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Background/Objectives: The management of differentiated thyroid cancer (DTC) patients has undergone a major paradigm shift in past years, especially regarding the role of a careful postoperative disease assessment both in deciding for or against the use of iodine-131 therapy (i.e., patients' selection) and in selecting the correct goal of the treatment: ablative, adjuvant or therapeutic. Furthermore, diagnostic and risk-oriented uses of iodine isotopes (i.e., 123/124/131I) should always be considered during both postoperative assessment and follow-up of DTC patients to improve early staging and response assessment to initial treatments, respectively. The present review summarizes current (and real-life-related) evidence and the emerging perspectives on the therapeutic, diagnostic, and theragnostic use of radioiodine isotopes. Methods: A review of the pertinent literature was performed in PubMed, Web of Science, and Scopus without language restrictions or time limits and using one or more fitting search criteria and terms. Results: According to the literature evidence and real-life clinical practice, a risk-oriented postoperative iodine-131 therapy remains pivotal for most DTC patients and improves early disease staging through post-therapy functional imaging (i.e., theragnostic aim). Accordingly, the goal of iodine-131 therapy, the optimal strategy (empiric vs. dosimetric approach), the appropriate stimulation method [i.e., levothyroxine (L-T4) withdrawal vs. recombinant human thyrotropin (rhTSH) administration] and, finally, the suggested radioiodine activity to deliver for iodine-131 therapy (RIT) should be personalized, especially in metastatic DTC patients. Conclusions: The evidence related to the diagnostic and theragnostic use of iodine isotopes leads to a significant improvement in the postoperative risk stratification and staging of DTC patients in addition to a more accurate assessment of the response to initial treatments. In conclusion, radioiodine is really an oldie but goldie radiotracer. It has both a current fundamental role and a future perspective for the more careful management of DTC patients. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to evaluate the clinical value of iodine-131 combined with levothyroxine sodium in the treatment of patients with differentiated thyroid cancer (DTC) after surgery. Methods: Prospective randomized controlled studies were conducted. A total of 374 DTC patients who underwent total or near-total thyroidectomy in the Department of Thyroid Surgery, Tianjin Union Medical Center and Tianjin Medical University General Hospital, from January 2019 to February 2022 were selected and divided into control group (187 cases) and observation group (187 cases) according to random number table method. The control group was treated with levothyroxine sodium after surgery, and the observation group was treated with iodine-131 on the basis of the control group. Gender, age, course of disease, tumor diameter, pathological type, TNM classification, treatment effect, thyroglobulin (Tg) levels before and after treatment, SF-36 health status questionnaires (SF-36), occurrence of adverse reactions after treatment, and recurrence rate of 1-year follow-up were compared and analyzed between the two groups. Results: There was no significant difference in baseline data between the two groups. After treatment, the effective rate of the observation group increased by 11.23% compared to the control group, with a statistically significant difference (91.98% vs. 80.75%, p < 0.05). There was no significant difference in Tg level and scores of SF-36 evaluation including physical functioning, physical problems, vitality, pain, mental health, emotional problems, social functioning, and general health perception between the two groups before surgery (p > 0.05), Tg levels and scores of SF-36 evaluation in all dimensions were significantly improved in both groups after treatment (p < 0.05), and the levels of Tg and scores of SF-36 in all dimensions in observation group were significantly better than those in control group after treatment (p < 0.001). There was no significant difference in the incidence of adverse reactions between the two groups (p > 0.05). The recurrence rate in the observation group was 5.89% lower than that in the control group 1 year after treatment, with a statistically significant difference (2.67% vs. 8.56%, p < 0.05). Conclusions: The combination of iodine-131 and levothyroxine sodium in the postoperative treatment of DTC can improve the therapeutic effect and reduce the postoperative recurrence rate without increasing adverse reactions, which is worthy of clinical reference and promotion. [ABSTRACT FROM AUTHOR]

Background/Objectives: Disease recurrence and resistance to radioiodine (RAI) therapy are major challenges in the management of differentiated thyroid cancer (DTC). In particular, the TENIS (Thyroglobulin Elevated Negative Iodine Scintigraphy) syndrome, characterised by elevated thyroglobulin (Tg) serum levels in addition to a negative radioiodine whole body scan (WBS), complicates disease monitoring and treatment decisions. Conventional imaging techniques often fail to detect disease in WBS-negative patients with rising Tg levels, leading to limitations in therapeutic intervention. This systematic review and meta-analysis aims to evaluate the diagnostic accuracy of nuclear imaging modalities in detecting disease recurrence in patients with the TENIS syndrome and to provide insights to guide therapeutic approaches in this complex clinical scenario. Methods: A comprehensive search of PubMed/MEDLINE and EMBASE databases up to March 2024 was performed according to PRISMA guidelines. Eligible studies were selected, and quality assessment was performed with the QUADAS-2 tool. For each study, relevant data were extracted and synthesised. A meta-analysis of the diagnostic accuracy of [18F]FDG PET/CT was performed, and patient-based pooled sensitivity and specificity were calculated using a random-effects model. Statistical heterogeneity between studies was assessed using the I2 statistic. Results: Of the 538 studies initially identified, 22 were included in the systematic review, of which 18 were eligible for meta-analysis. The eligible studies, mainly focused on [18F]FDG PET/CT, showed variable sensitivity and specificity for the detection of RAI-refractory thyroid cancer lesions. For [18F]FDG PET/CT, pooled estimates displayed a sensitivity of 0.87 (95% CI: 0.82–0.90) and a specificity of 0.76 (95% CI: 0.61–0.86), with moderate heterogeneity between studies. Conclusions: [18F]FDG PET/CT remains central in the detection of disease recurrence in patients with the TENIS syndrome. The emergence of novel radiopharmaceuticals with specific molecular targets is a promising way to overcome the limitations of [18F]FDG in these patients and to open new theranostics perspectives. This review highlights the great potential of nuclear medicine in guiding therapeutic strategies for RAI-refractory thyroid cancer. [ABSTRACT FROM AUTHOR]

Meilin Zhu,1 Lingzhou Zhao,2 Xia Lu2 1School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia, 750004, People’s Republic of China; 2Department of Nuclear Medicine, Northern Jiangsu People’s Hospital, Clinical Medical College, Yangzhou University, Yangzhou, 225001, People’s Republic of ChinaCorrespondence: Xia Lu, Department of Nuclear Medicine, Northern Jiangsu People’s Hospital, Clinical Medical College, Yangzhou University, Yangzhou, 225001, People’s Republic of China, Tel +86 18051061486, Email lxgf2222@163.comPurpose: Gold nanoparticles (Au NPs) are widely used as versatile templates to develop multifunctional nanosystems for disease diagnosis and treatment. Iodine can bind to gold via chemisorption, making this a simple method for labeling Au NPs with radioactive iodine. However, the evaluation of tumor radionuclide therapy is insufficient. In this study, we investigated the feasibility of 131I-adsorbed Au NPs as novel nanoprobes for tumor radionuclide therapy.Materials and Methods: Radiolabeling was performed by mixing Au NPs and 131I, and the radiochemical purity (RCP) and in vitro stability of 131I-adsorbed Au NPs were analyzed under different conditions, including various temperatures, pH values, and 131I concentrations. The tumor accumulation and therapeutic potential of 131I-adsorbed Au NPs were assessed using a subcutaneous tumor model after intratumoral injection.Results: The data showed that the chemisorption of the Au NPs onto 131I was instant, specific, and quantitative. The 131I-adsorbed Au NPs exhibited high in vitro stability in different media, distinct inhibitory effects on tumor cells in vitro, good retention ability, and therapeutic effects after intratumoral injection into tumor-bearing mice in vivo.Conclusion: Our work demonstrates that chemisorption of Au NPs and radioiodine has great potential as a strategy for constructing various nanosystems for theranostic applications.Keywords: gold nanoparticles, iodine-131, chemisorption, radionuclide therapy

