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This study evaluates the efficacy of [131I]I-ERIC1 in targeting and inhibiting the growth of SCLC tumors in mice, focusing on tumor accumulation and regression and potential side effects. NCAM-positive NCI-H69 SCLC cells were implanted in CB 17 SCID mice, and [131I]I-ERIC1 biokinetics were measured in organs and tissues at four post-injection time points (24, 72, 96, and 120 h). The experimental series compared tumor growth, survival, and changes in blood counts among three treatment groups (1, 2, or 3 MBq) and a control group, with treatments initiated either two or five days post implantation. [131I]I-ERIC1 was synthesized with >95% radiochemical purity and a specific activity of 15 TBq/mmol. Tumor activity peaked at 31.5 ± 6.6% ID/g after four days, demonstrating significant antitumor efficacy, which resulted in sustained remission and extended survival. Hematological toxicity was observed, with the optimal dose identified as 2 MBq per animal administered two days post implantation. [131I]I-ERIC1 shows promise as a theranostic agent for personalized cancer treatment by effectively targeting SCLC tumors with manageable side effects. However, further studies are required to optimize dosing strategies and minimize toxicity. [ABSTRACT FROM AUTHOR]

Purpose: Ionizing radiation-based technologies are extensively used in the diagnosis and treatment of diseases. While utilizing the technologies, exposure to a certain amount of radiation is unavoidable. Data can be obtained from participants who received radiation during medical imaging and therapeutic purposes to predict the effects of low-dose radiation. Methods: To understand the effects of low-dose radiation, participants (n = 22) who received radioactive I-131 for scan/therapy were used as a model in this study. Blood samples were drawn pre- and post-administration of I-131. Biological effects were measured using markers of DNA damage (γ-H2AX, micronucleus (MN), and chromosomal aberrations (CA)) and response to damage through gene expression changes (ATM, CDKN1A, DDB2, FDXR, and PCNA) in blood samples. Results: Mean frequency of γ-H2AX foci in pre-samples was 0.28 ± 0.16, and post-samples were 1.03 ± 0.60. γ-H2AX foci frequency obtained from post-samples showed significant (p < 0.0001) and a heterogeneous increase in all the participants (received I-131 for scan/therapy) when compared to pre-samples. A significant increase (p < 0.0001) in MN and CA frequency was also observed in participants who received the I-131 therapy. Gene expression analysis indicates that all genes (ATM, CDKN1A, DDB2, FDXR, and PCNA) were altered in post-samples, although with varying degrees, suggesting that the cellular responses to DNA damage, such as damage repair, cell cycle regulation to aid in repair and apoptosis are increased, which priority is given to repair, followed by apoptosis. Conclusion: The results of this study indicate that the participants who received I-131 (low doses of β- and γ-radiation) can produce substantial biological effects. [ABSTRACT FROM AUTHOR]

BACKGROUND: Thyroid nodules are a prevalent issue, with an estimated incidence of 19% to 35% based on ultrasound examination and 8% to 65% based on autopsy findings [1]. In some cases, Plummer’s disease is observed, and nodular masses may be observed in 10% to 35% of Graves’ disease cases, with iodine accumulation of a different nature [2, 3]. One of the principal treatments for Graves’ and Plummer’s diseases is radioiodine therapy, which serves to exclude the possibility of malignancy in nodules. Furthermore, the pharmacokinetics of iodine is investigated, which represents the most time-consuming and labor-intensive stage of preparation for radioiodine therapy. In clinical practice, ultrasound is performed in accordance with the TI-RADS system, followed (if necessary) by fine-needle aspiration puncture biopsy, stratified according to the Bethesda system. However, the interpretation of ultrasound examinations is inherently subjective, whereas the use of decision support systems can reduce the number of fine-needle aspiration puncture biopsies by 27% and the number of missed malignant neoplasms by 1.9%. Furthermore, the quantitative characterization of nodal ultrasound may enhance the investigation of the pharmacokinetics of I-131 [4, 5]. AIM: The study aimed to develop a method for quantitatively characterizing ultrasound images of thyroid nodular masses for predicting malignancy and I-131 accumulation by nodular masses. MATERIALS AND METHODS: The study included 125 nodules with pathomorphologic findings (65 benign, 60 malignant) and 25 benign nodules (established by cytologic examination) of patients who underwent radioiodotherapy as part of the Russian Science Foundation grant project No. 22-15-00135. Longitudinal and transverse projections of thyroid nodules were obtained using GE Voluson E8 (36% of all benign nodules and 27% of malignant nodules) and GE Logiq E (64% of benign and 73% of malignant nodules). A pharmacokinetics study was conducted on 25 nodes obtained on a GE Logiq V2 device. The accumulation index of I-131 was determined after 24 hours. A spatial adjacency matrix, gray level line length matrix, gray level zone size matrix, and histogram were employed to investigate features based on ultrasound images. RESULTS: The malignancy prediction model, developed on the basis of the most significant features and after KNN correlation analysis, exhibited a diagnostic accuracy value of 72±3%, a sensitivity of 73±5%, and a specificity of 73±5%. An investigation of I-131 pharmacokinetics revealed that the maximum histogram intensity gradient (r=–0.48, p=0.08) and intensity entropy (r=–0.51, p=0.06) exhibited the highest Spearman correlation coefficient modulus with I-131 accumulation after 24 hours. CONCLUSIONS: The present study demonstrates the feasibility of using quantitative characterization of ultrasound images of nodal masses as a tool to monitor nodules before radioiodotherapy. This is with a view to subsequent adjunctive fine-needle aspiration puncture biopsy and prediction of I-131 accumulation after 24 hours.

BACKGROUND: The management of differentiated thyroid cancer includes single-photon emission tomography combined with X-ray computed tomography after radioiodine therapy. Despite a good response to surgery and radioiodine therapy, recurrence is noted in some cases, leading to an unfavorable prognosis in 8% of cases [1]. A preliminary analysis of the distribution of I-131 in residual thyroid tissues and foci of metastasis allows for the estimation of the probability of differentiated cancer recurrence. Currently, there is no method that is simultaneously effective and easy to perform for predicting the recurrence of differentiated thyroid cancer. AIM: The aim of the study was to develop a technique for extracting and computing textural features of the I-131 accumulation region using a single-photon emission tomography system corresponding to differentiated thyroid cancer tissue. MATERIALS AND METHODS: A retrospective analysis of single-photon emission tomography combined with X-ray computed tomography of the neck and thorax of 23 patients was conducted. Regions of interest, including foci of I-131 accumulation in the primary tumor bed, regional and distant metastases, were delineated in Xeleris 4DR software. The obtained mask with the original image was processed in a program written with the help of the Matlab package, which localizes the foci. The textural features of foci are calculated based on the obtained spatial adjacency matrix. This matrix shows how often pixels with certain gray scale brightness values occur in an image. Therefore, the features based on the spatial adjacency matrix reflect the frequency distribution of different pixel neighborhoods in a given context. RESULTS: An algorithm for constructing three-dimensional matrices of a radiation source surrounded by tissue of differentiated thyroid cancer was developed. The textural features of three-dimensional matrices were investigated. It was demonstrated that there are tendencies for differences in texture features corresponding to the ordering of pixel values and image contrast. The values of the obtained features obey the lognormal distribution. CONCLUSIONS: An algorithm for extracting textural features of I-131 accumulation foci allows post-therapy single-photon emission tomography images combined with X-ray computed tomography to be analyzed for the likelihood of recurrence of differentiated thyroid cancer.

