Tc-pertechnetate Uptake Research Articles

Multi-time point imaging in 99m Tc-pertechnetate scintigraphy of ectopic gastric mucosa in duplication cysts: value-added services.

The aim of our study was to describe the scintigraphic patterns of 99m Tc-pertechnetate uptake in patients who were referred to the department of nuclear medicine for evaluating and diagnosing ectopic gastric mucosa in foregut and midgut duplication cysts. This hospital-based, retrospective cum prospective research spans a period of 8 years from April 2014 to January 2022. Previous hospital medical records were analyzed and subsequently, a database was prepared which included the age, sex, clinical indication of a 99m Tc-pertechnetate scan, and the planar and SPECT-computed tomography (CT) imaging findings. Postoperative histopathological reports were available for 21 patients. Dynamic and planar static imaging was performed. We included SPECT-CT in suspected duplication cysts to increase the sensitivity and specificity which is a tradeoff for a small amount of additional radiation exposure. A total of 69 patients were subjected to a 99m Tc-pertechnetate scan for suspected foregut or midgut duplication cysts. All were subjected to dynamic planar and delayed static images up to 24 h or until focal uptake of radiotracer was noted which corroborated the anatomical findings, whichever was earlier. SPECT-CT was performed along with the planar study in 31 patients which confirmed the findings. Previously performed CT scans were used for anatomical correlation in the remaining ones. Duplication cysts were localized in a total of 28 patients (19 foregut duplication cysts and 12 small bowel duplications - 3 patients had dual duplication cysts, both foregut, and midgut). Forty-one patients had no scintigraphic evidence of ectopic gastric mucosa. Of these 69 patients, histopathological diagnosis was available for 21 patients (22 lesions). The report was concordant with the scan findings in 15 patients (16 lesions) and 6 patients showed discordance in histopathological diagnosis and scan findings. In conclusion, multi-time point imaging is the key to diagnosing ectopic gastric mucosa of various sizes and in various locations. An abnormal radiotracer uptake in dynamic sequences, even before the appearance of the stomach in the region of the small bowel is indicative of intestinal duplication, and delayed radiotracer visualization in the region of the thorax is characteristic of intrathoracic foregut duplication cyst.

Predicting outcomes in hyperthyroid cats treated with radioiodine.

BackgroundRadioiodine (131I) is the treatment of choice for cats with hyperthyroidism. After 131I, however, euthyroidism is not always achieved, with 5% to 10% of cats remaining persistently hyperthyroid and 20% to 50% developing iatrogenic hypothyroidism.ObjectivesTo identify pretreatment factors that may help predict persistent hyperthyroidism and iatrogenic hypothyroidism after treatment of cats using a novel 131I dosing algorithm.AnimalsOne thousand and four hundred hyperthyroid cats treated with 131I.MethodsProspective, before‐and‐after study. Pretreatment predictors (clinical, laboratory, scintigraphic, 131I dose, 131I uptake measurements) of treatment failure or iatrogenic hypothyroidism were identified by multivariable logistic regression analysis.ResultsCats that developed iatrogenic hypothyroidism were more likely to be older (odds ratio [OR] = 1.10; 95% confidence interval [CI], 1.04‐1.17; P = .001), female (OR = 2.04; 95% CI, 1.54‐2.70; P < .001), have detectable serum thyroid‐stimulating hormone (TSH) concentrations (OR = 4.19; 95% CI, 2.0‐8.81; P < .001), have bilateral thyroid nodules (OR = 1.57; 95% CI, 1.19‐2.08; P < .001), have homogeneous, bilateral distribution of 99mTc‐pertechnetate uptake (OR = 2.93; 95% CI, 2.05‐4.19; P < .001), have milder severity score (OR = 0.62; 95% CI, 0.49‐0.79; P < .001), and have higher 131I uptake (OR = 2.40; 95% CI, 1.75‐3.28; P < .001). In contrast, cats remaining persistently hyperthyroid were more likely to be younger (OR = 0.81; 95% CI, 0.72‐0.92; P < .001), have higher severity score (OR = 1.87; 95% CI, 1.51‐2.31; P < .001), and have lower 131I uptake (OR = 3.50; 95% CI, 1.8‐6.80; P < .001).Conclusions and Clinical ImportanceAge, sex, serum TSH concentration, bilateral and homogeneous 99mTc‐pertechnetate uptake on scintigraphy, severity score, and percent 131I uptake are all factors that might help predict outcome of 131I treatment in hyperthyroid cats. Cats with persistent hyperthyroidism had many predictive factors that directly contrasted those of cats that developed 131I‐induced hypothyroidism.

