Dose Of 131I Research Articles

Male Sex Is Not a Risk Factor for Prognosis in Postoperative Thyroid Cancer Patients: A Propensity Score Matching Study.

To study whether male sex is a risk factor for prognosis in patients with differentiated thyroid cancer after 131I treatment using the propensity score matching (PSM) method. From April 2016 to October 2021, 1948 postoperative differentiated thyroid cancer patients aged 43 (interquartile range: 34, 54) years who received 131I treatment were retrospectively enrolled and divided into male (n = 645) and female groups (n = 1303). The PSM method was adopted to process all data to reduce the influence of data bias and confounding variables. The Mann-Whitney U test and χ2 test were used for data analysis. Multivariate logistic regression was used to analyze the risk factors affecting prognosis, and the receiver operating characteristic curve was used to analyze the relationship between stimulated thyroglobulin (sTg) level, 131I dose, and poor prognosis. Before PSM, the proportion of male patients with poor prognosis was significantly higher than that of female patients. After PSM, there was no difference in the proportion of poor prognosis between male and female groups. Multivariate logistic regression analysis showed that male sex; high T stage, N1b stage, and M1 stage; high sTg level; and high 131I dose were risk factors for poor prognosis before PSM. After PSM, high T stage, M1 stage, high sTg level, and 131I dose were still risk factors but male sex was no longer a risk factor for poor prognosis. After the reduction of selection bias by PSM, male sex was no longer a risk factor for prognosis after 131I treatment of differentiated thyroid cancer. In addition, high T stage (T3 + T4 stage), M1 stage, sTg ≥10.15 ng/mL, and 131I dose ≥260 mCi were risk factors for poor prognosis.

Clinical characteristics of nasolacrimal duct obstruction after iodine therapy in differentiated thyroid cancer patients.

To analyze the clinical characteristics of differentiated thyroid cancer (DTC) patients with nasolacrimal duct obstruction (NLDO) after Iodine-131 (131I) therapy and provide guidance for clinical decision-making. Thirty-one DTC patients with NLDO were retrospectively enrolled from the Nuclear Medicine Department of Shanxi Bethune Hospital during follow-up of 131I therapy between June 2018 and March 2021. Eight hundred and seventy-one thyroid cancer patients during this period without NLDO after 131I therapy were enrolled as the control group. Clinical characteristics, including sex, age, dose, anti-thyroglobulin antibodies (TGAb), and metastatic lesions, were analyzed by χ2 test and logistic multifactor regression. In the NLDO group and without NLDO group, there were statistically significant differences in gender, age, dose, and whether there was metastasis. Among the NLDO group, the proportion of women, age >55years old, dose >5.55GBq, and the presence of metastasis was higher, and the difference was statistically significant; There was no significant difference in the proportion of TGAb positive and negative patients based on 131I therapy (χ2 = 0.27, P = .782).Multivariate logistic regression analysis showed that sex (2.59), age (1.45), dose (2.36), and metastatic lesions (1.93) were all statistically significant influential factors of NLDO after iodine therapy. Significant differences were found in the incidence of NLDO between the number of treatment courses (χ2 = 23.541, P < .001). Prevalence rate of repeat radioiodine therapy (2 times or 3 times and more) is higher than 1 time. Women patients over 55 who had metastatic lesions, and received a dose >5.55GBq, were more likely to have NLDO. When determining therapeutic doses of 131I, doctors should weigh multiple factors and then give appropriate dosage and suggest that high risk populations be referred for appropriate ophthalmic surgical consultation, for timely diagnosis and therapy.

Cervical lymph node metastasis prediction of postoperative papillary thyroid carcinoma before 131I therapy based on clinical and ultrasound characteristics.

