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1
Yang, Yuanxi, Jinlong Li, Junyi Xu, and Jing Tang. "Generalised DOPs with Consideration of the Influence Function of Signal-in-Space Errors." Journal of Navigation 64, S1 (October 14, 2011): S3—S18. http://dx.doi.org/10.1017/s0373463311000415.
Abstract:
Integrated navigation using multiple Global Navigation Satellite Systems (GNSS) is beneficial to increase the number of observable satellites, alleviate the effects of systematic errors and improve the accuracy of positioning, navigation and timing (PNT). When multiple constellations and multiple frequency measurements are employed, the functional and stochastic models as well as the estimation principle for PNT may be different. Therefore, the commonly used definition of “dilution of precision (DOP)” based on the least squares (LS) estimation and unified functional and stochastic models will be not applicable anymore. In this paper, three types of generalised DOPs are defined. The first type of generalised DOP is based on the error influence function (IF) of pseudo-ranges that reflects the geometry strength of the measurements, error magnitude and the estimation risk criteria. When the least squares estimation is used, the first type of generalised DOP is identical to the one commonly used. In order to define the first type of generalised DOP, an IF of signal–in-space (SIS) errors on the parameter estimates of PNT is derived. The second type of generalised DOP is defined based on the functional model with additional systematic parameters induced by the compatibility and interoperability problems among different GNSS systems. The third type of generalised DOP is defined based on Bayesian estimation in which the a priori information of the model parameters is taken into account. This is suitable for evaluating the precision of kinematic positioning or navigation. Different types of generalised DOPs are suitable for different PNT scenarios and an example for the calculation of these DOPs for multi-GNSS systems including GPS, GLONASS, Compass and Galileo is given. New observation equations of Compass and GLONASS that may contain additional parameters for interoperability are specifically investigated. It shows that if the interoperability of multi-GNSS is not fulfilled, the increased number of satellites will not significantly reduce the generalised DOP value. Furthermore, the outlying measurements will not change the original DOP, but will change the first type of generalised DOP which includes a robust error IF. A priori information of the model parameters will also reduce the DOP.
2
Fiebrich, H., A. H. Brouwers, M. N. Kerstens, M. E. Pijl, I. P. Kema, J. R. de Jong, J. E. van der Wal, W. J. Sluiter, E. G. de Vries, and T. P. Links. "Sensitivity of 6-[F-18]fluoro-L-dihydroxyphenylalanine positron emission tomography for localizing tumors causing catecholamine excess." Journal of Clinical Oncology 27, no. 15_suppl (May 20, 2009): 11064. http://dx.doi.org/10.1200/jco.2009.27.15_suppl.11064.
Abstract:
11064 Background: Positron emission tomography (PET) using the catecholamine precursor 6-[F-18]fluoro-L-dihydroxyphenylalanine (18F-DOPA) has emerged as promising technique to localize tumors with catecholamine excess. This study investigated the sensitivity of 18F-DOPA PET, compared to 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy and computer tomography (CT)/ magnetic resonance imaging (MRI) in patients with catecholamine excess. Methods: In a single center prospective study 18F-DOPA PET was compared to 123I-MIBG and CT/MRI in patients with catecholamine excess. The performance of each imaging modality was analyzed for individual patients and individual lesions. 18F-DOPA PET, 123I-MIBG, and CT/MRI were compared using a composite reference standard derived from all available imaging, clinical and histological information. Sensitivities were calculated and discordance between imaging techniques was compared. 18F-DOPA PET uptake was measured to determine whole body metabolic burden. Correlations between 18F-DOPA PET imaging and biochemical data were evaluated. Results: 48 patients were included. The tumor localization was found in 45 patients, 43 with 18F-DOPA PET, 31 with 123I-MIBG and 32 with CT/MRI, resulting with surgery in final diagnosis of pheochromocytoma in 40, adrenal hyperplasia in 2, paraganglioma in 2, ganglioneuroma in 1 and 3 unknown (as yet no lesion detected). Per patient based analysis showed sensitivities for 18F-DOPA PET, 123I-MIBG and CT/MRI of 90, 65 and 67% (P<.01 18F-DOPA PET vs 123I-MIBG, P<.01 18F-DOPA PET vs CT/MRI, P=1.0 123I-MIBG vs CT/MRI). Corresponding sensitivities in the lesion based analysis were 73, 48 and 44%, respectively (P<.001 for both 18F-DOPA PET vs 123I-MIBG and vs CT/MRI, P=.51 123I-MIBG vs CT/MRI). The 8F-DOPA PET+CT/MRI combination was superior to 123I-MIBG+CT/MRI (93 vs 76%, P<.001) Whole body metabolic burden measured with 18F-DOPA PET correlated with plasma free normetanephrine (r=.82) and 24h urinary total normetanephrine (r=.84) and metanephrine (r=.57). Conclusions: The sensitivity of 18F-DOPA PET to localize tumors with catecholamine excess is superior to either 123I-MIBG scintigraphy or CT/MRI. No significant financial relationships to disclose.
3
Evangelista, Laura, Lea Cuppari, Luisa Bellu, Daniele Bertin, Mario Caccese, Pasquale Reccia, Vittorina Zagonel, and Giuseppe Lombardi. "Comparison Between 18F-Dopa and 18F-Fet PET/CT in Patients with Suspicious Recurrent High Grade Glioma: A Literature Review and Our Experience." Current Radiopharmaceuticals 12, no. 3 (October 1, 2019): 220–28. http://dx.doi.org/10.2174/1874471012666190115124536.
Abstract:
Purpose: The aims of the present study were to: 1- critically assess the utility of L-3,4- dihydroxy-6-18Ffluoro-phenyl-alanine (18F-DOPA) and O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) Positron Emission Tomography (PET)/Computed Tomography (CT) in patients with high grade glioma (HGG) and 2- describe the results of 18F-DOPA and 18F-FET PET/CT in a case series of patients with recurrent HGG. Methods: We searched for studies using the following databases: PubMed, Web of Science and Scopus. The search terms were: glioma OR brain neoplasm and DOPA OR DOPA PET OR DOPA PET/CT and FET OR FET PET OR FET PET/CT. From a mono-institutional database, we retrospectively analyzed the 18F-DOPA and 18F-FET PET/CT of 29 patients (age: 56 ± 12 years) with suspicious for recurrent HGG. All patients underwent 18F-DOPA or 18F-FET PET/CT for a multidisciplinary decision. The final definition of recurrence was made by magnetic resonance imaging (MRI) and/or multidisciplinary decision, mainly based on the clinical data. Results: Fifty-one articles were found, of which 49 were discarded, therefore 2 studies were finally selected. In both the studies, 18F-DOPA and 18F-FET as exchangeable in clinical practice particularly for HGG patients. From our institutional experience, in 29 patients, we found that sensitivity, specificity and accuracy of 18F-DOPA PET/CT in HGG were 100% (95% confidence interval- 95%CI - 81-100%), 63% (95%CI: 39-82%) and 62% (95%CI: 39-81%), respectively. 18F-FET PET/CT was true positive in 4 and true negative in 4 patients. Sensitivity, specificity and accuracy for 18F-FET PET/CT in HGG were 100%. Conclusion: 18F-DOPA and 18F-FET PET/CT have a similar diagnostic accuracy in patients with recurrent HGG. However, 18F-DOPA PET/CT could be affected by inflammation conditions (false positive) that can alter the final results. Large comparative trials are warranted in order to better understand the utility of 18F-DOPA or 18F-FET PET/CT in patients with HGG.
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Koopmans, Klaas P., Oliver C. Neels, Ido P. Kema, Philip H. Elsinga, Wim J. Sluiter, Koen Vanghillewe, Adrienne H. Brouwers, Pieter L. Jager, and Elisabeth G. E. de Vries. "Improved Staging of Patients With Carcinoid and Islet Cell Tumors With18F-Dihydroxy-Phenyl-Alanine and11C-5-Hydroxy-Tryptophan Positron Emission Tomography." Journal of Clinical Oncology 26, no. 9 (March 20, 2008): 1489–95. http://dx.doi.org/10.1200/jco.2007.15.1126.