To investigate the impact of the recently released pediatric reference voxel phantoms (0-, 1-, 5-, 10-, 15-year-old males and females) of the International Commission on Radiological Protection (ICRP) on organ dose estimates for radioactive iodine (RAI) treatment in pediatric patients, we calculated and analyzed pediatric-specific iodine-131 S values (rT ← thyroid) for the 30 radiosensitive organs by conducting Monte Carlo simulations using the Geant4. The gender dependency in the S values was frequently seen for the 15-year-old phantoms with higher S values of female than male. In addition, the age dependency in the S values was observed for most target organs; that is, the S values tend to decrease for older ages (e.g., ∼120 times for the gonads between the adult and newborn) due mainly to the inter-organ distances generally longer for older ages. Moreover, we observed that the iodine-131 S values tend to be significantly greater by up to ∼145.5 times than those of the stylized phantoms that have been widely used for organ dose estimates of pediatric RAI patients. We believe that the pediatric-specific iodine-131 S values (rT ← thyroid) of the ICRP pediatric reference voxel phantoms should be beneficial to improve the dosimetry of pediatric RAI patients.

Background: With recent interest in patient‐specific dosimetry for radiopharmaceutical therapy (RPT) and selective internal radiation therapy (SIRT), an increasing number of voxel‐based algorithms are being evaluated. Monte Carlo (MC) radiation transport, generally considered to be the most accurate among different methods for voxel‐level absorbed dose estimation, can be computationally inefficient for routine clinical use. Purpose: This work demonstrates a recently implemented grid‐based linear Boltzmann transport equation (LBTE) solver for fast and accurate voxel‐based dosimetry in RPT and SIRT and benchmarks it against MC. Methods: A deterministic LBTE solver (Acuros MRT) was implemented within a commercial RPT dosimetry package (Velocity 4.1). The LBTE is directly discretized using an adaptive mesh refined grid and then the coupled photon‐electron radiation transport is iteratively solved inside specified volumes to estimate radiation doses from both photons and charged particles in heterogeneous media. To evaluate the performance of the LBTE solver for RPT and SIRT applications, 177Lu SPECT/CT, 90Y PET/CT, and 131I SPECT/CT images of phantoms and patients were used. Multiple lesions (2–1052 mL) and normal organs were delineated for each study. Voxel dosimetry was performed with the LBTE solver, dose voxel kernel (DVK) convolution with density correction, and a validated in‐house MC code using the same time‐integrated activity and density maps as input to the different dose engines. The resulting dose maps, difference maps, and dose‐volume‐histogram (DVH) metrics were compared, to assess the voxel‐level agreement. Evaluation of mean absorbed dose included comparison with structure‐level estimates from OLINDA. Results: In the phantom inserts/compartments, the LBTE solver versus MC and DVK convolution demonstrated good agreement with mean absorbed dose and DVH metrics agreeing to within 5% except for the D90 and D70 metrics of a very low activity concentration insert of 90Y where the agreement was within 15%. In the patient studies (five patients imaged after 177Lu DOTATATE RPT, five after 90Y SIRT, and two after 131I radioimmunotherapy), in general, there was better agreement between the LBTE solver and MC than between LBTE solver and DVK convolution for mean absorbed dose and voxel‐level evaluations. Across all patients for all three radionuclides, for soft tissue structures (kidney, liver, lesions), the mean absorbed dose estimates from the LBTE solver were in good agreement with those from MC (median difference < 1%, maximum 9%) and those from DVK (median difference < 5%, maximum 9%). The LBTE and OLINDA estimates for mean absorbed dose in kidneys and liver agreed to within 10%, but differences for lesions were larger with a maximum 14% for 177Lu, 23% for 90Y, and 26% for 131I. For bone regions, the agreement in mean absorbed doses between LBTE and both MC and DVK were similar (median < 11%, max 11%) while for lung the agreement between LBTE and MC (median < 1%, max 8%) was substantially better than between LBTE and DVK (median < 16%, max 33%). Voxel level estimates for soft tissue structures also showed good agreement between the LBTE solver and both MC and DVK with a median difference < 5% (maximum < 13%) for the DVH metrics with all three radionuclides. The largest difference in DVH metrics was for the D90 and D70 metric in lung and bone where the uptake was low. Here, the difference between LBTE and MC had a median value < 14% (maximum 23%) for bone and < 4% (maximum 37%) for lung, while the corresponding differences between LBTE and DVK were < 23% (maximum 31%) and < 67% (maximum 313%), respectively. For a typical patient with a matrix size of 166 × 166 × 129 (voxel size 3 × 3 × 3 mm3), voxel dosimetry using the LBTE solver was as fast as ∼2 min on a desktop computer. Conclusion: Having established good agreement between the LBTE solver and MC for RPT and SIRT applications, the LBTE solver is a viable option for voxel dosimetry that can be faster than MC. Further analysis is being performed to encompass the broad range of radionuclides and conditions encountered clinically. [ABSTRACT FROM AUTHOR]

Personalised dosimetry based on molecular imaging is a field that has grown exponentially in the last decade due to the increasing success of Radioligand Therapy (RLT). Despite advances in imaging-based 3D dose estimation, the administered dose of a therapeutic radiopharmaceutical for RLT is often nonpersonalised, with standardised dose regimens administered every 4–6 weeks. Biodosimetry markers, such as chromosomal aberrations, could be used alongside image-based dosimetry as a tool for individualised dose estimation to further understand normal tissue toxicity and refine the administered dose. In this review we give an overview of biodosimetry markers that are used for blood dose estimation, followed by an overview of their current results when applied in RLT patients. Finally, an in-depth discussion will provide a perspective on the potential for the use of biodosimetry in the nuclear medicine clinic. [ABSTRACT FROM AUTHOR]

The current effort in environmental remediation is aimed at removing iodine-131 radionuclide from radioactive liquid waste produced by an Egyptian nuclear power plant using some synthesised alginate derivatives. Two different copolymers, namely sodium alginate poly (acrylic acid) (P1) and sodium alginate poly (acrylic acid-methacrylic acid) (P2), are prepared using gamma radiation. The ability of these polymers to remove 131I radionuclide as sorbents has been investigated. The synthesised polymers exhibit excellent adsorption performance for 131I ions, and the adsorption equilibrium requires only 30 min, which reveals that the sorption process is kinetically faster than most of the other materials reported previously. The removal percents for 131I radionuclide at a pH of 3.0 at room temperature on P1 and P2 are 77.7% and 84.2%, respectively. The sorption capacities of the two polymers demonstrate that P2 > P1, with capacities of 67.9 and 58.5 mg/g, respectively. Four linear kinetic models are investigated: pseudo-first order, pseudo-second order, Elovich, and Weber–Morris models. Regarding their calculated parameters, these models indicate that the adsorption process of I-ions on both P1 and P2 is controlled by chemisorption. Four equilibrium isotherm models (Redlich-Peterson, Langmuir, Freundlich, and Harkin-Jura) are investigated, revealing that the adsorption process is a monolayer and multilayer process on a heterogeneous surface. [ABSTRACT FROM AUTHOR]

