Automatic differentiation of thyroid scintigram by deep convolutional neural network: a dual center study.

BACKGROUND: 99mTc-pertechnetate thyroid scintigraphy is a valid complementary avenue for evaluating thyroid disease in the clinic, the image feature of thyroid scintigram is relatively simple but the interpretation still has a moderate consistency among physicians. Thus, we aimed to develop an artificial intelligence (AI) system to automatically classify the four patterns of thyroid scintigram. METHODS: We collected 3087 thyroid scintigrams from center 1 to construct the training dataset (n = 2468) and internal validating dataset (n = 619), and another 302 cases from center 2 as external validating datasets. Four pre-trained neural networks that included ResNet50, DenseNet169, InceptionV3, and InceptionResNetV2 were implemented to construct AI models. The models were trained separately with transfer learning. We evaluated each model's performance with metrics as following: accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), recall, precision, and F1-score. RESULTS: The overall accuracy of four pre-trained neural networks in classifying four common uptake patterns of thyroid scintigrams all exceeded 90%, and the InceptionV3 stands out from others. It reached the highest performance with an overall accuracy of 92.73% for internal validation and 87.75% for external validation, respectively. As for each category of thyroid scintigrams, the area under the receiver operator characteristic curve (AUC) was 0.986 for 'diffusely increased,' 0.997 for 'diffusely decreased,' 0.998 for 'focal increased,' and 0.945 for 'heterogeneous uptake' in internal validation, respectively. Accordingly, the corresponding performances also obtained an ideal result of 0.939, 1.000, 0.974, and 0.915 in external validation, respectively. CONCLUSIONS: Deep convolutional neural network-based AI model represented considerable performance in the classification of thyroid scintigrams, which may help physicians improve the interpretation of thyroid scintigrams more consistently and efficiently.

RADIOISOTOPE DIAGNOSTIC ALGORITHM FOR THE RELAPSE AND METASTASES DETECTION IN THE IODINE-NEGATIVE DIFFERENTIATED THYROID CANCER. / RADIONUKLIDNYI DIAGNOSTYChNYI ALGORYTM DLIa VYIaVLENNIa RETsYDYVIV I METASTAZIV U KhVORYKh Z IOD-NEGATYVNYMY FORMAMY DYFERENTsIIOVANOGO RAKU ShchYTOPODIBNOÏ ZALOZY.