Предикторы эффективности терапии радиоактивным йодом болезни Грейвса у детей и подростков

RATIONALE : Insufficient world–wide clinical experience in radioiodine therapy (RIT) for Graves’ disease (GD) in children and adolescents, and limited knowledge of the predictors of RIT efficacy. AIMS : Analysis and identification of the most significant predictors of the efficacy of RIT in children and adolescents with Graves’ disease. MATERIALS AND METHODS : A total of 55 patients (48 females and 7 males) aged from 8 to 18 years receiving primary RIT for GD were enrolled. RIT planning was based on the dosimetric method. Analyzed parameters included gender, age, ultrasound thyroid volume before and 6 months after treatment, the presence of endocrine ophthalmopathy, duration of antithyroid drug (ATD) therapy, relapse of thyrotoxicosis after ATD dose reduction, blood fT3, fT4 and TSH levels initially and at 1, 3, 6 months after treatment, TSH receptor Ab initially and at 3 and 6 months after treatment, thyroid 99m Tc–pertechnetate uptake at 10–20 minutes (%), maximum thyroid 131 I uptake (%), specific 131 I uptake (MBq/g) and therapeutic 131 I activity (MBq). Fisher exact test, non–parametric Mann–Whitney test, Wilcoxon signed–rank test, logistic regression modelling, ROC–analysis, proportional hazard model (the Cox regression), the Kaplan–Meier method and log–rank test were used for statistical analysis as appropriate. RESULTS : Six months after RIT, hypothyroidism was achieved in 45 (81.8%), euthyroid state – in 2 (3.6%), and in 8 (14.6%) patients thyrotoxicosis persisted. On univariate statistical analysis, the smaller thyroid volume, higher fT4 and lower TSH receptor Ab levels, lower 99m Tc–pertechnetate uptake and higher specific 131 I uptake were associated with hypothyroidism. On multivariate logistic regression analysis, the older patient’s age (p=0.011), smaller thyroid volume (p=0.003) and higher fT4 (p=0.024) were independent predictors of RIT efficacy. Thyroid volume was also the only variable associated with achievement of hypothyroidism in time after RIT (p=0.011). CONCLUSION : The efficacy of dosimetry–based RIT in children and adolescents with GD 6 months after treatment was 81.2%. Older patients’ age, smaller thyroid volume and higher fT4 level were independent predictors of therapy success. Smaller thyroid volume was also a predictor of the favorable time–related outcome. Statistical models obtained in this work may be used to prospectively estimate the chance of efficient RIT for GD in pediatric patients.

Radioprotective Effect of Epigallocatechin-3-Gallate on Salivary Gland Dysfunction After Radioiodine Ablation in a Murine Model.

Objectives.Radioiodine (RI) therapy is known to subject cellular components of salivary glands (SG) to oxidative stress leading to SG dysfunction. However, the protective effects of antioxidants on RI-induced SG damage have not been well investigated. The authors investigated the morphometric and functional effects of epigallocatechin-3-gallate (EGCG) administered prior to RI therapy and compared this with the effects of amifostine (a well-known antioxidant) in a murine model of RI sialadenitis.Methods.Four-week-old female C57BL/6 mice (n=48) were divided into four groups; a normal control group, a RI-treated group (0.01 mCi/g mouse, orally), an EGCG and RI-treated group, and an amifostine and RI-treated group. Animals in these groups were divided into 3 subgroups and euthanized at 15, 30, and 90 days post-RI treatment. Salivary flow rates and lag times were measured, and morphologic and histologic examinations and TUNEL (terminal deoxynucleotidyl transferase biotin-dUDP nick end labeling) assays were performed. Changes in salivary 99mTc pertechnetate uptake and excretion were followed by single-photon emission computed tomography.Results.Salivary flow rates and lag times to salivation in the EGCG or amifostine groups were better than in the RI-treated group. Histologic examinations of SGs in the EGCG or amifostine group showed more mucin-rich parenchyma and less periductal fibrosis than in the RI-treated group. Fewer apoptotic cells were observed in acini, ducts, and among endothelial cells in the EGCG or amifostine group than in the RI group. In addition, patterns of 99mTc pertechnetate excretion were quite different in the EGCG or amifostine group than in the RI group.Conclusion.EGCG supplementation before RI therapy could protect from RI-induced SG damage in a manner comparable to amifostine, and thus, offers a possible means of preventing SG damage by RI.