Hyperthyroidism, characterized by elevated thyroid hormone levels and thyroid gland hyperplasia or adenoma, is a prevalent endocrinopathy in older cats. Treatment options include antithyroid drugs, surgical thyroidectomy, and radioiodine therapy (RAIT), which is non-invasive treatment option that can achieve complete remission. However, efficacy and safety of RAIT in hyperthyroid cats have not been investigated in South Korea. This study includes 10 hyperthyroid cats with RAIT. Initial assessments comprised history, physical examination, blood analysis, and serum total T4 (tT4) concentration. Thyroid scintigraphy revealed hyperactivity and enlargement of thyroid gland at 24 hours before the RAIT. Radioiodine (RAI) was injected subcutaneously with 2 to 6 mCi, determined by the fixed dose or the scoring system based on severity of clinical signs, tT4 concentration, and thyroid size individually. After RAIT, the concentration of serum tT4 and liver enzymes were significantly decreased at discharge. However, no significant differences were noted in blood urea nitrogen, creatinine, symmetric dimethylarginine, hematocrits, and white blood cell counts pre- and post-treatment. Although 4 cats received RAI twice, clinical signs disappeared and tT4 levels decreased following the RAIT. All 10 cats achieved complete remission after 6 months without critical adverse effect. The safety and the effectiveness of RAIT was confirmed based on protocols reported other countries. Therefore, RAIT could be considered the treatment option and prevent adverse effects from medication or surgery. This preliminary study presents the first evaluation of RAIT for hyperthyroid cats using locally produced RAI in South Korea and provide valuable insight for clinicians and further studies. [ABSTRACT FROM AUTHOR]

Incidental findings in the post-treatment whole body iodine scan (WBIS) sometimes have a broad list of differentials. We present a case of differentiated thyroid carcinoma (DTC), pT3aN1b, with family history of DTC. She was treated with adjuvant 131I therapy (5.55 GBq). The patient's post-treatment WBIS revealed a large, round iodine-avid area above the bladder, which was attributed to a massive uterine fibroid. Physical examination as well as radiologic correlation with SPECT/CT were also concordant. Fibroids can trap the radioiodine by various mechanisms. This case serves as a reminder of an uncommon pitfall in WBIS, particularly in women of reproductive age. [ABSTRACT FROM AUTHOR]

Iodine nutrition plays a central role in the normal physiological function of the thyroid gland, and it is a major factor in thyroid hormone synthesis. A meta-analysis was used to measure the efficacy of oral iodine-131 combined with nutritional management in thyroid cancer patients after surgery. Computer searches were conducted on various databases, with the search time limited to January 2011 to December 2021, and the literature retrieved was limited to randomized controlled trials. Data extraction and quality evaluation were performed for the included literature, and meta-analysis was conducted by RevMan 5.3 software. A total of 9 literatures were obtained, all in English, with a sample size of 10,219 cases, containing 6,845 cases in the study group (oral iodine-131 + nutritional management) together with 3,374 cases in the control group (oral iodine-131 alone). The study group received oral administration of iodine-131 and nutritional management (low-iodine diet). The outcomes of the meta-analysis revealed that the clinical symptoms of thyroid cancer patients were improved after oral administration of iodine-131 after surgery. No statistical differences could be observed in the incidence of adverse reactions, recurrence rate, or metastasis rate of outcome indicators. To sum up, oral administration of iodine-131 combined with nutritional management has certain clinical effects in patients with thyroid cancer after surgery, but due to the limited literature included and low data quality, the conclusions of this study still need to be further verified. [ABSTRACT FROM AUTHOR]

Purpose: The effectiveness of iodine-131(131I) therapy in patients with papillary thyroid cancer (PTC) of various stage is controversial. This study aimed to use prognostic risk groups to guide 131I therapy in patients with PTC after radical thyroidectomy. Methods: Data of 53,484 patients with PTC after radical thyroidectomy were collected from the Epidemiology and End Results (SEER) database. Patients were divided into subgroups according to MACIS system and regional lymph node involvement. The prognostic role of 131I therapy was investigated by comparing Kaplan–Meier survival analysis and Cox proportional hazard models in different subgroups. Results: Sex, age, tumor size, invasion, regional lymph node involvement, and distant metastasis was related to the survival of patients with PTC. If MACIS < 7, 131I treatment didn't affect the cancer-specific survival (CSS) rate. If MACIS ≥ 7, 131I therapy didn't work on CSS rate for patients with N0 or N1a < 5 status; 131I therapy had improved CSS rate for patients in the N1a ≥ 5 or N1b status. If patients with distant metastasis, invasion, or large tumor, 131I therapy didn't improve CSS rate for patients in N0 or N1a < 5 stage. Conclusion: After radical thyroidectomy, if MACIS < 7, patients with PTC could avoid 131I therapy. If MACIS ≥ 7, patients in the N0 or N1a < 5 could avoid 131I therapy; those in the N1a ≥ 5 or N1b stage should be given 131I therapy. Among them, all patients with distant metastasis should be given 131I therapy. [ABSTRACT FROM AUTHOR]

Abstracts: Hyperthyroidism, often accompanied by hepatic insufficiency (HI), poses significant clinical challenges, highlighting the necessity for identifying optimal treatment strategies and early diagnostic biomarkers to improve patient outcomes. This study aimed to determine the optimal iodine-131 (131I) intervention dose for alleviating hyperthyroidism with HI and to identify serum metabolic biomarkers for early diagnosis using UPLC-Q/TOF-MS technology. A mouse model for early 131I intervention was established to monitor changes in physiological response, body weight, fur condition, thyroid, and liver function. Metabolite identification was achieved through UPLC-Q/TOF-MS and further analyzed via MetaboAnalyst. Six biomarkers were identified and subjected to ROC analysis. Early intervention with 80 μCi 131I per gram of thyroid tissue effectively controlled hyperthyroidism and improved liver function. Metabolomics analysis uncovered 63 differentially abundant metabolites, six of which (L-kynurenine, Taurochenodesoxycholic acid, Glycocholic acid, Phytosphingosine, Tryptamine, and Betaine) were identified as early warning biomarkers. Post-intervention, these biomarkers progressively returned to normal levels. This study demonstrates the efficacy of UPLC-Q/TOF-MS in identifying metabolic biomarkers for early diagnosis of hyperthyroidism with HI and highlights the therapeutic potential of early 131I intervention in normalizing these biomarkers.