OBJECTIVE: Developing of algorithm for the post-surgical management of patients with iodine-negative metastasesof differentiated thyroid cancer (DTC). MATERIALS AND METHODS: The DTC patients with iodine-negative metastases (n = 115) were enrolled in the study.Of them the whole body scintigraphy (WBS) was performed with technetium-99m-hexakis-2-methoxyisobutylisonitrile(99mTc-MIBI) (n = 30), WBS with technetium-99m dimercaptosuccinic acid (99mTc-DMSA) (n = 30), 18FDG PET (n = 30), andcomputer tomography (CT-scan) (n = 25). Complex 99mTc-pertechnetate scans including the dynamic and static scintigraphy was performed supplementary to 99mTc-MIBI WBS in 10 patients to obtain the angiographic curves from DTCmetastatic foci. The non-radioiodine radiopharmaceutical technologies, namely the labeled 99mTc-MIBI, 99mTc-DMSA, 99mTc-pertechnetate, and 18FDG were applied to detect the iodine-negative DTC metastases. Radioisotopic examinationswere performed at the dual-head gamma camera (Mediso Medical Imaging Systems Ltd., Hungary) and single photonemission computed tomography (SPECT) scanner «E.CAM¼ (Siemens, Germany). PET/CT scans were performed on the«Biograph 64 TruePoint¼ imaging platform (Siemens, Germany) in accordance with the European Association of NuclearMedicine (EANM) recommendations for the Siemens imaging devices with 3D-mode data acquisition. RESULTS: The conducted research suggested that it is feasible to use the non-radioiodine (99mTc-MIBI and 99mTc-DMSA)radiopharmaceutical technologies to detect the iodine-negative DTC metastases. 18FDG PET is a highly informativetechnology for the detection of iodine-negative DTC metastases in case of lung involvement in the process. Compareof the non-radioiodine radiopharmaceuticals, CT scan and 18FDG-PET/CT indicated the highest sensitivity of 18FDGPET/CT (p < 0.05). WBS with 99mTc-MIBI and 99mTc-DMSA featured the highest specificity (100 %, p < 0.05). X-ray CTis marked by the significantly lower either sensitivity, specificity, and accuracy rate (p > 0.05). Developing andapplication of algorithm for the post-surgical management of patients with iodine-negative forms of DTC will allowfor the betimes detection of relapses and metastases with administration of adequate surgical, radiation, and targeted treatment. CONCLUSIONS: Obtained results offer the opportunity to optimize the post-surgical management of patients withiodine-negative DTC forms using the options of radionuclide diagnostics with non-radioiodine radiopharmaceuticals. The latter are readily available providing the cost-cutting of diagnostic support in these patients. Place ofmorphological methods of diagnosis is determined and stage of monitoring of patients with the iodine-negativemetastases is established. Possibility of the 18FDG-PET tests for the early diagnosis of iodine-negative metastases inDTC for the first time have been studied and substantiated in Ukraine. A comprehensive radiation algorithm for thelong-term monitoring of this category of patients will allow the timely detection of recurrences and metastases ofDTC and appropriate surgery, radiation and targeted therapy administration. Data obtained as a result of the studyallowed to improve the overall and recurrence-free survival rates in the able-bodied DTC patients and reduce thecosts of follow-up of patients with iodine-negative forms of DTC.

Potential Applications of 68Ga-PSMA-11 PET/CT in the Evaluation of Salivary Gland Uptake Function: Preliminary Observations and Comparison with 99mTcO4 - Salivary Gland Scintigraphy.

Purpose: To preliminarily evaluate the feasibility and potential of using 68Ga-PSMA-11 PET/CT in evaluating the function of salivary glands and lacrimal glands in comparison with 99mTc-pertechnetate (99mTcO4 -) salivary gland scintigraphy (SGS). Methods: A retrospective study was performed in 15 patients with different degrees of xerostomia and suspected salivary gland dysfunction. Each patient underwent 68Ga-PSMA-11 PET/CT first and SGS the next day, and the findings of both scans were compared. Results: The results of 68Ga-PSMA-11 PET/CT and SGS were consistent in 12/15 patients (80%) and were inconsistent in the remaining patients (20%). For 5 (33.3%) of 15 patients, 68Ga-PSMA-11 PET/CT provided more information than did SGS. Additionally, 68Ga-PSMA-11 PET/CT corrected the misdiagnosis by SGS for 1 patient. Conclusions: 68Ga-PSMA-11 PET/CT is a potentially useful imaging tool for evaluating the function of salivary glands and lacrimal glands. 68Ga-PSMA-11 PET/CT can be a promising supplement to SGS, and its clinical value deserves further study.

Effect of Electroacupuncture on 99mTc-Sodium Pertechnetate Uptake and Extracellular Fluid Free Molecules in the Stomach in Acupoint ST36 and ST39.