Abstract:
PurposeTo evaluate and compare diagnostic sensitivity of positron emission tomography (PET) scanning in carcinoid and islet cell tumor patients with a serotonin and a catecholamine precursor as tracers.Patients and MethodsCarcinoid (n = 24) or pancreatic islet cell tumor (n = 23) patients with at least one lesion on conventional imaging including somatostatin receptor scintigraphy (SRS) and computed tomography (CT) scan underwent11C-5-hydroxytryptophan (11C-5-HTP) PET and 6-[F-18]fluoro-L-dihydroxy-phenylalanin (18F-DOPA) PET. PET findings were compared with a composite reference standard derived from all available imaging along with clinical and cytologic/histologic information.ResultsIn carcinoid tumor patients, per-patient analysis showed sensitivities for11C-5-HTP PET,18F-DOPA PET, SRS, and CT of 100%, 96%, 86%, 96%, respectively, and in islet cell tumors of 100%, 89%, 78%, 87%, respectively. In carcinoid patients, per-lesion analysis revealed sensitivities for11C-5-HTP PET,11C-5-HTP PET/CT,18F-DOPA PET,18F-DOPA PET/CT, SRS, SRS/CT, and CT alone of, respectively, 78%, 89%, 87%, 98%, 49%, 73%, and 63% and in islet cell tumors of 67%, 96%, 41%, 80%, 46%, 77%, and 68%, respectively. In all carcinoid patients18F-DOPA PET and11C-5-HTP PET detected more lesions than SRS (P < .001).11C-5-HTP PET was superior to18F-DOPA PET in islet cell tumors (P < .0001). In all cases, CT improved the sensitivity of the nuclear scans.Conclusion18F-DOPA PET/CT is the optimal imaging modality for staging in carcinoid patients and11C-5-HTP PET/CT in islet cell tumor patients.
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Kao, Chang-Long, Yan-Fu Chen, Ping-Chih Huang, Ching-Yun Hsu, and Chun-Hsiung Kuei. "A facile one-pot synthesis of l-DOPA imprinted silica nanospheres for chiral separation and in vitro controlled release." RSC Advances 5, no. 20 (2015): 15511–14. http://dx.doi.org/10.1039/c4ra16698a.
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Vora, Sujay A., Deanna Pafundi, Todd A. DeWees, Molly Voss, Jonathan Ben Ashman, Bernard Bendock, Nadia N. Laack, et al. "Phase II study of short course hypofractionated proton beam therapy incorporating 18F-DOPA-PET/MRI for elderly patients with newly diagnosed glioblastoma." Journal of Clinical Oncology 41, no. 16_suppl (June 1, 2023): 2002. http://dx.doi.org/10.1200/jco.2023.41.16_suppl.2002.
Abstract:
2002 Background: Elderly patients with glioblastoma have a poor prognosis with phase III trials reporting median overall survival (OS) and global time to deterioration of 6–9 and 1.2 months respectively. 18F-DOPA (3,4-dihydroxy-6-[18F]-fluoro-L-phenylalanine) positron emission tomography (PET) is sensitive and specific for identifying regions of high density and biologically aggressive glioblastoma. Proton beam therapy (PBT) can spare more healthy tissue that may improve quality of life for this patient population. With improved targeting of disease along with dosimetric advantages of PBT, this phase II trial tested whether hypofractionated PBT can offer both improved survival and quality of life. Methods: Patients with newly diagnosed glioblastoma aged ≥65 years without contraindications to 18F-DOPA were eligible. Target volumes were defined by PET (tumor/normal brain SUV ≥2.0) and MRI areas of contrast enhancement including surgical cavity. Patients received dose escalated hypofractionated PBT of 35-40 GyE to PET/MRI over 5-10 treatments with 10 mm margin. Patients received concurrent/adjuvant temozolomide. With an alpha of 0.1, 18 of 39 patients would be required to be alive at 12 months for the study to be considered a success. Kaplan-Meier/Cox regression analysis was performed for progression free survival (PFS) and OS. Toxicities were evaluated with CTCAE v4.0. Patients completed EORTC BN20, QLQ-C30, and MMSE questionnaires. Time to deterioration, defined as a 10-point decrease in the score of the function domain or 10-point increase in score of symptom domain, was evaluated. Results: Between 5/2019-6/2021, 43 patients were enrolled, with 4 patients withdrawing due to progression/insurance denial prior to beginning protocol therapy. The median age was 70.2 yrs. and median follow-up was 12.5 months. MGMT methylation was present in 13 (33%). Tumors were multifocal in 10 (26%) and unifocal in 29 (74%). The primary endpoint was met with median PFS/OS was 6.5/12.9 months for all patients and for MGMT methylated patients 11.9/29.8 months respectively. Grade 3 baseline adjusted treatment related adverse events included 1 (3%) confusion, 2 (5%) fatigue, and 1 (3%) seizure. There were no grade 4/5 events. Multivariate analysis revealed MGMT unmethylated, ECOG 2 and biopsy only patients had worse survival. PET volume was more predictive than MRI volume for OS with PET volume>26 cc having a hazard ratio of 3.7. The median time to global deterioration per QLC-C30 was 6.3 months. Conclusions: This phase II trial incorporating 18F-DOPA PET-guided dose escalated hypofractionated proton beam treatment for elderly patients with glioblastoma met its primary endpoint for improved OS and patient reported quality of life compared to historical controls. Further investigation is warranted. Clinical trial information: NCT03778294 .
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Kauhanen, Saila, Marko Seppänen, Heikki Minn, Risto Gullichsen, Anna Salonen, Kalle Alanen, Riitta Parkkola, et al. "Fluorine-18-l-Dihydroxyphenylalanine (18F-DOPA) Positron Emission Tomography as a Tool to Localize an Insulinoma or β-Cell Hyperplasia in Adult Patients." Journal of Clinical Endocrinology & Metabolism 92, no. 4 (April 1, 2007): 1237–44. http://dx.doi.org/10.1210/jc.2006-1479.
Abstract:
Abstract Context and Objective: Fluorine-18-l-dihydroxyphenylalanine (18F-DOPA) positron emission tomography (PET) is a promising method in localizing neuroendocrine tumors. Recently, it has been shown to differentiate focal forms of congenital hyperinsulinism of infancy. The current study was set up to determine the potential of 18F-DOPA PET in identifying the insulin-secreting tumors or β-cell hyperplasia of the pancreas in adults. Patients and Methods: We prospectively studied 10 patients with confirmed hyperinsulinemic hypoglycemia and presumed insulin-secreting tumor using 18F-DOPA PET. Anatomical imaging was performed with computed tomography (CT) and magnetic resonance imaging (MRI). All patients were operated on, and histological verification was available in each case. Semiquantitative PET findings in the pancreas using standardized uptake values were compared to standardized uptake values of seven consecutive patients with nonpancreatic neuroendocrine tumors. Results: By visual inspection of 18F-DOPA PET images, it was possible in nine of 10 patients to localize the pancreatic lesion, subsequently confirmed by histological analysis. 18F-DOPA uptake was enhanced in six of seven solid insulinomas and in the malignant insulinoma and its hepatic metastasis. Two patients with β-cell hyperplasia showed increased focal uptake of 18F-DOPA in the affected areas. As compared to CT or MRI, 18F-DOPA PET was more sensitive in localizing diseased pancreatic tissue. Conclusion: 18F-DOPA PET was useful in most patients with insulinoma and negative CT, MRI, and ultrasound results. In agreement with previous findings in infants, preoperative 18F-DOPA imaging seems to be a method of choice for the detection of β-cell hyperplasia in adults. It should be considered for the detection of insulinoma or β-cell hyperplasia in patients with confirmed hyperinsulinemic hypoglycemias when other diagnostic work-up is negative.
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Breen, William, S. Keith Anderson, Deanna Pafundi, Timothy Kaufmann, Christopher Hunt, Val Lowe, Diane Vogen, et al. "CTNI-28. VOLUMETRIC AND DOSIMETRIC PATTERNS OF FAILURE ANALYSIS OF A PHASE II CLINICAL TRIAL OF 18F-DOPA-PET DIRECTED DOSE ESCALATED RADIOTHERAPY FOR GLIOBLASTOMA." Neuro-Oncology 23, Supplement_6 (November 2, 2021): vi65. http://dx.doi.org/10.1093/neuonc/noab196.253.