Neuroblastoma is the most frequently diagnosed cancer during the first year of life. This neoplasm originates from neural crest cells derived from the sympathetic nervous system, adrenal medulla, or paraspinal ganglia. The clinical presentation can vary from an asymptomatic mass to symptoms resulting from local invasion and/or spread of distant disease spread. The natural history of neuroblastoma is highly variable, ranging from relatively indolent biological behavior to a high-risk clinical phenotype with a dismal prognosis. Age, stage, and biological features are important prognostic risk stratification and treatment assignment prognostic factors. The multimodal therapy approach includes myeloablative chemotherapy, radiotherapy, immunotherapy, and aggressive surgical resection. Hyperbaric oxygen therapy (HBOT) has been proposed as a complementary measure to overcome tumor hypoxia, which is considered one of the hallmarks of this cancer treatment resistance. This article aims to review the relevant literature on the neuroblastoma pathophysiology, clinical presentation, and different biological and genetic profiles, and to discuss its management, focusing on HBOT. [ABSTRACT FROM AUTHOR]

Abstract The optimization of the radiolabeling yield of carvedilol with iodine-131 was described. Dependence of the labeling yield of [131I]iodocarvedilol on the concentration of carvedilol, chloramine-T content, pH of the reaction mixture and reaction time was studied in details. Carvedilol was labeled with iodine-131 at pH 6 with a labeling yield of 92.6 ± 2.77% by using 100 µg carvedilol, 200 µg chloramin-T (CAT) and 30 min reaction time. The formed [131I]iodocarvedilol was nearly stable for a time up to one day. Biodistribution of [131I]iodocarvedilol was investigated in experimental animals. [131/123I]iodocarvedilol was located in the heart with a concentration of 19.6 ± 0.41% of the injected dose at 60 min post injection. It has a high heart uptake and heart to liver ratio, both of which are beneficial for high-quality SPECT (single-photon emission computerized tomography) myocardial imaging. [131/123I]iodocarvedilol solve most the drawbacks of the FDA (Food and Drug Administration) approved 99mTc-sestamibi.

Neuroblastoma is the most frequently diagnosed cancer during the first year of life. This neoplasm originates from neural crest cells derived from the sympathetic nervous system, adrenal medulla, or paraspinal ganglia. The clinical presentation can vary from an asymptomatic mass to symptoms resulting from local invasion and/or spread of distant disease spread. The natural history of neuroblastoma is highly variable, ranging from relatively indolent biological behavior to a high-risk clinical phenotype with a dismal prognosis. Age, stage, and biological features are important prognostic risk stratification and treatment assignment prognostic factors. The multimodal therapy approach includes myeloablative chemotherapy, radiotherapy, immunotherapy, and aggressive surgical resection. Hyperbaric oxygen therapy (HBOT) has been proposed as a complementary measure to overcome tumor hypoxia, which is considered one of the hallmarks of this cancer treatment resistance. This article aims to review the relevant literature on the neuroblastoma pathophysiology, clinical presentation, and different biological and genetic profiles, and to discuss its management, focusing on HBOT.

Patients treated with radionuclide therapy usually require restrictions on certain activities for a period of time following treatment to optimise protection of the public and ensure the legal dose limit is not exceeded. Software may be used to calculate necessary restriction periods for an individual based on longitudinal dose rate measurements from the time of radiopharmaceutical administration. A spreadsheet program has been used for this purpose in Australian hospitals for the last two decades. However, this spreadsheet has a limitation in that it uses an approximation in the calculation of dose from a contact pattern, which affects the calculated restriction period. A computer program called Dorn was developed that provides the same functionality as the spreadsheet but without this approximation. Proffered radiation safety advice from Dorn and the spreadsheet were compared. Advice from the spreadsheet and Dorn were compared for 55 patients who underwent iodine-131 therapy for differentiated thyroid cancer. The restriction periods for caring for infants, close contact with children and sleeping with a partner were typically about 13 h longer in Dorn than in the spreadsheet, but in some cases were over a week shorter or a month longer. If the Dorn program is used clinically in place of the spreadsheet, some patients will enjoy shorter restriction periods and the therapy provider can be more confident in their compliance with regulatory requirements and best practice. Dorn is freely available from https://doi.org/jg5f. [ABSTRACT FROM AUTHOR]

(1) Background: Thyroid tissue ablation with radioactive iodine (RAI) has been successfully used in the treatment of differentiated thyroid cancers. However, as a side effect, RAI may induce salivary gland (SG) hypofunction, which has been alternatively managed with photobiomodulation therapy (PBMT). In our study, we assessed the effects of RAI on the SGs and further analyzed whether PBMT can minimize tissue damage. (2) Methods: Balb/c mice were allocated into three groups, as follows: RI, submitted to RAI orally; RIL, similar to RI, but with PBMT for SG hypofunction; and C, control group. The animals were euthanized on days 0, 10, and 90 after RAI. (3) Results: A decrease in tri-iodothyronine (T3) and thyroxine (T4) serum levels was observed both in the RI and RIL groups. In addition, a decrease in SG weight and morphological alterations were shown in the RI group throughout the experimental period, as well as a significant increase in total protein and peroxidase concentrations, and catalase activity. On day 90, the RI group presented less collagen and fewer sodium/iodine channels, with higher rates of cell apoptosis. Pertechnetate (Na99mTcO4) uptake was also affected in the RI group in all experimental times. Interestingly, although the RIL group also presented some alterations regarding these parameters, they were not statistically different from those of the C group on day 90. (4) Conclusions: Our results provide evidence that RAI induces harmful effects on the SGs, which can be successfully managed with PBMT. [ABSTRACT FROM AUTHOR]

Purpose: The aim of our work is to develop an in situ ocular gellan gum–based nanoemulsion (NE) of tamoxifen TAM as an alternative drug delivery system to the oral route for the treatment of photoreceptor degeneration disorder. Method: Six pseudoternary phase diagrams were developed using oil (oleic acid), surfactants (Tween 80 or Tween 20), a co-surfactant (polyethylene glycol 400), and water. The particle size, polydispersity index, and zeta potential of the developed systems were all measured. The safety of ocular application of the optimum system was established via in vivo histopathological investigation. To track the biodistribution of the optimum gel, iodine-131 (131I) was incorporated into the gel via coupling with TAM via direct electrophilic substitution reaction. Results: Based on the obtained results, TAMNE-1 was chosen as the optimal system, with PS = 140.20 ± 1.50 nm, ZP = − 27.86 ± 1.13 mV, and PDI = 0.20 ± 0.00%. In vitro release displayed a prolonged and sustained release of TAMNE-1 gel compared to TAM solution (plain eye drop). Transparent in situ TAMNE-1 gel was developed after the incorporation of the TAMNE-1 system into gellan gum aqueous solution (0.3% w/w). In this study, TAM was successfully radiolabeled with 131I for subsequent evaluation of the efficacy of the developed in situ gel system (TAMNE-1 gel) in vivo. The developed TAMNE-1 gel system was nonirritant and safe and the biodistribution studies showed better retention of TAMNE-1 gel than plain TAM eye drops. Conclusion: The developed TAMNE-1 gel is able to enhance the ocular bioavailability of TAM and can go further with clinical evaluation. [ABSTRACT FROM AUTHOR]