Electroacupuncture (EA) is a therapeutic modality in which the electrical stimulation is integrated with concepts of acupuncture to treat diseases. This study was designed to evaluate the connection between the electro-acupuncture induced increase in Na99mTcO4 uptake in the stomach wall, and the ionic molecule levels in the extracellular fluid in the acupoints. Wistar rats were treated by 2 or 100 Hz EA at Zusanli (ST 36) and Xiajuxu (ST 39) bilaterally for 60 minutes. The accumulation of Na99mTcO4 in the gastric wall and the free ions, including Ca2+, K+, Na+, and Cl-, in the acupoints were measured every 60 minutes. The radioactivity uptake in the stomach was significantly increased during EA, reaching peak at 180 minutes after the EA. The concentration of extracellular ions was also significantly increased during EA. The Ca2+ level continued to rise until 60 minutes after EA, then started to decrease at 120 minutes post-EA. The results suggest this up-regulatory effect of EA on gastric activity might be triggered by the increase of the extracellular ion levels, this effect lasts longer than stimulating the release of transmembrane Ca2+ flow alone. This might aid in providing a better understanding of the long-lasting effect claimed in acupuncture treatment.

Enfermedad de Graves en un paciente de 3 años con agranulocitosis asociada a fármacos antitiroideos: terapia ablativa con radioyodo como una alternativa eficaz / Graves’ disease in a 3 year-old patient with agranulocytosis due to anti-thyroid drugs: radioiodine ablation therapy as an effective alternative

Se presenta el caso de una niña de 3 años pluripatológica, con una enfermedad genética mitocondrial (encefalomiopatía necrosante subaguda o síndrome de Leigh), insuficiencia renal crónica estadio v por una esclerosis mesangial difusa y alteraciones del desarrollo, que fue diagnosticada de hipertiroidismo autoinmune por enfermedad de Graves-Basedow. A las 6 semanas del inicio terapéutico con neocarbimazol, la paciente presentó un cuadro de agranulocitosis severa que obligó a suspender la medicación con fármacos antitiroideos, motivo por el cual fue tratada de manera eficaz con terapia metabólica con 131I. La relevancia del artículo radica en la infrecuencia de la enfermedad de Graves en niños prepuberales (especialmente menores de 6 años), las complicaciones en el desarrollo derivadas de un posible diagnóstico tardío, la aparición de agranulocitosis como efecto adverso potencialmente grave tras el uso de antitiroideos y los pocos casos reportados de terapia ablativa con 131I a esta edad, que otorgan singularidad al caso (AU)

The case is presented of a 3 year-old girl with mitochondrial disease (subacute necrotizing encephalomyelopathy of Leigh syndrome), v-stage chronic kidney disease of a diffuse mesangial sclerosis, as well as developmental disorders, and diagnosed with hyperthyroidism Graves-Basedow disease. Six weeks after starting the treatment with neo-carbimazole, the patient reported a serious case of agranulocytosis. This led to stopping the anti-thyroid drugs, and was treated successfully with 131I ablation therapy. The relevance of the article is that Graves’ disease is uncommon in the paediatric age range (especially in children younger than 6 years old), and developing complications due to a possible late diagnosis. Agranulocytosis as a potentially serious adverse effect following the use of anti-thyroid drugs, and the few reported cases of ablation therapy with 131I at this age, makes this case unique (AU)

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 (99m)Tc 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 (99m)Tc 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.

Percutaneous thermal microwave ablation of thyroid nodules. Preparation, feasibility, efficiency.

UNLABELLED: Microwave ablation (MWA) is a new minimal invasive method for thermal ablation of benign thyroid nodules. In contrast to well-established radiofrequency ablation (RFA), MWA offers several advantages with similarly successful results. There has not been any use of functional imaging with 99mTc-pertechnetate and 99mTc-MIBI-scans as a mere qualitative analysis of this imaging in the field of MWA in Europe until now. The aim of this study has been to demonstrate the feasibility of MWA as well as the applicability of functional imaging to verify effectiveness with a centerspecific score. PATIENTS, METHODS: 11 patients (5 women, 6 men, average age 62.3 years) with 18 benign thyroid nodules were treated. MWA was operated under local anesthesia with a system working in a wavelength field of 902 to 928 MHz (Avecure MWG881, MedWaves, Inc. San Diego, CA). Pre- and postablative scans were controlled by two specialists in nuclear medicine with longtime work experience. RESULTS: A center specific functional imaging score (CSFIS) was defined, a decrease of 1.4 points at an average was noticeable (range 1-3 points). In 66.7% (n = 12) of all nodules the score decreased by 1 point, 27.8% (n = 5) by 2 points and 5.6% (n = 1) by 3 points. The treatment was well tolerated and no severe complications were observed. CONCLUSION: The preliminary data suggests that MWA is an effective method to treat benign thyroid nodules. Functional imaging is a promising technique for early verification of effectiveness of thermal ablation.

