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Glomerular filtration rate (GFR) is an important indicator of renal function. Many methods have been developed to determine GFR in clinical examinations. This study aims to correlate between radionuclide plasma sampling methods (single and double blood samples, in vitro methods) and in vivo Gate's method using 99mTc-diethylene triamine penta-acetic acid (99mTc-DTPA) renography. Materials and Methods: 43 patients underwent this study, including 31 renal donors (Group 1) and 12 patients with obstructive uropathy (Group 2). All patients were administered with a range of 5–7 mCi of 99mTc-DTPA. Then, renography performed simultaneously after injection and GFR calculation followed by Gate's method. Blood samples were collected at 60- and 120-min postinjection, samples were counted by a thyroid uptake system, and GFR was calculated using a single plasma sample method (SPSM) and a double plasma sample method (DPSM). Results: The mean GFRs calculated by Gate's method in Groups 1 and 2 were 85.8 ± 18.2 ml/min and 118.4 ± 13.9 ml/min, respectively. Meanwhile, using the in vitro blood sampling methods (DPSM and SPSM), the mean GFRs in Group 1 were 73.8 ± 15.4 ml/min and 56.4 ± 20.9 ml/min, respectively, and in Group 2 were 116.8 ± 12.9 ml/min and 106.3 ± 18.5 ml/min, respectively. There is a high correlation between Gate's method and DPSM in two groups (r = 0.86 and 0.72, respectively), and a moderate correlation was found between Gate's method and SPSM in both groups (r = 0.49 and r = 0.37, respectively). The two in vitro methods (DPSM and SPSM) revealed that moderate correlation in both groups (r = 0.74 and r = 0.67, respectively) was observed. Conclusion: Renography is a simple method but considered inaccurate for GFR determination. However, in vitro plasma sampling is rarely used in Vietnam. In this study, Gate's method correlated well with DPSM and tended to overestimate GFR. Further, the in vitro methods can be applied to correct the in vivo method as a confirmatory test in some cases.

Objective: To determine the normal value of thyroid Technetium-99m uptake value in a single centre Pakistani population. Study Design: Cross-sectional study. Place and Duration of Study: Nuclear Medical Centre, Armed Forces Institute of Pathology, Rawalpindi, from Feb 2019 to Apr 2020. Methodology: A total of 90 patients who presented to Nuclear Medical Centre for parathyroid dual radiopharmaceutical scintigraphy were included in study and selected by non-probability consecutive sampling technique. Thyroid uptake studies were calculated via gamma camera acquisition. Pre injection counts were taken from the Technetium-99m pertechnetate filled syringe, thyroid counts were taken from the anterior thyroid image 20 minutes post injection and to look for any residual radiopharmaceutical counts of the empty syringe were also taken. Results: Out of total of 90 patients, 32 (35.6%) were male while 58 (64.4%) were female with male to female ratio of 1:2. The mean age was 38.4 ± 12.7. Mean Thyroid Stimulating Hormone values were 1.6 ± 0.8 and mean T4 values were 11.9 ± 3.5. The 5th-95th percentile range was 0.4-2.2% and median was 1.2%. The interquartile range was calculated to be 0.9-1.5%. Conclusion: Normal value of thyroid Technetium-99m uptake value in a single centre Pakistani population values varies significantly as compared to global figures i.e. 0.3-4.5% and is different than the one used in our own department i.e. 0.5-2.0%.