The status of lymph nodes is crucial to determine the dose of radioiodine-131(131I) for postoperative papillary thyroid carcinoma (PTC). We aimed to develop a nomogram for predicting residual and recurrent cervical lymph node metastasis (CLNM) in postoperative PTC before 131I therapy. Data from 612 postoperative PTC patients who underwent 131I therapy from May 2019 to December 2020 were retrospectively analyzed. Clinical and ultrasound features were collected. Univariate and multivariate logistic regression analyses were performed to determine the risk factors of CLNM. Receiver operating characteristic (ROC) analysis was used to weigh the discrimination of prediction models. To generate nomograms, models with high area under the curves (AUC) were selected. Bootstrap internal validation, calibration curves and decision curves were used to assess the prediction model's discrimination, calibration, and clinical usefulness. A total of 18.79% (115/612) of postoperative PTC patients had CLNM. Univariate logistic regression analysis found serum thyroglobulin (Tg), serum thyroglobulin antibodies (TgAb), overall ultrasound diagnosis and seven ultrasound features (aspect transverse ratio, cystic change, microcalcification, mass hyperecho, echogenicity, lymphatic hilum structure and vascularity) were significantly associated with CLNM. Multivariate analysis revealed higher Tg, higher TgAb, positive overall ultrasound and ultrasound features such as aspect transverse ratio ≥ 2, microcalcification, heterogeneous echogenicity, absence of lymphatic hilum structure and abundant vascularity were independent risk factors for CLNM. ROC analysis showed the use of Tg and TgAb combined with ultrasound (AUC = 0.903 for "Tg+TgAb+Overall ultrasound" model, AUC = 0.921 for "Tg+TgAb+Seven ultrasound features" model) was superior to any single variant. Nomograms constructed for the above two models were validated internally and the C-index were 0.899 and 0.914, respectively. Calibration curves showed satisfied discrimination and calibration of the two nomograms. DCA also proved that the two nomograms were clinically useful. Through the two accurate and easy-to-use nomograms, the possibility of CLNM can be objectively quantified before 131I therapy. Clinicians can use the nomograms to evaluate the status of lymph nodes in postoperative PTC patients and consider a higher dose of 131I for those with high scores.

Radioiodine Therapy in Patient with Differentiated Thyroid Cancer and Chronic Kidney Disease on Maintenance Hemodialysis: First Case of Bangladesh

The conventional course of differentiated thyroid cancer (DTC) treatment requires surgical resection followed by radioactive iodine (131I) therapy (RAIT). Patients are advised to drink plenty of water, as 131I gets eliminated through the kidneys and the burden of extra radiation is reduced. Treating a case of DTC with chronic kidney disease (CKD) by RAIT is challenging. As a result, when planning hemodialysis in a DTC patient with CKD, the dose of 131I, the timing of the dialysis, and radiation safety must all be carefully considered. Because 131I is dialyzable, a standard Geiger counter can observe and detect it. A post-thyroidectomized case of DTC with CKD was successfully treated with 131I while continuing scheduled peritoneal hemodialysis (HD) simultaneously during hospital isolation, as reported here. This case report was aimed at sharing the HD management procedures, challenges to any adverse effects, and exposure doses of 131I-treated DTC patients in their immediate post-ablative days. Geiger counter measurements in the patient after HD following 131 I administration revealed levels of less than 4.20 Sv/h on the fifth day, allowing safe hospital discharge in this case. Bangladesh J. Nuclear Med. 26(1): 71-74, 2023

Radioiodine (131I) treatment decision-making for low- and intermediate-risk differentiated thyroid cancer.

The purpose of this study was to investigate the effect and influencing factors of postsurgical radioactive iodine (RAI) therapy for patients with low- and intermediate-risk differentiated thyroid cancer (DTC). A retrospective analysis of 423 low- and intermediaterisk DTC patients admitted to the Department of Nuclear Medicine, Sichuan Provincial People's Hospital from January 2005 to December 2020 was performed. All patients were treated with surgery, had a postoperative pathological diagnosis, and were treated with RAI, including 89 males and 334 females. Recurrence risk stratification: 143 cases were low-risk, and 280 cases were intermediaterisk. The excellent response (ER) rate for low- and intermediate-risk were 93.7% and 78.2%, respectively (P < 0.05). There were significant differences in age, cumulative dose of [131I], and pretreatment stimulated-Tg (pre-Tg) levels between the low- and intermediate-risk groups (P < 0.05). There were significant differences in the cumulative dose of 131I and pre-Tg levels between ER and the non-ER group (P < 0.05). The area under the curve (AUC) values were 0.799 in the low-risk group, and 0.747 in the intermediate-risk group for the ROC curve by ER status of pre-Tg. The ER rate with RAI treatment decreased with an increase in pre-Tg levels. Pre-Tg was an important factor for RAI treatment decision-making and prognostic evaluation and differed between low-risk and intermediate-risk DTC. Aggressive RAI therapy was recommended for low-risk DTC with pre-Tg ≥ 20.0 ng/mL and in intermediate-risk group with pre-Tg ≥ 10.0 ng/mL.