Introdução/Justificativa: O câncer de tireoide é a neoplasia endócrina mais comum, sendo o câncer diferenciado de tireoide (CDT) o subtipo mais prevalente. O tratamento padrão envolve tireoidectomia total (TT) seguida de terapia com Iodo-131 (I131). Marcadores bioquímicos como a tireoglobulina sérica (Tg) e o TSH são frequentemente utilizados para prognóstico e detecção de doença metastática. Variáveis demográficas, como idade e sexo, também afetam o prognóstico, assim como o estadiamento patológico inicial. O sistema de estratificação de risco proposto pelas diretrizes da Associação Americana de Tireoide (ATA) de 2015 auxilia na prescrição de I131 pós-TT e basea-se principalmente em relatórios patológicos. Entretanto, pode apresentar falhas, como a deficiência em detectar doença persistente que requer uma intervenção terapêutica mais agressiva com I131. Em vista disso, a elaboração de um modelo preditivo pode prover uma estratificação de risco mais acurada e personalizada para pacientes com CDT submetidos a TT e terapia ablativa com I131. Em 2023, Giovanella e colaboradores elaboraram um modelo preditivo baseado em árvore de decisão para este cenário. Entretanto, todos os pacientes foram submetidos a suspensão de levotiroxina. Objetivos: Testar o modelo preditivo baseado em árvore de decisão descrito por Giovanella e colaboradores em pacientes submetidos a TT e terapia com I131 estimulados com TSH recombinante (rhTSH). Materiais e Métodos: Análise retrospectiva de 451 pacientes submetidos a tratamento com radioiodo entre 2016 e 2020. Foram incluídos pacientes adultos e com CDT comprovado histologicamente após TT, com níveis de anticorpo anti-tireoglobulina normais, uso de rhTSH pré-radioiodoterapia, além do resultado da PCI pós-tratamento. Foi aplicado o modelo de árvore de decisão descrito por Giovanella e colaboradores em pacientes com CDT estimulados por rhTSH. De forma simplicicada, o modelo proposto por Giovanella e colaboradores dividiu os pacientes em com e sem acometimento linfonodal. Aqueles com acometimento linfonodal e Tg estimulada acima de 35,0 ng/ml tinham alta probabilidade de doença metastática/persistente. O mesmo ocorrendo em pacientes sem acometimento linfonodal e com Tg estimulada acima de 23,3 ng/ml. Resultados: Dos 451 pacientes incluidos, 362 (80,3%) foram do sexo feminino, com uma mediana de idade de 41,41 anos (IQR 33,76 a 53,00) e de Tg estimulada sérica de 2,9 ng/mL (IQR 0,68 a 7,9). Aplicando o modelo de árvore de decisão descrito por Giovanella e colaboradores, foi obtido um valor preditivo positivo de 25,0% (IC 10,01– 49,9%), um valor preditivo negativo de 87,3% (IC 86,6 – 88,1%) e uma acurácia de 85,1% (IC 81,4 – 88,3%). Gênero masculino e valor de Tg foram associados com PCI positiva (p < 0,05). Os resultados encontrados foram inferiores aos descritos por Giovanella e colaboradores (porém, semelhantes a um dos centros participantes). Isto pode ser explicado pela menor prevalência de PCI positiva e pela diferença dos valores de Tg com suspensão da levotiroxina e com TSH recombinante. Conclusão: Evidenciamos que o modelo de árvore de decisão descrito pode ser aplicado a pacientes com CDT estimulados por rhTSH com bons resultados, embora um modelo especificamente adaptado para essa população seja preferível. A Tg estimulada e o gênero apresentaram o melhor desempenho na previsão de doença persistente ou metastática na PCI após a cirurgia.

This novel radiolabeled chitosan nanoparticle, facilitated with curcumin, increased doxorubicin cytotoxicity and radiosensitivity to MG-63 osteosarcoma cells in a three-dimensional model. Delivery of the anti-epidermal growth factor receptor (EGFR) targeted carboxymethyl chitosan nanoparticles, directly labeled with Na131I (ICED-N), achieved deep tumor penetration in a three-dimensional model. Of three kinetic models, the Higuchi model more closely matched the experimental curve and release profiles. The anti-EGFR targeting resulted in a 513-fold greater targeting efficacy to MG-63 (EGFR+) cells than the control fibroblast (EGFR−) cells. The curcumin-enhanced ICED-N (4 × 0.925 MBq) fractionated-dose regime achieved an 18.3-fold increase in cell cytotoxicity compared to the single-dose (1 × 3.70 MBq) doxorubicin-loaded nanoparticle, and a 13.6-fold increase in cell cytotoxicity compared to the single-dose Na131I nanoparticle. Moreover, the ICED-N fractionated dose increased cells in the G2/M phase 8.78-fold, indicating the cell cycle arrest in the G2/M phase is associated with DNA fragmentation, and the intracellular damage is unable to be repaired. Overall, the results indicate that the fractionated dose was more efficacious than a single dose, and curcumin substantially increased doxorubicin cytotoxicity and amplified osteosarcoma cell radiosensitivity to Na131I. [ABSTRACT FROM AUTHOR]

Objective: The present study aimed to assess the thyroid outcomes six-months after radioactive Iodine-131 therapy (RIT) among hyperthyroid patients and identify the factors associated with them. Methods: This retrospective observational study was conducted at the department of Nuclear Medicine and Molecular Imaging, Northwest General Hospital & Research Centre during 2013 to 2019. For the study purpose, the thyroid outcomes of 153 hyperthyroid patients were studied retrospectively for six months after RIT. The data was obtained from the medical records. Patient baseline characteristics, clinical features, laboratory investigations, results of thyroid imaging, and therapeutic investigations were acquired and recorded in a structured questionnaire. Results: Out of the 153 screened records of hyperthyroid patients, 19.6% became euthyroid, 9.2% remained hyperthyroid, and 25.5% developed hypothyroidism after six months of RIT. The observed remission rate by the end of six months was 80.95%. Three months post-RIT, gender and RAI doses had a significant effect on thyroid function. The frequency of hypothyroidism was higher among those treated with an RAI dose of ≤ 20 mCi (83.0%) than those treated with a higher dose > 20 mCi (17%). Moreover, most patients receiving > 20 mCi radioiodine became euthyroid (64.5%). Similar outcomes were observed after six months of the therapy, except gender was replaced by etiologies of hyperthyroidism (p=0.009). Conclusion: Radioactive iodine (131-I) therapy is effective for the treatment of hyperthyroidism. However, the appropriate dose is still debatable, as there was a high incidence of hypothyroidism post-therapy. [ABSTRACT FROM AUTHOR]

Abstract Background Accurate quantification of radioactivity in a source of interest relies on accurate registration between SPECT and anatomical images, and appropriate correction of partial volume effects (PVEs). For small volumes, exact registration between the two imaging modalities and recovery factors used to correct for PVE are unreliable. There is currently no guidance relating to quantification or the associated uncertainty estimation for small volumes. Material and methods A method for quantification of small sources of interest is proposed, which uses multiple oversized volumes of interest. The method was applied to three Na[131I]I activity distributions where a Na[131I]I capsule was situated within a cylindrical phantom containing either zero background, uniform background or non-uniform background and to a scenario with small lesions placed in an anthropomorphic phantom. The Na[131I]I capsule and lesions were quantified using the proposed method and compared with measurements made using two alternative quantification methods. The proposed method was also applied to assess the absorbed dose delivered to a bone metastasis following [131I]mIBG therapy for neuroblastoma including the associated uncertainty estimation. Results The method is accurate across a range of activities and in varied radioactivity distributions. Median percentage errors using the proposed method in no background, uniform backgrounds and non-uniform backgrounds were − 0.4%, − 0.3% and 1.7% with median associated uncertainties of 1.4%, 1.4% and 1.6%, respectively. The technique is more accurate and robust when compared to currently available alternative methods. Conclusions The proposed method provides a reliable and accurate method for quantification of sources of interest, which are less than three times the spatial resolution of the imaging system. The method may be of use in absorbed dose calculation in cases of bone metastasis, lung metastasis or thyroid remnants.