BACKGROUND: Thyrotoxicosis is a common medical problem. Thyroid nuclear imaging with either I 123 or technetium-99m (Tc-99m) pertechnetate are used to determine the cause. Although I 123 has been the standard technique, Tc-99m pertechnetate is now commonly used, acceptable and easier to perform. The commonly used normal value of Tc-99m pertechnetate is 1–4%, but lower normal values have been reported in different populations. OBJECTIVE: Determine normal reference range of Tc-99m pertechne-tate thyroid uptake for thyroid scintigraphy in Saudi Arabia. DESIGN: Retrospective, cross-sectional. SETTING: Nuclear medicine service at tertiary care center in Riyadh. PATIENTS AND METHODS: We used data from biochemically euthyroid patients who underwent a thyroid Tc-99m pertechnetate scan while having parathyroid scintigraphy for hyperparathyroidism between April 2009 to April 2019. Medical records and biochemical thyroid function tests were reviewed and Tc-99m pertechnetate thyroid uptake values were determined for each patient. MAIN OUTCOME MEASURES: Thyroid uptake of Tc-99m pertechne-tate in euthyroid patients. SAMPLE SIZE: 167 RESULTS: The mean and median uptake of Tc-99m pertechnetate in euthyroid patients were 0.86% and 1.0%, respectively, and the inter-quartile range was 0.0–1.0%. The normal reference range in the study population was 0.2-2%. Thyroid uptake inversely correlated with age in females (r=−0.37, P P =.001), and for all patients (r=?0.39, P CONCLUSION: The range for normal thyroid Tc-99m pertechnetate was lower than the standard 1-4% range. Moreover, uptake decreased with age. Further studies are needed to establish the normal age-adjusted uptake for the thyroid Tc-99m pertechnetate scan. LIMITATIONS: Single center and retrospective. CONFLICT OF INTEREST: None.

Objective Radioiodine (131I) is an established modality of definitive treatment of hyperthyroidism. In spite of the vast experience available, there are still several aspects to be clarified, such as whether fixed or calculated doses should be used. The aim of this study was to assess whether efficacy of this treatment could be improved by implementing a simple dosimetric calculation method including ultrasonographic estimation of thyroid volume and a single measurement of 24-h 131I thyroid uptake. Methods A prospective non-inferiority study was designed to compare two procedures to calculate radioiodine activity: the “semi-fixed” dose method (A), and the “calculated” dose method (B). The first consisted of activity escalation (185 MBq steps) based on etiology of hyperthyroidism, 131I uptake, and treatment objective. The second method was based on the “dosimetric compromise” concept, considering 24-h uptake and thyroid volume as the only factors and using a standard half-life of 5.5 days. The target absorbed dose was 150 Gy, but after a preliminary analysis (first 100 cases) it was increased to 200 Gy in diffuse toxic goiters (DTGs). Results A total of 212 patients were included. Method B was at least as effective in terms of final and functional outcome, with a trend to more success and less hypothyroidism. In addition, activities administered were significantly lower. Conclusion In radioiodine therapy of hyperthyroidism, a simple dosimetric method that provided results at least equal to those of a fixed dose-based method, with lower administered activities, could be implemented.

COTI (collar therapy indicator) has been recently introduced for the detection of gamma rays with emphasis on thyroid investigations. The aim of this study was to test the feasibility of a prototype version of COTI including activity detectors with low sensitivity in performing thyroid uptake measurements for a large group of patients. Consequently, thyroid uptake tests were carried out for a total of 89 patients (22 males and 67 females; age: 44 ± 13 years) with thyroid cancer (n = 74), hyperthyroidism (n = 16) at 2 and 24 h after administration of 0.44–2 MBq of 131I. Eight individuals among the thyroid cancer patients were monitored up to 96 h after administration. The COTI device was equipped with two CsI (Tl) detectors, known as LoHi type, sensitive to activity ranges from 0.02 to 30 MBq of 131I. The uptake values from COTI were compared with those measured with a standard probe. It was found that the mean uptake of thyroid activity in thyroid cancer patients was 2.1 ± 1.3% at 2 h when measured with the standard probe, while it was 2.2 ± 1.2% when measured with COTI. In addition, the average uptake at 24 h after administration was 2.5 ± 3.2% and 3.2 ± 3.8% measured with COTI and the standard probe, respectively. A strong correlation was found at 24 h between the results obtained with COTI and the standard probe, while a weaker correlation was seen at 2 h. Overall, there was no significant difference between the results obtained with the standard probe and those obtained with COTI at both 2 and 24 h (Pvalue ≥ 0.05). Besides, 85% of the uptake values measured with COTI were less than those measured with the standard probe at the 24 h after administration. The average uptake value was 0.9 ± 0.8% after 96 h by COTI, and 1.4 ± 1.3% by the standard probe. Pertaining to the hyperthyroidism patients, COTI showed mean uptake values of 20 ± 16% and 23 ± 18% at 2 and 24 h, respectively. In contrast, the standard probe suggested higher mean uptake values of 26 ± 18% and 30 ± 22%, respectively. It is concluded that the prototype of COTI used in the present study has been proved to be a feasible and promising tool in thyroid investigations. It is noted, however, that the next COTI generation should include detectors equipped with collimator and energy discrimination.

