99mTc Uptake Research Articles

Predicting thyroid cancer ablation success: Pre-ablative 99mTc-Pertechnetate and post-ablative 131I scan comparison

IntroductionThe purpose of this study was to evaluate the relationship between pre-ablative 99mTc-pertechnetate scintigraphy, and therapeutic iodine-131 (131I) whole-body scan (TxWBS), with ablation status and to investigate the possible predictive factors for successful ablation in differentiated thyroid carcinoma (DTC) patients. Materials and methodsA total of 330 DTC patients underwent 99mTc-pertechnetate scintigraphy after thyroidectomy. Uptake values were determined using the region-of-interest technique. All patients had neck ultrasonography and TxWBS. Both scintigraphic scans were interpreted visually and qualitatively. The ablation status was evaluated with a diagnostic 131I whole-body scan. ResultsThe success rate for residual thyroid ablation was 88.8%. The sensitivity, specificity, accuracy, PPV, and NPV of 99mTc-Pertechnetate scintigraphy were 82.4%, 87.5%, 82.7%, 99.2%, and 20.2%, respectively. Pre-ablative TG values and 99mTc uptake (%) were significantly lower in successfully ablated patients. The 99mTc uptake was determined as a significant predictive factor for ablation success (P=0.000). The optimal 99mTc uptake cut-off value of 0.75% was demonstrated for successful ablation. There were significant positive correlations between the visual and the calculated uptake (%) of residual tissues on both scintigraphic scans, Considering the number of remnant tissue foci, significant positive correlations were found between 99mTc-Pertechnetate scintigraphy, TxWBS, and USG. ConclusionPre-ablative 99mTc-Pertechnetate uptake (%) value of the remnant tissue can predict the ablation status in DTC patients. 99mTc-Pertechnetate scintigraphy, which is an easily applicable and accessible imaging method, has maintained its place in the postoperative and pre-ablative period in DTC patients over the years and has not lost any of its value.

A Novel Dual-labeled Peptide for Multimodal Imaging of EGFR with L858R Mutation.

The development of molecular imaging agents targeting epidermal growth factor receptor (EGFR) with L858R mutation may help with the selection of non-small cell lung carcinoma (NSCLCL) patients who may benefit from EFGR tyrosine kinase inhibitor (TKI) therapy. In this study, we developed 99mTc STHHYYP-GHEG-ECGK-tetramethylrhodamine (STHHYYP-ECGK-TAMRA) to target EGFR with L858R mutation in NSCLC tumors and verified its probability as a molecular imaging agent. Fmoc solid-phase peptide synthesis was used to synthesize STHHYYP-ECGKTAMRA. 99mTc labelled STHHYYP-ECGK-TAMRA was prepared. Gamma imaging, fluorescent imaging and biodistribution were performed in murine models bearing NCI-H1975 and NCI-H1650 tumors. The binding affinity value (Kd) of 99mTc STHHYYP-ECGK-TAMRA was estimated to be 130.6 ± 29.2 nM in NCI-H1975 cells. The gamma camera images showed a substantial uptake of 99mTc STHHYYP-ECGK-TAMRA in the NCI-H1975 tumor. The % injected dose/gram of the NCI-H1975 tumor tissue was 2.77 ± 0.70 and 3.48 ± 1.01 at 1 and 3 h, respectively. Specific binding of 99mTc STHHYYP-ECGK-TAMRA to L858R-mutated EGFRpositive NCI-H1975 cells and tumors was demonstrated in in vivo and in vitro studies. The results suggest that 99mTc STHHYYP-ECGK-TAMRA is a good candidate agent for dualmodality imaging targeting EGFR with L858R mutation.

Enabling Non-invasive Tracking of Vascular Endothelial Cells Derived from Induced Pluripotent Stem Cells Using Nuclear Imaging.

The absence of clinically applicable imaging techniques for continuous monitoring of transplanted cells poses a significant obstacle to the clinical translation of stem cell-based therapies for vascular regeneration. This study aims to optimize a clinically applicable, non-invasive imaging technique to longitudinally monitor vascular endothelial cells (ECs) for vascular regeneration in peripheral artery disease (PAD). Human induced pluripotent stem cells (HiPSCs) were employed to generate ECs (HiPSC-ECs). Lentiviral vectors encoding human sodium iodide symporter (hNIS) and enhanced green fluorescent protein (eGFP) genes were introduced to HiPSCs and HiPSC-ECs at varying multiplicities of infection (MOI). Through a combination of fluorescence microscopy and flow cytometry, an optimized transduction technique for introducing hNIS-eGFP into HiPSC-ECs was established. Subsequently, single-photon emission computed tomography (SPECT) was utilized for imaging of the transduced cells in vitro and in vivo after transplantation into the gastrocnemius muscle of nude mice. Lentiviral transduction resulted in sustained co-expression of hNIS and eGFP in HiPSC-ECs when transduced post-endothelial differentiation. An optimal MOI of five yielded over 90% hNIS-eGFP expression efficiency without compromising cell viability. hNIS-eGFP+ HiPSC-ECs exhibited 99mTc uptake and were detectable through SPECT in vitro. Additionally, intramuscular injection of hNIS-eGFP+ HiPSC-ECs with MatrigelTM into the hindlimbs of nude mice enabled real-time SPECT/CT tracking, from which a reduction in signal exceeding 80% was observed within 7days. This study establishes an optimized cell modification and imaging protocol for tracking transplanted cells. Future efforts will focus on enhancing cell survival and integration via improved delivery systems, thereby advancing the potential of cell-based therapies for PAD.