Cutoff value of thyroid uptake of (99m)Tc-pertechnetate to discriminate between Graves' disease and painless thyroiditis: a single center retrospective study.

Thyroid uptake of (99m)Tc-pertechnetate is a useful way to determine the cause of thyrotoxicosis. In daily clinical practice, (99m)Tc-pertechnetate uptake is used to discriminate between Graves' disease and painless thyroiditis when clinical information is not enough to make the distinction. However, since the optimal cutoff value of (99m)Tc-pertechnetate uptake has not yet been elucidated, our aim was to determine this value. We recruited patients with thyrotoxicosis in whom (99m)Tc-pertechnetate uptake was measured in clinical settings between 2009 and 2013. Three experienced endocrinologists (who were blinded to the value of (99m)Tc-pertechnetate uptake and initial treatment) diagnosed the cause of thyrotoxicosis based on thyrotropin, free triiodothyronine, free thyroxine, and thyrotropin receptor antibody levels, and by ultrasound findings and using images of thyroid uptake of (99m)Tc-pertechnetate without the actual values. Ninety-four patients diagnosed as having Graves' disease or painless thyroiditis were finally included. According to the diagnosis, the optimal cutoff value of (99m)Tc-pertechnetate uptake was determined by receiver operating characteristics analysis. A cutoff value of 1.0% provided optimal sensitivity and specificity of 96.6% and 97.1%, respectively. Then, its validity was confirmed in 78 patients with confirmed Graves' disease or painless thyroiditis diagnosed at another institute. Applying this cutoff value to the patients with thyrotoxicosis revealed positive and negative predictive values for Graves' disease of 100% and 88.9%, respectively. In conclusion, a cutoff value for (99m)Tc-pertechnetate uptake of 1.0% was useful to discriminate between Graves' disease and painless thyroiditis.

Establishment of an Effective Radioiodide Thyroid Ablation Protocol in Mice

Due to the high variance in available protocols on iodide-131 (¹³¹I) ablation in rodents, we set out to establish an effective method to generate a thyroid-ablated mouse model that allows the application of the sodium iodide symporter (NIS) as a reporter gene without interference with thyroidal NIS. We tested a range of ¹³¹I doses with and without prestimulation of thyroidal radioiodide uptake by a low-iodine diet and thyroid-stimulating hormone (TSH) application. Efficacy of induction of hypothyroidism was tested by measurement of serum T₄ concentrations, pituitary TSHβ and liver deiodinase type 1 (DIO1) mRNA expression, body weight analysis, and ^99mTc-pertechnetate scintigraphy. While 200 µCi (7.4 MBq) ¹³¹I alone was not sufficient to abolish thyroidal T₄ production, 500 µCi (18.5 MBq) ¹³¹I combined with 1 week of a low-iodine diet decreased serum concentrations below the detection limit. However, the high ¹³¹I dose resulted in severe side effects. A combination of 1 week of a low-iodine diet followed by injection of bovine TSH before the application of 150 µCi (5.5 MBq) ¹³¹I decreased serum T₄ concentrations below the detection limit and significantly increased pituitary TSHβ concentrations. The systemic effects of induced hypothyroidism were shown by growth arrest and a decrease in liver DIO1 expression below the detection limit. ^99mTc-pertechnetate scintigraphy revealed absence of thyroidal ^99mTc-pertechnetate uptake in ablated mice. In summary, we report a revised protocol for radioiodide ablation of the thyroid gland in the mouse to generate an in vivo model that allows the study of thyroid hormone action using NIS as a reporter gene.