BACKGROUND. Scintigraphy using 99mTc-pertechnetate (TS) is the diagnostic test to differentiate thyroiditis following Graves’ disease (GD) from painless thyroiditis (PT). However, TS may be contraindicated or unavailable. OBJECTIVE. We compared the diagnostic effectiveness of two TSH receptor antibody (TRAb) immunoassays in untreated PT, already confirmed by qualitative and quantitative(99m) Tc-pertechnetate thyroid uptake (TCTU). METHOD. TRAb assay and TS were performed in suspected PT patients. All 67 subjects (27 males) with confirmed diagnosis of PT based on qualitative (subjective) low uptake and quantitative uptake below 0.4% (Normal TcTU: 0.4-4%). During the period of study, we used two 2(nd) generation TRAb assays. RESULT. Mean age, TSH, free T4 and TcTU were 40.5± 12.7 years, 0.066±0.089 mIU/L, 2.46±2.18 ng/mL and 0.188±0.0503% respectively. Fifteen (22.39%) of our PT patients were TRAb positive. Sensitivity, specificity, accuracy, PPV and NPV of TRAb in predicting thyroiditis were 81%, 75%, 78.2%, 83.6% and 74.4% in Assay 1. The same parameters were 74%, 64%, 71.2%, 76.8% and 62.7% respectively in TRAb Assay 2. However, ROC curve did not reveal any difference between the two assays. CONCLUSION. Negative TRAb value does not reliably distinguish PT from mild GD, in situations where TS is contraindicated or unavailable.

Thyroid uptake and scintigraphy using Tc-99m pertechnetate has proven to be more advantageous than with I-131 iodide, since the images have better quality, the procedure is faster and the patient is submitted to a lower radiation dose. Tc-99m has been used worldwide to study the thyroid function because of a number of advantages such as short half-life, short biological half-life, short effective half-life, short retention in gland and no Beta (β-) radiation, providing low dose to gland (10,000 times less than that of I-131), low cost and readily availability. Otherwise, I-131 with its high radiation burden (1-3 rad/mCi) has long half-life and causes Beta (β-) particle emission. Its main gamma photon has high energy (364 keV) which also causes poor image quality. The experiment is carried out at the Institute of Nuclear Medicine and Allied Sciences (INMAS), Bangladesh Atomic Energy Commission, Dhaka Medical College Hospital Campus, Dhaka-1000. In the present work, the study consists of 109 patients (76 female and 33 male) with ages ranging from 14 to 66 years. The patients studied with Tc-99m found to be hyperthyroid of 57 and in case of I-131, the findings were 60. The agreement between I-131 and Tc-99m is 95% and the correlation coefficient, r between Tc-99m & I-131 is = 0.879, which indicates strong correlation between them. So, it is statistically significant and makes a good agreement. The outcome of this study may provide valuable information about thyroid treatment and also may play important role in the management of thyroid patient.