This retrospective study aimed to investigate whether there was a difference in the success rate of removal of residual thyroid tissue in patients with the same cutoff serum thyroglobulin (Tg) value―measured 2 weeks after thyroid hormone withdrawal (THW)―for different radioactive iodine (RAI) activities. We identified 132 patients with papillary thyroid cancer who were treated with total thyroidectomy and RAI therapy to evaluate the efficacy of three radioactivities of I-131: 1,110, 3,700, and 5,550 MBq. Serum Tg testing was performed 1 week before RAI treatment and 2 weeks after THW (pre-Tg); the cutoff pre-Tg level was below 10 ng/mL. Stimulated Tg levels were measured on the day of I-131 administration (off-Tg). After 6 months of treatment, we compared the groups for complete ablation, defined as no uptake on a diagnostic I-131 scan, stimulated Tg level of

Deterministic effects of medical exposure to ionising radiation can be associated with both the effectiveness of treatment and adverse drug reactions to it. The latter may drastically deteriorate the quality of life of a patient after radionuclide therapy. In addition, the regulations of the Russian Federation require indicating the effective dose of radiation as a measure of damage (risk), but the presence of a deterministic effect in individual organs and tissues complicates monitoring and recording patient exposure doses. The aim of the study was to investigate the effect of radiopharmaceuticals containing 131I on the development of secondary nasolacrimal duct obstruction (NLDO). Materials and methods: the study of secondary NLDO predictors analysed medical history data, post-therapy head-and-neck scintigrams, and methods to prepare patients for treatment. It involved sodium iodide, 131I, formulated as a solution (marketing authorisation number: FS-002065) by the FSUE Federal Center of Nuclear Medicine Projects Design and Development of the FMBA of Russia. Results: the authors unambiguously localised the lacrimal ducts in post-therapy 131I scintigrams of the head and neck and quantified 131I uptake ratios for the lacrimal duct area. Also, they identified a set of NLDO predictors: the age of a patient, the administered activity, the administration of recombinant human thyroid-stimulating hormone, the 131I uptake ratio, etc. The article describes a method for identifying the groups at risk of NLDO following radioiodine therapy for differentiated thyroid cancer. Conclusions: secondary NLDO is a deterministic effect of 131I exposure. The authors have developed a new method for predicting secondary NLDO by a combination of the patient’s individual parameters and treatment plan; the identified predictors help to personalise radioiodine therapy. The authors suggest the following: to include information on secondary NLDO as a complication of therapy to the SmPC section on undesirable effects; to develop approaches to secondary NLDO prevention; and to improve the algorithms for reporting adverse events in case of delayed manifestation and those for following patients up in the medical organisations having administered the radiopharmaceutical or in other medical organisations being applied to for medical care afterwards.

Natural products (NPs) have been the basis for the discovery and development of pharmacologically relevant drug-related molecules, including radiopharmaceuticals. Xanthine (3,7-dihydropurine-2,6-dione) and hypoxanthine (1,9-dihydro-6H-purin-6-one) are purine-based natural heterocyclic alkaloids that are generally found in some plants, animals, and the human body (e.g., muscle tissue, blood, and urine). The purpose of this study was to label xanthine and hypoxanthine with radioactive iodine-131 (a theranostic radionuclide) by a direct labeling method using chloramine-T as an oxidizing agent. Several experiments were performed to optimize the labeling efficiency by changing reaction conditions, including the ratio of starting material and chloramine-T, pH, solvent, temperature, and reaction time. Overall, labeling at acidic conditions in dimethyl sulfoxide (DMSO) resulted in considerable low radiochemical yields (RCYs) (less than 4.0 %), and therefore the focus was shifted to exploit the alkaline reaction conditions. The optimized reaction condition: pH (10.5-11.0), xanthine:chloramine-T ratio (1:2), reaction temperature (27 ºC), and reaction time (30 min), provided [131I]-xanthine with a RCY of 65.8 ± 0.1 %. After purification with extraction using chloroform (CHCl2), the radiochemical purity (RCP) of 95.1 % was achieved, as indicated by radio-thin layer chromatography (radio-TLC) analysis. In addition, the labeling of hypoxanthine was accomplished in a maximum 60.3 ± 0.2 % RCY, and after purification a RCP of 94.2 % was obtained. The present results provide an efficient and practical labeling method for xanthine and hypoxanthine with iodine-131, suggesting that these radiolabeled compounds can be further investigated in in vitro and in vivo studies for their theranostics potential.

Fibroblast activation proteins (FAP) are overexpressed in the tumor stroma and have received attention as target molecules for radionuclide therapy. The FAP inhibitor (FAPI) is used as a probe to deliver nuclides to cancer tissues. In this study, we designed and synthesized four novel 211At-FAPI(s) possessing polyethylene glycol (PEG) linkers between the FAP-targeting and 211At-attaching moieties. 211At-FAPI(s) and piperazine (PIP) linker FAPI exhibited distinct FAP selectivity and uptake in FAPII-overexpressing HEK293 cells and the lung cancer cell line A549. The complexity of the PEG linker did not significantly affect selectivity. The efficiencies of both linkers were almost the same. Comparing the two nuclides, 211At was superior to 131I in tumor accumulation. In the mouse model, the antitumor effects of the PEG and PIP linkers were almost the same. Most of the currently synthesized FAPI(s) contain PIP linkers; however, in our study, we found that PEG linkers exhibit equivalent performance. If the PIP linker is inconvenient, a PEG linker is expected to be an alternative. [ABSTRACT FROM AUTHOR]

Lead shielding materials are standard for radiation protection to limit exposure for patients and health care workers. However, lead is both heavy and highly toxic. The benefits of non-lead products are becoming and interesting because they offer the benefits of being cheaper, lighter and non-toxicity. This study has explored the radiation shielding efficacy of bismuth oxide (Bi2O3) loaded into the epoxy-resin for a Technetium-99m (99mTc) and Iodine-131 (131I) radiopharmaceutical container. Gamma ray attenuation parameters of the samples were investigated and compared with original lead shielding. The results showed that linear attenuation coefficient and percentage attenuation are increased with increasing filler loading. In contrast, the half-value layer values were decreased when more Bi2O3 was added. The 50 wt% Bi2O3 provided the best gamma ray attenuation efficacy with attenuations of 99.99% and 99.87% at gamma ray energy 140 and 364 keV, respectively. In comparison to lead, the 50 wt% Bi2O3 presented a slightly different attenuation of about 1.64%, while the heaviness was halved. Therefore, we hypothesize that Bi2O3 loaded into the epoxy-resin has gamma ray shielding potential for containing 99mTc and 131I radiopharmaceuticals while both reducing cost and weight. [ABSTRACT FROM AUTHOR]