The correlation of post-operative radioiodine uptake and Tc-99m pertechnetate thyroid scintigraphy and the result of thyroid remnant ablation.

OBJECTIVE: Determine the relationship between postoperative thyroid remnant using 24 h radioiodine uptake and Tc-99m pertechnetate scintigraphy, and the success of high dose radioiodine ablation. MATERIAL AND METHOD: Retrospectively enrolled 250 patients with DTC who underwent thyroidectomy and radioiodine ablation. Postoperative Tc-99m pertechnetate and 24 h 1-131 uptake were reviewed to evaluate thyroid remnant and the directly compared with ablation outcome. The successful ablation was defined using negative WBS and stimulated Tg < 10 ng/ml in the absence of TgAb at six to 12 months after treatment. The relationship between success of ablation and other variables were evaluated RESULTS: One hundred twenty four patients (49.6%) were successfully ablated after single high dose radioiodine ablation. The authors found no association with age, sex, extent of surgery, tumor histology, tumor size, mutifocal, extrathyroidal invasion, 1-131 administered dose, interval from surgery to radioiodine ablation, Tc-99m pertechnetate scan, or 24 h 1-131 uptake, and successful ablation. The initial Tg level was the only variable found to be associated with success (p < 0.001). CONCLUSION: Neither Tc-99m pertechnetate thyroid scintigraphy nor 24 h 1-131 uptake percentage in the evaluation of postsurgical thyroid remnant can predict radioiodine ablation outcome in patients with DTC. Serum Tg level at the time of ablation could be a reasonable predictor of the success of ablation.

Determination of in vivo behavior of mitomycin C-loaded o/w soybean oil microemulsion and mitomycin C solution via gamma camera imaging.

In this study, a microemulsion system was evaluated for delivery of mitomycin C (MMC). To track the distribution of the formulated drug after intravenous administration, radiochemical labeling and gamma scintigraphy imaging were used. The aim was to evaluate a microemulsion system for intravenous delivery of MMC and to compare its in vivo behavior with that of the MMC solution. For microemulsion formulation, soybean oil was used as the oil phase. Lecithin and Tween 80 were surfactants and ethanol was the cosurfactant. To understand the whole body localization of MMC-loaded microemulsion, MMC was labeled with radioactive technetium and gamma scintigraphy was applied for visualization of drug distribution. Radioactivity in the bladder 30 minutes after injection of the MMC solution was observed, according to static gamma camera images. This shows that urinary excretion of the latter starts very soon. On the other hand, no radioactivity appeared in the urinary bladder during the 90 minutes following the administration of MMC-loaded microemulsion. The unabated radioactivity in the liver during the experiment shows that the localization of microemulsion formulation in the liver is stable. In the light of the foregoing, it is suggested that this microemulsion formulation may be an appropriate carrier system for anticancer agents by intravenous delivery in hepatic cancer chemotherapy.

Hyposalivation: the roles of radioactive iodine and stapes surgery.

PURPOSE: The aim of this study is to call attention to the role that radioactive iodine ((131)I) and stapes surgery may play in causing hyposalivation. MATERIALS AND METHODS: The manner in which (131)I and stapes surgery can cause salivary damage was reviewed. A case report is presented to illustrate the involved pathophysiology. RESULTS: The case report clearly shows the significant injury to the parotid glands caused by the (131)I. However, subjective symptoms of oral dryness only developed after injury to the chorda tympani nerve (CTN) during stapes surgery. CONCLUSIONS: The loss of function of both parotid glands after (131)I therapy for thyroid cancer was initially compensated by the secretions of the more radiation-resistant submandibular and sublingual salivary glands (SMSG/SLSG). Damage to the CTN's secretory fibers in one SMSG/SLSG complex led to subjective oral dryness by accentuating an existing objective hyposalivation.