Combination chemotherapy is still the standard clinical care for triple-negative breast cancer (TNBC). However, sodium iodide symporter (NIS) uptake by TNBC has opened the potential of NIS as a molecular target for radioiodine theranostic treatments. Radiolabeled poly(lactic-co-glycolic) acid nanocarrier (NINP) was developed for NIS targeted delivery of I-131 to MDA-MB-231 cells to overcome I-131 low uptake in cancer cells and rapid clearance. The NINP diameter of 237 nm has good particle size uniformity and excellent particle stability. Radiochemical purity, radioactive stability, and radiolabeling yield of NINPs over 72 h were >95%. Cytotoxicity confirmed fractionated NINPs over 72 h to be more effective in cell death than single-dose NINP and both single and fractionated Na131I. Cellular uptake in a three-dimensional spheroid confirmed that NINP fractionated-dose achieved ~4.8-fold-higher mean fluorescent intensity than Na131I and ~2.7-fold greater reduction in cell viability compared to single-dose. The NINP fractionated-dose initiated greater cellular DNA damage to cells than single-dose NINP, resulting in inhibition of cell cycle progression, resulting in cell cycle progression being inhibited by cyclin-dependent kinases, which play a vital role in the control of MDA-MB-231 cell cycle. NINPs are biocompatible with blood, and were found to have no negative impact on red blood cells. [ABSTRACT FROM AUTHOR]

Iodine-131 has become an essential radionuclide used in nuclear medicine for clinical and research purposes. The increase use of this radionuclide in medicine for diagnostic and treatment of thyroid diseases creates a demand to obtain a feasible methodology for occupational or accidental monitoring of internal contamination. In this study, two techniques were employed to find an appropriate one of in vivo bioassay for evaluating Iodine-131 body content. A scanning Whole Body Counter (WBC) equipped with 6NaI (Tl) scintillation detector, an anthropomorphic phantom and point source were used. The results showed that the counter sensitivity, as a first approach (conventional method), had a logarithmic and significant correlation with neck weight. On the other hand, the counting rate in the Compton band was considered, which is a measure of gamma ray attenuation, and found to have a direct relationship with body weight. The new technique, which is considered the variation of the counter sensitivity with the Compton to photopeak counting rate ratio, had the same regression but less uncertainty than the conventional approach. Finally, the theoretical MDA with neck weight was calculated for all the phantom configurations. [ABSTRACT FROM AUTHOR]

Abstract Background Hyperthyroidism has been treated with radioiodine therapy for eight decades, with known benefits and side-effects. No consensus exists on which activity dosage and pre-therapeutic measurements are required for optimal treatment, balancing risk of incomplete response, therapy-induced hypothyroidism and radiation exposure. A retrospective analysis was performed to assess these questions. Methods Data was collected on radioiodine treatment outcomes for 904 patients treated for Graves' disease or toxic nodular goitres at our institution during 2016–2020. The prescribed absorbed doses were 120 Gy (Graves’ disease), 200 Gy (toxic multinodular goitre) and 300 Gy (solitary toxic adenoma). Univariate analysis and multivariate regression modelling were used to find factors linked to treatment outcome. Results The cure rate of hyperthyroidism after one administration of radioiodine was 79% for Graves' disease, 94% for toxic multinodular goitre and 98% for solitary toxic adenoma. Thyroid mass, uptake and effective half-life were all significantly associated with cure in Graves’ disease, but not in toxic multinodular goitre. The rates of therapy-induced hypothyroidism were 20% and 29% for toxic multinodular goitre and solitary toxic adenoma. Neither the cure rate nor the hypothyroidism rate was found to be superior among patients with individualised effective half-life measurements in toxic nodular goitres. Poor renal function was associated with dubious iodine uptake measurements but was not found to correlate with worse outcome. Conclusions Multiple measurements of individual iodine uptake for kinetics estimation may be unnecessary, and a population-based value can be used instead. Patients with renal impairment had similar outcome as other patients, but with a higher risk of dubious uptake measurements.

One of the most effective methods of treating thyroid cancer is iodine therapy. Patients are prescribed orally after thyroidectomy or thyroid tissue resection to control tumor growth and prevent secondary symptoms after iodine surgery. Also, due to the dose of radioactive iodine absorbed by cancer cells in the thyroid gland, it may have many side effects for those around the patient, which in this study in the radiotherapy center of Afshar Clinic in Yazd, using germanium dosimeters TLD-100 is the average absorbed dose of thyroid area on the skin surface after 24 hours to receive 100 to 150 mCi of iodine 131 and the deeply absorbed dose of thyroid at a distance of 7 cm from the skin, which includes the thyroid and surrounding soft tissue 388.933 and 379.155 cGy, respectively. After 48 hours, these values were 350.643 and 344.124 cGy, respectively. Moreover, the measured dose was around the patient. At distances of 1 to 3 m from them during 24 to 48 hours of hospitalization after radiation, iodine intake is on average 30.93 cGy, which is a high risk for those around the patient compared to the set standards. According to the results of studies published so far, age and gender are very effective in the incidence of this disease, and its prevalence is higher in women than men. Therefore, it is suggested that research be conducted on genetic factors and common underlying diseases in each region.

A 50-year-old man undergone total thyroidectomy and histopathology revealed papillary thyroid carcinoma with a tumor size of 4.5 cm. The patient was referred to a nuclear medicine clinic for radioiodine therapy. Since the thyroglobulin level before the treatment was 495 ug/L, lowdose (185 MBq) I-131 scan was performed. In addition to multiple liver metastases, bone metastases were detected in the sacrum and right 7th rib in I-131 whole body scanning and single photon emission computed tomography/computed tomography (CT) imaging at the time of initial staging. We present a case of multiple metastatic papillary thyroid carcinoma whose radioiodine treatment response and clinical outcome were evaluated with 18F-fluorodeoxyglucose and Gallium-68 FAPI-04 positron emission tomography/CT. [ABSTRACT FROM AUTHOR]

Background: Accurate quantification of radioactivity in a source of interest relies on accurate registration between SPECT and anatomical images, and appropriate correction of partial volume effects (PVEs). For small volumes, exact registration between the two imaging modalities and recovery factors used to correct for PVE are unreliable. There is currently no guidance relating to quantification or the associated uncertainty estimation for small volumes. Material and methods: A method for quantification of small sources of interest is proposed, which uses multiple oversized volumes of interest. The method was applied to three Na[131I]I activity distributions where a Na[131I]I capsule was situated within a cylindrical phantom containing either zero background, uniform background or non-uniform background and to a scenario with small lesions placed in an anthropomorphic phantom. The Na[131I]I capsule and lesions were quantified using the proposed method and compared with measurements made using two alternative quantification methods. The proposed method was also applied to assess the absorbed dose delivered to a bone metastasis following [131I]mIBG therapy for neuroblastoma including the associated uncertainty estimation. Results: The method is accurate across a range of activities and in varied radioactivity distributions. Median percentage errors using the proposed method in no background, uniform backgrounds and non-uniform backgrounds were − 0.4%, − 0.3% and 1.7% with median associated uncertainties of 1.4%, 1.4% and 1.6%, respectively. The technique is more accurate and robust when compared to currently available alternative methods. Conclusions: The proposed method provides a reliable and accurate method for quantification of sources of interest, which are less than three times the spatial resolution of the imaging system. The method may be of use in absorbed dose calculation in cases of bone metastasis, lung metastasis or thyroid remnants. [ABSTRACT FROM AUTHOR]