Background: Following thyroidectomy, radioiodine therapy is the standard management of differentiated thyroid cancer. The effects of such treatment on testicular function remained a concern for cases and clinicians. Objective: We aimed to observe changes in fertility indicators in men treated with ablation. Materials and Methods: In this prospective cohort study, 18 men with differentiated thyroid cancer from June to December 2020 underwent thyroidectomy plus radioiodine therapy. Participants were grouped based on iodine dose (8 men with 30 mCi vs. 10 men with = 150 mCi). Baseline values (VB) of the follicular stimulating hormone, luteinizing hormone, testosterone, and sperm analyses were measured 3 wk before iodine ablation and repeated 3 (V3) and 12 (V12) months later. They were analyzed once as a whole and once based on their groups via ANOVA and Friedman's tests where appropriate. Results: The mean age of participants was 35.61 ± 9.74 yr. Follicular stimulating hormone levels showed a significant trend among all participants (VB: 12.51 ± 1.72, V3: 13.54 ± 1.41, and V12: 13.10 ± 1.67 IU/mL; p < 0.001). Luteinizing hormone showed a similar pattern (VB: 4.98 ± 1.27, V3: 5.65 ± 1.29, and V12: 5.21 ± 0.95 IU/mL; p < 0.001). Testosterone levels did not differ significantly from baseline. Sperm count decreased at the first checkpoint and returned to normal after 12 months (VB: 38.22 ± 19.40, V3: 32.05 ± 17.96, and V12: 36.66 ± 18.81 million/mL; p < 0.001). Sperm motility and morphology did not change significantly. Conclusion: Our research showed that even less than 5 GBq irradiation could induce a transient testicular dysfunction in the first 3 months of therapy, but it was mostly reversible after 12 months. [ABSTRACT FROM AUTHOR]

The optimization of the radiolabeling yield of carvedilol with iodine-131 was described. Dependence of the labeling yield of [131I]iodocarvedilol on the concentration of carvedilol, chloramine-T content, pH of the reaction mixture and reaction time was studied in details. Carvedilol was labeled with iodine-131 at pH 6 with a labeling yield of 92.6 ± 2.77% by using 100 µg carvedilol, 200 µg chloramin-T (CAT) and 30 min reaction time. The formed [131I]iodocarvedilol was nearly stable for a time up to one day. Biodistribution of [131I]iodocarvedilol was investigated in experimental animals. [131/123I]iodocarvedilol was located in the heart with a concentration of 19.6 ± 0.41% of the injected dose at 60 min post injection. It has a high heart uptake and heart to liver ratio, both of which are beneficial for high-quality SPECT (single-photon emission computerized tomography) myocardial imaging. [131/123I]iodocarvedilol solve most the drawbacks of the FDA (Food and Drug Administration) approved 99mTc-sestamibi. [ABSTRACT FROM AUTHOR]

The main indications for therapeutic use of I-131 are treatment of hyperthyroidism, radioactive removal of residual thyroid tissue in malignant thyroid cancers that accumulate iodine, and possible adjuvant therapy of extensive malignancies that accumulate iodine. Treatment with radioactive iodine is used for diffuse hyperthyroidism when medications are not effective for a period or when medications fail to control elevated hormone levels in the blood, as well as for drug-related side effects. I-131 therapy is increasingly replacing surgical treatment because it is simple, economical, practical, and usually has no complications. The aim of this study is to investigate the quality of health of the target group before and after thyroid therapy with radioactive iodine. The study is a prospective study that is conducted from November 2019 to November 2020 in the Clinic for Nuclear Medicine and Endocrinology of the Clinical Center of the of Sarajevo (KCUS) from November 2019 to November 2020. The study including 30 patients who have been injected with I-131 for the treatment of thyroid disease and undergo regular check-ups and examinations at the Nuclear Medicine and Endocrinology Clinic of KCUS. The results show that patients felt better after treatment with radioactive iodine, which is confirmed by the Wilcoxon test for paired samples (p = 0.001). In both time periods, the most frequent rating is 3. However, the mean rating of general health before therapy is 2.6 and after therapy is 3.2. Since improvement in health and quality of life was observed in almost all treatment groups, this indicates that radioactive iodine therapy is suitable for all age groups. The quality of health of the target group of subjects before and after thyroid therapy with radioactive iodine I-131 increased significantly after therapy. [ABSTRACT FROM AUTHOR]

Personalised dosimetry based on molecular imaging is a field that has grown exponentially in the last decade due to the increasing success of Radioligand Therapy (RLT). Despite advances in imaging-based 3D dose estimation, the administered dose of a therapeutic radiopharmaceutical for RLT is often non-personalised, with standardised dose regimens administered every 4–6 weeks. Biodosimetry markers, such as chromosomal aberrations, could be used alongside image-based dosimetry as a tool for individualised dose estimation to further understand normal tissue toxicity and refine the administered dose. In this review we give an overview of biodosimetry markers that are used for blood dose estimation, followed by an overview of their current results when applied in RLT patients. Finally, an in-depth discussion will provide a perspective on the potential for the use of biodosimetry in the nuclear medicine clinic.

Covid-19 has changed the practice of present-day medicine. Social-distancing, hand-sanitation and use of face-mask are important measures taken against its spread. Post-thyroidectomy whole-body diagnostic I-131 scan is an important preliminary investigation for risk stratification and further management in thyroid cancer. False positive findings on diagnostic scan are not uncommon and must be evaluated to avoid unnecessary work-up and treatment. Clinical and biochemical correlation with adjunct SPCET/CT imaging may differentiate true from false-positive lesions. We report a case of unusual false positive linear neck tracer on whole-body diagnostic I-131 scan due to the use of an I-131 contaminated face mask.

Background Radioactive iodine (RAI) therapy is a successful therapeutic modality for Graves’ disease. However, RAI therapy can fail, and RAI therapy after antithyroid drugs (ATDs) has a lower remission rate. Therefore, many patients require repeated RAI therapy. This study investigated the clinical outcomes of repeated RAI therapy for Graves’ disease. Methods Patients who underwent RAI therapy as second-line therapy after failure of ATD treatment between 2001 and 2015 were reviewed. Remission was defined as hypothyroid or euthyroid status without ATD, and with or without levothyroxine at 12 months after RAI therapy. Results The 1-year remission rate after 2nd RAI therapy (66%, 152/230) is significantly higher than that after 1st RAI therapy (48%, 393/815) or long-term ATD treatment after 1st RAI therapy failure (42%). The clinical response to 2nd RAI therapy was more rapid. The median time intervals from the 2nd RAI therapy to ATD discontinuation (1.3 months) and to the start of levothyroxine replacement (2.5 months) were significantly shorter than those for the 1st RAI therapy. A smaller goiter size, a longer time interval between the 1st and 2nd RAI therapies, and a longer ATD discontinuation period predicted remission after the 2nd RAI therapy. Finally, in 78 patients who failed the 2nd RAI therapy, the mean ATD dosage significantly reduced 5.1 mg over 12 months. Conclusion Repeated RAI therapy can be a good therapeutic option, especially in patients with smaller goiters and those who are more responsive to the 1st RAI therapy.