Functional Radionuclide Imaging, In-Vitro Radioiodine Uptake Estimation and RT-PCR in the Evaluation of Sodium Iodide Symporter (NIS) Expression and Functionality in Breast Cancer: A Pilot Study

Breast cancer is a common malignancy in females, which is considered as a systemic disease, whose treatment involves combined modality including systemic as well as local treatment. Recent studies have shown that breast cancer also expresses Sodium Iodide Symporter (NIS) gene, like in the thyroid, which is the factor responsible for the uptake of iodide by the thyroid, enabling radioiodine therapy of thyroid disorders. This study aimed to evaluate various radionuclide imaging characteristics, in vitro radioiodine uptake (RAIU) and evaluation of NIS expression by using Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) to explore sodium iodide symporter (NIS) expression and iodine uptake in breast cancer and to explor e whether radioiodine can be used for the diagnosis and treatment of breast cancer. Ways of differential regulation of NIS expression in breast cancer has also been explored. Female patients with palpable breast lump and histologically proven infiltrating duct carcinoma were taken up for the study, which included 50 females of mean age 49years. (range: 23-73years). The patients were categorized into different groups, depending on the type of the study performed. The uptake patterns in various imaging modalities were analyzed and compared with invitro and RT-PCR studies. 68% of breast cancer cases showed (99m)Tc-pertechnetate uptake at the initial images. This finding could partly be due to tumor vascularity, which is usually higher compared to the normal tissues. The uptake in the delayed imaging could be related to that due to NIS in the breast. Use of perchlorate or stable iodine did not alter the pertechnetate uptake pattern in breast tumor. Good correlation between (99m)Tc-pertechnetate and (99m)Tc-tetrofosmin uptake in breast cancer was demonstrated. In vitro radioactive iodine uptake in the breast tumor was significantly higher than that in the normal breast tissue. Only 42% of breast tumor samples studied using RT-PCR showed NIS expression. Correlation between (99m)Tc-pertechnetate uptake and NIS expression could not be well established. Further studies with higher dose of radioiodine and/or mechanisms of differentially blocking the thyroid are required to assess the feasibility of radioiodine therapy for breast cancer.

A Case of Painful Hashimoto Thyroiditis that Mimicked Subacute Thyroiditis

Hashimoto thyroiditis (HT) is an autoimmune thyroid disorder that usually presents as a diffuse, nontender goiter, whereas subacute thyroiditis (SAT) is an uncommon disease that is characterized by tender thyroid enlargement, transient thyrotoxicosis, and an elevated erythrocyte sedimentation rate (ESR). Very rarely, patients with HT can present with painful, tender goiter or fever, a mimic of SAT. We report a case of painful HT in a 68-year-old woman who presented with pain and tenderness in a chronic goiter. Her ESR was definitely elevated and her thyroid laboratory tests suggested subclinical hypothyroidism of autoimmune origin. 99mTc pertechnetate uptake was markedly decreased. Fine needle aspiration biopsy revealed reactive and polymorphous lymphoid cells and occasional epithelial cells with Hürthle cell changes. Her clinical symptoms showed a dramatic response to glucocorticoid treatment. She became hypothyroid finally and is now on levothyroxine therapy.

Enhanced antiproliferative effects of combination hexokinase II shRNA and NIS gene therapy on vascular smooth muscle cells