Ginkgo biloba and Angelica archangelica bring back an impartial hepatic apoptotic to anti-apoptotic protein ratio after exposure to technetium 99mTc.

PURPOSE: The aim of this study was to study the effect of ionizing radiation on apoptosis-related protein concentrations as well as the radio-protective role of Ginkgo biloba and Angelica archangelica. The experiments were performed on 68 adult Wistar rats weighing 175 g (±10 g). Animals were subdivided into control group in which the animals received neither the protector nor the isotopes. The second group represents the animals that received 1 mCi of (99m)Tc only. The third group represents the animals that received A. archangelica for 7 days. The fourth group represents the animals that received G. biloba for 7 days. The fifth group represents the animals that received 1 mCi of (99m)Tc once after receiving A. archangelica for 7 days. The sixth group represents the animals that received mCi of (99m)Tc once after receiving G. biloba for 7 days. Radiation was administered as intravenous injection by 1 mCi of (99m)Tc with the legend methoxyisobutylisonitrile for 24 h. The concentration of p53, Bcl2 and malondialdehyde in liver as well as histopathological examination of liver cells were carried out. Results showed that apoptotic to anti-apoptotic protein ratio significantly (p < 0.05) returned to its normal ratio when radioisotopic injection was administered after the protection period for a week by both A. archangelica and G. biloba in a dose based on the animal body weight. Electron microscope photographing supported this finding. CONCLUSION: It was concluded that both antioxidants can be used as radio-protective agents in cases of ionizing radiation exposure.

Cellular bioenergetics is an important determinant of the molecular imaging signal derived from luciferase and the sodium-iodide symporter.

RATIONALE: Molecular imaging is useful for longitudinal assessment of engraftment. However, it is not known which factors, other than cell number, can influence the molecular imaging signal obtained from reporter genes. OBJECTIVE: The effects of cell dissociation/suspension on cellular bioenergetics and the signal obtained by firefly luciferase and human sodium-iodide symporter labeling of cardiosphere-derived cells were investigated. METHODS AND RESULTS: (18)Fluorodeoxyglucose uptake, ATP levels, (99m)Tc-pertechnetate uptake, and bioluminescence were measured in vitro in adherent and suspended cardiosphere-derived cells. In vivo dual-isotope single-photon emission computed tomography/computed tomography imaging or bioluminescence imaging (BLI) was performed 1 hour and 24 hours after cardiosphere-derived cell transplantation. Single-photon emission computed tomography quantification was performed using a phantom for signal calibration. Cell loss between 1 hour and 24 hours after transplantation was quantified by quantitative polymerase chain reaction and ex vivo luciferase assay. Cell dissociation followed by suspension for 1 hour resulted in decreased glucose uptake, cellular ATP, (99m)Tc uptake, and BLI signal by 82%, 43%, 42%, and 44%, respectively, compared with adherent cells, in vitro. In vivo (99m)Tc uptake was significantly lower at 1 hour compared with 24 hours after cell transplantation in the noninfarct (P<0.001; n=3) and infarct (P<0.001; n=4) models, despite significant cell loss during this period. The in vivo BLI signal was significantly higher at 1 hour than at 24 hours (P<0.01), with the BLI signal being higher when cardiosphere-derived cells were suspended in glucose-containing medium compared with saline (PBS). CONCLUSIONS: Adhesion is an important determinant of cellular bioenergetics, (99m)Tc-pertechnetate uptake, and BLI signal. BLI and sodium-iodide symporter imaging may be useful for in vivo optimization of bioenergetics in transplanted cells.