Simple Summary: Thyroid carcinoma is the most common cancer of the endocrine system and accounts for 12% of all cancer cases in adolescents in the United States. In this paper, we present a double-blind, randomized, placebo-controlled clinical trial aimed at evaluating the effect of probiotics supplementation in reducing the acute side-effects of radioiodine therapy in DTC patients. The probiotics' effectiveness was confirmed for dry mouth and taste loss or change when it was administered prior to the radioiodine treatment. The benefit was not confirmed for other radiation-induced complications such as pain and swelling in the neck, nausea and vomiting, salivary gland swelling, and diarrhea. Further large-scale clinical trials are warranted to improve our knowledge of this quickly evolving field. Thyroid carcinoma is the most common cancer of the endocrine system, accounting for 12% of all cancer cases in adolescents in the United States. Radioiodine therapy plays a key role in differentiated thyroid cancer (DTC) treatment. This double-blind, randomized, placebo-controlled clinical trial was aimed at evaluating the effect of probiotics supplementation in reducing the acute side-effects of radioiodine therapy in PTC patients. Fifty-six patients were randomly divided into four groups: one placebo and three intervention groups. The probiotics product used in this study was LactoCare (ZistTakhmir Co., Tehran, Iran), a multi-strain commercially available symbiotic containing 12 strains of probiotic species including Lactobacillus strains, Bifidobacteria strains, and Streptococcus thermophilus, plus Fructo-oligosaccharides as the prebiotic. Group 0 was our placebo group (no probiotics), while the other three groups received probiotics capsules for 2/4 days, starting only 2 days prior to radioiodine therapy, only 4 days after radioiodine therapy or 2 days prior and 4 days after radioiodine therapy. Six patients were withdrawn during the study because of poor compliance or at their own request. The symptoms reported by patients including data about the incidence and duration of each complication were recorded. The probiotics' effectiveness was confirmed for dry mouth and taste loss or change when it was administered prior to the radioiodine treatment. The benefit was not confirmed for other radiation-induced complications such as pain and swelling in the neck, nausea and vomiting, salivary gland swelling, and diarrhea. Further large-scale clinical trials are warranted to improve our knowledge in this quickly evolving field. [ABSTRACT FROM AUTHOR]

Improved therapeutic strategies are required to minimize side effects associated with radioiodine gene therapy to avoid unnecessary damage to normal cells and radiation-induced secondary malignancies. We previously reported that codon-optimized sodium iodide symporter (oNIS) enhances absorption of I-131 and that the brahma-associated gene 1 bromodomain (BRG1-BRD) causes inefficient DNA damage repair after high-energy X-ray therapy. To increase the therapeutic effect without applying excessive radiation, we considered the combination of oNIS and BRG1-BRD as gene therapy for the most effective radioiodine treatment. The antitumor effect of I-131 with oNIS or oNIS+BRD expression was examined by tumor xenograft models along with functional assays at the cellular level. The synergistic effect of both BRG1-BRD and oNIS gene overexpression resulted in more DNA double-strand breaks and led to reduced cell proliferation/survival rates after I-131 treatment, which was mediated by the p53/p21 pathway. We found increased p53, p21, and nucleophosmin 1 (NPM1) in oNIS- and BRD-expressing cells following I-131 treatment, even though the remaining levels of citrulline and protein arginine deiminase 4 (PAD4) were unchanged at the protein level. [ABSTRACT FROM AUTHOR]

Background: Aggressive thyroid carcinoma (ATC) usually loses radioiodine avidity to iodine-131 (131I) due to the downregulation of sodium/iodide symporter (NIS). The expression of thyroid stimulating hormone receptor (TSHR) is more persistent than NIS and the administration of recombinant human thyroid stimulating hormone (rhTSH) promotes de novo NIS synthesis. Hence, exploring methods integrating 131I with rhTSH might be a feasible therapeutic strategy for selective delivery of 131I into thyroid cancer to fortify the effect of radioiodine ablation. Methods: The 131I, poly (lactic-co-glycolic acid) (PLGA) and rhTSH were used to synthesize of the 131I-PLGA-rhTSH nanoparticles. The characteristics of the 131IPLGA-rhTSH nanoparticles was determined using a light microscopy, scanning electron microscopy (SEM), autoradiography and immunofluorescence (IF) staining. The diameter of the 131I-PLGA-rhTSH nanoparticles was measured with a Mastersizer 3000, and the encapsulation efficiency (EF) of 131I in 131I-PLGA-rhTSH nanoparticles and the radioactivity of a single nanoparticle were determined. Then, the mouse tumor xenograft model was established, and the biodistribution and effect of 131I-PLGA-rhTSH nanoparticles on apoptosis of thyroid cance cells were investigated in vivo. Thereafter, the role of 131I-PLGA-rhTSH nanoparticles in cell viability using cell counting kit-8 and lactate dehydrogenase (LDH) release assays. Subsequently, the underlying mechanism of 131I-PLGA-rhTSH nanoparticles in reducing cell viability was assessed using immunostaining, boyden invasion assays and phalloidin staining. Results: Our results showed that the method of developing nanoparticlesencapsulated 131I using poly (lactic-co-glycolic acid) (PLGA) and modified with rhTSH (131I-PLGA-rhTSH), was a feasible avenue for the integration of 131I and rhTSH. Meanwhile, the encapsulation efficiency (EF) of 131I-PLGA-rhTSH nanoparticles was approximately 60%, and the radioactivity of a single nanoparticle was about 1.1×10-2 Bq. Meanwhile, the 131I-PLGA-rhTSH nanoparticles were selectively delivered into, gradually enriched and slowly downregulated in xenograft tumor after the administration of 131I-PLGA-rhTSH nanoparticles through tail vein in mouse tumor xenograft model. Thereafter, the tumor weight was significantly reduced after the administration of 131I-PLGArhTSH nanoparticles. Subsequently, the application of 131I-PLGA-rhTSH nanoparticles facilitated apoptosis and attenuated immobilization via inhibiting F-actin assembling of FTC-133 cells. Conclusion: The present study develops a suitable approach integrating 131I and rhTSH, and this strategy is a feasible regimen enhancing the effect of radioiodine ablation for the treatment of thyroid cancer. [ABSTRACT FROM AUTHOR]

Radionuclides theranostic are ideal "partners" for bispecific antibodies to explore the immune response of patients and synergistic treatment. A bispecific single-domain antibody-Fc fusion protein, KN046, exhibits a good treatment effect by binding to programmed cell death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). An ionizing-radiation stimulus mediated by a low-dose of [131I] may be used for immunopotentiation. In this study, we established [131I]-labeled KN046 as a novel radioimmunotherapy agent to treat malignant melanoma and explored the mechanism. Methods: After intravenous injection of [131I]-KN046, SPECT/CT imaging was applied to identify candidate targets for KN046 immunotherapy. [18F]-FDG and [68 Ga]-NOTA-GZP (granzyme B-specific PET imaging agent) micro-PET/CT imaging was used to assess the immune response in vivo after [131I]-KN046 treatment. The synergistic treatment effect of [131I]-KN046 was evaluated by exploring the [131I]-based radionuclide-induced release of tumor immunogenicity-related antigens as well as the histology and survival of tumor-bearing mice after treatment. Results: The constructed [131I]-KN046 exhibited high affinity and specificity for PD-L1/CTLA-4 immune targets and had excellent in vivo intratumoral retention capability so as to achieve good antitumor efficacy. More importantly, the combination of low-dose [131I] and KN046-enhanced immunosensitivity increased the immunotherapy response rates significantly. Exposure of tumor cells to [131I]-KN046 led to upregulated expression of MHC-I and Fas surface molecules and significant increases in the degree of T-cell activation and counts of tumor-infiltrating immunocytes. Conclusion: Use of low-dose [131I] combined with a dual-target immunosuppressant could be exploited to identify the subset of treatment responders but also exhibited great potential for enhancing antitumor immune responses. [ABSTRACT FROM AUTHOR]