This study was designed to determine the antiproliferative effects of combination gene therapy using sodium iodide symporter (NIS)-based radioiodine and lentivirus-mediated short hairpin RNA (shRNA) against hexokinase II (HKII) on vascular smooth muscle cells (VSMCs). A7r5 rat VSMCs were stably transfected with a dual-expression vector of NIS and Fluc (A7r5-NL cells). Functional assessment was performed by radioiodine uptake assay, luciferase assay and confocal microscopy. After exposure to lentivirus-HKII-shRNA, the (18)F-FDG uptake test and HK activity assay were performed. The effects of combination therapy with (131)I and lentivirus-HKII-shRNA on VSMCs were assessed with an in vitro clonogenic assay. In vivo bioluminescence and nuclear imaging were undertaken using a xenografted mouse model. In vitro functional assessment confirmed expression of NIS and Fluc genes in A7r5-NL, but not in parent A7r5 cells. Transfection of lentivirus-HKII-shRNA resulted in a significant decrease in messenger RNA expression of the HKII gene, (18)F-FDG uptake and HK activity. The cell survival rate of A7r5-NL decreased to 61.9% and 90.5% by single therapy with 7.4 MBq of (131)I or lentivirus-HKII-shRNA, respectively, and further decreased to 42.9% by combined therapy (P<.05). In vivo bioluminescent and gamma camera images clearly demonstrated optical signals and (99m)Tc pertechnetate uptake at the site of A7r5-NL cell inoculation in nude mice. The enhanced antiproliferative effect on VSMCs was achieved by a combination of NIS-based radioiodine and lentivirus-mediated HKII shRNA gene therapy. Successful demonstration of in vivo dual reporter gene imaging assures the potential for further application in an animal model.

Postsurgical thyroid remnant estimation by 99mTc‐pertechnetate scintigraphy predicts radioiodine ablation effectiveness in patients with differentiated thyroid carcinoma

The purpose of this study was to evaluate the relationship between postsurgical neck (⁹⁹m) technetium ((⁹⁹m) Tc)-pertechnetate uptake and the rate of successful remnant ablation after radioiodine treatment in patients with differentiated thyroid carcinoma (DTC). Retrospectively enrolled were 232 patients with DTC who underwent total thyroidectomy and fixed activity ablation with 3.7 GBq ¹³¹I. The (⁹⁹m) Tc scans were performed on all patients before ¹³¹I administration. Thyroid ablation was assessed after 6 to 12 months by thyroid-stimulating hormone (TSH)-stimulated ¹³¹I-WBS and thyroglobulin measurement. The rate of successful ablation, occurrence of radioiodine-induced thyroiditis, and length of hospitalization were correlated with the (⁹⁹m) Tc-pertechnetate scintigraphy results. A (⁹⁹m) Tc uptake was significantly lower in ablated versus nonablated patients (p < .001). High (⁹⁹m) Tc-pertechnetate uptake, especially greater than 1.4%, predicted a high-risk of unsuccessful ablation. Higher (⁹⁹m) Tc-pertechnetate uptake was also related to prolonged hospitalization and the occurrence of radioiodine-induced thyroiditis. The (⁹⁹m) Tc-pertechnetate scintigraphy is a simple and feasible tool to evaluate thyroid remnants and to predict radioiodine ablation results in patients with DTC.

Distribution and Dynamics of 99mTc-Pertechnetate Uptake in the Thyroid and Other Organs Assessed by Single-Photon Emission Computed Tomography in Living Mice

(99m)Tc pertechnetate is a well-known anion, used for clinical imaging of thyroid function. This gamma emitter is transported by the sodium iodide symporter but is not incorporated into thyroglobulin. Scintigraphy using (99m)Tc pertechnetate or (123)iodide represents a powerful tool for the study of sodium iodide symporter activity in different organs of living animal models. However, in many studies that have been performed in mice, the thyroid could not be distinguished from the salivary glands. In this work, we have evaluated the use of a clinically dedicated single-photon emission computed tomography (SPECT) camera for thyroid imaging and assessed what improvements are necessary for the development of this technique. SPECT of the mouse neck region, with pinhole collimation and geometric calibration, was used for the individual measurement of (99m)Tc pertechnetate uptake in the thyroid and the salivary glands. Uptake in the stomach was studied by planar whole-body imaging. Uptake kinetics and biodistribution studies were performed by sequential imaging. This work has shown that thyroid imaging in living mice can be performed with a SPECT camera originally built for clinical use. Our experiments indicate that (99m)Tc pertechnetate uptake is faster in the thyroid than in the salivary glands and the stomach. The decrease in (99m)Tc pertechnetate uptake after injection of iodide or perchlorate as competitive inhibitors was also studied. The resulting rate decreases were faster in the thyroid than in the salivary glands or the stomach. We have shown that a clinically dedicated SPECT camera can be used for thyroid imaging. In our experiments, SPECT imaging allowed the analysis of (99m)Tc pertechnetate accumulation in individual organs and revealed differences in uptake kinetics.