The destruction of thyroid follicular cells by iodine-131 treatment for Graves' hyperthyroidism to a large extent depends on the amount of intrathyroidal activity absorbed (IAA). A thyroid weighing 50 g should receive an iodine-131 therapeutic dosage of between 110 MBq and 350 MBq for the effective treatment of Graves' hyperthyroidism. An IAA received of more than 350 MBq to the thyroid will bestow an unnecessary high iodine-131 therapeutic dosage. The objective of the study was to determine if the IAA would remain between 110 MBq and 350 MBq if the calculated administered activity (CAA) has been used with the highest radioactive iodine uptake (RAIU) value. A retrospective analysis was made of the 6- and 24-hr iodine-131 RAIU results of Graves' hyperthyroid patients (n = 124). Male (n = 18) and female (n = 106) patients from different racial groups and ranging from 15 to 75 years of age were included in the study. Overall, the CAA using the 6-hr RAIU value was higher. The CAA by the 6-hr RAIU values was used with the 24-hr RAIU values to calculate the IAA. 53.3% (n = 66) of the study group would have received IAA higher than 350 MBq when the CAA by the 6-hr RAIU values was used with the 24-hr RAIU values to calculate the IAA. These results suggested that the 24-hr RAIU value was most valuable for the calculation of an administered activity so that IAA of between 110 and 350 MBq can be achieved.

Although technetium-99m (99mTc) pertechnetate thyroid uptake rate can be measured by gamma camera with scintigraphy as well as by gamma probe, the normal reference range known as quite different between them. This study was performed to compare their diagnostic accuracy for evaluating patients with hyperthyroidism. We retrospectively reviewed consecutive 371 patients (euthyroid 89, Graves 167, and thyroiditis 115) who had simultaneously measured data of thyroid uptake rates by both gamma probe and camera methods in our hospital from November 2019 to June 2020. The reference ranges in euthyroid patients were 2.0-4.7% and 0.3–1.9% for probe and camera methods, respectively. For differentiating Graves’ disease and thyroiditis, the area under the curve of the camera method was significantly greater than that of the probe method (0.988 vs 0.975, p = 0.030) on receiver operating characteristic curve analysis. With a cutoff value of 0.7%, the sensitivity and specificity for the camera method were 93.4% and 94.8%, respectively. With a cutoff value of 3.0%, those for the probe method were 92.2% and 91.3%, respectively. In conclusion, 99mTc pertechnetate thyroid uptake rate measured by the camera method with scintigraphy had higher diagnostic accuracy than the probe method for evaluating patients with hyperthyroidism.

Amaç: Bu çalışmada Türk bir popülasyonda normal tiroid teknesyum-99m perteknetat alım aralığını belirlemek amaçlanmıştır.Yöntem: Retrospektif çalışmamız paratiroid adenom lokalizasyonu için uygulanan paratiroid sintigrafisinin bir bileşeni olarak teknesyum-99m perteknetat ile tiroid sintigrafisi yapılan ardışık 73 (54 kadın, 19 erkek) ötiroid hasta içerdi. Her hasta için 20. dakikada tiroid teknesyum- 99m perteknetat alım değeri hesaplandı.Bulgular: Ortalama hasta yaşı 56,4±15,2 yıl, ortalama tiroid uyarıcı hormon düzeyi 1,15±0,48 uIU/mL idi. Medyan ve çeyrekler arası aralık teknesyum-99m perteknetat alım değerleri sırasıyla %0,8 ve %0,56–1,15 idi. Belirlenen normal tiroid teknesyum-99m perteknetat alım aralığı %0,26–1,64 oldu. Yaş ve teknesyum-99m perteknetat alımı arasında negatif korelasyon gözlendi (r=-0,33; p=0,002).Sonuç: Türkiye’de kullanımda olanlara kıyasla anlamlı biçimde daha düşük değerlere dayanan yeni normal tiroid teknesyum-99m perteknetat alım aralığımızın, İstanbul nüfusunda tiroid hastalıklarında tiroid fonksiyonu değerlendirmelerinde kullanılmaya uygun olduğu savındayız., Aim: This study aimed to determine the normal range for thyroid uptake of technetium-99m (99mTc) pertechnetate in a Turkish population.Methods: The retrospective study included 73 (54 females, 19 males) consecutive euthyroid patients, all of whom underwent thyroid scintigraphy using 99mTc-pertechnetate as a component of parathyroid scintigraphy for parathyroid adenoma localization. The value of thyroid uptake of 99mTc-pertechnetate at the 20th minute was calculated for each patient.Results: The mean patient age was 56.4±15.2 years; the mean thyroid-stimulating hormone level was 1.15±0.48 uIU/mL. The median and interquartile range values of 99mTc-pertechnetate uptake were 0.8% and 0.56–1.15%, respectively. The normal range for thyroid uptake of 99mTc-pertechnetate was determined to be 0.26–1.64%. There was a negative correlation between 99mTc-pertechnetate uptake and age (r =-0.33, p=0.002).Conclusion: We propose that our new normal range for thyroid uptake of 99mTc-pertechnetate based on significantly lower values compared with those currently in use in Turkey is appropriate for use to evaluate thyroid function in thyroid disorders in the population of Istanbul.