Standardizing Normal Reference Value for Thyroid Uptake of Technetium-99m Pertechnetate in Nepalese Population.

Objective Changes in normal reference values of thyroid uptake for iodine have been reported due to geographical and chronological fluctuations in dietary iodine intake in different populations. Nepal is a country with mixed ethnicity, with access to dietary iodine in the form of successful universal salt iodination program by the government of Nepal since 1973. The aim of this study was to establish the normal reference values for thyroid uptake of technetium-99m (Tc-99m) pertechnetate in the Nepalese population in iodine sufficiency era. Methods We prospectively evaluated 52 clinically and biochemically euthyroid participants (46 females and 6 males) with age range from 20 to 71 years who underwent a thyroid Tc-99m pertechnetate scan and uptake between December 2019 to November 2023 in the Department of Nuclear Medicine, Chitwan Medical College fulfilling inclusion/exclusion criteria. Biochemical thyroid function tests were reviewed and Tc-99m pertechnetate thyroid uptake values were determined for each patient. Blood was withdrawn for thyroid hormone assessment. Euthyroid participants were then administered 3.5 to 4.5 mCi of Tc-99m pertechnetate intravenously and their percentage thyroid uptake was calculated after 20 minutes. Results The mean and median uptake of Tc-99m pertechnetate in euthyroid patients were 1.26 and 0.85%, respectively, and the interquartile range was 0.7 to 1.7%. The normal reference uptake value for Tc-99m pertechnetate in the studied population ranged between 0.3 and 3.6%. The fifth and 95th percentiles for pertechnetate uptake were 0.5 and 2.9%, respectively. Conclusion The normal reference range for Tc-99m pertechnetate thyroid uptake in Nepalese population was 0.5 to 2.9% that is lower than the currently accepted international standard of 0.75 to 4.5%. Uptake also increased with increasing age. This study highlights the importance of periodically redefining the geographic location specific normal thyroid uptake reference values.

99mTc(CO)3-labeled 1-(2-Pyridyl)piperazine derivatives as radioligands for 5-HT7 receptors.

The 5-hydroxytryptamine receptor (5-HTR) family includes seven classes of receptors. The 5-HT7R is the newest member of this family and contributes to different physiological and pathological processes. As a pathology, glioblastoma multiform (GBM) overexpresses 5-HT7R; hence, this study aims to develop radiolabeled aryl piperazine derivatives as 5-HT7R imaging agents. METHODS: Compounds 6 and 7 as 1-(3-nitropyridin-2-yl)piperazine derivatives were radiolabeled with fac-[99mTc(CO)3(H2O)3]+ and 99mTc(CO)3-[6] and 99mTc(CO)3-[7] were obtained with high radiochemical purity (RCP > 94%).The stability of the radiotracers was evaluated in both saline and mouse serum. Specific binding on different cell lines including U-87 MG, MCF-7, SKBR3, and HT-29 was performed. The biodistribution of these radiotracers was evaluated in normal and U-87 MG Xenografted models. Finally, 99mTc(CO)3-[6] and 99mTc(CO)3-[7] were applied for in vivo imaging in U-87 MG Xenografted models. Specific binding study indicates that 99mTc(CO)3-[6] and 99mTc(CO)3-[7] can recognize 5-HT7R of U87-MG cell line. The biodistribution study in normal mice indicates that the brain uptake of 99mTc(CO)3-[6] and 99mTc(CO)3-[7] is the highest at 30min post-injection (0.8 ± 0.25 and 0.64 ± 0.18%ID/g, respectively). The data of the biodistribution study in the U87-MG xenograft model revealed that these radiotracers could accumulate in the tumor site, and the highest tumor uptake was observed at 60min post-injection (3.38 ± 0.65 and 3.27 ± 0.5%ID/g, respectively). The injection of pimozide can block the tumor's radiotracer uptake, indicating the binding of these radiotracers to the 5-HT7R. The imaging study in the xenograft model also confirms the biodistribution data. The acquired images clearly show the tumor site, and the tumor-to-muscle ratio for 99mTc(CO)3-[6] and 99mTc(CO)3-[7] at 60min was 3.33 and 3.88, respectively. CONCLUSIONS: 99mTc(CO)3-[6] and 99mTc(CO)3-[7] can visualize tumorin theU87-MG xenograft modeldueto their affinitytoward5-HT7R.