A NEW HYPOTHESIS IN THE TREATMENT OF RECURRENT GLIOBLASTOMA MULTIFORME (GBM). PART 2: IS THERE AN ALTERNATIVE THERAPY OPTION IN RECURRENT GM WHEN ALL STANDARD TREATMENTS HAVE BEEN EXHAUSTED?

Glioblastoma multiforme (GBM) is the most aggressive and malignant brain tumor. The average survival time for a patient diagnosed with GBM, using standard treatment methods, is several months. Besides the routinely applied treatments such as neurosurgery, radiotherapy, and chemotherapy, progress is being made in the field of oncology, offering hope for improved treatment outcomes. New treatment methods include individualized multimodal immunotherapy (IMI) and modulated electro-hyperthermia. The coauthor of the above series of articles (parts 1 and 2) - A.Cz. presents the concept of a new, potentially breakthrough treatment option for recurrent GBM. A.Cz. was diagnosed with GBM in August 2021. Exhaustion of standard treatment methods, as well as immunotherapy and virotherapy, only provided temporary relief. Unfortunately, after a few months, the disease recurred. Having little to lose, A.Cz. accepted an ablative dose of 2960 MBq (80 mCi) of I131, based on available literature data. Three days before the administration of radioiodine therapy (RIT), A.Cz. prophylactically blocked the thyroid's ability to absorb the radioisotope. In June 2023, approximately 7 weeks after receiving single I131 dose, the MRI examination confirmed a 30% reduction in the tumor's size. Based on this, one can speculate that Iodine-131 therapy may be an alternative treatment option for GBM patients in the future. However, this hypothesis requires confirmation in further clinical studies.

Ultrasound combined with Ki67 detection for analyzing contributing factors of failure to cure and recurrence of hyperthyroidism in patients with Graves disease after 131I treatment

To analyze factors associated with failure to cure or recurrence of hyperthyroidism in patients with Graves disease (GD) after 131I treatment using ultrasound combined with Ki67 detection. Eighty-nine patients with GD receiving 131I treatment in the Department of Nuclear Medicine at our hospital from January, 2020 to November, 2021 were enrolled. Before treatment, thyroid volume, shear wave elastic value and Ki67 expression in the follicular epithelial cells were measured using three-dimensional ultrasonic virtual organ computer-aided analysis, shear-wave elastic imaging and ultrasound-guided fine needle aspiration. The data including age, gender, antithyroid drug (ATD) history, dose of 131I, and TRAb were collected from all the cases. The patients were followed up for up to 1 year, starting at 1 month after 131I treatment, and the follow-up results of the patients were divided into failure to cure or recurrence of hyperthyroidism, premature hypothyroidism and euthyroidism or loss to follow-up. The proportional hazards model and fine-Gray test were used to estimate the adjusted hazard ratio (HR) and 95% confidence interval (95% CI) for patients with failure to cure or recurrence of hyperthyroidism. Among the 89 patients, 27 patients were found to have failure to cure or recurrence of hyperthyroidism, 50 had premature hypothyroidism, 1 patient had euthyroidism, and 11 patients were lost to follow-up at the end of the 1-year follow-up. Analysis of the competitive risk model showed that status of Ki67 expression, 131I dose and thyroid volume were independently correlated with failure to cure or recurrence of hyperthyroidism after the treatment with HR (95% CI) of 0.36 (0.15, 0.86), 0.81 (0.68, 0.96) and 1.11 (1.07, 1.15), respectively. In patients with GD, the expression of Ki67 in thyroid follicular epithelial cells, 131I dose and thyroid volume are independently correlated with failure to cure or recurrence of hyperthyroidism after 131I treatment. New ultrasound techniques can play an important role in evaluating the therapeutic outcome of 131I treatment in GD patients.