BACKGROUND: Thyroid metabolism involves iodine, which allows us to use radioactive iodine for diagnostic and therapy purposes. The efficiency of radioiodine therapy depends on several parameters; the ability of thyroid tissue to uptake radioactive iodine is one of them. OBJECTIVE: The objective of this work is to quantify the radioactive iodine uptake on thyroid tissue. METHODS: In this work, we developed a method to quantify the in vivo uptake of iodine-131 on sections of thyroid glands removed by thyroidectomies. We performed an analysis of histological sections of the thyroid tissue by beta imaging. We had the opportunity to quantify the fixed radioactivity and to analyze its distribution in the thyroid gland, thanks to the good spatial resolution available with the type of detector used. RESULTS: The results gave a high image resolution showing the heterogeneity of iodine-131 fixation by the thyroid tissue. We were able to quantify the tissue radioactivity in mega Becquerel (MBq) per volume unit. CONCLUSION: This work has shown that the direct quantification of the thyroid tissue uptake is possible using the beta imaging system.

Thyroid uptake and scan (TUS) is a clinical tool used for differentiation of thyrotoxicosis etiologies. Although guidelines recommend ordering a TUS for evaluation of low TSH levels, no specific value is defined. This study aimed to determine a TSH cutoff at which TUSs yield a greater likelihood of successful determination of etiology to avoid unnecessary testing.This was a retrospective study on 137 patients seen by an endocrinologist who underwent TUS for evaluation of low TSH (0.4 μU/mL). A receiver operating curve analysis was performed to determine the TSH cutoff with maximal sensitivity and specificity for prediction of diagnostic utility.Ninety percent of TUSs (n = 123) led to a diagnosis, while 10% (n = 14) were inconclusive or normal. Diagnoses included Graves' diseases (52%), toxic multinodular goiter (19%), thyroiditis (12%), and solitary toxic adenoma (7%). The median TSH value was 0.008 μU/mL (IQR 0.005, 0.011), and the median free T4 value was 1.7 μU/mL (IQR 1.3, 2.8). The ROC analysis produced an area under the curve of 0.86. The optimal TSH cutoff value was 0.02 μU/mL (sensitivity 80%, specificity 93%) for prediction of diagnostic yield.This study demonstrates that TSH is a useful predictor of the utility of TUS in yielding an etiology of thyrotoxicosis. Our analysis showed that TUS had a greater likelihood of determining an etiology when TSH was ≤0.02 μU/mL. This information can help clinicians avoid unnecessary cost and patient time burden when TUS is unlikely to aid in determining the etiology of thyrotoxicosis.

PURPOSE: The aim of this study was to determine the influence of H2RAs to the 24-h I-131 uptake in the thyroid gland. MATERIAL AND METHODS: A prospective study with quasi-experimental pre- and post-study design was done. Subjects with normal fT4 level who fulfilled the inclusion criteria were selected. All subjects received 0.2 mCi of I-131 orally, and the thyroid uptake calculations were performed at 24 h later. The same procedure was performed 4 weeks later. All of the subjects were asked to consume H2RAs 1 h before the administration of I-131 of the second procedure. Both 24-h thyroid uptakes were statistically analysed. RESULTS: A total of 14 subjects were enrolled in this study. Most of them were women (78%) with an average age of 37.6 years old (range: 20–55). This study showed a median of 24-h thyroid uptake of I-131 before and after H2-receptor antagonist of 20.6% (range: 11.1–57.8%) and 16.7% (range: 8.1–39.4%) respectively. CONCLUSION: H2-receptor antagonist caused a significance reduction of 24-h I-131 uptake value in the thyroid gland.