Extremely high doses of radioiodine required for treatment of Graves' hyperthyroidism: a case report

IntroductionRadioactive iodine (131I) is widely prescribed for treatment of Graves’ disease. A dose of 370 to 555 MBq (10 to 15 mCi) is usually enough, but reports of improved remission rates with single doses up to 20-30 mCi, and 38.5 mCi at most, exist.Case presentationA 53-year-old male patient was evaluated in September 2005, with symptoms of thyrotoxicosis for 2 years. He presented with tachycardia (130 bpm) and a large goiter. Thyrotropin was <0.01 uIU/ml (0,41-4,5), free thyroxin >7.77 ng/dl (0.9-1.8), anti-thyreoperoxidase antibody: 374 IU/ml (<35) and anti-thyroglobulin antibody: 749 IU/ml (<115). Ultrasound: diffuse goiter, no nodules; right lobe: 7.9 × 3.8 × 3.8 cm; left: 7.7 × 3.5 × 3.8 cm; isthmus: 1.6 cm. Propylthiouracil 300 mg t.i.d. and propranolol were prescribed. Thyroid 99mTc-pertechnetate uptake: 52% (0.35-1.7%) and estimated thyroid volume: 149 mL. After 30 days, he received 555 MBq (15 mCi) of 131I-iodide. Six months after radioiodine therapy, under methimazole 40 mg, thyroid stimulating hormone was 1.5 uIU/ml; free thyroxine 0.54 ng/dl. Methimazole was suspended. In 21 days, thyroid stimulating hormone was 0.03 uIU/ml; free thyroxine 0.96 ng/dl. Methimazole was reintroduced. One year later, thyroid stimulating hormone was <0.01 uIU/ml and free thyroxine >7.77 ng/dl. Thyroid 99mTc-pertechnetate uptake was 45% and estimated thyroid volume 144 mL. A 1110 MBq (30 mCi) radioiodine therpy was administered. He used Methimazole for 8 months, when overt hypothyroidism appeared (TSH: 25.30 uIU/ml; free thyroxine: 0.64 ng/dl). Methimazole was interrupted. Hyperthyroidism returned 6 weeks later (thyroid stimulating hormone <0.01 uIU/ml; free thyroxine >7.77 ng/dl). Thyroid 99mTc-pertechnetate uptake was 25% and estimated thyroid volume 111 mL. Methimazole was prescribed again. In March 2008 he received a 2590 MBq (70 mCi) radioiodine therapy. By may/2008, under methimazole 20 mg, his TSH was 0.07 uIU/ml; free thyroxine 1.31 ng/dl. In October 2008 he presented overt hypothyroidism (TSH 91.6 uIU/ml; free thyroxine 0.34) and was given levothyroxine 75 mcg/day. He remains euthyroid under hormone replacement.ConclusionOur presented case of Graves’ disease received a cumulative dose of 4255 MBq (115 mCi). The high uptake could indicate accelerated iodine turnover with 131I short time of action. Impaired hormone synthesis could also be present. We believe the extremely high dose required was due to the initial very high iodine uptake and large thyroid volume.

Efficacy of 99mTc pertechnetate and 131I radioisotope therapy in sodium/iodide symporter (NIS)-expressing neuroendocrine tumors in vivo

There is growing interest in the human sodium/iodide symporter (NIS) gene both as a molecular imaging reporter gene and as a therapeutic gene. Here, we show the feasibility of radioisotope therapy of neuroendocrine tumors. As a separate application of NIS gene transfer, we image NIS-expressing tumors with pinhole SPECT in living subjects. Biodistribution studies and in vivo therapy experiments were performed in nude mice carrying stably NIS-expressing neuroendocrine tumor xenografts following i.v. injection of (131)I and (99m)Tc pertechnetate. To show the usefulness of NIS as an imaging reporter gene, (99m)Tc pertechnetate uptake was imaged in vivo using a clinical gamma camera in combination with a custom-made single pinhole collimator, followed by SPECT/small animal MRI data coregistration. NIS-expressing neuroendocrine tumors strongly accumulated (131)I and (99m)Tc pertechnetate, as did thyroid, stomach, and salivary gland. The volume of NIS-expressing neuroendocrine tumors decreased significantly after therapeutic administration of (131)I or (99m)Tc pertechnetate, whereas control tumors continued to grow. NIS-mediated uptake of (99m)Tc pertechnetate could be imaged in vivo at high resolution with a clinical gamma camera equipped with a custom-made single pinhole collimator. High-resolution functional and morphologic information could be combined in a single three-dimensional data set by coregistration of SPECT and small animal MRI data. Lastly, we demonstrated a therapeutic effect of (99m)Tc pertechnetate on NIS-expressing neuroendocrine tumors in cell culture and, for the first time, in vivo, thought to be due to emitted Auger and conversion electrons. NIS-expressing neuroendocrine tumors efficiently concentrate radioisotopes, allowing for in vivo high-resolution small animal SPECT imaging as well as rendering possible successful radioisotope therapy of neuroendocrine tumors.