The effect of exposure on cattle thyroid after the Fukushima Daiichi nuclear power plant accident

Nuclear plant accidents can be a risk for thyroid cancer due to iodine radioisotopes. Near the Fukushima Daiichi nuclear power plant, cattle were exposed to radiation after the accident occurred in May 2011. Here we estimated the total radiation exposure to cattle thyroid and its effects on thyroid function. Until October 2016, the estimated external exposure dose in Farm A was 1416 mGy, while internal exposure dose of 131I, 134Cs, and 137Cs were 85, 8.8, and 9.7 mGy in Farm A and 34, 0.2, and 0.3 mGy in Farm B, respectively. The exposed cattle had thyroid with relatively lower weight and lower level of stable iodine, which did not exhibit any pathological findings. Compared with the control, the plasma level of thyroid-stimulating hormone (TSH) was higher in Farm A cattle born before the accident, while the plasma thyroxine (T4) was higher in Farm A cattle born after the accident, suggesting that exposed cattle showed slight hyperactivation of the thyroid gland. In addition, Farm A cattle have higher level of cortisol, one of the anterior pituitary gland-derived hormones. However, we did not observe a causal relationship between the radiation exposure and cattle thyroid.

Outcome of Radioiodine Treatment in Hyperthyroidism and Predictive Factors of Treatment Failure: A 10-Year Experience

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. Keywords: Radioiodine treatment; I-131; Hyperthyroidism; First dose

Recombinant human thyrotropin versus thyroid hormone withdrawal preparation for radioiodine ablation in differentiated thyroid cancer: Experience in a South Taiwanese medical center.

This retrospective study was designed to compare the treatment response of patients with differentiated thyroid cancer (DTC) prepared for radioiodine ablation (RIA) with thyroid hormone withdrawal (THW) or recombinant human thyrotropin (rhTSH) stimulation. Patients with DTC were followed-up retrospectively between 2013 and 2018 in Kaohsiung Chang Gung Memorial Hospital, Taiwan. We compared the excellent response ratios between THW (49.9%) and rhTSH (50.1%) stimulation. Patients were then divided into subgroups, on the basis of age, sex, extrathyroidal extension, lymph node metastasis, and tumor-node-metastasis stage, for analysis. In all, 647 patients were followed-up after RIA. The ratios of THW or rhTSH use in the different subgroups were not statistically significant. In all the patients, the excellent response rate with THW and rhTSH was 80% and 76.5%, respectively, which was not statistically significant. The subgroup analysis, including age, sex, extrathyroidal extension, lymph node metastasis, and tumor-node-metastasis stage (low and high risk), showed similar results. Furthermore, the logistic regression analysis revealed no statistically significant differences among the subgroups. The multivariate analysis showed extrathyroidal extension, lymph node metastasis, and high I131 dose were the prognostic factors affecting the excellent response rate. In conclusion, the THW and rhTSH preparations for RIA were similar in terms of the excellent response rates and subgroup clinical outcomes.

Value of thyroid 99mTcO4- imaging ROI ratio for estimating 131I dose in individualized treatment of hyperthyroidism