THU665 Unilateral Graves’ Disease In A Bilobar Thyroid Gland: Unusual Cause Of Hyperthyroidism

Abstract Disclosure: K.H. Alaybaa: None. O. Alhuzaim: None. Introduction: Graves' disease (GD) is an autoimmune condition that affects both thyroid gland lobes. GD patients with unilateral thyroid scan uptake are rare. These patients present with classic Graves' symptoms, occasionally with Graves' ophthalmopathy characteristics and increased thyroid hormones, and scintigraphic assessment reveals radiotracer uptake in only one lobe of the thyroid gland. Patient Findings: In this case, a 48-year-old female presented with symptoms and signs indicative of thyrotoxicosis. Lab results revealed that thyroid-stimulating hormone (TSH) was undetectable, while free thyroxine (T4) and free triiodothyronine (T3) were in the high-normal range. Positive results were observed for both thyroid-stimulating immunoglobulin and TSH receptor antibodies. Ultrasonography of the thyroid gland revealed an enlarged left lobe with heterogeneous echotexture and a hyperemic gland without any focal lesions, distinct nodules, or cysts. The NM TC-99M thyroid scintigraphy revealed enlarged and increased radioisotopes uptake in the left thyroid lobe and decreased uptake in the right thyroid lobe, with no hot or cold nodules. The calculated thyroid uptake is 4.5 percent (normal range: 0.5% to 3.5 percent). The most likely diagnosis was unilateral GD. The patient was administered carbimazole and within eight weeks had improved clinically and biochemically. Summary: This patient has thyrotoxicosis symptoms and positive autoantibodies. Tc99m uptake was increased in the left thyroid lobe and decreased in the right thyroid lobe. The left thyroid lobe was hypervascular and enlarged on ultrasonography, indicating the presence of unilateral GD. Unilateral GD is a rare disease with a poorly understood pathophysiology. Presentation: Thursday, June 15, 2023

PO-05-100 DETECTION OF THE CRITICAL SUBSTRATE FOR VENTRICULAR TACHYCARDIA ABLATION WITH THE COMBINED IMAGE OF TC-99M SCINTIGRAM AND LATE IODINE ENHANCEMENT CT

Late potentials (LPs) are the important target for ventricular tachycardia(VT) abltion. However, LPs sometimes cannot be observed sufficiently because of intramural localization of VT substrates. Efficacy of CT for prediction of VT substrates even in intramural layer has been reported. On the other hand, Tc-99m scintigram has been reported to determine the viability of myocardium. The uptake of Tc-99m scintigram could quantify the viability of VT substrates and predict the localization of critical VT substrates such as LPs. Moreover, combination of CT and Tc-99m scintigram could show intramural VT substrates. We evaluated the relationship between the localization of LPs and uptake rate of Tc-99m scintigram. Moreover, we evaluated VT substrates with combined image of scintigram and CT. In eight patients (age, 67.5±8.6 years ; left ventricular(LV) ejection fraction, 26.0±8.7%) with ischemic cardiomyopathy and VT, electroanatomical map (EAM) and Tc-99m scintigrafic image of LV were obtained and were divided into twenty segments. LPs were determined as isolated potentials after QRS and were evaluated in EAM. The relationship between LPs and scintigrafic characteristics was evaluated in total of 160 segments. Electrocardiogram gated CT was performed and late iodine enhancement(LIE) was recorded 8 minutes after administration of contrast media. LPs were recorded in 59 segments. According to the Tc-99m uptake rate, cut off value 35% was set for the prediction of the location of LPs with ROC curve. LPs were observed in the lower scintigram perfusion segments with ≤35% uptake rate (n=61) more than the segments with >35% uptake rate (n=99) with statistical significance (78.6% vs 11.1% p<0.0001). With this cutoff value, we performed another VT ablation with intramural substrate. EAM revealed the exit site of VT circuit from endocardium and the existence of intramural substrate (Fig.A). Low Tc-99m uptake area observed around the apical aneurysm and made the borderline between the basal normal voltage area (Fig.B). LIE showed the transmural damaged tissue on the apical aneurysm and the intramural damaged tissue of mid anterior wall(Fig.C). This border zone of Tc-99m uptake and intramural LIE was similar to the exit site of VT circuit. Long cauterization on this area terminated VT. Lower perfusion area of Tc-99m scintigram could be utilized to predict VT substrates in ICM patients and combination of LIE of CT could add the information of the depth of the VT substrate.