Normal values of [99mTc]pertechnetate uptake and excretion fraction by major salivary glands

The assessment of the functional status of the salivary glands has been used in the scintigraphic evaluation of xerostomia. Several quantitative methods derived from standard dynamic scintigraphy have been suggested. However, the indices proposed are quite variable and unlikely to be useful in clinical practice. The objectives of this study were to obtain reference values of major salivary glands uptake and excretion fraction in healthy subjects and to obtain normal ratios of Tc-pertechnetate uptake by the major salivary glands in comparison to the thyroid gland uptake. The standardization of these values has the purpose of making this evaluation faster and more objective. Fifty volunteers without clinical evidence of xerostomia or thyroid disease underwent static salivary glands scintigraphy with Tc-pertechnetate. Static images were obtained at 20 minutes and then at 3 minutes after oral stimulation with lemon juice. Percent uptake, excretion fraction and salivary gland to thyroid ratio rates were calculated for the parotid and the submandibular glands. The mean of the uptake values at 20 minutes for the right and left parotid glands were respectively 0.31% and 0.26%, and for the submandibular glands 0.15%. The excretion fraction of the tracer after the lemon juice stimulation was 70% for the parotids glands, 50% for the right and 49% for the left submandibular glands. The mean+/-SD salivary gland to thyroid count ratio was 0.79+/-0.45 for the right parotid, 0.78+/-0.5 for the left parotid, 0.67+/-0.33 and 0.66+/-0.34 for the right and left submandibular glands, respectively. Salivary glands scintigraphy with uptake and excretion fraction calculation is an easy to perform, non-invasive and objective method to investigate salivary glands function. These findings help the nuclear physician to interpret salivary gland scintigraphy more objectively, even in patients with thyroid gland dysfunction in whom Tc-pertechnetate thyroid uptake may be abnormal.

99mTc-sestamibi thyroid uptake in euthyroid individuals and in patients with autoimmune thyroid disease

We investigated the biokinetics of (99m)Tc-sestamibi in the thyroid of euthyroid volunteers (EVs) and in patients with autoimmune thyroid diseases and determined the best time interval between (99m)Tc-sestamibi injection and calculation of uptake. Forty EVs, 30 patients with Graves' disease (GD), 15 patients with atrophic Hashimoto's thyroiditis (AHT) and 15 patients with hypertrophic Hashimoto's thyroiditis (HHT) underwent (99m)Tc-sestamibi thyroid scintigraphy. Dynamic images were acquired for 20 min, and static images were obtained 20 min, 60 min and 120 min post injection. Five-, 20-, 60- and 120-min uptake, time to maximal uptake (T(max)) and T(1/2) of tracer clearance were calculated. Thyroid hormones and antibodies were measured. (99m)Tc-pertechnetate uptake was investigated in GD patients. T(max) was approximately 5 min in all four groups. The mean T(1/2) value for EVs was similar to the GD value and lower than the HHT and AHT values. The mean (+/-SD) 5-min uptake was 0.13% (+/-0.05%) for EVs. The 5-min uptake in GD was higher than that in EVs(P<0.001) and correlated with free thyroxine (r=0.54) and with (99m)Tc-pertechnetate uptake (r=0.68). Uptake in HHT was higher than that in AHT (P=0.0003) and EVs (P=0.002). Uptake in AHT was lower than uptake in EVs (P=0.0001). Five minutes is the optimal time interval between (99m)Tc-sestamibi injection and calculation of thyroid uptake. Five-minute uptake differentiates euthyroid individuals from GD patients. There is a high correlation between (99m)Tc-sestamibi and (99m)Tc-pertechnetate uptake in GD. The reduced (99m)Tc-sestamibi uptake in AHT patients is probably due to glandular destruction and fibrosis. Inflammatory infiltrate and high mitochondrial density in thyrocytes possibly explain the increased uptake in GD and HHT.

