H versus Pleistocene ages from ¹⁴C—highlight the unreliability of previous paleoclimatic reconstructions based on unvalidated datasets. These findings underscore the crucial role of robust QA/QC and integrated tracer analysis in groundwater studies. Full article

Background: Radiolabeled compounds can serve as diagnostic or therapeutic agents depending on the characteristics of the isotopes used. IMPY (6-iodo-2-(4′-dimethylamino)-phenyl-imidazo[1,2-a]pyridine) is a lipophilic derivative of thioflavin-T, designed to function as a tracer when labeled with radioactive iodine. While it has been primarily studied for imaging applications, its potential therapeutic effects when labeled with iodine-125 (¹²⁵I) remain to be explored. Methods: In this study, IMPY was synthesized and labeled with ¹²⁵I for therapeutic purposes. Three different labeling methods were employed: isotope exchange reaction, redox reaction, and the Iodogen technique. The radiochemical yield of each method was determined to identify the most effective approach. Additionally, the effects of ¹²⁵I-IMPY on neuroblastoma cells were evaluated by assessing its toxicity and cellular uptake. Results: The radiochemical yields for the isotope exchange reaction, redox reaction, and Iodogen technique were found to be 0.96%, 10.74%, and 96.52%, respectively. The Iodogen technique exhibited the highest yield, exceeding 90% even after 48 h, making it the most efficient method. Furthermore, the impact of ¹²⁵I-IMPY on neuroblastoma cells was analyzed, revealing significant cellular uptake and potential therapeutic effects. Conclusions: This study demonstrated that the Iodogen technique is the most effective method for labeling IMPY with ¹²⁵I. The high labeling efficiency and observed cellular effects suggest that ¹²⁵I-IMPY could be considered not only as a tracer but also as a potential therapeutic agent for neuroblastoma. Further studies are needed to explore its full therapeutic potential and mechanism of action. Full article

Renal cell carcinoma (RCC) is a major global health issue with an increasing incidence and mortality rate. Current diagnostic methods are either invasive or limited in their ability to accurately differentiate between benign and malignant tumours and to predict early treatment response. This can lead to incorrect diagnosis, delayed treatment, patient anxiety, and suboptimal outcomes. RCC subtypes are known to exhibit distinct metabolic alterations, for example in glucose metabolism. These metabolic phenotypes offer potential targets for non-invasive imaging techniques to improve diagnosis and treatment, but current clinically available metabolic imaging tools such as ¹⁸F-FDG-PET and ^99mTc-sestamibi SPECT have limitations. Therefore, new approaches are required to assess this metabolism, and novel metabolic MRI techniques including hyperpolarised [1-¹³C]pyruvate MRI and deuterium metabolic imaging offer promising alternatives. These techniques are non-radioactive, demonstrate spatial metabolic heterogeneity, and can probe metabolic flux beyond tracer uptake. This review aims to explore the potential of metabolic MRI in the clinical management of RCC by (1) summarising current clinical guidelines; (2) reviewing metabolic heterogeneity across RCC subtypes; (3) discussing the potential of metabolic MRI to advance the understanding of in vivo metabolism; (4) and finally suggesting future directions for research in this field. Full article

Gamma-ray analysis is a widely used technique for radioactive element characterization in environmental samples, contributing significantly to natural and anthropogenic radioactivity evaluations, particularly in areas such as natural reservations or regions that have been affected by nuclear pollutants. As the Danube Delta belongs to both categories, we decided to conduct a study in order to find out whether gamma spectroscopy is suited for pattern identification in common biota constituents such as reed and whether anthropogenic tracers can still be found in the samples. The answer to both questions is affirmative, as shown by the pattern and cluster analyses. Furthermore, our conclusions point out that it would be interesting to extend the spectroscopy and correlation studies to sediment and trophic chains over a certain period in order to obtain the transfer factors and information on radionuclide dynamics. The HPGe detector used proves this is the best class of sensing devices for such purposes. Full article

Background: While sentinel lymph node (SLN) biopsy has been integrated into international guidelines for endometrial cancer, a standardized technique is still lacking. This study addresses whether the concurrent use of two tracers, technetium-99 (Tc) and indocyanine green (ICG), administered intracervically through distinct techniques, enhances the performance of SLN biopsies. As the blue dye is used routinely by some centers, it can be used alone; however, our analysis focused on only Tc and ICG (as is used in the majority of centers). Methods: A prospective multicentric observational study was designed to evaluate the unilateral detection rate, bilateral detection rates, sensitivity, and consistency of SLNs when using both tracers simultaneously in patients with early-stage endometrial cancer. Results: Our findings demonstrated that the simultaneous use of ICG and Tc significantly outperformed the use of either tracer alone. Unilateral detection rates were 69.2% for Tc, 84.9% for ICG, and 88.4% for both. Bilateral detection rates were 57.0% for Tc, 77.9% for ICG, and 83.6% for both. Additionally, the incidence of “empty pockets” was low with both tracers, at 2.7%. Notably, the concurrent application of both tracers identified instances where the Tc-labeled sentinel node differed from the ICG-labeled sentinel node. Conclusions: The combined use of Tc and ICG in SLN biopsy for early-stage endometrial cancer significantly enhances detection rates and reduces the occurrence of “empty pockets”, potentially decreasing the need for site-specific lymphadenectomy. Full article

Over the last decades, a novel immunological function was established for the sodium–glucose co-transporter 1 (SGLT1), a protein involved in sugar absorption in the small intestine. High-glucose dosage and pharmacological concentrations of a C-glucoside analog showed a protective role in in vitro and in vivo models of severe inflammation states; experimental evidence suggests the engagement of SGLT1 in these processes. The mechanism of action underlying the protection is still unclear. To enhance our understanding of the molecular mechanisms responsible for this protection, we have developed a synthesis for the preparation of hydrogen isotope-labeled versions of the C-glucoside hit compound. Specifically, we report the synthesis of the deuterium-labeled derivative, which can be utilized for mass spectrometry-based research to examine the compound’s metabolic pathway, distribution, and cellular/tissue localization. The synthetic method developed can be extended to produce the tritiated analog, serving as a radioactive tracer. Full article