Radioisotopic evaluation of reparative osteogenesis in various forms of osteomyelitis of the mandible

The aim of this work is the rationale for using radiological method of examination in diagnosing and monitoring the mandibular osteomyelitis treatment. A total of 60 patients with traumatic (first group) and odontogenic (second group) mandibular osteomyelitis were examined. Among them, there were 24 (40%) males and 36 (60%) females aged between 20 and 45 years. The patients received intravenous injection of Technefor (99MTc) with the radiation activity of 300-400 megabecquerel 3-4 hours before scintigraphy. The mandible radiopharmaceutical uptake was measured using a computerized gamma camera. The level of 99MTc accumulation in the bone tissue was quantified by gamma-radiation. A patient was examined on the day of hospital admission and on day 14 after surgical treatment of osteomyelitis of the mandible. Our studies have shown that all forms of traumatic and odontogenic osteomyelitis are accompanied by significant changes in 99MTc uptake in the mandible, however, both 99MTc uptake and its decrease after surgical treatment were most obvious in odontogenic osteomyelitis. The increase in 99MTc uptake in traumatic mandibular osteomyelitis was 38,1% (up to 1669,9 gamma-radiation pulses), 140,9% (up to 2913,7 gamma-radiation pulses) and 129% (up to 2772,7 gamma-radiation pulses) in the acute, subacute and chronic stages of the disease, respectively. The increase in 99MTc uptake in odontogenic mandibular osteomyelitis was 160,0% (up to 3144,1 gamma-radiation pulses), 218,1% (up to 3846,6 gamma-radiation pulses) and 275,2% (up to 4537,6 gamma-radiation pulses) in the acute, subacute and chronic stages of the disease, respectively. The increase in 99MTc uptake was due to blood flow enhancement, metabolic disorders, activation of osteoblast and osteoclasts in the bone tissue. The decrease in 99MTc uptake after the treatment indicated the positive response to treatment. Scintigraphic examination was more sensitive and specific in comparison to X-ray diagnostics of mandibular ostemyelitis. The sensitivity of scintigraphic findings ranged from 60.0% to 100%, and the specificity was 100% at different stages of ostemyelitis.

Preparation and Preliminary Evaluation of a Promising 99mTc-Labeled Isonitrile-Containing 6-Thia-Fatty Acid Derivative for Myocardial Metabolism Imaging.

For over 40 years, none of the previous 99mTc-labeled fatty acids for myocardial imaging has potential clinical use. 99mTc-(C10-6-thia-CO2H)(MIBI)5 is the first 99mTc-labeled fatty acid to exhibit good myocardial uptake (2.06 ± 0.06%ID/g) at 60 min post injection, high heart-to-liver ratio (6.43 ± 1.85 and 9.68 ± 0.76), high heart-to-lung ratio (9.48 ± 1.39 and 11.02 ± 0.89), and high heart-to-blood ratio (164.01 ± 43.51 and 197.36 ± 32.29) at 60 and 120 min in Sprague-Dawley (SD) rats, respectively. It also demonstrated excellent myocardial imaging quality. The above target-to-nontarget ratios exceeded those of [123I]BMIPP and were higher than or close to those of 99mTc-MIBI at 60 and 120 min. Most of 99mTc-(C10-6-thia-CO2H)(MIBI)5 was partially β-oxidized to protein-bound metabolites in myocardium. Administration of trimetazidine dihydrochloride (TMZ, a fatty acid β-oxidation inhibitor) to rats caused 51% reduction in the myocardial uptake of 99mTc-(C10-6-thia-CO2H)(MIBI)5 and 61% reduction in the distribution of 99mTc-radioactivity in a residual tissue pellet at 60 min, indicating its considerable sensitivity to myocardial fatty acid β-oxidation.

Long-term outcome of thyroid abnormalities in patients with severe Covid-19.