The role of 99 mTc pertechnetate uptake in the evaluation of thyroid function

To investigate the usefulness of the 20 min 99 m Tc-per-technetate uptake test, the records of 246 consecutive patients were reviewed. Of these, 192 patients (151 females, 41 males; 10 weeks to 78 years) had at least one year clinical follow-up or a confirmed diagnosis by biopsy or surgery and were included in our study. In these patients, the 99 m Tc pertechnetate uptake and hormonal values (T3 resin uptake, T4 RIA, T-index) were obtained. These results were then compared to the clinical diagnosis at the time of the uptake and one year later. All patients received an i.v. injection of 5 mCi of 99 m Tc pertechnetate. Imaging was performed using a pinhole collimator and a scintillation camera interfaced to a computer. Regions of interest for the thyroid and the background were used to calculate the 20 min 99 m Tc pertechnetate uptake as a percentage of the injected dose. 99 m Tc uptake and hormonal values were confirmatory in 158 patients (82.3%): 138 were euthyroid, 18 were hyperthyroid and 2 were hypothyroid. In 29 other patients (15.1%) the pertechnetate uptake provided useful additional information and helped to identify Hashimoto's thyroiditis (8 patients); thyroid suppression by exogenous iodide, steroids or T4 (7 patients); overtreated hyperthyroidism (1 patient); persistent hyperthyroidism (5 patients); different stages of Grave's disease (4 patients); and toxic nodular goiter (4 patients). The 99 m Tc uptake was misleading in 5 euthyroid patients (2.6%). We have found the 99 m Tc pertechnetate uptake a useful adjunct to measurement of hormonal levels in patients with suspected thyroid disease.

A new pertechnetate thyroid uptake technique

A method of measuring early thyroid uptake of pertechnetate and excluding extrathyroidal radioactivity is described. Data derived from 100 patients are statistically analysed and the clinical significance of the results obtained are discussed. 99m Tc pertechnetate uptake values obtained at 15 and 30 minutes after intravenous injection of the tracer are compared with results of standard 4 hour and 24 hour 131 I iodide uptake.

Simultaneous quantitative measurement of 131 I-iodine and 99m Tc-pertechnetate uptake by human salivary glands using scintiscanning with validation by direct estimation in biopsy samples.

Abstract. 131I‐iodide and 99Tc‐pertechnetate concentration in human salivary glands has been measured simultaneously in vivo by quantitative scintiscanning in 7 thyrotoxic subjects. The mid scan times were 5, 12 and 20 min. and the gland to plasma ratio (G/P) of 131I rose to 4.03±0.82 (s.e.) in the parotid and 10.7 ±3.1 (s.e.) in the submandibular glands. Corresponding values for G/P 99mTcO4‐were 2.70 ±0.34 in the parotid and 5.3 ± 1.2 in the submandibular glands. Values obtained at parotidectomy 1 h after intravenous administration of a mixture containing 125I‐ and 99mTcO4‐ to 6 patients were 4.13 ± 0.85 for G/P 125I‐ and 2.50 ± 0.62 for G/P99mTcO4‐. G/P131I‐ (or G/P125I‐) and G/P 99mTeO4‐, derived by both methods, were significantly correlated in parotid and submandibular glands. There was a significant correlation between G/P 131I‐/G/P 99mTcO4‐ in the parotid glands and G/P131I‐/G/P99mTcO4‐ in the submandibular glands. ‐It is concluded that 1. salivary gland values of 131I‐ and 99mTcO4,‐as measured by scintiscanning are very close to values obtained by direct counting of excised human salivary gland tissue and 2. that the secretion processes in both glands are physiologically related.