To investigate the feasibility of using thyroid 99mTcO4- imaging ROI ratio instead of 24 h radioactive iodine uptake (RAIU) for estimating 131I dose in individualized treatment of hyperthyroidism. We retrospectively analyzed the clinical data of 132 patients receiving 131I treatment in our department between January and June, 2019. According to their 3 h/24 h RAIU peak ratio, the patients were divided into peak forward (≥80%) group and no peak forward (< 80%) group. In the former group, the therapeutic 131I dose was calculated based the Marinelli formula (131I dose=thyroid mass×planned amount/24 h RAIU), and in the latter group, the correlation between the ROI ratio and the 24 h RAIU was analyzed, and the 131I dose was calculated using a modified Marinelli formula where 24 h RAIU was replaced by a converted ROI ratio. The two groups of patients were compared for antithyroid drug type and discontinuation time, thyroid hormones and related antibodies, thyroid area, thyroid mass and 131I dose. All the patients were and followed up for one year to analyze the treatment efficacy. The ROI ratios after the treatment were analyzed in the two groups using ROC curves. There was a significant positive correlation between the ROI ratio and 24 h RAUI in the no peak forward group (Y=58.13 + 0.2X, R2=0.118, P < 0.05), and the formula for calculating 131I dose was converted into: 131I dose=thyroid mass× planned amount/(58.13+0.2×ROI ratio)%. Before the treatment, therapeutic 131I dose, thyroid hormone levels, TRAb, 3 h and 24 h RAIU, thyroid area, thyroid mass, and ROI ratio all differed significantly between the two groups (P < 0.05). At 3 months after treatment, thyroid hormone levels, TRAb, TPOAb, thyroid area, thyroid mass, ROI ratio, response rate, hypothyroidism rate, cure rate, remission rate, and nonresponse rate were similar between two groups (P>0.05). At the 1-year follow-up, the composition ratios of hyperthyroidism, hypothyroidism and cured cases remained similar between two groups (P>0.05). ROC curve analysis showed that at 3 months after treatment, the optimal cutoff values of ROI ratio for predicting hyperthyroid recurrence and hypothyroidism were 15.79 and 6.33, respectively. Thyroid 99mTcO4- imaging ROI ratio can be used for calculating 131I dose in individualized treatment of hyperthyroidism and for prognostic evaluation of the patients.

One institutions' experience with a true standard 15 mCi dose of I-131 for the treatment of Graves' disease.

Currently, there is a lack of consensus on the fixed dosage of RAI to be administered for this purpose between the main guideline frameworks set forth by the American Thyroid Association (ATA), Society of Nuclear Medicine and Molecular Imaging (SNMMI), European Association of Nuclear Medicine (EANM) and the European Thyroid Association (ETA). In this retrospective study, we will investigate the effectiveness of using a standard dose of 15 mCi ±10% of RAI in the treatment of Graves'. A retrospective chart review was conducted for the period between 1 May 2014 and 2 September 2020, to identify patients diagnosed with hyperthyroidism due to Graves' disease. The patients were grouped based on outcome and assessed for the efficacy of the dosage of 15 mCi ±10% of RAI in a successful treatment. Sixty-seven patients were identified that met the inclusion criteria between 1 May 2014 and 2 September 2020. Of the 67 RAI ablations; 60 patients became hypothyroid [60/67, (89.55%)], 2 euthyroid [2/67, (2.99%)] and 5 remained hyperthyroid [5/67, (7.46%)]. For the treatment of Graves' disease, the use of a standard low dose of 15 mCi ±10% has a high success rate without additional measurements or calculations beyond a standard planar image and 24-h uptake %. The adoption of a standard low dose of 15 mCi of I-131 across institutional guidelines would streamline dosage questions and eliminate the need to determine the weight of the thyroid for calculations in all RAI treatments for hyperthyroidism caused by Graves' disease.

Factors Associated With Radioactive Iodine Therapy–Acquired Nasolacrimal Duct Obstruction

ObjectiveTo identify factors associated with radioactive iodine (RAI)-acquired nasolacrimal duct obstruction (NLDO). MethodsRetrospective chart review and telephone surveys of patients who received RAI therapy for thyroid carcinoma at an academic institution were conducted. Telephone surveys were used to screen for post-RAI NLDO diagnoses. Databases were reviewed for documented NLDO, demographics, RAI dose, total number of RAI treatments, and sialadenitis. Routine post-RAI whole-body scintigraphy (WBS) images were analyzed for the presence or absence of 131I sodium iodide (I-131) in the nasolacrimal duct. Intranasal I-131 activity was graded as none, low, moderate, and high; those with moderate or high activity were considered to have “increased” activity. Logistic and ordinal logistic regression models were used to evaluate the associations with NLDO while adjusting for I-131 dose. ResultsOf the 209 patients who completed the survey, 15 (7%) had NLDO diagnoses. Increased intranasal I-131 activity on WBS, presence of nasolacrimal I-131 WBS activity, presence of documented post-RAI sialadenitis, and history of >1 RAI treatment were associated with the development of NLDO from univariate analyses (P ≤ .013). After adjusting for the administered dose of I-131, the presence of sialadenitis and nasolacrimal I-131 activity on WBS were the remaining 2 factors significantly associated with NLDO development (P < .001 and P = .01, respectively). ConclusionsThe presence of sialadenitis and nasolacrimal I-131 activity on WBS are I-131 dose-independent correlative factors for RAI-associated NLDO. Patients with these characteristics should be counseled on their increased risk of NLDO after RAI therapy for thyroid carcinoma.