Abstract:
Abstract While dose escalation of radiotherapy (DERT) has failed to improve overall survival (OS) or progression-free survival (PFS) for glioblastoma in previous studies, a recent phase II clinical trial utilizing 18F-DOPA-PET-directed DERT demonstrated improved PFS in MGMT-unmethylated patients and OS in MGMT-methylated patients compared to historical controls. This planned secondary analysis sought to determine 1) how 18F-DOPA-PET changes RT volumes beyond standard MRI-planning, 2) which patients benefit most and least from this protocol, 3) which are mostly likely to experience clinically significant radionecrosis after DERT, and 4) patterns of failure after DERT. For 69 evaluable patients, median MRI-defined, PET-defined, and combined low-dose gross tumor volumes (GTV51) were 54 cc (range 9-248), 23 cc (0.4-179), and 62 cc (10-260), respectively. Median MRI-defined, PET-defined, and combined high-dose GTVs (GTV76) were 32 cc (range 4-136), 6 cc (0.1-138), and 34 cc (4-162), respectively. 18F-DOPA-PET resulted in a median volumetric expansion of 13% (0-243%) and 5% (0-217%) from MRI-defined low-dose and high-dose GTV’s, respectively. Central failures ( >95% of recurrence tumor volume) occurred within the 76 Gy, 60 Gy, and 51 Gy isodose lines in 32 (46%), 60 (87%), and 64 (93%) patients, respectively. Recursive partitioning analysis stratified patients by OS and PFS. Patients with 18F-DOPA-PET-defined GTV76 > 7.8cc, MRI-defined GTV76 > 42.7cc, and MGMT promotor-unmethylated tumors had the shortest OS, while patients with smaller PET and MRI-defined tumors had the longest OS (median 10.4 vs. 64.6 months, p< 0.001). Similarly, PFS was worst in patients with 18F-DOPA-PET-defined GTV76 > 2.17 cc who had biopsy only (median PFS 3.2 months, p< 0.001). Patients with 18F-DOPA-PET-defined GTV51 > 50 cc had the highest risk of grade 3+ radionecrosis (p< 0.001). In conclusion, larger 18F-DOPA-PET and MRI-defined tumor volumes were associated with worse outcomes, and 18F-DOPA-PET-directed DERT appears to reduce risk of central recurrence in high-dose volumes.
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Li, Cong, Chang Yi, Yingshen Chen, Shaoyan Xi, Cheng-Cheng Guo, Xiangsong Zhang, and Zhongping Chen. "NIMG-18. THE CLINICAL SIGNIFICANCE OF 13N-NH3, 18F-DOPA, AND 18F-FDG PET/CT IN THE DIFFERENTIAL DIAGNOSIS BETWEEN GLIOMA RECURRENCE AND TREATMENT EFFECTS." Neuro-Oncology 22, Supplement_2 (November 2020): ii150—ii151. http://dx.doi.org/10.1093/neuonc/noaa215.631.
Abstract:
Abstract BACKGROUND Glioma often recurs and the imaging evaluation whether the tumor has returned after glioma treatment is still challenging. PET/CT is one of the most important techniques to assess the post-treatment of glioma. However, differentiating tumor recurrence (TuR) from treatment effects (TrE) remains difficult. In this study, we aim to retrospectively compare the diagnostic performance of three PET tracers 13N-NH3, 18F-DOPA, and 18F-FDG on PET/CT in differentiating between TuR and TrE in post-treatment glioma patients. METHODS Forty-three patients with MRI-suspected recurrent glioma were included. The maximum and mean standardized uptake value (SUVmax and SUVmean) of the lesion and the lesion-to-normal Gray-matter cortex uptake (L/G) ratio were recorded and the reference standard was verified by surgical histopathology or more than 6 months of follow-up with clinical/radiological. The diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis. RESULTS 34 patients were confirmed as glioma TuR and 9 patients met the standard of TrE. The median time interval from primary diagnosis surgery to PET/CT was 14.83 months (range, 4.10-62.77 months). The SUVmax of 13N-NH3 and 18F-DOPA PET/CT at the lesions was significantly higher than normal brain tissue (13N-NH3 0.696±0.095 vs 0.486±0.071, 18F-DOPA 0.455±0.079 vs 0.194±0.031, both P< 0.001), while 18F-FDG was not (6.918±0.525 vs 6.356±0.510, P=0.290). TuR showed significantly higher L/G ratios than TrE both in 13N-NH3 and 18F-DOPA PET/CT (13N-NH3, 1.573±0.099 vs 1.025±0.128, P=0.008; 18F-DOPA, 2.729±0.131 vs 1.514±0.141, P< 0.001). The sensitivity, specificity and the area under the curve (AUC) by ROC analysis were 57.7, 100% and 0.803 for 13N-NH3, and 84.6, 100% and 0.938 for 18F-DOPA respectively. CONCLUSIONS PET/CT is a powerful tool to distinguish glioma TuR from TrE, and 18F-DOPA PET/CT has remarkably better differential diagnosis efficacy than 13N-NH3 and 18F-FDG.
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Nanni, C., S. Fanti, and D. Rubello. "18F-DOPA PET and PET/CT." Journal of Nuclear Medicine 48, no. 10 (October 1, 2007): 1577–79. http://dx.doi.org/10.2967/jnumed.107.041947.
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Mossine, Andrew V., Sean S. Tanzey, Allen F. Brooks, Katarina J. Makaravage, Naoko Ichiishi, Jason M. Miller, Bradford D. Henderson, Marc B. Skaddan, Melanie S. Sanford, and Peter J. H. Scott. "One-pot synthesis of high molar activity 6-[18F]fluoro-l-DOPA by Cu-mediated fluorination of a BPin precursor." Organic & Biomolecular Chemistry 17, no. 38 (2019): 8701–5. http://dx.doi.org/10.1039/c9ob01758e.
Abstract:
A one-pot two-step synthesis of 6-[18F]fluoro-l-DOPA has been developed, involving Cu-mediated radiofluorination of the corresponding pinacol boronate ester precursor, and validated for production of doses for human use.
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Kauhanen, Saila, Marko Seppänen, Jari Ovaska, Heikki Minn, Jörgen Bergman, Pirkko Korsoff, Pasi Salmela, et al. "The clinical value of [18F]fluoro-dihydroxyphenylalanine positron emission tomography in primary diagnosis, staging, and restaging of neuroendocrine tumors." Endocrine-Related Cancer 16, no. 1 (March 2009): 255–65. http://dx.doi.org/10.1677/erc-08-0229.
Abstract:
The study was set up to determine the clinical value of dihydroxyphenylalanine positron emission tomography-computed tomography ([18F]DOPA PET-CT) in patients with neuroendocrine tumors (NETs). Eighty-two patients with suspected/known NET were imaged with PET(-CT) using [18F]DOPA. Patients were divided into two groups: primary diagnosis/staging and restaging of disease. All patients without previous diagnosis of NET had biochemical proof of disease. The diagnostic accuracy of PET was assessed by comparing the histopathology and clinical follow-up. The overall accuracy of [18F]DOPA PET was 90%. In patients having PET for primary diagnosis/staging (n=32), the accuracy of PET was 88%, and for restaging 92% (n=61). The mean s.d. sizes of primary and metastatic lesions detected by PET were 26±11 and 16±9 mm respectively. In organ-region-specific analysis, the sensitivity and specificity were 100% in the primary diagnosis of pheochromocytoma (n=16) and metastases were found in all cases with recurrent disease (n=5). The accuracy for NET of gastrointestinal tract was 92% in restaging (n=24). For the NETs located in the head–neck–thoracic region (n=19), the overall accuracy of PET was 89% including 12 cases of recurrent medullary thyroid cancer with a sensitivity of 90%. In analysis of patients with biochemical proof of disease combined with negative conventional imaging methods, PET had positive and negative predictive value of 92% and 95% respectively. [18F]DOPA PET-CT provided important additional information in the diagnosis of pheochromocytoma and restaging of known NET. Both in primary diagnosis and in patients with formerly known NET and increasing tumor markers, [18F]DOPA PET-CT is a sensitive first-line imaging method.
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Saini, Amardeep Singh, and Jose Savio Melo. "One-pot green synthesis of eumelanin: process optimization and its characterization." RSC Advances 5, no. 59 (2015): 47671–80. http://dx.doi.org/10.1039/c5ra01962a.
Abstract:
Herein, we propose the importance of Taguchi’s design of experiment methodology for increasing the yield of eumelanin using l-Dopa as the substrate and tyrosinase enzyme from Amorphophallus campanulatus as the biocatalyst.
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Hoshi, Hiroaki, Hiroto Kuwabara, Gabriel Léger, Paul Cumming, Mark Guttman, and Albert Gjedde. "6-[18F]fluoro-l-DOPA Metabolism in Living Human Brain: A Comparison of Six Analytical Methods." Journal of Cerebral Blood Flow & Metabolism 13, no. 1 (January 1993): 57–69. http://dx.doi.org/10.1038/jcbfm.1993.8.