We have previously observed thyroid dysfunction, i.e. atypical thyroiditis (painless thyrotoxicosis associated with non-thyroidal illness syndrome), in patients with severe acute respiratory syndrome coronavirus 2 disease (Covid-19). This study aimed to analyse the evolution of thyroid dysfunction over time. One hundred eighty-three consecutive patients hospitalised for severe Covid-19 without known thyroid history were studied at hospital admission (baseline). Survivors were offered 12-month longitudinal follow-up including assessment of thyroid function, autoantibodies and ultrasound scan (US). Patients showing US focal hypoechoic areas suggestive of thyroiditis (focal hypoechogenicity) also underwent thyroid 99mTc or 123I uptake scan. At baseline, after excluding from TSH analysis, 63 out of 183 (34%) Covid-19 patients commenced on steroids before hospitalisation, and 12 (10%) showed atypical thyroiditis. Follow-up of 75 patients showed normalisation of thyroid function and inflammatory markers and no increased prevalence of detectable thyroid autoantibodies. Baseline US (available in 65 patients) showed focal hypoechogenicity in 28% of patients, of whom 82% had reduced thyroid 99mTc/123I uptake. The presence of focal hypoechogenicity was associated with baseline low TSH (P = 0.034), high free-thyroxine (FT4) (P = 0.018) and high interleukin-6 (IL6) (P = 0.016). Focal hypoechogenicity persisted after 6 and 12 months in 87% and 50% patients, respectively, but reduced in size. After 9 months, thyroid 99mTc/123I uptake partially recovered from baseline (+28%) but was still reduced in 67% patients. Severe Covid-19 induces mild transient thyroid dysfunction correlating with disease severity. Focal hypoechogenicity, associated with baseline high FT4, IL6 and low TSH, does not seem to be related to thyroid autoimmunity and may persist after 1 year although decreasing in size. Long-term consequences seem unlikely.

Comparison of 18-FDG SUV Value with Bone Scintigraphy Findings in Diagnosed Cases of Malignancy with Sclerotic Bony Metastasis

Objective: To determine the correlation of 18F-FDG SUV value with bone scintigraphy findings, i.e. uptake of Tc-99m in diagnosed cases of malignancy with sclerotic bone metastasis.&#x0D; Study Design: Prospective longitudinal study.&#x0D; Place and Duration of Study: Armed Forces Institute of Radiology and Imaging, Rawalpindi Pakistan, from Sep 2020 to Mar 2021.&#x0D; Methodology: This study included 30 patients of age 18 to 80 years who had sclerotic bone metastasis as confirmed in histopathology. All patients underwent whole-body PET/CT scanning to evaluate sclerotic bone metastasis and determined 18-FDG SUV after 5MBq/kg body weight of 18-FDG was injected. After two weeks of PET/CT scan, Tc-99m bone scintigraphy was carried out, and SUV of Tc-99m was determined after 20-25mCi technetium-99 methylene disphosphonate was injected, and the correlation was assessed between SUV of 18-FDG and Tc-99m.&#x0D; Results: The mean 18-FDG SUVmax and mean Tc-99m SUVmax, were, 21.31±8.77g/ml and 15.29±6.49g/ml respectively.21(70%) lesions on 18-FDG PET/CT and 8(26.7%) on Tc-99m bone scintigraphy were metastatic in bones. 18-FDG SUV on PET/CET and Tc-99m SUV on bone scintigraphy correlated positively with each other, and this correlation was found to be statistically significant (r=0.491, p=0.006).&#x0D; Conclusion: 18-FDG SUV PET/CT significantly correlated with Tc-99m SUV on bone scintigraphy and helped detect metastatic lesions earlier and modulate treatment response.Keywords: Bone metastasis, Bone scintigraphy, 18-FDG PET/CT, Tc-99m SUV.

Familial Dysalbuminemic Hyperthyroxinemia Induced by Mutation R218H of Albumin

Familial Dysalbuminemic Hyperthyroxinemia (FDH) is thought of no clinical significance, but tends to to misdiagnosed and mistreated as Graves’ hyperthyroidism with long time. In a Chinese family to explore clinical characteristics, hereditary features and gene variation of FDH and its effect on pregnancy. Methods: Two propostitus (a father and his son) with hyperthyroidism were re-diagnosed as FDH due to the canonical profile of measured thyroid hormones. After screening thyroid function of the whole family, eight affected of FDH were identified among total thirteen lineal relatives. They were studied in terms of clinical history, biochemical and hormone examination, thyroid imaging and TSH secreting test by dexamethasone and bromocriptine. Three members accepted gene analysis with the next generation sequencing followed by Sanger method. Productive history was investigated in five spouse of the whole family. Results: In the two propostitus, FDH exhibited very high total thyroxine (T4) and mild high total triiodinethyronine (T3), and normal free T4 and T3 besides normal thyroid stimulating hormone (TSH). In addition, ultrasound discovered diffuse goiter and enhanced blood flow, and 99mTc uptake increased, while TSH receptor antibody and pituitary MRI scan remained normal. Other six family members had similar changes of the thyroid hormones and normal TSH which could be suppressed dramatically by dexamethasone and bromocriptine, then were suspected of FDH and thereafter confirmed with gene analysis. Among these eight FDH, four were misdiagnosed with hyperthyroidism and mistakenly received anti-thyroid medication at least one year. Gene analysis of three members revealed R218H variation of albumin gene. Conclusions: R218H associated FDH shows canonical changes of thyroid hormones with increased thyroid function, high penetrance and misdiagnose rate with hyperthyroidism, it exerts no effect on pregnancy.

Radioiodine Ablation of Thyroid Remnants in Patients with Graves' Orbitopathy.