Preclinical pharmacokinetics of radiolabelled hyaluronan.

BACKGROUND: Hyaluronan (HYA) is a high molecular weight glucosaminoglycan with a great perspective for medical applications. Because HYA is widespread in the body, it is difficult to determine the fate of exogenously administered HYA. METHODS: In this study, HYAof different molecular weights (0.1-1 MDa) was labelled with (99m)Tc, and the distribution profiles were determined after administrating the HYA to rats. RESULTS: After the intravenous administration of (99m)Tc-HYA, a rapid decrease in the radioactivity of blood samples was observed, presumably because of (99m)Tc-HYA uptake by the liver; only minimal signs of liver radioactivity washout were detected. After the oral administration of (99m)Tc-HYA, no significant absorption to the central compartment was found. A preliminary study using (14)C-HYA exhibited a different distribution profile than (99m)Tc-HYA because of the different administered dose and the fate of the degradation products. Even with (14)C-HYA, only traces of radioactivity were absorbed after oral administration. CONCLUSION: This paper provides quantitative information regarding the distribution parameters of radiolabelled HYA in preclinical experiments.

Effect of parotid gland massage on parotid gland Tc-99m pertechnetate uptake.

BACKGROUND: Salivary dysfunction is the most common side effect associated with (131)I therapy in patients with differentiated thyroid cancer. The purpose of this study was to evaluate the effect of parotid gland (PG) massage on radioisotope accumulation in the salivary gland. METHODS: Sixty patients were included in this study. Using Tc-99m pertechnetate, two salivary scans were performed in all patients. In 30 patients, PG massage was performed between the two salivary gland scans, whereas in the other 30 patients no massage was performed between the two scans. Total counts of both PGs and accumulation ratios were calculated. RESULTS: In the patients who received massage, no difference was observed between the mean PG counts of first and second images (8556.9±3333.4 count vs. 8598.3±3341.3 count, p=0.39). In the patients who did not receive massage, the mean PG count on second images was significantly higher than that on first images (8581.2±3618.0 count vs. 9096.4±3654.0 count, p<0.01). Mean accumulation ratio in the patients who received massage was significantly lower than in the patients who did not receive massage (0.5%±3.3% vs. 6.8%±3.8%, p<0.01). Further, among the patients who received massage there was a higher percentage of patients with a negative accumulation ratio than among the patients who did not receive massage (43.3% vs. 0%, p<0.01). CONCLUSIONS: PG massage can reduce Tc-99m pertechnetate accumulation in the PG, and thus, should be helpful to prevent salivary damage associated with (131)I therapy.

Radioprotective effect of Ocimum sanctum and amifostine on the salivary gland of rats after therapeutic radioiodine exposure.

The current study investigated the radioprotective effect of Ocimum sanctum on the salivary gland of rats administered radioiodine ((131)I) and compared its efficacy with a known radioprotectant, amifostine. The experimental rats were divided in four groups and sacrificed in three different batches at 1, 3, and 6 months of time interval after 18.5 MBq/100g (i.p.) (131)I exposure. Six months duration batch received (131)I exposure twice with the gap of 3 months. Two groups of experimental rats were presupplemented with O. sanctum (40 mg/kg for 5 days, orally) and amifostine (200 mg/kg, s.c) before (131)I exposure separately. Increased Technetium-99m-pertechnetate ((99m)TcO(4)(-)) uptake at 30 minutes post injection in salivary glands of only (131)I exposed rats may imply delay in clearance at 6 months of exposure in comparison to their counterparts sacrificed at 1 month. Parotid gland histology showed atrophy with lipomatosis in only (131)I exposed rats at 3 and 6 months of duration. O. sanctum and amifostine presupplemented and subsequently exposed to (131)I rats at 3 and 6 months duration exhibited comparable histopathology with controls. Our study indicates possible radioprotective effect of O. sanctum and amifostine against high-dose (131)I exposure.