Abstract:
In 11 normal volunteers and six patients with Parkinson's disease, we compared six different analyses of dopaminergic function with l-3,4-dihydroxy-6-[18F]fluorophenylalanine (FDOPA) and positron emission tomography (PET). The caudate nucleus, putamen, and several reference regions were identified in PET images, using magnetic resonance imaging (MRI). The six analyses included two direct determinations of DOPA decarboxylase activity ( kD3, k*3), the slope–intercept plot based on plasma concentration ( K), two slope–intercept plots based on tissue content ( kr3, ks3), and the striato–occipital ratio [ R( T)]. For all analyses, the difference between two groups of subjects (normal volunteers and patients with Parkinson's disease) was larger in the putamen than in the caudate. For the caudate nucleus, the DOPA decarboxylase activity ( kD3, k*3), tissue slope–intercept plots ( kr3, ks3), and striato–occipital ratio [ R( T)] analyses significantly discriminated between the normal volunteers and the patients with Parkinson's disease ( p < 0.005) [with least significance for k*3 ( p < 0.05)], while the plasma slope–intercept plot ( K) failed to do so. For the putamen, the values for kD3, k*3, K, kr3, ks3 and R( T) of normal volunteers were significantly higher than those of patients ( p < 0.005) [with least significance for K ( p < 0.025)]. Linear correlations were significant between kD3 and ks3; kD3 and kr3; kD3 and R( T); and kD3 and k*3, in this order of significance. We found no correlation between kD3 and K values in the caudate nucleus.
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Qian, Jing, Deanna Pafundi, William Breen, Paul Brown, Christopher Hunt, Mark Jacobson, Derek Johnson, et al. "RADT-15. 18F-DOPA PET/CT SURVEILLANCE FOR GLIOBLASTOMA: A RADIOMIC MODEL FROM A PROSPECTIVE PHASE II CLINICAL TRIAL PREDICTING SURVIVAL IN IDH-WILDTYPE, MGMT-UNMETHYLATED PATIENTS." Neuro-Oncology 24, Supplement_7 (November 1, 2022): vii52. http://dx.doi.org/10.1093/neuonc/noac209.205.
Abstract:
Abstract BACKGROUND Interpretation of serial magnetic resonance imaging (MRI) for glioblastoma following radiation therapy (RT) is complicated by difficulty differentiating tumor from treatment-related changes, even using updated RANO criteria. The incorporation of novel imaging such as 3,4-dihydroxy-6-[18F]-fluoro-L-phenylalanine (18F-DOPA) PET/CT to post-treatment serial imaging may improve prognostication and better facilitate future treatment decisions. METHODS The secondary analysis of a recent phase II prospective clinical trial of 18F-DOPA PET/CT-directed dose-escalated RT included patients with IDH-wildtype, MGMT-unmethylated glioblastoma who underwent post-treatment serial 18F-DOPA PET/CT surveillance. Quantitative features were extracted from pre-RT and post-RT serial PET/CT images, and robust prognostic features were selected using an in-house workflow. Both an automated machine learning (ML) algorithm and an interpretable ML algorithm were utilized to correlate surveillance PET image features with subsequent survival of greater than 12 months versus less than 12 months from the surveillance timepoint. Changes from pre-RT to post-RT PET/CT (delta model) were also assessed for association with post-RT survival and validated with a separate cohort. RESULTS Thirty-five patients with IDH-wildtype, MGMT-unmethylated glioblastoma who had at least one available (range: 1-14) post-treatment 18F-DOPA PET/CT were included. Twenty-four were used for model training, while 11 were used for validation. Ultimately, a five-feature post-RT model utilizing two shape, two texture, and one first-order radiomic feature was selected. For the delta model, five texture, two shape, and one first order radiomic feature were selected. The models show 90% accuracy in predicting survival < 12 months post-surveillance on the training set, and 68%-73% accuracy (AUC 0.64-0.73) for the validation cohort. Delta features were significantly associated with overall survival (p < 0.05). CONCLUSIONS Post-RT serial 18F-DOPA PET/CT imaging can help distinguish true tumor progression in patients with glioblastoma using a radiomics model. Tumor response evaluated for changes from pre-RT to post-RT 18F-DOPA PET/CT also predicted subsequent overall survival.
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Manso, Jacopo, Loris Bertazza, Susi Barollo, Alberto Mondin, Simona Censi, Sofia Carducci, Alfonso Massimiliano Ferrara, et al. "Overexpression of miR-375 and L-type Amino Acid Transporter 1 in Pheochromocytoma and Their Molecular and Functional Implications." International Journal of Molecular Sciences 23, no. 5 (February 22, 2022): 2413. http://dx.doi.org/10.3390/ijms23052413.
Abstract:
Pheochromocytoma (Pheo) is a tumor derived from chromaffin cells. It can be studied using 18F-dihydroxyphenylalanine (DOPA)—positron emission tomography (PET) due to its overexpression of L-type amino acid transporters (LAT1 and LAT2). The oncogenic pathways involved are still poorly understood. This study examined the relationship between 18F-DOPA-PET uptake and LAT1 expression, and we explored the role of miR-375 and putative target genes. A consecutive series of 58 Pheo patients were retrospectively analyzed, performing 18F-DOPA-PET in 32/58 patients. Real-time quantitative PCR was used to assess the expression of LAT1, LAT2, phenylethanolamine N-methyltransferase (PNMT), miR-375, and the major components of the Hippo and Wingless/Integrated pathways. Principal germline mutations associated with hereditary Pheo were also studied. Pheo tissues had significantly higher LAT1, LAT2, and PNMT mRNA levels than normal adrenal tissues. MiR-375 was strongly overexpressed. Yes-associated protein 1 and tankyrase 1 were upregulated, while beta-catenin, axin2, monocarboxylate transporter 8, and Frizzled 8 were downregulated. A positive relationship was found between 18F-DOPA-PET SUV mean and LAT1 gene expression and for 24 h-urinary norepinephrine and LAT1. This is the first experimental evidence of 18F-DOPA uptake correlating with LAT1 overexpression. We also demonstrated miR-375 overexpression and downregulated (Wnt) signaling and identified the Hippo pathway as a new potentially oncogenic feature of Pheo.
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Khamis, K., N. Giladi, C. Levine, M. Kesler, J. Kuten, H. Lerman, and E. Even-Sapir. "The Added Value of 18F-FDOPA PET/CT in the Work-Up of Patients with Movement Disorders." Neurographics 9, no. 5 (October 1, 2019): 344–48. http://dx.doi.org/10.3174/ng.1900004.
Abstract:
Movement disorders represent a common clinical feature in many different neurologic diseases. However, although the clinical features are often similar, there are many different possible etiologies of these movement disorders, which represent a valid diagnostic challenge. Management of these patients is dependent on an accurate diagnosis of the underlying etiology because the clinical course and treatment may vary significantly. 18F-Fluor-l-dopa has been used as a positron-emitting compound for PET evaluation of patients with movement disorders and parkinsonism. To emphasize the diagnostic value of combining both morphologic and functional imaging in 18F-Fluor-l-dopa PET/CT, we describe the clinical history and 18F-Fluor-l-dopa PET/CT imaging findings of 5 patients in whom the cause of movement impairment was unclear.
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Zschieschang, P., V. Prasad, D. Moskopp, B. Knie, and M. Plotkin. "A family with pheochromocytoma-paraganglioma inherited tumour syndrome." Nuklearmedizin 55, no. 01 (2016): 34–40. http://dx.doi.org/10.3413/nukmed-0755-15-07.
Abstract:
SummaryAim: Hereditary pheochromocytoma-paraganglioma syndromes are characterized by multiple pheochromocytomas (PCC) and paragangliomas (PGLs), inherited in an autosomal dominant manner. Early detection and removal of tumours may prevent or minimize complications related to mass effects and malignant transformation. Having confirmed the diagnosis, it is important to localize the tumours and reveal their extent preoperatively. This study aimed to introduce 18F-DOPA PET/CT as a highly sensitive noninvasive diagnostic tool for early detection of mass lesions in patients with pheochromocytoma-paraganglioma inherited tumour syndrome and to report about its impact on patient management. Patients, methods: We are currently supervising one of the largest documented families in Germany with genetically determined SDHD gene mutation. We performed 18F-DOPA PET/CT in order to detect tumours in asymptomatic gene carriers and enable subsequent surgical therapy. Results: In seven patients undergoing 12 18F-DOPA PET/CT scans 17 lesions have been detected. Three of these lesions, located in the head and neck region, have had no morphologic correlate in CT and one had also no morphologic correlate in MRI. Of the six histologically analyzed lesions five have been tumors (PGL or PCC) and one has been a nodular hyperplasia. This means the 18F-DOPA PET/CT scan in our study group had a sensitivity of 83%. 18F-DOPA PET/CT investigations lead to change in the management in 5/7 studied patients (70%). Conclusion: The benefits of PET/ CT in detection of pheochromocytoma and paraganglioma are well documented, but we are the first to use this technique for screening of a rare hereditary disease (estimated prevalence 0.3/100 000).
