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The radionuclides released from the Fukushima Daiichi nuclear power plant in 2011 pose a health risk. In this study, we estimated the 1st-year average doses resulting from the intake of iodine 131 (131I) and cesium 134 and 137 (134Cs and 137Cs) in drinking water and food ingested by citizens of Fukushima City (∼50 km from the nuclear power plant; outside the evacuation zone), Tokyo (∼230 km), and Osaka (∼580 km) after the accident. For citizens in Fukushima City, we considered two scenarios: Case 1, citizens consumed vegetables bought from markets; Case 2, citizens consumed vegetables grown locally (conservative scenario). The estimated effective doses of 134Cs and 137Cs agreed well with those estimated through market basket and food-duplicate surveys. The average thyroid equivalent doses due to ingestion of 131I for adults were 840 µSv (Case 1) and 2700 µSv (Case 2) in Fukushima City, 370 µSv in Tokyo, and 16 µSv in Osaka. The average effective doses due to 134Cs and 137Cs were 19, 120, 6.1, and 1.9 µSv, respectively. The doses estimated in this study were much lower than values reported by the World Health Organization and the United Nations Scientific Committee on the Effects of Atomic Radiation, whose assessments lacked validation and full consideration of regional trade in foods, highlighting the importance of including regional trade. The 95th percentile effective doses were 2-3 times the average values. Lifetime attributable risks (LARs) of thyroid cancers due to ingestion were 1.7-37×10-6 (Case 1) and5.6-79×10-6 (Case 2) in Fukushima City, 0.73-13×10-6 in Tokyo, and 0.04-0.49×10- 6 in Osaka. The contributions of LARs of thyroid cancers due to ingestion were 5.4%-11% of all exposure (Case 1) and 11%-25% (Case 2) in Fukushima City [corrected].

PurposeDiverse radionuclide imaging techniques are available for the diagnosis, staging, and follow-up of phaeochromocytoma and paraganglioma (PPGL). Beyond their ability to detect and localise the disease, these imaging approaches variably characterise these tumours at the cellular and molecular levels and can guide therapy. Here we present updated guidelines jointly approved by the EANM and SNMMI for assisting nuclear medicine practitioners in not only the selection and performance of currently available single-photon emission computed tomography and positron emission tomography procedures, but also the interpretation and reporting of the results.MethodsGuidelines from related fields and relevant literature have been considered in consultation with leading experts involved in the management of PPGL. The provided information should be applied according to local laws and regulations as well as the availability of various radiopharmaceuticals.ConclusionSince the European Association of Nuclear Medicine 2012 guidelines, the excellent results obtained with gallium-68 (68Ga)-labelled somatostatin analogues (SSAs) in recent years have simplified the imaging approach for PPGL patients that can also be used for selecting patients for peptide receptor radionuclide therapy as a potential alternative or complement to the traditional theranostic approach with iodine-123 (123I)/iodine-131 (131I)-labelled meta-iodobenzylguanidine. Genomic characterisation of subgroups with differing risk of lesion development and subsequent metastatic spread is refining the use of molecular imaging in the personalised approach to hereditary PPGL patients for detection, staging, and follow-up surveillance.

IntroductionScintigraphic evaluation of the thyroid gland enables determination of the iodine-123 iodide or the 99mTc-pertechnetate uptake and distribution and remains the most accurate method for the diagnosis and quantification of thyroid autonomy and the detection of ectopic thyroid tissue. In addition, thyroid scintigraphy and radioiodine uptake test are useful to discriminate hyperthyroidism from destructive thyrotoxicosis and iodine-induced hyperthyroidism, respectively.MethodsSeveral radiopharmaceuticals are available to help in differentiating benign from malignant cytologically indeterminate thyroid nodules and for supporting clinical decision-making. This joint practice guideline/procedure standard from the European Association of Nuclear Medicine (EANM) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI) provides recommendations based on the available evidence in the literature.ConclusionThe purpose of this practice guideline/procedure standard is to assist imaging specialists and clinicians in recommending, performing, and interpreting the results of thyroid scintigraphy (including positron emission tomography) with various radiopharmaceuticals and radioiodine uptake test in patients with different thyroid diseases.