To determine the present state of radioiodine therapy for pediatric Gravesʼ disease in Japan, a nationwide questionnaire survey was conducted among 164 councilors of the Japan Thyroid Association. Responses were received from 46 individuals, and the rate of collection of questionnaires was 28%（46/164）. Fourteen respondents experienced treating children with I-131 during the previous decade. The age bracket of patients most frequently underwent this therapy was 16-18. Administration of I-131 to children younger than 5 years is deemed contraindication by 39 respondents. In 25 respondents radioiodine is indicated only when no other mode of treatment is available, while in 10 respondents the same criteria as adults are applied. When thyroid eye disease is present, 26 prefer alternative means of therapy. Only 3 will not inform to the pediatric patients themselves about the use of radionuclide. None of the respondents experienced radioiodine-induced tumorigenesis. Our results confirmed I-131 treatment for children is conducted mostly in accordance to the guidelines issued from responsible academic societies, and elucidated remaining challenges such as developing better way of explaining the therapy to very young subjects and radioprotective consideration to siblings of the patients. [ABSTRACT FROM AUTHOR]

Objective: To analyze the effectiveness of the first dose of radioiodine (I-131) treatment in patients with hyperthyroidism in Southern Thailand. The second objective was to predict the factors implicated in treatment failure. Materials and Methods: Patients with hyperthyroidism who received first dose of I-131 between January 2010 and December 2019 at Songklanagarind Hospital were enrolled in the present retrospective study. The data collected included age, gender, duration of the disease, type of disease, thyroid gland size (by palpation), type of antithyroid drug (ATD), ATD dose, and time of withholding ATD before and after I-131 treatment. The effectiveness of the first dose of I-131 treatment was assessed after six months of treatment. Treatment success was defined as a euthyroid or hypothyroid status. Results: One thousand four hundred twenty-four patients with hyperthyroidism at a median age of 44.5 years and including 73.2% women were included in this study. Graves' disease was the most common cause at 95.8%. The median I-131 dose was 7 mCi. Six months after treatment, 703 patients or 49.4%, achieved treatment success, which increased to 859 patients (60.3%) after 12 months. The authors found three factors that influenced treatment failure, duration of disease of seven months or longer (p=0.001), thyroid gland size of 100 g or larger (p=0.004), and I-131 treatment dose 10 to 19 mCi (p=0.021). The patient cohort was divided into three groups based on thyroid gland size at less than 50 g, 50 to 99 g, and more than 100 g, the I-131 treatment dose that increased the success rate of treatment in each group was 5 mCi or more, 6 mCi or more, and 15 mCi or more, respectively. Conclusion: A single dose of I-131 could successfully treat hyperthyroidism. The duration of the disease, size of the thyroid gland, and the dose of I-131 treatment had a substantial impact on the result. Thus, the authors recommended early treatment with I-131 at a suitable dose for patients with hyperthyroidism. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate immunohistochemical staining of sodium iodide symporter (NIS) and its effect on response to I-131 therapy in differentiated thyroid carcinoma patients. Methods: We evaluated NIS expression, the intracellular distribution of NIS, iodine-131 uptake in residual tissues on post-ablation I-131 whole body scan, and the ablation status after 100 mCi I-131 therapy. We also investigated NIS expression and localization in tumoral paraffin-embedded tissues. Results: In this retrospective study, 35 patients (mean age 44.17 ± 12.9 years, 27 female, 8 male) were studied. Twenty-one of these patients responded to radioiodine therapy, and 14 did not. NIS expression and iodine-131 uptake in residual tissues post-ablation I-131 whole body scan were not statistically significant. When we compared the patients who responded to radioiodine therapy and the poor responder group, NIS expression and iodine-131 uptake in residual tissues did not demonstrate statistically significant difference [(p = 0.308) (p = 0.985) respectively]. 47.6% of the patients in the successful ablation group and 85.7% in the unsuccessful ablation group had intracellular NIS immunostaining. The difference was not statistically significant (p = 0.139). 52.4% of the patients in the successful ablation group and 7% in the unsuccessful ablation group had NIS immunostaining at the basolateral membrane. The difference was statistically significant (p < 0.05). Conclusions: In conclusion, we did not find any significant difference between successful and unsuccessful ablation groups in terms of NIS expression; however, we concluded that the intracellular (cytoplasmic) localization of NIS is one of the leading causes of ablation failure regardless of NIS expression in DTC patients. [ABSTRACT FROM AUTHOR]

Shang Lin,1 Ya-ru Wei,2 Hong-xiang Yao3 1Department of Nuclear Medicine, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325002, People’s Republic of China; 2Department of Radiology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325002, People’s Republic of China; 3Department of Interventional Radiology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325002, People’s Republic of ChinaCorrespondence: Hong-xiang YaoDepartment of Interventional Radiology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, 325002, Zhejiang, People’s Republic of ChinaEmail lsyhx2004@163.comBackground: Hundreds of studies have reported the application of iodine-131 (I-131) in thyroid carcinoma (THCA) in past years. However, the status of research in the field and other related topics have not been investigated. This study aimed to identify the cooperation of authors, countries, and institutions, as well as explore the hot topics and prospects regarding I-131 therapy in THCA based on previous studies.Methods: Publications from 2010 to 2020 were retrieved from Web of Science Core Collection according to research strategy. Bibliometric analyses were performed using VOSviewer 1.6.15 and CiteSpace 5.7.3 to evaluate and visualize the cooperation network, hot topic, and research frontier.Results: The number of publications showed a trend of fluctuation between 2010 and 2020. We identified 1387 publications related to I-131 therapy in THCA, which were published by 1628 institutions from 82 countries. The largest proportion of publications were emanated from the USA, and the majority of papers were published by Thyroid. Shanghai Jiao Tong University of China contributed the most papers. Although many authors participated in the research of this field, high-yield authors were few. Co-occurrence analysis classified keywords into five clusters, including assessment, efficacy measurement, monitoring, hormone regulation, and guidelines of I-131 therapy. The terms “bone marrow dosimetry and time” were among the latest hotspots. The research frontier topic in I-131 therapy focused on the “P53 and anti-Müllerian hormone”.Conclusion: The attention to I-131 therapy in THCA should be increased considerably. It was necessary to construct active co-operations between authors, countries, and institutions to promote the development of this field. Recent researches referred to the timing and dose assessment of I-131 therapy in THCA. Future studies likely focused on targeted therapy and adverse effects evaluation were worthy of research as well.Keywords: I-131, thyroid carcinoma, bibliometric analysis, hot spots, research trend

PICO question In clinically hyperthyroid cats, is iodine-131 (I-131) treatment superior to unilateral or bilateral thyroidectomy in normalising serum thyroxine (T4) levels? Clinical bottom line Category of research question Treatment. The number and type of study designs reviewed 35 papers were critically reviewed. These were mostly retrospective studies with a small proportion of prospective cohort studies. Strength of evidence Moderate. Outcomes reported More papers were available evaluating the effect of radioiodine therapy on T4 levels compared to thyroidectomy. Long-term follow-up of T4 is a relatively new component of study designs. Most papers suggested between 40–87% cats had normal T4 6 months after treatment. 19–47% cats receiving unilateral or bilateral thyroidectomy, and 100% cats receiving radioiodine therapy were in long-term remission in one study. Conclusion In view of the evidence and outcomes from the studies, there is moderate evidence that I-131 treatment is superior to unilateral or bilateral thyroidectomy. How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources. Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.