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Burroni, Luca, Andrea Palucci, Giuseppina Biscontini, and Valentino Cherubini. "Early diagnosis of focal congenital hyperinsulinism: A fluorine-18-labeled l-dihydroxyphenylalanine positron emission tomography/computed tomography study." World Journal of Nuclear Medicine 20, no. 04 (October 2021): 395–97. http://dx.doi.org/10.4103/wjnm.wjnm_159_20.
Abstract:
AbstractCongenital hyperinsulinism (CHI) is responsible for hyperinsulinemic hypoglycemia which needs aggressive treatment in order to prevent neurological damages. Recent advances in genetics have linked CHI to mutations in many different genes that play a key role in regulating insulin secretion from pancreatic β-cells. Furthermore, histopathological lesions, diffuse and focal, have been associated with these different genetic alterations. This short manuscript describes how the advent of fluorine-18-labeled L-dihydroxyphenylalanine-positron emission tomography/computed tomography (18F-DOPA-PET/CT) scanning has changed the management of patients with CHI. 18F-DOPA PET/CT imaging differentiates focal from diffuse disease and is 100% accurate in localizing the focal lesion. In these patients, the lesion can be surgically removed allowing complete resolution of clinical alterations. We report a case in which clinical experience together with rapid genetic analysis and imaging with 18F-DOPA-PET/CT, were able to guide the correct clinical management of this condition. We confirm that advances in molecular genetics, imaging methods (18F-DOPA PET-CT), medical therapy, and surgical approach have completely changed the management and improved the outcome of these children.
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Michalicha, Anna, Cristina Canal, Albert Espona-Noguera, Mateusz Piet, Barbara Budzyńska, Stanislaw Przywara, and Anna Belcarz. "Collagen-Sealed Polyester Vascular Prostheses Functionalized by Polycatecholamine Coatings." International Journal of Molecular Sciences 23, no. 16 (August 19, 2022): 9369. http://dx.doi.org/10.3390/ijms23169369.
Abstract:
Collagen-sealed polyester (PET) prostheses are commonly used in reconstructive vascular surgery due to their self-sealing properties. To prevent post-surgical infection, different modification methods have been tested but so far none have showed long-term satisfactory efficiency. For this reason, in the present study, a commercial collagen-sealed PET prosthesis was coated by a highly adhesive poly (L-DOPA) layer maintaining the sealing protein without losing the original properties and functionality. This modified (as proven by SEM, FTIR, XPS and contact angle) graft exhibited comparable wettability and elasticity as pristine commercial graft, as well as reduced hemolysis-inducing effect, lowered toxicity against human endothelial cells and reduced toxicity in Danio rerio model. Poly (L-DOPA)-coated grafts were shown to bind six times more aminoglycoside antibiotic (gentamicin) than pristine graft. Poly (L-DOPA)-coated antibiotic-bound prostheses exhibited an improved antibacterial activity (bacterial growth inhibition and anti-adhesive capacity) in comparison with pristine antibiotic-bound graft. Overall, poly (L-DOPA)-coatings deposited on PET vascular grafts can effectively functionalize collagen-sealed prostheses without the loss of protein sealing layer and allow for antibiotics incorporation to provide higher safety in biomedical applications.
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Lange-Nolde, A., T. Zajic, M. Slawik, M. Reincke, E. Moser, S. Hoegerle, and I. Brink. "PET with 18F-DOPA in the imaging of parathyroid adenoma in patients with primary hyperparathyroidism." Nuklearmedizin 45, no. 05 (2006): 193–96. http://dx.doi.org/10.1055/s-0038-1625218.
Abstract:
Summary:Preoperative localization of parathyroid adenomas (PA) can shorten operation time and improve curative rate; it becomes especially important in minimally invasive surgical techniques. Aim of this study was to investigate whether positron emission tomography (PET) with 3-,4-dihydroxy- 6-18F-fluorophenylalanine (18F-DOPA), which showed very promising results in other neuroendocrine tumours, also helps to localize PA. Patients, methods: Eight patients with proven primary hyperparathyroidism were studied preoperatively with PET. Seven also underwent scintigraphy with 99mTc-MIBI and ultrasonography of the neck. All patients were operated and the histological finding was used as a gold standard. Results: All eight patients had a histologically proven PA. None of the PA showed any detectable uptake of 18F-DOPA. However, ultrasonography detected 5/7 PA, scintigraphy detected 3/7 PA. Conclusion: These results suggest that PET with 18F-DOPA is not useful in the detection of PA in patients with primary hyperparathyroidism.
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Zanzi, Italo, Yana Studentsova, David Bjelke, Richard Warner, Barry Babchyck, and Thomas Chaly. "Fluorine-18-fluorodihydroxyphenylalanine Positron-emission Tomography Scans of Neuroendocrine Tumors (Carcinoids and Pheochromocytomas)." Journal of Clinical Imaging Science 7 (May 22, 2017): 20. http://dx.doi.org/10.4103/jcis.jcis_107_16.
Abstract:
Objectives: Conventional methods of imaging neuroendocrine tumors with computed tomography, magnetic resonance imaging, indium-111-octreotide, or radiolabeled metaiodobenzilguanidine scintigraphy have limitations. This pilot study tried to improve the localization of these tumors with fluorine-18-fluorodihydroxyphenylalanine (F-DOPA) positron-emission tomography (PET) scanning. Materials and Methods: We studied 22 patients, the majority of whom were referred with clinical diagnosis or suspicion of carcinoid (n = 11), neuroendocrine tumors (n = 7) or pheochromocytoma/paraganglioma (PGL) (n = 4). The comparison was made with the prior conventional imaging. Results: The F-DOPA findings were compared with the results of subsequent surgery (2), endoscopy (1), or a long-term follow-up (mean duration, 49 months) for 17 patients. Two patients were lost to follow-up. Foci of F-DOPA deposition were detected in eight patients (final diagnosis of carcinoid in six, of neuroendocrine tumors in one, and of PGL in another). Comparison with the final diagnoses revealed concordance in 16 of the 22 patients. F-DOPA results appeared superior to those obtained with conventional imaging. Despite the small number and diagnostic heterogeneity, in a substantial fraction of patients F-DOPA PET added information relevant to clinical management. Conclusion: F-DOPA scanning added prognostic value, particularly when multiple abnormal foci versus a negative examination were considered.
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Tsentr, N. V., A. A. Zyryanova, M. A. Rusnak, and D. V. Ryzhkova. "Diagnostic capabilities of PET/CT with <sup>18</sup>F-DOPA in biochemical recurrence of medullary thyroid carcinoma: a retrospective study." Diagnostic radiology and radiotherapy 15, no. 1 (April 9, 2024): 87–95. http://dx.doi.org/10.22328/2079-5343-2024-15-1-87-95.
Abstract:
INTRODUCTION: Medullary thyroid carcinoma (MTС) is a rare neuroendocrine malignant neoplasm of the thyroid gland. In most cases, sporadic MTС is diagnosed at late stages due to the absence of specific symptoms. The main method of treatment of MTС is surgical — thyroidectomy and in most cases cervical lymphodissection. Current international guidelines suggest the use of basal calcitonin levels and cancer embryonic antigen (CEA) as markers of biochemical recurrence. In biochemical recurrence of the disease, it is advisable to search for tumor foci regardless of the level of cancer markers. Positron emission tomography combined with computed tomography (PET/CT) has the highest sensitivity and specificity for searching for local recurrence and distant metastases. Anatomical imaging methods (computed tomography (CT), magnetic resonance imaging (MRI)) have suboptimal sensitivity and specificity in detection of a recurrent tumor.OBJECTIVE: To explore the diagnostic capabilities of PET/CT with 18F-DOPA in patients with biochemical recurrence of medullary thyroid carcinoma, depending on the concentration of calcitonin in blood plasma.MATERIALS AND METHODS: To evaluate the diagnostic capabilities of PET/CT with 18F-DOPA in patients with biochemical recurrence of medullary thyroid carcinoma, 81 PET/CT studies were analyzed in patients after thyroidectomy. In most cases (76/81), at the time of the study, patients had elevated basal calcitonin levels (>10 pg/ml, including in 52/81 cases >150 pg/ml), which corresponded to a biochemical recurrence of the disease. In 6 cases, the calcitonin level was <10 pg/ml. PET/CT results were processed by visual image analysis, measurement of a semi-quantitative indicator of the maximal standardized level of radiopharmaceutical accumulation normalized to lean body mass (SUVlbm max) and the total volume of PET-positive tumor tissue (metabolic tumor volume).RESULTS: In 41 studies, foci of pathological accumulation of 18F-DOPA were identified, corresponding to recurrent tumor foci. DOPA-negative results in patients with elevated calcitonin levels were regarded as false negative. The highest sensitivity of the method was achieved at calcitonin levels >150 pg/ml. A noticeable positive correlation was found between the concentration of basal serum calcitonin, the number of pathological foci of 18F-DOPA hyperaccumulation and the total metabolic volume of tumor tissue. In most cases of biochemical recurrence, the PET method was superior to the CT method in detecting recurrent tumor foci.CONCLUSION: PET/CT with 18F-DOPA is the most informative method for molecular and structural imaging in patients with biochemical recurrence of medullary thyroid carcinoma. The results of the study directly correlate with the level of basal calcitonin in the blood.