Background: There is no standardized approach to iodine-131 (I-131) therapy of hyperthyroidism in pediatric Graves disease. This prevents systematic study of outcomes. Objective: To characterize current radioiodine dosing and define therapeutic outcomes at multiple institutions that use ultrasound to measure thyroid size to guide I-131 ablation of Graves disease. Materials and methods: This was a retrospective cohort study conducted at three institutions. The three sites collected demographic data, thyroid volume measured by ultrasound (mL), pre-ablation radioiodine uptake, I-131 activity administered, and outcomes at 6 and 12 months for children younger than 18 years of age treated with I-131 between November 2004 and October 2019. Comparisons of continuous variables were performed using the Mann-Whitney U test. Results: Sixty-nine patients (mean age: 14.5±2.5 years) were included, 59 (85.5%) of whom were female. The mean administered I-131 radioiodine activity was 12.5 mCi (463 MBq) (range: 3.8–29.9 mCi [141–1,106 MBq]). At 6 months post-ablation, 54 (80.5% of 67) patients were hypothyroid, 8 (11.9% of 67) were euthyroid and 5 were hyperthyroid. Two of the five hyperthyroid patients had become euthyroid at 12 months. At 12 months, 1 previously euthyroid patient was hyperthyroid. Administered activity per mL of thyroid tissue adjusted for 24-h uptake was lower (0.18 mCi [6.7 MBq] x %/mL vs. 0.31 mCi [11.5 MBq] x %/mL, P=0.0054) for patients who remained hyperthyroid at 6 months. Conclusion: There is substantial variability in administered activity for radioiodine ablation of Graves disease in children. Efforts to standardize practice should start by standardizing administered activity guided by measurement of thyroid size by ultrasound. Our results and those of previous studies suggest the need for administered activities ≥0.25 mCi [9.3 MBq] x %/mL of thyroid tissue. [ABSTRACT FROM AUTHOR]

Study including 61 differentiated thyroid cancer (DTC) patients who received ablative doses of I-131 after total thyroidectomy. Biodosimetry was performed by dicentric chromosomes analysis before and after treatment, determining dicentric yield and blood absorbed dose. An increased yield of dicentrics after treatment was demonstrated. With an average administered activity of 4.32 ± 0.879 GBq, the absorbed dose in bone marrow was 0.28 Gy (0.25–0.30 95% CI). These data were compared with the administered I-131 activity and body mass index. Increased genotoxic effects were observed, with a slightly higher dicentric yield rising along I-131 activity. No correlation was found between administered activity and BMI. No significant risk of myelotoxicity due to dose regimens of I-131 intended for ablative purposes in "de novo" treated patients was found among the ranges of activities used in clinical practice. Biodosimetric data was included in patients' Clinical History, which translates into a more detailed dosimetric report. With this information, physicians can take a more patient-specific approach. Personalized administration would be of special consideration in the event of re-treatments, be it due to recurrent disease or I-131 refractory DTC patients. • Significant increase in dicentric chromosomal aberrations was found. • Myelotoxicity risk induced by therapeutic regimens of I131 was discarded. • No relation between body mass index and estimated dose was demonstrated. • In some cases metastases were identified before clinical signs. • Precaution is advised in the event of retreatments. [ABSTRACT FROM AUTHOR]

In the present study, iodine-131 S values (rT ← thyroid) were calculated for 30 target organs and tissues using the most recently developed Korean reference computational phantoms. The calculated S values were then compared with those of the International Commission on Radiological Protection (ICRP) reference computational phantoms to investigate the dosimetric impact of the Korean S values against those of the ICRP reference phantoms. The results showed significant differences in the S values due to the different anatomical/morphological characteristics between the Korean and ICRP reference phantoms. Most target organs/tissues showed that the S values of the Korean reference phantoms are lower than those of the ICRP reference phantoms, by up to about 4 times (male spleen and female thymus). Exceptionally, three target organs/tissues (gonads, thyroid, and extrathoracic region) showed that the S values of the Korean reference phantoms are greater, by 1.5–3.7 times. We expect that the S values calculated in the present study will be beneficially used to estimate organ/tissue doses of Korean patients under radioiodine therapy.

Abstract Background High-dose radioactive iodine-131 (I-131) is generally used post-total or subtotal thyroidectomy in differentiated thyroid cancer (DTC) patients. I-131 whole-body scan (WBS) is performed to localize I-131 accumulation in the body and for restaging after therapy. Nonetheless, there are numerous causes of false-positive uptake in I-131 WBS in the absence of residual thyroid tissue or thyroid cancer metastasis. Case presentation We present a case of 51-year-old lady with false-positive uptake in I-131 WBS mimicking lung metastasis. Patient underwent total thyroidectomy, and histopathological examination showed well-differentiated papillary thyroid microcarcinoma. Diagnostic I-131 WBS followed by two subsequent high-dose radioiodine ablation showed persistent I-131 uptake in the left lower lung field. However, the serum thyroglobulin (Tg) is incessantly undetectable (

Purpose: Risk of second primary malignancy (SPM) after radioiodine (RAI) therapy has been continuously debated. The aim of this study is to identify the risk of SPM in thyroid cancer (TC) patients with RAI compared with TC patients without RAI from matched cohort. Methods: Retrospective propensity-matched cohorts were constructed across 4 hospitals in South Korea via the Observational Health Data Science and Informatics (OHDSI), and electrical health records were converted to data of common data model. TC patients who received RAI therapy constituted the target group, whereas TC patients without RAI therapy constituted the comparative group with 1:1 propensity score matching. Hazard ratio (HR) by Cox proportional hazard model was used to estimate the risk of SPM, and meta-analysis was performed to pool the HRs. Results: Among a total of 24,318 patients, 5,374 patients from each group were analyzed (mean age 48.9 and 49.2, women 79.4% and 79.5% for target and comparative group, respectively). All hazard ratios of SPM in TC patients with RAI therapy were ≤ 1 based on 95% confidence interval(CI) from full or subgroup analyses according to thyroid cancer stage, time-at-risk period, SPM subtype (hematologic or non-hematologic), and initial age (< 30 years or ≥ 30 years). The HR within the target group was not significantly higher (< 1) in patients who received over 3.7 GBq of I-131 compared with patients who received less than 3.7 GBq of I-131 based on 95% CI. Conclusion: There was no significant difference of the SPM risk between TC patients treated with I-131 and propensity-matched TC patients without I-131 therapy. [ABSTRACT FROM AUTHOR]

As trastuzumab is known to target the human epidermal growth factor receptor type (HER2), the potential of [131I]I-trastuzumab as a radioimmunotherapy agent was evaluated in vitro and in vivo for HER2-overexpressing ovarian cancer cells (SKOV-3). [131I]I-trastuzumab showed promising in vitro properties and high tumor uptake in SKOV-3 xenografts. Its cellular toxicity was dose- and time-dependent, and it retained in the SKOV-3 cells in the G2/M phase of cell cycle. The mode of cell death was predominantly by apoptosis. These results demonstrate the potential of [131I]I-trastuzumab for further therapeutic evaluation in HER2-overexpressing ovarian cancers. [ABSTRACT FROM AUTHOR]