AimDescribe the results of brachytherapy in the prevention of recurrences in conjunctival melanoma (CM) and describe a dosimetric protocol.MethodsRetrospective and descriptive case report. Eleven consecutive patients with a confirmed histopathological diagnosis of CM treated with brachytherapy between 1992 and 2023 were reviewed. Demographic, clinical, and dosimetric characteristics as well as recurrences were recorded. Quantitative variables were represented by the mean, median, and standard deviation, and qualitative variables by frequency of distribution.ResultsOf a total of 27 patients diagnosed with CM, 11 who were treated with brachytherapy were included in the study (7 female; mean age at time of treatment: 59.4 years). Mean follow-up was 58.82 months (range 11–141 months). Of a total of 11 patients, 8 were treated with ruthenium-106 and 3 with iodine-125. Brachytherapy was performed in 6 patients as adjuvant therapy after biopsy-proven CM on histopathology and in the other 5 patients after recurrence. The mean dose was 85 Gy in all cases. Recurrences outside of the previously irradiated area were observed in 3 patients, metastases were diagnosed in 2 patients, and one case of an ocular adverse event was reported.ConclusionBrachytherapy is an adjuvant treatment option in invasive conjunctival melanoma. In our case report, only one patient had an adverse effect. However, this topic requires further research. Furthermore, each case is unique and should be evaluated by experts in a multidisciplinary approach involving ophthalmologists, radiation oncologists, and physicists.

Iodine can exist in the form of radioactive and non-radioactive states. Radioactive Iodine-131 (I-131) has been utilized in nuclear facilities. Due to its ability to be absorbed by the thyroid gland, I-131 is used for therapy in thyroid cancer cases. Contrary to the benefit, Iodine is a volatile material that becomes a health problem if humans inhale more than a certain dose under a certain period. Thus, to prevent overexposure to Iodine, all Iodine-related facilities must equip their facilities with Iodine detection systems. The most common radioactive detection system uses an expensive Na(Tl), and HPGe detector. So, this study will build a low-cost iodine detection system by means of a low-cost color-based sensor utilizing the color property of the Iodine gasses. This finding showed that the color sensor will detect the Iodine gas leaks in the air in a range of 0 - 100 ppm, resulting in a pink-dark purple color. This finding showed that the sensor could detect low concentrations of Iodine gas in particular areas very well. Since the good resolution of this detection system, it will be promising to be applied in a real-time iodine gasses detection system.

The recent identification of a novel binding site for angiotensin (Ang) II as the peptidase neurolysin (E.C. 3.4.24.16) has implications for the renin-angiotensin system (RAS). This report describes the distribution of specific binding of 125I-Sarcosine1, Isoleucine8 Ang II (125I-SI Ang II) in neurolysin knockout mouse brains compared to wild-type mouse brains using quantitative receptor autoradiography. In the presence of p-chloromercuribenzoic acid (PCMB), which unmasks the novel binding site, widespread distribution of specific (3 µM Ang II displaceable) 125I-SI Ang II binding in 32 mouse brain regions was observed. Highest levels of binding >700 fmol/g initial wet weight were seen in hypothalamic, thalamic and septal regions, while the lowest level of binding <300 fmol/g initial wet weight was in the mediolateral medulla. 125I-SI Ang II binding was substantially higher by an average of 85% in wild-type mouse brains compared to neurolysin knockout brains, suggesting the presence of an additional non-AT1, non-AT2, non-neurolysin Ang II binding site in the mouse brain. Binding of 125I-SI Ang II to neurolysin in the presence of PCMB was highest in hypothalamic and ventral cortical brain regions, but broadly distributed across all regions surveyed. Non-AT1, non-AT2, non-neurolysin binding was also highest in the hypothalamus but had a different distribution than neurolysin. There was a significant reduction in AT2 receptor binding in the neurolysin knockout brain and a trend towards decreased AT1 receptor binding. In the neurolysin knockout brains, the size of the lateral ventricles was increased by 56% and the size of the mid forebrain (-2.72 to +1.48 relative to Bregma) was increased by 12%. These results confirm the identity of neurolysin as a novel Ang II binding site, suggesting that neurolysin may play a significant role in opposing the pathophysiological actions of the brain RAS and influencing brain morphology.