Analysis of Excellent Response, Persistent Disease and Recurrent Diseases of Radioiodine Treatment on Differentiated Thyroid Carcinoma Patients- 42 Years’ Experience at NINMAS

Background: Radioiodine treatment in thyroidectomized differentiated thyroid carcinoma (DTC) patients was introduced in the world in 1940s and in Bangladesh in 1980. Long experience of treatment and lifelong follow up of DTC patients with proper documentation of medical records enriched the archive of the thyroid division of National Institute of Nuclear Medicine &amp; Allied Sciences (NINMAS). Aims: To evaluate the response of radioiodine treatment in DTC patients at NINMAS and analyze the outcome and prognostic factors in this cohort of patients in a single institute of a developing country. Patients and Methods: This is a retrospective cohort study. A total of 7525 patients with DTC received RAI ablation therapy from 1980-2021 at NINMAS, among them 5448 patients were treated with radioiodine from 1980-2017. Data were obtained from the medical records of 3482 DTC patients who were followed up until 2021 and all relevant data were available. Demographical, histopathological, surgical, radioiodine ablation doses of 131I, serum biomarkers thyroglobulin (Tg), antithyroglobulin antibody (TgAb) and biochemical investigation data were analyzed systematically. Age, gender, tumor size, presence of local and distant metastases at presentation, extrathyroidal extension (ETE), disease recurrence, and cancer-specific survival were also evaluated. Risk stratifications for recurrence and staging were calculated for dosing of radioiodine. The single dose of radioiodine ranged from 30 mCi to 200 mCi was given according to the postsurgical risk assessment. Repeated doses of radioiodine were given in the cases of persistent disease (PD) and recurrent disease (RD). Results: The median age of DTC patients was 38 years, with a range of 5-87 years (39.90± 12.67 years), with the majority of patients falling within the 30-39 age group. The ratio of female to male was 3.74:1. Compared to the previous decade, patient number increased about 72 and 16-folds in relation to the 1980s and 1990s respectively at this institute. Papillary thyroid carcinoma (PTC) and follicular variant of thyroid carcinoma (FVPTC) together were evaluated in 3311(95.09%) cases and follicular thyroid carcinoma (FTC) was diagnosed in 171(4.91%). Excellent response (ER) was observed by a single dose of radioiodine ablation in 2853(81.94%) and PD and RD were noted in 388(11.14%) and 241(6.92%) respectively. Tg and TgAb levels at pre-therapy state were significantly higher in patients who had PD (P &lt;0.000) and RD (P &lt;0.000). Conclusion: Significant increase in the number of DTC patients was observed in the last two decades. ER was noted in 81.94% with a single dose of radioiodine. Serum Tg and TgAb are two prognostic factors for disease outcomes showing high Tg and TgAb in PD and RD cases. Bangladesh J. Nuclear Med. 25(2): 81-87, 2022

Radioiodine treatment of hyperthyroidism in cats: results of 165 cats treated by an individualised dosing algorithm in Spain.