Objective: Radioactive iodine (RAI) therapy is a useful treatment for Graves' disease (GD). Most RAI sessions administer ≤ 500 MBq of iodine (I)-131. Sometimes patients require repeated RAI, often for longer periods of remission. We investigated the characteristics of patients for whom high dose (mostly 1110 MBq of I-131) RAI was effective as RAI therapy for GD.Methods: We retrospectively analyzed the cases of 79 patients who underwent RAI for GD in a multicenter setting. We divided the patients into two groups based on the I-131 dose administered: the low dose (LD) group who received ≤ 500 MBq (n = 44) and the high dose (HD) group who received > 500 MBq (n = 35). The therapeutic effect was defined as achieving remission and reaching the point of participating in thyroid hormone replacement therapy within 1 year after RAI. We compared the LD and HD groups' remission rates and conducted a multivariate logistic regression analysis of predictive factors for remission. In a simulation, using the formula for predicting the probability of remission obtained from the analysis results, we estimated how much the remission rate would change if the I-131 dose is increased from 500 to 1110 MBq.Results: The mean ± standard deviation I-131 dose administered in the LD group was 480 ± 6 MBq, and that of the HD group was 1054 ± 265 MBq. Thirty-five patients (80%) in the LD group and 26 patients (74%) in the HD group achieved remission; this difference in the remission rate was not significant. The multivariate analysis results demonstrated that the absorbed dose and thyroid-stimulating antibody (TSAb) were independent predictors of remission. Seven patients (8.9%) showed an increased probability of remission from < 50% to > 50% when the higher RAI dose was applied (1110 MBq instead of 500 MBq). The thyroid volume and TSAb values in these patients were relatively large at 54.7 ± 34.2 mL and 1378.4 ± 586.3%, respectively.Conclusion: Although the overall remission rate was not significantly different between the patients who received high- or low-dose I-131, treatment with high-dose RAI may improve the probability of remission in patients with a massive thyroid volume and/or high-TSAb Graves' disease. [ABSTRACT FROM AUTHOR]

The systemic delivery of doxorubicin (DOX) to treat osteosarcoma requires an adequate drug concentration to be effective, but in doing so, it raises the risk of increasing organ off-target toxicity and developing drug resistance. Herein, this study reveals a multiple therapeutic nanocarrier delivery platform that overcomes off-target toxicity by providing good specificity and imparting enhanced tumor penetration in a three-dimensional (3D) human MG-63 spheroid model. By synthesizing PEG-PLGA nanoparticles by the double emulsion method, encapsulating DOX and Na131I in the inner core, and conjugating with an epidermal growth factor receptor (EGFR) antibody, it is intended to specifically target human MG-63 cells. The nanocarrier is biocompatible with blood and has good stability characteristics. Na131I encapsulation efficiency was >96%, and radiochemical purity was >96% over 96 h. A DOX encapsulation efficacy of ~80% was achieved, with a drug loading efficiency of ~3%, and a sustained DOX release over 5 days. The nanocarrier EGFR antibody achieved a ~80-fold greater targeting efficacy to MG-63 cells (EGFR+) than fibroblast cells (EGFR−). The targeted multiple therapeutic DIE-NPs have a higher penetration and uptake of Na131I to the 3D model and a ~3-fold higher cytotoxicity than the DOX monotherapy (D-NPs). The co-administration of DOX and Na131I (DIE-NPs) disrupts DNA repair and generates free radicals resulting in DNA damage, triggering the activation of apoptosis pathways. This leads to inhibition of MG-63 cell proliferation and promotes cell cycle arrest in the G0/G1 phase. Furthermore, the PEGylated anti-EGFR functionalized DIE-NPs were found to be biocompatible with red blood cells and to have no adverse effects. This anti-EGFR targeted multifunctional I-131 radio-nanotherapeutic signifies a customizable specific targeted treatment for osteosarcoma. [ABSTRACT FROM AUTHOR]

This case presents a pragmatic approach to the management of a radioiodine remnant ablation patient on hemodialysis which required no pretherapeutic dosimetric measurements. Pretreatment radiation dose modeling was performed using literature values for radioiodine hemodialysis extraction efficacies to determine a safe treatment regimen including adjustment of the administered activity and hemodialysis frequency. The pretreatment modeling was subsequently verified using external and blood radiation monitoring during treatment. [ABSTRACT FROM AUTHOR]

Hyperthyroidism and chronic kidney disease (CKD) are common diseases of geriatric cats, and often occur concurrently. Thus, a thorough understanding of the influence of thyroid function on renal function is of significant value for all feline practitioners. Among other effects, hyperthyroidism causes protein catabolism and increases renal blood flow and glomerular filtration rate (GFR). These effects render traditional renal markers insensitive for the detection of CKD in cats with uncontrolled hyperthyroidism. Furthermore, the development of iatrogenic hypothyroidism with over treatment of hyperthyroidism can be detrimental to renal function and may negatively affect long‐term survival. This review discusses important diagnostic considerations of feline hyperthyroidism, as well as key treatment modalities, with an emphasis on the use of radioiodine and the importance of post treatment monitoring of thyroid and renal parameters. In Australia, a common curative treatment for cats with benign hyperthyroidism (i.e. thyroid hyperplasia or adenoma) is a fixed dose of orally administered radioiodine, regardless of the serum total thyroxine concentration at the time of diagnosis. This review discusses the long term outcomes of this standard of care in comparison with current, relevant research literature from around the world. Finally, this review explores the use of symmetric dimethylarginine (SDMA) in assessing renal function before and after treatment in hyperthyroid cats. SDMA correlates well with GFR and creatinine in non‐hyperthyroid cats, but our understanding of its performance in hyperthyroid cats remains in its infancy. [ABSTRACT FROM AUTHOR]

Combination chemotherapy is still the standard clinical care for triple-negative breast cancer (TNBC). However, sodium iodide symporter (NIS) uptake by TNBC has opened the potential of NIS as a molecular target for radioiodine theranostic treatments. Radiolabeled poly(lactic-co-glycolic) acid nanocarrier (NINP) was developed for NIS targeted delivery of I-131 to MDA-MB-231 cells to overcome I-131 low uptake in cancer cells and rapid clearance. The NINP diameter of 237 nm has good particle size uniformity and excellent particle stability. Radiochemical purity, radioactive stability, and radiolabeling yield of NINPs over 72 h were >95%. Cytotoxicity confirmed fractionated NINPs over 72 h to be more effective in cell death than single-dose NINP and both single and fractionated Na131I. Cellular uptake in a three-dimensional spheroid confirmed that NINP fractionated-dose achieved ~4.8-fold-higher mean fluorescent intensity than Na131I and ~2.7-fold greater reduction in cell viability compared to single-dose. The NINP fractionated-dose initiated greater cellular DNA damage to cells than single-dose NINP, resulting in inhibition of cell cycle progression, resulting in cell cycle progression being inhibited by cyclin-dependent kinases, which play a vital role in the control of MDA-MB-231 cell cycle. NINPs are biocompatible with blood, and were found to have no negative impact on red blood cells.

Background: This study aims to demonstrate the superiority of Single Photon Emission Computed Tomography-Computed Tomography (SPECT-CT) over planar imaging in distinguishing benign from malignant foci and patient management after 131I ablation therapy in patients with differentiated thyroid cancer (DTC). Material and Methods: Planar and SPECT-CT imaging findings were retrospectively analyzed in Eighty patients who received I-131 therapy for thyroid cancer. Possible foci in whole body scanning (WBS), neck, and thorax were compared with SPECT-CT. Anatomical localization of the foci and differential diagnosis of the benign and malignant lesion was made with SPECT-CT. Those without anatomical counterparts were recorded as equivocal foci. According to the 2015 American Thyroid Association (ATA) guidelines, patients were divided into three groups: High, intermediate, and low-risk groups. Interpretation changes between both scannings were recorded as downstage and upstage. Results: A total of 80 patients, 53 female, and 27 male, were included in the study. The patients' age ranged from 21 to 88 years with a mean age of 47 ±14.2. In 80 patients, 139 foci were detected in planar images and SPECT-CT images (neck: 118, thorax: 21). SPECT-CT revealed that 50% of the lateral neck foci were compatible with pathologies of malignant nature and 50% with pathologies of benign nature. Foci in the middle part of the neck were not only thyroid remnant (56%) but also thyroglossal duct remnant (40%) foci at a significant rate. It was determined that 66% of the foci in the thorax region were lung metastases, and 34% were bone metastases. It was proved that 33% of the foci in the mediastinal area were lymph nodes. Although only one of the remaining patients had a pathological diagnosis, it was thought that all of them might have thymus pathologies. SPECT-CT images changed the interpretation of 18 patients (22.5%), 5 of whom (6.25%) were upstage and 13 (16.25%) were downstage. Conclusions: SPECT-CT will be very effective in, facilitating patient management and avoiding unnecessary procedures, especially in moderate/high-risk patients with suspicious focal lesions. Knowing the benign iodine uptake foci (thyroglossal duct remnant, etc.) that show iodine uptake other than the thyroid residue in the neck may be influential in deciding whether to ablate in low-risk patients. [ABSTRACT FROM AUTHOR]