PurposeIodine 123 labeled meta-iodobenzylguanidine ([123I]MIBG) scan with SPECT/CT imaging is one of the most commonly used imaging modalities in the evaluation of neuroblastoma. [18F]-meta-fluorobenzylguanidine ([18F]MFBG) is a novel positron emission tomography (PET) tracer which was reported to have a similar biodistribution to [123I]MIBG. However, the experience of using [18F]MFBG PET/CT in the evaluation of patients with neuroblastoma is limited. This preliminary investigation aims to assess the efficacy of [18F]MFBG PET/CT in the evaluation of neuroblastomas in comparison to [123I]MIBG scans with SPECT/CT.Materials and methodsIn this prospective, single-center study, 40 participants (mean age 6.0 ± 3.7 years) with history of neuroblastoma were enrolled. All children underwent both [123I]MIBG SPECT/CT and [18F]MFBG PET/CT studies. The number of lesions and the Curie scores revealed by each imaging method were recorded.ResultsSix patients had negative findings on both [123I]MIBG and [18F]MFBG studies. Four of the 34 patients (11.8%) were negative on [123I]MIBG but positive on [18F]MFBG, while 30 patients were positive on both [123I]MIBG and [18F]MFBG studies. In these 34 patients, [18F]MFBG PET/CT identified 784 lesions while [123I]MIBG SPECT/CT detected 532 lesions (p < 0.001). The Curie scores obtained from [18F]MFBG PET/CT (11.32 ± 8.18, range 1-27) were statistically higher (p < 0.001) than those from [123I]MIBG SPECT/CT (7.74 ± 7.52, range 0-26). 30 of 34 patients (88.2%) with active disease on imaging had higher Curie scores based on the [18F]MFBG study than on the [123I]MIBG imaging.Conclusion[18F]MFBG PET/CT shows higher lesion detection rate than [123I]MIBG SPECT/CT in the evaluation of pediatric patients with neuroblastoma.Clinical trial registrationClinicaltrials.gov: NCT05069220 (Registered: 25 September 2021, retrospectively registered); Institute Review Board of Peking Union Medical College Hospital: ZS-2514

The long half‐life of 129I makes it useful for dating marine sediments aged 2–90 Ma. However, the lack of initial value dating hinders its application for dating terrestrial sediments. A large scatter of 129I/127I in prenuclear terrestrial samples has been reported; however, the key influencing factors remain unclear. This study presented iodine isotope data from three Argentine Entisol profiles and developed an iodine‐source model to determine the influence of the source on iodine isotopic composition. The temporal patterns demonstrated clear climate modulations in natural terrestrial iodine isotopes over the last ∼15 Kyr. The model identified rock weathering as a major source of iodine in continental sediments. Higher 129I/127I ratios at mid‐high latitudes arise from weak geomagnetic shielding of cosmic rays and thus a high production rate, implying limited meridional diffusion of atmospheric iodine. These findings reveal that environmental factors are significant for constraining the initial value of terrestrial 129I. Plain Language Summary In terrestrial sediments, the absence of a specific initial value poses a challenge for 129I dating. Through examination of three profiles of Argentine Entisols, this study investigated how changes in the environment over the past 15 Kyr affected iodine isotopic composition. The climate modulations of iodine isotopes were indicated by comparing them with climatic proxies. A simple multi‐source model of iodine suggested that “old” iodine from catchment rock weathering was a major iodine provider, and decreased 129I/127I with the enhanced South American Summer Monsoon and South Westerly Wind indicated a low‐129I iodine input. The deviant 129I/127I of the most southern site was hypothesized to be caused by a greater cosmogenic 129I production rate at high latitudes than at mid‐low latitudes. Key Points Natural 129I/127I was for the first time found to co‐vary with the summer monsoon and westerlies in South America Rock weathering contributes more iodine to terrestrial sediments than oceanic emissions High 129I/127I values at mid‐high latitudes imply low geomagnetic shielding and limited meridional diffusion of atmospheric iodine