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Xu, Bo, Shouao Zhu, Siheng Zhao, and Xiangdong Wang. "A High-Phosphorus-Content Polyphosphonate with Combined Phosphorus Structures for Flame Retardant PET." Polymers 15, no. 7 (March 30, 2023): 1713. http://dx.doi.org/10.3390/polym15071713.
Abstract:
A high-phosphorus-content polyphosphonate (PBDA), containing two phosphorus-based structures: phosphaphenanthrene (DOPO) and phenyl phosphonate groups, was synthesized and used in flame retardant polyethylene terephthalate (PET). Good self-extinguishing property (high UL 94 grade and LOI value), superior flame retardancy (lower heat/smoke release), and high quality retention (high carbon residue) were endowed to PET by PBDA. When 10 wt% PDBA was added, the peak heat release rate (pHRR), total heat release (THR), and total smoke rate (TSR) of PDBA/PET were found to be significantly reduced by 80%, 60.5%, and 21%, respectively, compared to the pure PET, and the LOI value jumped from 20.5% for pure PET to 28.7% with a UL-94 V-0 rating. The flame-retardant mode of action in PET was verified by thermogravimetric analysis-Fourier transform infrared (TGA-FTIR), pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), real-time FTIR, and scanning electron microscopy (SEM). Phosphaphenanthrene and phosphonate moieties in PDBA decomposed in sequence during heating, continuously releasing and keeping high-content PO· and PO2· radicals with a quenching effect and simultaneously promoting the formation of viscous crosslinked char layers causing a high barrier effect. PDBA mainly acted in the gas phase but the condensed-phase flame retardant function was also considerable.
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Priya S, Vishnu, and Somasundaram P. "INDUCED PHENOLOXIDASE PROFILES IN SILKWORM Bombyx mori (L.) UNDER BIOTIC STRESS." International Journal of Engineering Technologies and Management Research 4, no. 10 (February 3, 2020): 46–52. http://dx.doi.org/10.29121/ijetmr.v4.i10.2017.105.
Abstract:
Phenol oxidase (PO) is one of the stress enzyme protein in living organism. The conversion of Pro-PO into an activation form of PO required a stress protein. In the present study has emerged with the novel finding of induced phenoloxidase was identified under bacterial endotoxin viz., Lipopolysaccharide (LPS) activity using silkworm Bombyx mori as an animal model. The PO enzyme plays an important role for insect survival during pathophysiological conditions. The enzyme activity was analyzed from ten different silkworm races with two phenolic substrates viz., L-Dopa and Dopamine by Native-PAGE. The bacterially induced PO was found in hemolymph and midgut of silkworm, PO3 were induced by LPS injection. In control PO1 & PO2 are non-bacterially induced protein having the molecular weight of 72 and 71. The results shown that there is no substrate specificity and similar functional activity was found in hemolymph and midgut under pathogenic condition. It was observed that bacterially inducible PO clearly differed from non-inducible PO (control). At final observation of induced isozymes of PO in the haemolymph and midgut system of tolerant silkworm races points out the existence of biochemical immunity against biotic stress of LPS. This is the first report to document the silkworm immunity under the LPS toxin in different silkworm races to identify the tolerant and susceptibility against a biotic stress.
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Todorovic-Tirnanic, Mila, Vera Artiko, Smiljana Pavlovic, Dragana Sobic-Saranovic, and Vladimir Obradovic. "Contemporary nuclear medicine diagnostics of neuroendocrine tumors." Srpski arhiv za celokupno lekarstvo 143, no. 1-2 (2015): 108–15. http://dx.doi.org/10.2298/sarh1502108t.
Abstract:
The new positron emission tomography (PET/CT) methods for neuroendocrine tumors detection are presented and compared with classic, conventional methods. Conventional methods use a gamma scintillation camera for patients with neuroendocrine tumor imaging, after intravenous injection of one of the following radiopharmaceuticals: 1) somatostatin analogues labeled with indium-111 (111In-pentetreotide) or technetium-99m (99mTc-EDDA/HYNIC-TOC); 2) noradrenaline analogue labeled with iodine-131 or -123 (131I/123I-MIBG); or 3) 99mTc(V)-DMSA. Contemporary methods use PET/CT equipment for patients with neuroendocrine tumor imaging, after intravenous injection of pharmaceuticals labeled with positron emitters [fluorine-18 (18F), galium-68 (68Ga), or carbon-11 (11C)]: 1) glucose analogue (18FDG); 2) somatostatin analogue (68Ga-DOTATOC/68Ga-DOTATATE/68Ga-DOTANOC); 3) aminoacid precursors of bioamines: [a) dopamine precursor 18F-DOPA (6-18F-dihydroxyphenylalanine), b) serotonin precursor 11C-5HTP (11C-5-hydroxytryptophan)]; or 4) dopamine analogue 18F-DA (6-18F-fluorodopamine). Conventional and contemporary (PET/ CT) somatostatin receptor detection showed identical high specificity (92%), but conventional had very low sensitivity (52%) compared to PET/CT (97%). It means that almost every second neuroendocrine tumor detected by contemporary method cannot be discovered using conventional (classic) method. In metastatic pheochromocytoma detection contemporary (PET/ CT) methods (18F-DOPA and 18F-DA) have higher sensitivity than conventional (131I/123I-MIBG). In medullary thyroid carcinoma diagnostics contemporary method (18F-DOPA) is more sensitive than conventional 99mTc(V)-DMSA method, and is similar to 18FDG, computed tomography and magnetic resonance. In carcinoid detection contemporary method (18F-DOPA) shows similar results with contemporary somatostatin receptor detection, while for gastroenteropancreatic neuroendocrine tumors it is worse. To conclude, contemporary (PET/CT) methods for somatostatin receptor detection (68Ga-DOTATOC/-NOC/-TATE) in neuroendocrine tumors are much more sensitive (almost twice) and more accurate than conventional. Therefore the classical methods should be urgently replaced by contemporary methods.
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Zemskova, Marina S., Bhaskar Gundabolu, Ninet Sinaii, Clara C. Chen, Jorge A. Carrasquillo, Millie Whatley, Iffat Chowdhury, Ahmed M. Gharib, and Lynnette K. Nieman. "Utility of Various Functional and Anatomic Imaging Modalities for Detection of Ectopic Adrenocorticotropin-Secreting Tumors." Journal of Clinical Endocrinology & Metabolism 95, no. 3 (March 1, 2010): 1207–19. http://dx.doi.org/10.1210/jc.2009-2282.
Abstract:
Abstract Context: Because ectopic ACTH-secreting (EAS) tumors are often occult, improved imaging is needed. Objective: Our objective was to evaluate the utility of [111In-DTPA-d-Phe]pentetreotide scintigraphy [octreotide (OCT)] imaging at 6 mCi [low OCT (LOCT)] and 18 mCi [high OCT (HOCT)], [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET) and [18F]l-3,4-dihydroxyphenylalanine (F-DOPA)-PET scans, computed tomography (CT), and magnetic resonance imaging (MRI). Design and Setting: The study was a prospective evaluation at a clinical research center. Patients: Forty-one subjects participated, 30 (17 female) with resected EAS tumors and 11 (three female) with occult EAS, based on inferior petrosal sinus sampling results and imaging studies. Intervention: Intervention included CT and MRI of neck, chest, abdomen, LOCT (with or without HOCT) and FDG- or F-DOPA-PET without CT every 6–12 months. Main Outcome Measure: Tumor identification was the main outcome measure. Results: Most recent results were analyzed. Eighteen patients had tumor resected on the first visit; otherwise, surgery occurred 33 ± 25 (9–99) months later. Tumor size was 1.9 ± 1.7 (0.8–8.0) cm; 83% were intrathoracic. CT, MRI, LOCT, HOCT, FDG-PET, and F-DOPA-PET had sensitivities per patient of 93% [95% confidence interval (CI) = 79–98%], 90% (95% CI = 74–96%), 57% (95% CI = 39–73%), 50% (95% CI = 25–75%), 64% (95% CI = 35–85%), and 55% (95% CI = 28–79%) and positive predictive values (PPV) per lesion of 66, 74, 79, 89, 53, and 100%, respectively. LOCT and PET detected only lesions seen by CT/MRI; abnormal LOCT or F-DOPA-PET improved PPV of CT/MRI. By modality, the fraction of patients with one or more false-positive findings was 50% by CT, 31% by MRI, 18% by L/HOCT, and 18% by FDG-PET. Eight occult EAS patients had 64 ± 58 (9–198) months follow-up; others had none. Conclusions: High sensitivity and PPV suggest thoracic CT/MRI plus LOCT scans for initial imaging, with lesion confirmation by two modalities.