Currently, breast-cancer treatment has a number of adverse side effects and is associated with poor rates of progression-free survival. Therefore, a radiolabeled anti-EpCAM targeted biomimetic coated nanocarrier (EINP) was developed in this study to overcome some of the treatment challenges. The double emulsion method synthesized the poly(lactic-co-glycolic acid) (PLGA) nanoparticle with Na131I entrapped in the core. The PLGA nanoparticle was coated in human red blood cell membranes and labeled with epithelial cell adhesion molecule (EpCAM) antibody to enable it to target EpCAM overexpression by breast-cancer cells. Characterization determined the EINP size as 295 nm, zeta potential as −35.9 mV, and polydispersity as 0.297. EINP radiochemical purity was >95%. Results determined the EINP efficacy against EpCAM positive MCF-7 breast cancer at 24, 48, and 72 h were 69.11%, 77.84%, and 74.6%, respectively, demonstrating that the EINPs achieved greater cytotoxic efficacy supported by NIS-mediated Na131I uptake than the non-targeted 131INPs and Na131I. In comparison, fibroblast (EpCAM negative) treated with EINPs had significantly lower cytotoxicity than Na131I and 131INPs (p < 0.05). Flow cytometry fluorescence imaging visually signified delivery by EINPs specifically to breast-cancer cells as a result of anti-EpCAM targeting. Additionally, the EINP had a favorable safety profile, as determined by hemolysis. [ABSTRACT FROM AUTHOR]

The thyroid biokinetic model of radioactive I-131 was re-evaluated using a refined nine-compartmental model and applied to twelve thyroid cancer patients. In contrast to the simplified four-compartmental model regulated by the ICRP-56 report, the revised model included nine compartments specified in the ICRP-128 report, namely, oral, stomach, body fluid, thyroid, whole body, liver, kidney, bladder, and remainder (i.e., the whole body minus kidney and bladder). A self-developed program run in MATLAB was designed to solve the nine first-order simultaneous linear differential equations. The model was realized in standard and simplified versions. The latter neglected two feedback paths (body fluid to oral, i31, and kidney to the whole body, i87) to reduce computations. Accordingly, the biological half-lives for the major compartments (thyroid and body fluid + whole body) were 36.00 ± 15.01, 15.04 ± 5.63, 34.33 ± 15.42, and 14.83 ± 5.91 of standard and simplified version. The correlations between theoretical and empirical data for each patient were quantified by the dimensionless AT (agreement) index and, the ATtot index integrated each individual AT of a specific organ of one patient. Since small AT values indicated a closer correlation, the obtained range of ATtot (0.048 ± 0.019) proved the standard model's reliability and high accuracy, while the simplified one yielded slightly higher ATtot (0.058 ± 0.023). The detailed outcomes among various compartments of twelve patients were calculated and compared with other researchers' work. The correlation results on radioactive I-131 evolution in thyroid cancer patients' bodies are instrumental in viewpoint of radioactive protection of patients and radiological personnel. [ABSTRACT FROM AUTHOR]

I-131 is an important artificial radionuclide and an important detection object in nuclear facilities. The current mainstream method is to use a uniformly distributed Ba-133 source instead of an iodine source to calibrate the I-131 detection instrument. However, in the process of value transmission, the distribution of the I-131 calibration standard source directly affects the setting value of the standard source and affects the calibration of the testing instrument. The plane source is used to determine the detection efficiency at different depths, and the depth efficiency curve is established. The fitting result is η(x)=0.007 655e-0.020 6x. Therefore, the activity efficiency equation of I-131 was established through mathematical analysis, and the positive and negative measurement results were used to solve it to determine its activity distribution. The distribution of the three I-131 sources is uniform distribution, exponential distribution and plane distribution. The deviation of exponential distribution source is between the deviation of the positive and negative measurement results of the uniform distribution source，which does not exceed 1%，and the deviation of the positive and negative measurement results of the planar distribution source，which exceeds 50%. By judging the quick solution of the source distribution, it is easy to prepare the calibration standard source and establish the on-site calibration process.

Background: Hyperthyroidism has been treated with radioiodine therapy for eight decades, with known benefits and side-effects. No consensus exists on which activity dosage and pre-therapeutic measurements are required for optimal treatment, balancing risk of incomplete response, therapy-induced hypothyroidism and radiation exposure. A retrospective analysis was performed to assess these questions. Methods: Data was collected on radioiodine treatment outcomes for 904 patients treated for Graves' disease or toxic nodular goitres at our institution during 2016–2020. The prescribed absorbed doses were 120 Gy (Graves' disease), 200 Gy (toxic multinodular goitre) and 300 Gy (solitary toxic adenoma). Univariate analysis and multivariate regression modelling were used to find factors linked to treatment outcome. Results: The cure rate of hyperthyroidism after one administration of radioiodine was 79% for Graves' disease, 94% for toxic multinodular goitre and 98% for solitary toxic adenoma. Thyroid mass, uptake and effective half-life were all significantly associated with cure in Graves' disease, but not in toxic multinodular goitre. The rates of therapy-induced hypothyroidism were 20% and 29% for toxic multinodular goitre and solitary toxic adenoma. Neither the cure rate nor the hypothyroidism rate was found to be superior among patients with individualised effective half-life measurements in toxic nodular goitres. Poor renal function was associated with dubious iodine uptake measurements but was not found to correlate with worse outcome. Conclusions: Multiple measurements of individual iodine uptake for kinetics estimation may be unnecessary, and a population-based value can be used instead. Patients with renal impairment had similar outcome as other patients, but with a higher risk of dubious uptake measurements. [ABSTRACT FROM AUTHOR]

After the Chernobyl accident, as in many countries, the short half-life I-131 radioactivity could not be measured in Turkey-Aegean Region. By using Cs-137 radioactivity, which is easy to monitor, I-131 radioactivity was tried to be predicted, but it was thought that the results obtained by these two radioisotopes because of their different chemical properties would not be correct. In this study I-129 was studied to predict the retrospective I-131 radioactivity. I-129, another iodine radioisotope, was thought to be more appropriate as a predictive agent because of the same chemical properties as I-131 and also its long half-life. I-129 was measured in the Bafa Lake sediments by using microwave digestion, extraction and AMS methods and retrospective I-131 activity was predicted. As a result, it was found that I-131 radioactivity values in Bafa Lake habitat is between 9.78x10-3 Bqkg-1 and 1.02x10-2 Bqkg-1 and the accuracy of the method used has been proved. [ABSTRACT FROM AUTHOR]

Abstract Background Serum symmetric dimethylarginine (SDMA) is a sensitive renal biomarker for detecting early chronic kidney disease (CKD) in nonhyperthyroid cats, but knowledge regarding its performance in hyperthyroid cats remains limited. Objectives To determine the relationship between serum SDMA, creatinine and total thyroxine (TT4) concentrations in hyperthyroid cats before (T0) and 3 months after (T1) receiving a PO fixed dose of radioiodine. Animals Eighty client‐owned hyperthyroid cats. Methods Prospective cohort study. Serum TT4, and SDMA, creatinine concentrations, and urine specific gravity were measured at T0 and T1. Nonparametric tests were used to determine the relationship among SDMA, and creatinine and TT4 concentrations. Agreement between SDMA and creatinine regarding CKD staging at both time points was assessed using Goodman and Kruskal's gamma statistic. Results Mean serum SDMA concentration increased after treatment of hyperthyroidism. However, 21 of 75 cats experienced a decrease in SDMA between T0 and T1, whereas creatinine decreased in only 2 cats. A moderate correlation between SDMA and creatinine was seen at T1 (r = 0.53; P < .001) but not at T0 (r = 0.13; P = .25). Where assessable at T1, poor agreement was observed between SDMA and creatinine and CKD stage (Goodman and Kruskal's gamma 0.20; P = .29). Conclusions and clinical importance Discordant outcomes between SDMA and creatinine after radioiodine treatment in cats with hyperthyroidism suggest extrarenal factors may interfere with the reliability of SDMA to adequately reflect renal function. As a result, SDMA should not be interpreted in isolation in hyperthyroid cats treated with radioiodine.