Our purpose was to assess response after ablation of thyroid remnants (ATR) with radioactive iodine therapy in patients with unstable Graves' orbitopathy (GO) after subtotal thyroidectomy. Methods: Thirty patients with mild (n = 4, 13%), moderate-to-severe (n = 25, 83%), or very severe GO (n = 1, 3%) were analyzed in this retrospective study. The primary endpoint was the improvement of GO-related symptoms as assessed by clinical activity scores, NOSPECS, and soft-tissue inflammation scores at 3 and 12 mo after ATR. Ablation success was defined by a decrease in 99mTc uptake on thyroid scintigraphy, remnant volume, and thyrotropin receptor antibody levels at 3 mo after ATR. Results: Twelve months after ATR, clinical activity scores, NOSPECS, and soft-tissue inflammation scores showed a significant decrease from 3.4 to 1.3 (P < 0.0001), 5.9 to 4.9 (P = 0.007), and 4.7 to 2.1 (P = 0.0001), respectively. The GO was inactive in 27 of the 30 (90%) patients after 3 mo and in 29 (97%) after 12 mo. No new activation of GO occurred. Remnant volume (1.4 vs. 0.4 cm3, P = <0.0001), mean thyrotropin receptor antibody level titer (19.02 vs. 13.37 IU/L, P < 0.0001), and 99mTc uptake (0.5% vs. 0.1%; n = 12; P = 0.04) decreased significantly until 3 mo after ATR. Discussion: Radioactive iodine therapy after thyroidectomy can successfully ablate residual thyroid remnants, leading to an improvement in GO, a reduction in inflammatory activity, and stabilization of thyroid function. Thus, scintigraphy should be considered for patients with unstable GO after thyroidectomy to rule out thyroid remnants.

Radiosynthesis, quality control, biodistribution, and infection-imaging study of a new 99mTc-labeled ertapenem radiopharmaceutical.

Ertapenem is a member of carbapenem antibiotics used for the treatment of moderate-to-severe intra-abdominal, urinary tract, acute pelvic, and post-surgical gynecologic infections. The antibacterial activity of ertapenem is mediated through binding to penicillin-binding proteins which results in inhibiting the cross-linking of the peptidoglycan layer of the bacterial cell wall. Therefore, ertapenem can be labeled with technetium-99m (99mTc), a gamma emitter radionuclide, for the diagnosis of deep-seated bacterial infections, such as urinary tract, intra-abdominal, osteomyelitis, and post-surgical gynecologic infections. The labeling procedure was carried out by varying the reaction conditions, such as the amount of the ligand and reducing agent, pH, reaction time and temperature, and radioactivity. At optimized reaction conditions more than 93% 99mTc-ertapenem radioconjugate was obtained. 99mTc-ertapenem was found 90% intact in saline medium up to 6 h, while 88% intact in human blood serum up to 3h. Biodistribution study showed target-to-non-target ratios of 2.91 ± 0.19, 2.39 ± 0.31, and 1.23 ± 0.22 in S. aureus, E. coli, and turpentine oil-infected rat models, respectively. The SPECT scintigraphy showed high uptake of 99mTc-ertapenem in bacterial-infected abscesses, and low counts were recorded in normal and turpentine oil-inflamed tissues. In conclusion, 99mTc-ertapenem can be a potent infection-imaging agent, which can diagnosis deep-seated bacterial infections at early stage but need further pre-clinical evaluation in variety of infection models.

Case series of Euthyroid Graves’ Ophthalmopathy in patients seronegative for TSH receptor autoantibody (TRAb) &amp; developed Hyperthyroidism in follow-up visits

We reported cases of Graves’ ophthalmopathy who presented solely with symptoms of the eyes and normal thyroid function tests, negative TSH receptor autoantibody (TRAb). These cases were referred to our hospital for unilateral or bilateral eye swelling with painful eye movements, with or without double vision, without any signs or symptoms of hyper- or hypothyroidism. Serum thyroid function tests and 99mTc uptake studies were within the normal range. Anti-thyroid autoantibodies (TRAb) were negative in all the cases. Since orbital CT scan and MRI gave typical results compatible with Graves’ ophthalmopathy and after exclusion of other possibilities, these patients were treated with corticosteroid pulse therapy and orbital radiation therapy, leading to a partial improvement of the symptoms. We followed up those cases with serial thyroid profile testing and TRAb estimation and they were subsequently developed clinical &amp; biochemical hyperthyroidism within the next 18 months follow-up. At that time, they also became TRAb positive. These cases give us insight into the potential pathophysiologic mechanism underlying Graves’ ophthalmopathy and cast light upon the difficulties of establishing the diagnosis in biochemically euthyroid &amp; thyroid autoantibody negative cases. Clinicians should be aware of the variable temporal relationship between the clinical expression of thyroid dysfunction and orbital disease in the natural course of Graves’ disease.