International audience; Purpose To determine performances of 2-deoxy-2-(18F)fluoro-d-glucose (18F-FDG) positron emission tomography (PET) to detect the development of permanent thyroid dysfunction (PTD), and to evaluate the prognostic value of early increased thyroid uptake in stage IV melanoma patients treated with anti-programmed death 1 (anti-PD-1) antibodies. Methods Twenty-nine patients were retrospectively enrolled. PTD was defined as symptomatic thyroid disorder requiring long-term specific treatment. On the first PET performed during follow-up, maximal standardized uptake value of the thyroid (SUVmax-Th) and SUVmax-Th/SUVmax-blood-pool ratio (Th/B) were measured. Areas under ROC curves (AUC) of these parameters for the diagnostic of PTD were compared. Cutoff values were defined to maximize the Youden's index. Survival analyses were performed according to the Kaplan-Meier method and compared using the log-rank method between patients with and without enhanced thyroid uptake according to cutoff values defined with the Hothorn and Lausen method. Results Four patients presented PTD. Median SUVmax-Th and Th/B were, respectively, 2.11 and 1.00. The median followup period was 21.7 months. AUC were 1.0 (CI 95% 0.88-1.0) for both parameters. Optimal cutoff values were, respectively, SUVmax-Th > 4.1 and Th/B > 2.0, both conferring sensitivities of 100% (CI 95% 40-100%) and specificities of 100% (CI 95% 86-100%). The median progression-free survival and overall survival were 11.3 months and 33.5 months, respectively. Using optimized cutoffs, there was no statistically significant difference of survival. Conclusion SUVmax-Th > 4.1 and Th/B > 2.0 provided perfect diagnostic performances to detect patients that developed PTD. No significant survival difference was found between patients with and without increased thyroid uptake.

Thyroid scintigraphy is an important investigation for the clinical diagnosis of thyroid diseases. Thyroid diseases often present characteristic abnormal patterns in scintigraphic images. In this study, we developed an automated recognition model for thyroid uptake patterns. These patterns were classified into six categories, and they are diffusely increased, diffusely decreased, heterogeneous, focally increased, focally decreased, and normal. This study is the first report on such data for automated thyroid pattern interpretation to the best of our knowledge. A thyroid uptake pattern recognition network (TPRNet) was developed, using deep and handcrafted features of thyroid patterns to perform classification. The method can be trained using the traditional back-propagation algorithm. An in-house dataset that contains 4263 thyroid scintigraphic images was constructed to train and validate the TPRNet. Furthermore, an external test dataset that includes 1318 images was constructed to test the TPRNet. Experimental results show that the proposed method is effective for recognizing thyroid patterns in scintigraphic images. It outperforms compared methods, notably in the external test dataset, demonstrating the good generalization ability of the TPRNet. The proposed method is also compared against four physicians’ judgments on recognizing thyroid patterns, resulting in a performance that is comparable to that of experienced doctors, showing that it could be used in clinical practice.

The role of radioactive iodine uptake and scintigraphy were studied over 111 subjects with a mean age of 42±13 years, 65% females and 35% males, in the evaluation of hyperthyroidism with multinodular goiter. The uptake study was performed by oral administration of 4.5 – 10.0 μCi of 131I as sodium-iodide thyroid scintigraphy was performed 20 minutes after an intravenous injection of 2.0 – 4.0 mCi of 99mTc as pertechnetate. The Mean ± SD uptake values for the study subjects were found to be 36.1±15.4% ranging from 14% to 75% at 2 h and 59.9±15.9% ranging from 32% to 90% at 24 h measurements. The present results of uptake values clearly exceed the normal range (3% – 12% for 2 h; 8% – 25% for 24 h), which indicate the hyper-functioning of thyroid, and therefore, demonstrated successfully the efficient role of radioactive iodine uptake and scintigraphy to diagnose the hyperthyroidism.