I-131 is a radioisotope widely used in nuclear medicine for the treatment of pathologies such as thyroid cancer or hyperthyroidism. When I-131 is ingested, it rapidly accumulates in the thyroid gland, emitting radiation that affects the targeted thyroid tissue while also impacting other organs. To ensure patients receive the appropriate dose for desired therapeutic outcomes while minimizing the risk of adverse effects, accurate estimations of absorbed doses after the treatment is crucial. This study focuses on evaluating organ doses following I-131 pill administration. It leverages the recent High-Resolution Anthropomorphic Computational Phantom distributed by the International Commission on Radiological Protection (ICRP), known as the Mesh Type Reference Computational Phantom. Additionally, a biokinetic analysis of iodine is conducted using a Matlab- developed tool based on the ICRP compartment model for oral iodine administration. Furthermore, Monte Carlo simulation techniques employing the MCNP6.2 code have been used to examine the radiation transport within the phantom at various time points. Consequently, the study provides dose data for each affected organ throughout the treatment, demonstrating the suitability of this simulation methodology for conducting dosimetric investigations in thyroid treatment. • The study provides dose data for each affected organ during the I-131 treatment. • MatLab developed tool analyzes iodine distribution with ICRP-based biokinetic model. • Monte Carlo simulations analyze patient fluence and dose distribution. • After I-131 ingestion, it accumulates in the thyroid, affecting other organs. • The Mesh Type Reference Computational Phantom (ICRP) is used as a patient. [ABSTRACT FROM AUTHOR]

• The bone marrow absorbed dose is required for personalising iodine treatment. • Bone marrow absorbed doses can be estimated by using the blood as a surrogate. • Blood withdrawal post I-131 therapy results in high radiation exposure to staff. • Finger-tip blood collection, as an alternative to venous-blood, was investigated. • An accurate radioactivity quantification was achieved in capillary-blood sampling. Collecting venous blood samples from patients post administration of high therapeutic activities results in radiation exposure to staff collecting the blood. This study investigated the use of finger-tip capillary-blood collection as an alternative to the venous-blood collection method recommended by the European Association of Nuclear Medicine (EANM) dosimetry protocol for quantifying 131I concentration in the critical organ after therapeutic dose of 131I. The study included differentiated thyroid cancer patients referred to a thyroid cancer centre at St James's Hospital, Ireland, for therapeutic and diagnostic oral administration of 131I. The 15 patients recruited for this study provided 30 venous and capillary paired-blood samples. The activity concentration of the blood samples was compared between the type of blood (venous vs capillary) and the geometry/volume of the blood (1.0 ml versus 0.03 ml). Other variables were also investigated including administered activities, dose to staff performing the sampling, duration of sampling and time since administration. Blood samples were taken at 2.0–91.9 h post administration using 0.2 ± 0.0 GBq (n = 2) or 4.0 ± 0.1 GBq (n = 28) 131I activities. There was no significant difference found between different blood sampling types (−1.0 ± 4.3 %, p = 0.223), different blood volumes (−3.2 ± 10.0 %, p = 0.070), or between their combination. No significant correlation was found between the percentage differences and investigated parameters. A high degree of accuracy was achieved with blood radioactivity quantified using capillary blood collection using the finger-prick method. Further validation of the method would be required prior to implementation, to investigate patient specific factors which may affect accuracy. [ABSTRACT FROM AUTHOR]

Introduction: Nuclear accidents release large quantities of radioactive materials into the environment. Iodine-131 and cesium-137 are two radionuclides released during nuclear accident, which can pose the greatest cancer risks. These radionuclides can be moved to other areas through rain and wind. The aim of this study was to develop efficient and economical biological methods for the absorption of water-soluble radionuclides released after a nuclear accident. Material and Methods: The exposure of the algae to an aqueous solution of I-131 radionuclide was performed for 1, 2, and 3 h. The concentration activities of the samples were 27 μCi/ml and 270 μCi/ml. After the removal of the alga by centrifuging, the activities of the sample solutions were measured using a calibrated dose calibrator. The measured activities at the mentioned periods of time were statistically significant for both groups (P Results: The obtained results of the current study revealed that the activity of radioiodine-131 decreased 1, 2, and 3 h after adding algae, compared to the control group at the same time (21.8, 32.33, 39.84 for 27 μCi/ml and 15.38, 21.53, and 30% for 270 μCi/ml, respectively). Furthermore, radioactive iodine is absorbed very well with this type of algae. Conclusion: It can be concluded that Dunaliella salina can be used for the decontamination of radioiodine. This method can play a significant role in the decontamination of hazardous radioiodine after nuclear accidents.

Objective: Recombinant human TSH (rhTSH) is commonly used to prepare patients for postoperative radioiodine (I‐131) ablation after surgery for differentiated thyroid cancer (DTC). In adults, rhTSH is associated with equivalent oncologic efficacy in comparison to thyroid hormone withdrawal (THW), but its use has not been well studied in children. We aimed to measure time to disease progression after rhTSH stimulation vs. THW in paediatric patients under the age of 21 with DTC following total thyroidectomy. Design: Retrospective cohort study (March 2001–July 2018). Patients: Sixteen children and adolescents (75% female, median age, 17.4 years) who received rhTSH were compared to 29 historical controls (72% female, median age, 18.5 years) prepared with THW, followed for a median of 2.4 years (range, 0.5–14). Measurements: Stimulated serum TSH concentrations prior to I‐131 ablation and time to disease progression, as determined by a component outcome variable encompassing both structural and biochemical disease persistence/recurrence. Results: No differences were observed in tumour characteristics and I‐131 dose (median 2.3 [1.8–2.90] mCi/kg rhTSH) between groups. Patients who received rhTSH achieved a similar median stimulated TSH level (163 [127–184] mU/L), compared to those who underwent THW (136 [94.5–197] mU/L; p =.20). Both groups exhibited similar time to progression (p =.13) and disease persistence/recurrence rates (rhTSH 31% vs. THW 59%, p =.14). Conclusion: In this cohort of children and adolescents with DTC, we observed similar time to disease progression among those who received rhTSH or underwent THW prior to postoperative I‐131 ablation. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to predict the dose absorbed by normal organs with neuroendocrine tumors for 131I using single photon emission computed tomography/computed tomography (SPECT/CT) images and Geant4 application for tomographic emission (GATE) simulation. Materials and Methods: Four to 5 whole-body planar scan series, along with one SPECT/CT image, were taken from four patients following 99mTc-hynic-Tyr3-octreotide radiotracer injection. After image quantification, the residence time of each organ was calculated using the image analysis and the activity time curves. The energy deposit and dose conversion (S-value) were extracted from the GATE simulation for the target organs of each patient. Using the residence times and S-values, the mean absorbed dose for the target organs of each patient was calculated and compared with the data obtained from the standard method. Results: Very close agreement was obtained between the S-value of the self-organ irradiation. The mean percentage difference between the two methods (i.e. GATE and Medical Internal Radiation Dose [MIRD]) was 1.8%, while a weak agreement was observed for cross-organ irradiation. The percentage difference between the total absorbed doses by the organs was 2%. The percentage difference between the absorbed doses obtained for tumors and three considered normal organs estimated by the GATE method was slightly higher than the MIRD method (about 11% on average for tumors). Conclusion: Regardless of the small difference between the obtained results for the organs and absorbed doses of the tumors in the present study, patient-specific dosimetry by the GATE methods is useful and essential for therapeutic radionuclides such as 131I due to high cross-dose effects, especially for young adult patients, to ensure the radiation safety and increase the effectiveness of the treatment. [ABSTRACT FROM AUTHOR]