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Bhat, Vighneshwar S., T. S. Tilakraj, Mallikarjun K. Patil, Vikram Pujari, and Sanjeev R. Inamdar. "One-Pot Synthesis of Biocompatible Glycine Protected Chromium Doped ZnS Nanoparticles and their Optical Properties." IOP Conference Series: Materials Science and Engineering 1221, no. 1 (March 1, 2022): 012029. http://dx.doi.org/10.1088/1757-899x/1221/1/012029.
Abstract:
Abstract Here in, we report the synthesis and characterization of Chromium doped Zinc Sulfide nanoparticles (ZnS NPs). Initially, ZnS NPs are synthesized by bio-compatible glycine cap using simple one-pot co-precipitate method, and further it is doped by Chromium. The structure and morphology of these ZnS NPs was confirmed by X-Ray Diffractometry (XRD) and Scanning Electron Microscope with Elementary Dispersive Spectrum (SEM with EDS) techniques. The optical characterization techniques reveal that the Chromium doping affected the absorption and photoluminescence properties of the NPs. Photoluminescence of these NPs shifts from 384 nm to 428 nm upon Chromium doping. By using Tauc plot we obtained the energy band gap of 4.7 eV and it reduces to 3.9 eV for Chromium dope. The resultant ZnS NPs have size of 2.17nm and 1.86nm (with Chromium doping), also it gives Cubic Zinc blend phase as proved by XRD. The instrumentation techniques SEM with EDS, XRD, FTIR confirms that high purity Chromium doped ZnS NPs can be obtained by the proposed simple, low cost and highly effective method.
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Lee, Wen-Lung, Lung-Chang Liu, Chien-Ming Chen, and Jian-Shian Lin. "Syntheses and flame retarding properties of DOPO polymers, melamine polymers, and DOPO-melamine copolymers." Polymers for Advanced Technologies 25, no. 1 (October 3, 2013): 36–40. http://dx.doi.org/10.1002/pat.3201.
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Samanta, Suman, Saon Banerjee, Asis Mukherjee, Pulak K. Patra, and Pramiti K. Chakraborty. "Determining the radiation use efficiency of potato using sunshine hour data: a simple and costless approach." Spanish Journal of Agricultural Research 18, no. 2 (May 18, 2020): e0801. http://dx.doi.org/10.5424/sjar/2020182-15561.
Abstract:
Aim of study: Radiation parameters and photoperiod influence potato biomass and tuber yield significantly. Lack of instrument facilities in developing countries is the main hindrance to estimate global solar radiation (GSR) and radiation use efficiency (RUE). Considering these facts, an experiment was conducted to estimate light extinction coefficient (K) and RUE using a simple but indirect approach that can be implied in any location lacking sophisticated instruments.Area of study: Field experiments were conducted in Kalyani, West Bengal, representing the Indo-Gangetic Plains.Material and methods: Angstrom-Prescott (A-P) equation was used to calculate GSR. The experiment was laid out in a split-plot design with three dates of planting (DOP), 15th Nov, 29th Nov and 13th Dec, as main plot treatment and three potato cultivars (ˈKufri Suryaˈ, ˈKufri Chandramukhiˈ and ˈKufri Jyotiˈ) as sub-plot treatment. Leaf area indices and K values were used to determine intercepted PAR (IPAR) as well as RUE.Main results: The cumulative IPAR from emergence to harvest ranged 246-429 MJ m-2 depending on planting time and varieties. Irrespective of DOPs, the highest mean RUE (4.19 g MJ-1) was calculated in ˈKufri Chandramukhiˈ, showing that it used the radiation more efficiently that the other two cultivars (ˈKufri Suryaˈ= 3.75 g MJ-1 and ˈKufri Jyotiˈ= 3.14 g MJ-1).Research highlights: Statistical indices confirmed that the A-P model can be reliably used in the study region for estimation of GSR. This simple way to estimating RUE using bright sunshine hours data can be used in developing countries, where costly radiation instruments are not available.
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Li, Qiaoguang, Xugang Shu, Puyou Jia, and Yonghong Zhou. "Preparation of Biomass-Based Ester End-Capped Hyperbranched Poly(ether)s via Facile One-Pot Reaction and Their Performance as Non-Toxic Plasticizers." Polymers 12, no. 4 (April 15, 2020): 913. http://dx.doi.org/10.3390/polym12040913.
Abstract:
The aim of this study was to develop a facile one-pot reaction for the synthesis of biomass-based hyperbranched poly(ether)s end-capped as acetate esters (BHE) for use as a sustainable, safe and feasible plasticizer for flexible poly(vinyl chloride) (PVC) materials. BHE is completely miscible with PVC but shows weaker plasticizing effect than dioctyl phthalate (DOP) (EΔTg value of BHE reaches 64.8%). PVC plasticized with BHE displays greater thermal stability than that of PVC or PVC plasticized with DOP materials. BHE improves the thermal stability and flexibility of PVC materials. As a plasticizer, BHE displays lower solvent extractability and greater volatilization resistance than DOP. Acute oral toxicity indicates that BHE has toxic doses of 5 g/kg, suggesting that BHE is non-toxic.
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Trébossen, Régine, Bernard Bendriem, Maria-Joao Ribeiro, Anne Fontaine, Vincent Frouin, and Philippe Remy. "Validation of the Three-Dimensional Acquisition Mode in Positron Emission Tomography for the Quantitation of [18F]Fluoro-DOPA Uptake in the Human Striata." Journal of Cerebral Blood Flow & Metabolism 18, no. 9 (September 1998): 951–59. http://dx.doi.org/10.1097/00004647-199809000-00004.
Abstract:
Three-dimensional (3D) positron emission tomography (PET) is attractive for [18F]fluoro-DOPA studies, since the sensitivity improvement is maximal for radioactive sources located in central planes, which is usually the case for the human striata. However, the image quantitation in that mode must be assessed because of the nearly threefold increase in scattered coincidences. We report the results of [18F]fluoro-DOPA studies performed on six normal volunteers. Each one was scanned in the 3D and two-dimensional(2D) modes on the same tomograph. The quantitation in the 3D and 2D modes was compared for a Patlak graphical analysis with the occipital counts as the input function (Ki) and a striatooccipital ratio analysis. We find that, in 3D PET, a scatter correction is required to preserve the same quantitation as in 2D PET. When the 3D data sets are corrected for scatter, the quantitation of the [18F]fluoro-DOPA uptake, using the Patlak analysis, is similar in the 2D and 3D acquisition modes. Conversely, analysis of the striatooccipital ratio leads to higher values in 3D PET because of a better in-plane resolution. Finally, using the 3D mode, the dose injected to the subjects can be reduced by a factor greater than 1.5 without any loss in accuracy compared to the 2D mode.
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Yue, Lipei, Yingjie Cao, Tong Huang, Lei Huang, Yongping Bai, and Yongfeng Zhou. "Synthesis of Aromatic Hyperbranched Polyester (HBPE) and its Use as a Nonmigrating Plasticiser." Australian Journal of Chemistry 67, no. 1 (2014): 22. http://dx.doi.org/10.1071/ch13195.
Abstract:
A series of aromatic hyperbranched polyesters (HBPEs) were synthesised through one-pot reaction of benzene-1,2,4-tricarboxylic anhydride, diethylene glycol, and methanol. The molecular structure of HBPEs was characterised by 1H-NMR, Fourier transform infrared spectroscopy, gel permeation chromatography, differential scanning calorimetry (DSC), and thermogravimetric analysis. HBPE was used as plasticiser for poly(vinyl chloride) (PVC), and compared with traditional plasticiser bis(2-ethylhexyl) phthalate (DOP). When the plasticiser concentration in PVC was below 40 wt-%, HBPE showed better plasticisation efficiency than DOP, with enhanced impact strength and ultimate elongation. Volatility and extractability tests for PVC films indicated that there was no migration if HBPE was used as plasticiser, even under very harsh conditions, while the migration in PVC films plasticised by DOP was much greater, indicating that HBPE could be used as a substitution for DOP to lower the potential health risk from migrating phthalates during the use of PVC products.