An experimental model to study the effects of a senna extract on the blood constituent labeling and biodistribution of a radiopharmaceutical in rats.

Cassia angustifolia Vahl (senna) is a natural product that contains sennosides, which are active components that affect the intestinal tract and induce diarrhea. Authors have shown that senna produces DNA (deoxyribonucleic acid) lesions in Escherichia coli cultures and can act as an antifungal agent. Natural drugs can alter the labeling of blood constituents with technetium-99m (99mTc) and can affect the biodistribution of radiopharmaceuticals. In this work, we have evaluated the influence of a senna extract on the radiolabeling of blood constituents and on the biodistribution of the radiopharmaceutical sodium pertechnetate (Na99mTcO4)in Wistar rats. Twelve animals were treated with senna extract for 7 days. Blood samples were withdrawn from the animals and the radiolabeling procedure was carried out. The senna extract did not modify the radiolabeling of the blood constituents. A biodistributional assay was performed by administering Na99mTcO4 and determining its activity in different organs and in blood. The senna extract altered the biodistribution of Na99mTcO4 in the thyroid, liver, pancreas, lungs and blood. These results are associated with properties of the chemical substances present in the aqueous senna extract. Although these assays were performed in animals, our findings suggest that caution should be exercised when nuclear medicine examinations using Na99mTcO4 are conducted in patients who are using senna extract.

Effect of an extract of Aloe vera on the biodistribution of sodium pertechnetate (Na99mTcO4) in rats.

PURPOSE: Aloe vera is a tropical plant popularly known in Brazil as babosa. We have investigated the effect of aqueous extract of Aloe vera on the biodistribution of Na99mTcO4 and laboratorial parameters in Wistar rats. METHODS: Twelve animals were divided into treated and control groups. In the treated group, Aloe vera was given by gavage (5mg/mL/day) during 10 days. The control group received sorbitol by the same way and period. One hour after the last dose, we injected 0.1mL of Na99mTcO4 by orbital plexus. After 60 min, all the animals were killed. Samples were harvested from the brain, liver, heart, muscle, pancreas, stomach, femur, kidneys, blood, testis and thyroid and the percentage of radioactivity (%ATI/g) was determined. Biochemical dosages were performed. RESULTS: There was a significant increase of %ATI/g in blood, femur, kidneys, liver, stomach, testis and thyroid and also in blood levels of AST and ALT. A significant decrease in levels of glucose, cholesterol, triglycerides, creatinine and urea occurred. The statistical analyses were performed by Mann-Whitney test and T-Student test (p<0.05). CONCLUSION: The aqueous extract of Aloe vera facilitated the uptake of Na99mTcO4 in organs of rats and it was responsible to a high increase of levels of AST and ALT.

Effect of Zusanli (ST.36) electroacupuncture at two frequencies on the bioavailability of (99m)Tc-sodium pertechnetate and on labeling of blood constituents in rats.