The thyroid biokinetic model of radioactive I-131 was re-evaluated using a refined nine-compartmental model and applied to twelve thyroid cancer patients. In contrast to the simplified four-compartmental model regulated by the ICRP-56 report, the revised model included nine compartments specified in the ICRP-128 report, namely, oral, stomach, body fluid, thyroid, whole body, liver, kidney, bladder, and remainder (i.e., the whole body minus kidney and bladder). A self-developed program run in MATLAB was designed to solve the nine first-order simultaneous linear differential equations. The model was realized in standard and simplified versions. The latter neglected two feedback paths (body fluid to oral, i31, and kidney to the whole body, i87) to reduce computations. Accordingly, the biological half-lives for the major compartments (thyroid and body fluid + whole body) were 36.00 ± 15.01, 15.04 ± 5.63, 34.33 ± 15.42, and 14.83 ± 5.91 of standard and simplified version. The correlations between theoretical and empirical data for each patient were quantified by the dimensionless AT (agreement) index and, the ATtot index integrated each individual AT of a specific organ of one patient. Since small AT values indicated a closer correlation, the obtained range of ATtot (0.048 ± 0.019) proved the standard model’s reliability and high accuracy, while the simplified one yielded slightly higher ATtot (0.058 ± 0.023). The detailed outcomes among various compartments of twelve patients were calculated and compared with other researchers’ work. The correlation results on radioactive I-131 evolution in thyroid cancer patients’ bodies are instrumental in viewpoint of radioactive protection of patients and radiological personnel.

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Background: Serum symmetric dimethylarginine (SDMA) is a sensitive renal biomarker for detecting early chronic kidney disease (CKD) in nonhyperthyroid cats, but knowledge regarding its performance in hyperthyroid cats remains limited. Objectives: To determine the relationship between serum SDMA, creatinine and total thyroxine (TT4) concentrations in hyperthyroid cats before (T0) and 3 months after (T1) receiving a PO fixed dose of radioiodine. Animals Eighty client‐owned hyperthyroid cats. Methods: Prospective cohort study. Serum TT4, and SDMA, creatinine concentrations, and urine specific gravity were measured at T0 and T1. Nonparametric tests were used to determine the relationship among SDMA, and creatinine and TT4 concentrations. Agreement between SDMA and creatinine regarding CKD staging at both time points was assessed using Goodman and Kruskal's gamma statistic. Results: Mean serum SDMA concentration increased after treatment of hyperthyroidism. However, 21 of 75 cats experienced a decrease in SDMA between T0 and T1, whereas creatinine decreased in only 2 cats. A moderate correlation between SDMA and creatinine was seen at T1 (r = 0.53; P <.001) but not at T0 (r = 0.13; P =.25). Where assessable at T1, poor agreement was observed between SDMA and creatinine and CKD stage (Goodman and Kruskal's gamma 0.20; P =.29). Conclusions and clinical importance: Discordant outcomes between SDMA and creatinine after radioiodine treatment in cats with hyperthyroidism suggest extrarenal factors may interfere with the reliability of SDMA to adequately reflect renal function. As a result, SDMA should not be interpreted in isolation in hyperthyroid cats treated with radioiodine. [ABSTRACT FROM AUTHOR]

Mushroom poisonings caused by Amanita phalloides are the leading cause of mushroom-related deaths worldwide. Alpha-Amanitin (α-AMA), a toxic substance present in these mushrooms, is responsible for the resulting hepatotoxicity and nephrotoxicity. The objective of our study was to determine the distribution of α-AMA in Balb/c mice by labeling with Iodine-131. Mice were injected with a toxic dose (1.4 mg/kg) of α-AMA labeled with Iodine-131. The mice were sacrificed at the 1st, 2nd, 4th, 8th, 24th, and 48th hours under anesthesia. The organs of the mice were removed, and their biodistribution was assessed in all experiments. The percent injected dose per gram (ID/g %) value for kidney, liver, lung, and heart tissues at 1st hour were 1.59 ± 0.07, 1.25 ± 0.33, 3.67 ± 0.80 and 1.07 ± 0.01 respectively. This study provides insights into the potential long-term effects of α-AMA accumulation in specific organs. Additionally, this study has generated essential data that can be used to demonstrate the impact of antidotes on the biological distribution of α-AMA in future toxicity models. [Display omitted] • Alpha-Amanitin toxin was radiolabeled with I-131 with high labeling yield. • Radiolabeled alpha-amanitin was injected into mice at a toxic dose. • It was mostly distributed in tissues within the first 4 h after injection. • Biodistribution of a toxic dose of α-AMA in mice was determined. [ABSTRACT FROM AUTHOR]

The radioisotope production facility at PUSPIPTEK Serpong produces and processes 131I that can disperse to the settlements (community) and the environment around the Serpong Nuclear Area (SNA). 131I is produced routinely for medical uses in hospitals and pharmacies, for both domestic uses and export. 131I is a beta and gamma emitting radioactive material and can cause thyroid cancer. The problem was that there was so far no research and in-depth assessment of the aerial dispersion of 131I radioactivity emitted from the radioisotope production stack to the environment at actual conditions. The research was conducted through simultaneous measurement of 131I radioactivity in the stack of the 131I radioisotope production facility, Serpong, and outdoor in house courtyards around SNA in normal condition (no accident) based on the variations of the distance and wind direction. Direct measurements were carried out with a portable in-situ NaI(Tl) detector at outdoor, and with a LaBr3 detector in the stack. Indirect measurements were carried out by using charcoal filter and vacuum pump in the stack and outdoor. The direct measurement method has many advantages over the indirect measurement. The direct measurement method was found to be more accurate, less expensive, easier to operate, needing just one operator in its implementation, portable, and can be operated continuously and for long durations. The overall activity concentrations of 131I on average obtained by either direct or indirect method were still below the upper limit of 131I activity concentration in the air (530 Bq/m3) stipulated by the Regulation of the Chairman of BAPETEN (Perka BAPETEN) No. 7/2013.

Abstract Background Struma ovarii is a rare monodermal germ cell tumor where the ovary is comprised of at least half thyroid tissue. This phenomenon may indicate an embryological origin. Case presentation A 30-year old nulliparous woman presented with acute right lower quadrant pain and underwent laparoscopic right salpingo-oophorectomy. The excised ovarian mass showed evidence of struma-derived papillary thyroid carcinoma. Ultrasound of the thyroid showed mild enlargement with two solid nodules. A fine needle aspirate of a thyroid nodule was positive for malignancy and a total thyroidectomy was performed. Microscopic features of the thyroid were consistent with papillary thyroid carcinoma. The two tumours were considered as synchronous independent primaries based on their histological presentation. Conclusions We believe that aggressive surgical management followed by radioiodine therapy is best to reduce recurrence risk and optimize survival. The broad scope of interventions needed to treat malignant struma ovarii require a strong interdisciplinary team.