Although radioiodine (131I) is the treatment of choice for feline hyperthyroidism, 131I-dosing protocols commonly induce iatrogenic hypothyroidism and expose azotaemia. A recently reported patient-specific 131I dosing algorithm minimised the risk of 131I-induced hypothyroidism and azotaemia, while maintaining high cure rates. The aim of the study was to report results of 131I treatment in a European population of hyperthyroid cats using this patient-specific dosing algorithm. This prospective case series (before-and-after study) evaluated 165 hyperthyroid cats referred for 131I treatment. All cats had serum concentrations of thyroxine (T4), triiodothyronine (T3) and thyroid-stimulating hormone (TSH) measured (off methimazole ⩾1 week). Thyroid volume and percentage uptake of 99mTc-pertechnetate (TcTU) were determined using thyroid scintigraphy. An initial 131I dose was calculated by averaging dose scores for T4/T3 concentrations, thyroid volume and TcTU; 70% of that composite dose was then administered. Twenty-four hours later, percentage 131I uptake was measured, and additional 131I administered as needed to deliver an adequate radiation dose to the thyroid tumour(s). Serum concentrations of T4, TSH and creatinine were determined 6-12 months later. Median calculated 131I dose was 2.15 mCi (range 1.2-7.5), with only 51 (30.9%) receiving ⩾2.5 mCi. Of 165 cats, 124 (75.2%) became euthyroid, seven (4.2%) became overtly hypothyroid, 27 (16.4%) became subclinically hypothyroid and seven (4.2%) remained hyperthyroid. A higher proportion of overtly (85.7%) and subclinically (26.9%) hypothyroid cats developed azotaemia than euthyroid cats (13.6%; P = 0.0002). Hypothyroid cats were older (P = 0.016) and more likely to have detectable TSH concentrations (P = 0.025) and symmetrical bilateral distribution of 99mTc-pertechnetate uptake (P = 0.0002), whereas persistently hyperthyroid cats had higher severity scores (P = 0.012). Our results confirm that 131I dosing with this new algorithm results in high cure rates, with a lowered prevalence of 131I-induced overt hypothyroidism and azotaemia. Age, serum TSH concentrations, bilateral, symmetrical uptake and severity score help predict outcome.

Therapeutic Response and Long-term Outcome of Differentiated Thyroid Cancer with Pulmonary Metastases Treated by Radioiodine Therapy

Objective: This retrospective study was conducted to assess the efficacy of radioactive iodine therapy (RAIT) and investigate the prognostic factors for patients with pulmonary metastasis from differentiated thyroid carcinoma (DTC). Materials &amp; Methods: A total of 80 patients treated with radioactive iodine (131I)-avid pulmonary metastasis from DTC treated with 131I from 2001 to 2016 at National Institute of Nuclear Medicine &amp; Allied Sciences (NINMAS) were enrolled in this study. Treatment response was mainly measured by serum thyroglobulin (Tg) levels, diagnostic 131I whole-body scan (DxWBS) and patients clinical response. According to the treatment response patients were classified in two groups-complete response (CR) and persistent disease (PD). Result: Among 80 patients; 53(66.25%) males and 27(33.75%) females. Six patients were lost to follow-up; this study was done on the rest 74 patients. Out of 74 patients according to histological pattern 65(87.84%) were PTC and FTC 09(12.16%). Among 74 patients 50 had LN metastases; lung metastases were in 18 cases and six patients showed both lungs and bone metastases initially. RxWBS revealed lung metastasis in all of these 74 patients. The average received a dose of 131I was 537 ± 17.6 m Ci. Average postoperative serum Tg level at the time of presentation at NINMAS was 97.3 ng/ml with a decline in serum Tg levels after RAIT to 90 ng/ml. In the case of CR 14 patients showed diffuse lung uptake and 13 showed focal uptake; among PD 40 patients showed diffuse uptake and 14 showed focal lung uptake (p-value-0.004). The average follow-up period was 06 years. We observed CR in 25 (33.78%) patients and PD in 49 (66.21%) patients. The patient with CR; their an initial Tg level average of 38.9 ng/ml and after receiving last therapy their follow-up average Tg was 1.9 ng/m (p value-0.001). For the patient who had PD, their initial Tg level was 126.2 ng/ml, follow up average Tg was150 ng/dl with rising Tg level. Conclusion: From this study, it may be concluded that patients with DTC with lung metastases, most of the patients showed persistence of disease (66.21%) even after giving repeated radioiodine therapy. DxWBS and serum Tg levels at diagnosis are both important factors to evaluate the therapeutic response. Patients presenting with high serum Tg at initial diagnosis and subsequent bony metastases are likely to show a poor outcome Bangladesh J. Nuclear Med. 24(1&amp;2): 42-47, 2021

Cardiovascular Effects of Cumulative Doses of Radioiodine in Differentiated Thyroid Cancer Patients with Type 2 Diabetes Mellitus.