OBJECTIVES: A study was performed on the effects of stimulation at Zusanli-point (ST.36) by electroacupuncture (EA) at two frequencies on the bioavailability of (99m)Tc-sodium pertechnetate (Na(99m)TcO(4)) in rats. METHODS: Forty Wistar rats were divided into four groups: untreated control, treated by manual acupuncture at ST.36 bilaterally, treated by EA at 2 Hz at ST.36 bilaterally, and the same site at 100 Hz bilaterally. Na(99m)TcO(4) (7.4 MBq) was administrated via the ocular-plexus and, 20 minutes before sacrifice, blood was withdrawn for radiolabeling assay (BRL). In the bioavailability analysis, organs and tissues were isolated, their radioactivity determined, and the percentage of injected dose per gram of organ or tissue (%ID/g) and the %ID were calculated for each organ or tissue (%ID/ot). For BRL, the plasma and blood cells isolated, and the fractions also precipitated with 5% trichloroacetic acid to separate the soluble and insoluble fractions; these were assessed as percentage of injected dose (%ID) in blood (%ID/b). RESULTS: The results showed significant differences in the %ID/g in some organs and tissues in comparison with controls; lung (p = 0.0013), spleen (p = 0.0085), pancreas (p = 0.0167), liver (p = 0.0003), stomach (p < 0.0001), small-intestine (p = 0.0181), large-intestine (p = 0.04099), urinary-bladder (p = 0.0271), thyroid (p < 0.0001), muscle (p = 0.0187); %ID/ot in spleen (p = 0.0349); and %ID/b in blood sample (p = 0.0235). In the blood labeling analyses, EA in either frequency significantly increased insoluble fraction/blood cells (p < 0.0001). CONCLUSIONS: These findings suggested that acupuncture procedures at ST.36 could modulate responses in some organs, tissues, and blood in rats. Further rigorous experimental studies to examine the effectiveness in either acupuncture therapy need to be pursued.

Ectopic expression of the sodium-iodide symporter enables imaging of transplanted cardiac stem cells in vivo by single-photon emission computed tomography or positron emission tomography.

OBJECTIVES: We examined the sodium-iodide symporter (NIS), which promotes in vivo cellular uptake of technetium 99m ((99m)Tc) or iodine 124 ((124)I), as a reporter gene for cell tracking by single-photon emission computed tomography (SPECT) or positron emission tomography (PET) imaging. BACKGROUND: Stem cells offer the promise of cardiac repair. Stem cell labeling is a prerequisite to tracking cell fate in vivo. METHODS: The human NIS complementary deoxyribonucleic acid was transduced into rat cardiac-derived stem cells (rCDCs) using lentiviral vectors. Rats were injected intramyocardially with up to 4 million NIS(+)-rCDCs immediately after left anterior descending coronary artery ligation. Dual isotope SPECT (or PET) imaging was performed, using (99m)Tc (or (124)I) for cell detection and thallium 201 (or ammonia 13) for myocardial delineation. In a subset of animals, high resolution ex vivo SPECT scans of explanted hearts were obtained to confirm that in vivo signals were derived from the cell injection site. RESULTS: NIS expression in rCDCs did not affect cell viability and proliferation. NIS activity was verified in isolated transduced cells by measuring (99m)Tc uptake. NIS(+) rCDCs were visualized in vivo as regions of (99m)Tc or (124)I uptake within a perfusion deficit in the SPECT and PET images, respectively. Cells could be visualized by SPECT up to 6 days post-injection. Ex vivo SPECT confirmed that in vivo (99m)Tc signals were localized to the cell injection sites. CONCLUSIONS: Ectopic NIS expression allows noninvasive in vivo stem cell tracking in the myocardium, using either SPECT or PET. The general approach shows significant promise in tracking the fate of transplanted cells participating in cardiac regeneration, given its ability to observe living cells using clinically applicable imaging modalities.

Effects of Passiflora edulis flavicarpa on the radiolabeling of blood constituents, morphology of red blood cells and on the biodistribution of sodium pertechnetate in rats.

The aim of this study was to evaluate possible effects of Passiflora edulis flavicarpa (P. flavicarpa) extract on the labeling of blood constituents with (99m)Tc, on the morphology of red blood cells, and on the biodistribution of sodium pertechnetate (sodium (99m)Tc). Male Wistar rats were treated with either P. flavicarpa extract or 0.9% NaCl. After that, radiolabeling of blood constituents, morphological analysis of red blood cells and biodistribution of sodium (99m)Tc was evaluated. Radiolabeling of blood constituents and shape of red blood cells were not modified, but a significant (p<0.05) alteration of the biodistribution of sodium (99m)Tc was observed after treatment with P. flavicarpa extract. Although our results were obtained with animals, they could contribute to reduce the risk of misdiagnosis and/or repetition of the examinations in nuclear medicine.