The prevalence and significance of nonuniform thyroid radio-isotope uptake in patients with Graves' disease.

ObjectiveTo evaluate the prevalence and clinical significance of nonuniform technetium (99mTc) uptake among patients with Graves’ disease (GD).Design, Patients and MeasurementsPatients with GD, referred between July 2005 and March 2018, had Tc99‐ uptake scans and TSH‐receptor antibody (TRAb) measured before antithyroid drug (ATD) therapy. Risk of relapse after ATD cessation was monitored until June 2021 and compared between GD patients based on uptake patterns.ResultsOf the 276 GD patients (mean age, 49.8 years; 84% female), 25 (9.0%) had nonuniform Tc99 uptake. At diagnosis, individuals with nonuniform uptake were older (mean age of 61.8 vs. 48.5 years, p < .001), had lower mean thyroid hormone levels (free thyroxine: 36.3 vs. 45.4 pmol/L, p = .04 and free triiodothyronine: 10.0 vs. 17.8 pmol/L, p < .001) and median TRAb levels (4.2 vs. 6.6 U/L, p = .04) compared with those with a uniform uptake. Older age was a significant predictor for the presence of nonuniform uptake in GD patients; odds ratio (95% confidence intervals) of 1.07 (1.03 – 1.10). The risk of relapse was similar in both groups after a median (IQR) follow‐up of 41 (13–74) months after ATD cessation (56.0% vs. 46.3%, respectively); hazard ratio (95% confidence intervals) of 1.74 (0.96–3.15).ConclusionsNonuniform radio‐isotope uptake is seen in 1 in 11 patients with GD which could be misdiagnosed as toxic multinodular goitre if TRAb levels are not measured. Treatment of GD patients with nonuniform radio‐isotope uptake with ATD therapy as first‐line appears to be equally effective as compared with those with uniform uptake. TRAb testing should be the main diagnostic test for patients with suspected GD with radio‐labelled uptake scans being reserved for those who are TRAb negative.

Difference Uptake of 99mTc-Pyrophosphate vs 99mTc- Methylenediphosphate in Detecting Cardiac Amyloidosis; First Experience in Hasan Sadikin General Hospital

Cardiac amyloidosis (CA) is a disorder caused by deposits of insoluble fibrils in the myocardium and an underdiagnosed cause of heart failure. Immunoglobulin Light Chain-Associated Amyloid (AL) and Amyloidosis Transthyretin-related (ATTR) are the two protein precursors that most commonly cause cardiac amyloidosis. It is important to distinguish between these two types of amyloidosis because the treatment and prognosis of each types is different. Recent advances in cardiac radionuclide imaging, in particular using bone-seeking agents such as 99mTc-Pyrophosphate (PYP) and 99mTc-Methylenediphosphate (MDP), can differentiate AL from ATTR. This study aimed was to investigate the uptake characteristic of both tracers in CA. Three patients with suspected of having cardiac amyloidosis underwent two cardiac radionuclide imaging examinations using those two different radiopharmaceuticals. The cardiac images were analyzed quantitatively and semi-quantitatively based on ASNC (American Society of Nuclear Medicine) criteria. Cardiac radioactivity uptake of 99mTc-PYP was better from those of 99mTc-MDP based on quantitative as well as semi-quantitative (visual assessment).&#x0D; Keywords: cardiac amyloidosis; cardiac imaging; 99mTc-PYP; 99mTc-MDP

A novel dual-labeled small peptide as a multimodal imaging agent for targeting wild-type EGFR in tumors.

The epidermal growth factor receptor (EGFR) is over-expressed in various human cancer. The over-expression of EGFR in tumors is an excellent target for the development of cancer imaging agents. In the present study, we developed Tc-99m SYPIPDT-GHEG-ECG-K-tetramethylrhodamine (SYPIPDT-ECG-TAMRA) as a molecular imaging agent targeting wild-type EFGR (wtEGFR)-positive tumor cells, and verified its feasibility as molecular imaging agent. SYPIPDT-ECG-TAMRA was synthesized using Fmoc solid-phase peptide synthesis. The radiolabeling of SYPIPDT-ECG-TAMRA with Tc-99m was accomplished using ligand exchange via tartrate. Cellular uptake and binding affinity studies were performed. In vivo gamma camera imaging, ex vivo imaging and biodistribution studies were performed using NCI-H460 and SW620 tumor-bearing murine models. After radiolabeling procedures with Tc-99m, Tc-99m SYPIPDT-ECG-TAMRA complexes were prepared at high yield (> 95%). The binding affinity value (Kd) of Tc-99m SYPIPDT-ECG-TAMRA for NCI-H460 cells was estimated to be 76.5 ± 15.8 nM. In gamma camera imaging, the tumor to normal muscle uptake ratios of Tc-99m SYPIPDT-ECG-TAMRA increased with time (2.7 ± 0.6, 4.0 ± 0.9, and 6.2 ± 1.0 at 1, 2, and 3 h, respectively). The percentage injected dose per gram of wet tissue for the NCI-H460 tumor was 1.91 ± 0.11 and 1.70 ± 0.22 at 1 and 3 h, respectively. We developed Tc-99m SYPIPDT-ECG-TAMRA, which is dual-labeled with both radioisotope and fluorescence. In vivo and in vitro studies demonstrated specific uptake of Tc-99m SYPIPDT-ECG-TAMRA into wtEGFR-positive NCI-H460 cells and tumors. Thus, the results of the present study suggest that Tc-99m SYPIPDT-ECG-TAMRA is a potential dual-modality imaging agent targeting wtEGFR.