Simple SummaryThe cardiovascular effects of radioiodine (131I) therapy on people with differentiated thyroid cancer (DTC) and concomitant type 2 diabetes mellitus (T2DM) are unknown. To the best of our knowledge, this study is the first of its kind. Our aim was to assess the relationship between the left ventricular ejection fraction (LVEF) and high cumulative 131I doses in DTC/−T2DM and DTC/+T2DM female patients. In the DTC/−T2DM group, LVEF was negatively associated with high cumulative doses of 131I. This association did not exist in patients with DTC/+T2DM.Radioiodine (131I) therapy for differentiated thyroid cancer (DTC) involves exposure of the whole body, including the heart, to ionizing radiation. This exposure to the subsequent risk of heart disease is uncertain, especially in patients with DTC associated with type 2 diabetes mellitus (DTC/+T2DM). The current study aimed to assess the relationship between left ventricular ejection fraction (LVEF), high cumulative 131I dose, and peripheral blood parameters in patients with DTC/−T2DM and DTC/+T2DM. The study enrolled 72 female patients with DTC/−T2DM and 24 with DTC/+T2DM who received cumulative 131I doses above 150 mCi (5.55 GBq). LVEF was lower in patients with concomitant T2DM than those without (p < 0.001). The cumulative 131I dosage was inversely correlated with LVEF only in DTC/−T2DM patients (r = −0.57, p < 0.001). In the DTC/+T2DM group, LVEF was negatively associated with absolute platelet count (r = −0.67, p < 0.001) and platelet-to-lymphocyte ratio (r = −0.76, p < 0.001). Our results demonstrate that exposure to high cumulative 131I doses has different cardiovascular effects in DTC/−T2DM and DTC/+T2DM.

Efficacy of radioactive iodine treatment in Graves Disease using a calculated 131I dose and predictive factors of success in a Portuguese cohort

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Quantitative Scintigraphy Evaluated the Relationship between 131I Therapy and Salivary Glands Function in DTC Patients: A Retrospective Analysis.

Purpose Quantitative scintigraphy to evaluate salivary gland function changes in patients with differentiated thyroid cancer (DTC) after iodine-131 (131I) treatment. Methods A total of 458 patients with DTC grouped by sex and age were included. Salivary gland scintigraphy was performed to evaluate salivary gland function before and after 131I treatment. The uptake fraction (UF), uptake index (UI), and excretion fraction (EF) of two pairs of parotid glands and submandibular glands were measured and compared. The Chi-square test was conducted according to function impairment count. Results Salivary gland function in different age groups and sexes were quite different, especially for women <55 years old, who had decreased UF, UI, and EF of all four glands without basal injury. The secretion or uptake function of some salivary glands with basic function impairment before 131I treatment was increased after iodine treatment. Only a small percentage of males showed reduced functional parameters after several treatments. The most significant difference in the count of impairment for the four salivary glands were the first and third examinations, which was more evident in women. The submandibular gland had the most significant reduction in uptake. Conclusion Changes in salivary gland function are more common in young females being treated for DTC. Impairment of salivary gland function is correlated with the number of treatments and the cumulative dose of 131I. Some salivary gland functions impaired before 131I treatment were enhanced in the early treatment.

Hidden in plain site: Papillary thyroid carcinoma with metastases to branchial cleft cyst

30-year-old female with a history of papillary thyroid carcinoma, status post thyroidectomy and radioactive iodine ablation presented for a routine follow up visit for management of hypothyroidism. Patient was noted to have a congenital branchial cleft cyst in the right superolateral cervical area (Figure 1). Total body scan conducted following ablative I131 dose, 150 mCi had demonstrated no uptake throughout the body including branchial cyst indicative of metastasis. Elevated thyroglobulin tumor marker (14 ng/mL) at this visit was attributed to production by residual thyroid tissue. However, the level continued to rise over the next year to 42 ng/ml. Thyroid ultrasound failed to demonstrate any residual thyroid tissue. Total body scan with I123 scan revealed no uptake anywhere in the body. She also revealed that she has experienced some difficulty swallowing. Repeat thyroid ultrasound noted increase in size of a congenital submandibular branchial cleft cyst with increased vascularity. Therefore, ultrasound guided core needle biopsy of the enlarging right neck mass was performed. Pathology report of the previously known benign branchial cleft cyst showed presence of thyroid epithelium arranged in delicate papillary structures (Figure 2A and 2B). Patient underwent a branchial cyst excision and cervical lymph node dissection.