We investigate the spatiotemporal distribution of the radionuclides including iodine-131 (131I) and cesium-137 (137Cs), transported to Qatar from fictitious accidents at the upwind Barakah nuclear power plant (B-NPP) in the United Arab Emirates (UAE). To model the dispersion of radionuclides, we use the Lagrangian particle–air parcel dispersion model FLEXible PARTicle (FLEXPART) and FLEXPART coupled with the Weather Research and Forecasting model (FLEXPART–WRF). A four-member mini-ensemble of meteorological inputs is used to investigate the impact of meteorological inputs on the radionuclide dispersion modeling. The mini-ensemble includes one forecast dataset (Global Forecast System, GFS) and three (re)analysis datasets (native-resolution and downscaled NCEP final analysis – FNL, as well as downscaled ERA5). Additionally, we explore the sensitivity of the radionuclide dispersion simulations to variations in the turbulence schemes, as well as the temporal and vertical emission profiles, and the location of emission sources. According to the simulated age spectrum of the Lagrangian particles, radionuclides enter southern Qatar about 20 to 30 h after release. Most of the radionuclide deposition in the study area occurs within 80 h after release. The most populated areas of Qatar coincide with moderate 131I concentrations and 137Cs deposition, while uninhabited areas in southern Qatar receive the highest amounts. A larger number of long-lived particles is found in the FNL-based simulations, which is interpreted as a greater dispersion of particles at a greater distance from the emission location. The highest simulated 131I and 137Cs deposition shows a pronounced spatiotemporal pattern. The largest impacts are found in the south and southeast of Qatar, during the early daytime development of the boundary layer, and during the cold period of the year. The results show remarkable differences in the spatiotemporal distribution of 131I and 137Cs simulations based on the FNL and GFS datasets, which share a common base meteorological model. As part of a sensitivity analysis involving different model setups, changing the emission point from B-NPP to Bushehr NPP (Bu-NPP) results in a reduced transfer of radioactive materials to Qatar, except in the spring season. Bu-NPP simulations reveal distinct spatial patterns, with peak 131I concentrations and 137Cs deposition observed in northern and eastern Qatar during winter and spring.

Lung cancer, a leading cause of death, sees variable outcomes with iodine-125 seed implantation. Predictive tools are lacking, complicating clinical decisions. This study integrates radiomics and clinical features to develop a predictive model, advancing personalized treatment. To construct a nomogram model combining enhanced CT image features and general clinical characteristics to evaluate the efficacy of radioactive iodine-125 seed implantation in lung cancer treatment. Patients who underwent lung iodine-125 seed implantation at the Nuclear Medicine Department of Xiling Campus, Yichang Central People's Hospital from January 1, 2018, to January 31, 2024, were randomly divided into a training set (73 cases) and a test set (31 cases). Radiomic features were extracted from the enhanced CT images, and optimal clinical factors were analyzed to construct clinical, radiomics, and combined models. The best model was selected and validated for its role in assessing the efficacy of iodine-125 seed implantation in lung cancer patients. Three clinical features and five significant radiomic features were successfully selected, and a combined nomogram model was constructed to evaluate the efficacy of iodine-125 seed implantation in lung cancer patients. The AUC values of the model in the training and test sets were 0.95 (95% CI: 0.91-0.99) and 0.83 (95% CI: 0.69-0.98), respectively. The calibration curve demonstrated good agreement between predicted and observed values, and the decision curve indicated that the combined model outperformed the clinical or radiomics model across the majority of threshold ranges. A combined nomogram model was successfully developed to assess the efficacy of iodine-125 seed implantation in lung cancer patients, demonstrating good clinical predictive performance and high clinical value.