Rat thyroid graft transplantation after cryopreservation with scintigraphic standardization for an experimental study

PurposeBudget cuts among other factors undermine the use of state-of-the-art equipment by many research groups. This doesn't mean that their scientific data are not reliable or top-notch. Resort to adaptations is a recurrent need in their reality. The aim of this study was to assess whether scintigraphy with 99mTcO4 is effective in evaluating the functionality of thyroid grafts after cryopreservation in rats. Material and methods24 rats were randomly distributed into 3 groups: Control Group (CG), without surgical procedure, Hypothyroidism Group (HTG), submitted to total thyroidectomy, and Transplanted Group (TG), with total thyroidectomy and cryopreservation of the thyroid gland for 7 days followed by grafting of a thyroid lobe. A protocol using a gamma camera imaging was conducted fourteen weeks after transplantation, and the whole body 99mTc, focusing on the topic of heterotopic thyroid uptake was evaluated. ResultsThe images acquired had good quality with no noise and artifacts that could jeopardize its analysis. On the 14th day, HTG displayed no thyroid uptake, and the TG had a clear uptake of the thyroid graft in the topography of the biceps femoris muscle. Presented data also showed that both equipment spatial resolution and alignment (4.375 mm) did not interfere with the physiological uptake of 99mTc by the thyroid graft. ConclusionThe viability and functionality of cryopreserved thyroid autotransplantation in rats who underwent total thyroidectomy were successfully accessed by the scintigraphy protocol developed.

P091 Osteoid osteoma of the trapezoid bone: a diagnostic pitfall of a wrist chronic monoarthritis

Abstract Background Osteoid osteoma is a benign bone tumor representing ∼10% of all benign bone tumors. Although osteoid osteoma of the long bones is usual, the location in the carpus, especially, in the trapezoid bone is rare [1,2]. The Objective is toreport a case of osteoid osteoma of the trapezoid bone with extension to the adjacent second metacarpal bone that was missed diagnosis at initial presentation. Methods We describe the clinical, radiological features and outcomes after surgical resection. Results A 24-year-old right-handed female, presented with a three-year history of pain at the left wrist, particularly, in the radial-side. She didn’t report any trauma to the wrist. The pain increased over time. She couldn’t use her hand in daily activities and could hardly sleep because of increasing pain at night. Before being referred to our department, she consulted a surgeon. She was treated with oral anti-inflammatory drugs, steroids, several intraarticular steroid injections without relieving pain. The Magnetic resonance imaging (MRI) showed bone marrow oedema in the trapezium and the trapezoid bone, synovial effusion, and tenosynovitis of the flexors of the thumb. A synovectomy was performed and the histopathology revealed non-specific chronic inflammation. One year later in our department, examination showed wrist swelling, tenderness and pain on palpation. The erythrocyte sedimentation rate was 12 mm/h and the mean C-reactive protein was 2 mg/l. Autoantibodies testing were negative. Initial radiography was read as normal. Initially, Naproxen (550 mg/day) and Morphine (60 mg/day) were prescribed with partially relieving pain. Scintigraphy showed increased uptake of 99mTc in the radial-side of the left wrist. Then, a bone tumor was suspected. The Computed tomography (CT) images revealed a well-demarcated sclerotic nidus surrounded by a halo of radiolucent osteoid tissue, consistent with an osteoid osteoma of the trapezoid bone and the adjacent second metacarpal bone. Surgical resection of the osteoid osteoma was performed. Histopathological examination confirmed the diagnosis. The patient reported complete pain relief since her surgery. She had no recurrence to date. Conclusion Osteoid osteoma should be in the differential diagnosis list of chronic wrist pain/arthritis. In this case, careful attention is necessary for patients unresponsive to treatment with long-lasting symptoms. If radiographs are inconclusive, CT or MRI should be considered to better visualize the nidus of osteoid osteoma in the small bones of the hand.