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Snow, B. J., H. Takahashi, Poppy Schofield, Sandra Cooper, Vesna Sossi, S. Morrison, D. B. Calne, and M. Cordes. "L-18F-DOPA-PET bei Parkinson-Plus-Syndromen zum Nachweis einer gestörten präsynaptischen dopaminergen Funktion." Nuklearmedizin 31, no. 02 (1992): 43–47. http://dx.doi.org/10.1055/s-0038-1629599.
Abstract:
ZusammenfassungBei 14 Patienten mit Parkinson-Plus-Syndromen (PPLUS) wurden PET-Unter- suchungen mittels L-18F-DOPA unter Verwendung einer arteriellen Inputfunktion durchgeführt. Aufgrund von Modellannahmen konnte für den radioaktiven Tracer die Influxkonstante Ki in Abhängigkeit von Korrekturen der unspezifischen Aktivität im Kortex oder Zerebellum bestimmt werden. Die Ergebnisse wurden mit denen von 20 gesunden Kontrollen verglichen und im Hinblick auf die Intra- und Interuntersucher-Variabilität ausgewertet. Bei Patienten mit Parkinson-Plus-Syndromen war in allen Fällen die Influxkonstante Ki erniedrigt. Ihr Mittelwert betrug 0,154 (ml/Striatum/min) bei PPLUS gegenüber 0,690 (ml/ Striatum/min) bei Gesunden. Der Korrelationskoeffizient war für die Intraunter- sucher-Variabilität r = 0,973 und die Interuntersucher-Variabilität r = 0,879 bei Gesunden bzw. 0,989 und 0,973 bei PPLUS nach Korrektur der unspezifischen Aktivität über eine kortikale Region. Weder bei Gesunden noch bei PPLUS waren nach Korrektur der unspezifischen Aktivität über eine zerebellare Region Unterschiede der gemessenen Werte für Ki nachweisbar (p = 0,1). PET- Untersuchungen mittels L-18F-DOPA können das Ausmaß der nigrostriatalen Degeneration in vivo sicher erfassen. Aufgrund der irreversiblen Bindung von L-18F-DOPA innerhalb des Striatums läßt sich durch PET eine untersucherunabhängige Quantifizierung der gestörten präsynaptischen dopaminergen Funktion vornehmen.
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Lopci, Egesta, Arnoldo Piccardo, Cristina Nanni, Vania Altrinetti, Alberto Garaventa, Andrea Pession, Angelina Cistaro, Arturo Chiti, Giampiero Villavecchia, and Stefano Fanti. "18F-DOPA PET/CT in Neuroblastoma." Clinical Nuclear Medicine 37, no. 4 (April 2012): e73-e78. http://dx.doi.org/10.1097/rlu.0b013e3182485172.
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Chondrogiannis, Sotirios, Maria Cristina Marzola, and Domenico Rubello. "18F-DOPA PET/Computed Tomography Imaging." PET Clinics 9, no. 3 (July 2014): 307–21. http://dx.doi.org/10.1016/j.cpet.2014.03.007.
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Tsentr, N. V., A. E. Ertman, and D. V. Ryzhkova. "PET/CT with various radiopharmaceuticals in the complex diagnosis of medullary thyroid carcinoma: a review." Diagnostic radiology and radiotherapy 14, no. 2 (July 5, 2023): 31–41. http://dx.doi.org/10.22328/2079-5343-2023-14-2-31-41.
Abstract:
INTRODUCTION: Medullary carcinoma is a rare malignant neuroendocrine tumor of the thyroid gland. Medullary thyroid carcinoma (MTC) has no specific clinical symptoms. Due to the absence of specific symptoms, the disease is usually diagnosed at the stage of metastatic lesions of regional lymph nodes, and sometimes, internal organs. The five- and ten-year survival after detection of distant metastases is 25% and 10%, respectively.OBJECTIVE: To analyze the available foreign and domestic literature to determine the role of PET/CT with various radiopharmaceuticals in the complex radiological diagnosis of MTC.MATERIALS AND METHODS: A search was made for scientific publications and clinical recommendations in the information and analytical systems PudMed, elibrary over the past ten years, dedicated to the diagnosis of MTC, including PET/CT with 18F-DOPA, 18F-FDG, 68Ga-DOTA peptides, etc. by keywords «medullary thyroid cancer», «medullary thyroid carcinoma», «PET/CT», «18F-L-dihydroxyphenylalanine», «18F-DOPA», «18F-DOPA», «68Ga-DOTA peptides», «68Ga-DOTA-peptides», «theranostics», «theranostics».RESULTS: The analysis of publications demonstrated the prospects for the use of PET/CT with various radiopharmaceuticals for the diagnosis of recurrent tumors and the prevalence of the process in biochemical recurrence of MTC, as well as the possibility of peptide-receptor radionuclide therapy for the treatment of advanced forms of the disease. The choice of radiopharmaceuticals is based on the results of laboratory diagnostics and conventional methods of anatomical imaging. PET/CT with 68Ga-DOTA peptides is performed to predict the effectiveness of peptide-receptor radionuclide therapy.CONCLUSION: PET/CT with various radiopharmaceuticals makes a significant contribution to the diagnosis of recurrent tumors, assessment of the prevalence of the tumor process and selection of patients for peptide-receptor radionuclide therapy.
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Mulyati, Sri, Syawaliah Muchtar, Nasrul Arahman, Friska Meirisa, Yanna Syamsuddin, Zuhra Zuhra, Cut Meurah Rosnelly, et al. "One-Pot Polymerization of Dopamine as an Additive to Enhance Permeability and Antifouling Properties of Polyethersulfone Membrane." Polymers 12, no. 8 (August 12, 2020): 1807. http://dx.doi.org/10.3390/polym12081807.
Abstract:
This paper reports the fabrication of polyethersulfone membranes via in situ hydrogen peroxide-assisted polymerization of dopamine. The dopamine and hydrogen peroxide were introduced into the dope solution where the polymerization occurred, resulting in a single-step additive formation during membrane fabrication. The effectivity of modification was evaluated through characterizations of the resulting membranes in terms of chemical functional groups, surface morphology, porosity, contact angle, mechanical strength and filtration of humic acid solution. The results confirm that the polydopamine was formed during the dope solution mixing through peroxide-assisted polymerization as proven by the appearance of peaks associated OH and NH groups in the resulting membranes. The presence of polydopamine residual in the membrane matric enhances the pore properties in terms of size and porosity (by a factor of 10), and by lowering the hydrophilicity (from 69° to 53°) which leads to enhanced filtration flux of up to 217 L/m2 h. The presence of the residual polydopamine also enhances membrane surface hydrophilicity which improve the antifouling properties as shown from the flux recovery ratio of > 80%.
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Nausch, Monika, Lennart Thomas Bach, Jan Czerny, Josephine Goldstein, Hans-Peter Grossart, Dana Hellemann, Thomas Hornick, Eric Pieter Achterberg, Kai-Georg Schulz, and Ulf Riebesell. "Effects of CO<sub>2</sub> perturbation on phosphorus pool sizes and uptake in a mesocosm experiment during a low productive summer season in the northern Baltic Sea." Biogeosciences 13, no. 10 (May 24, 2016): 3035–50. http://dx.doi.org/10.5194/bg-13-3035-2016.
Abstract:
Abstract. Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in many aquatic systems. The aim of our study was to analyse effects of elevated CO2 levels on phosphorus pool sizes and uptake. The phosphorus dynamic was followed in a CO2-manipulation mesocosm experiment in the Storfjärden (western Gulf of Finland, Baltic Sea) in summer 2012 and was also studied in the surrounding fjord water. In all mesocosms as well as in surface waters of Storfjärden, dissolved organic phosphorus (DOP) concentrations of 0.26 ± 0.03 and 0.23 ± 0.04 µmol L−1, respectively, formed the main fraction of the total P-pool (TP), whereas phosphate (PO4) constituted the lowest fraction with mean concentration of 0.15 ± 0.02 in the mesocosms and 0.17 ± 0.07 µmol L−1 in the fjord. Transformation of PO4 into DOP appeared to be the main pathway of PO4 turnover. About 82 % of PO4 was converted into DOP whereby only 18 % of PO4 was transformed into particulate phosphorus (PP). PO4 uptake rates measured in the mesocosms ranged between 0.6 and 3.9 nmol L−1 h−1. About 86 % of them was realized by the size fraction < 3 µm. Adenosine triphosphate (ATP) uptake revealed that additional P was supplied from organic compounds accounting for 25–27 % of P provided by PO4 only. CO2 additions did not cause significant changes in phosphorus (P) pool sizes, DOP composition, and uptake of PO4 and ATP when the whole study period was taken into account. However, significant short-term effects were observed for PO4 and PP pool sizes in CO2 treatments > 1000 µatm during periods when phytoplankton biomass increased. In addition, we found significant relationships (e.g., between PP and Chl a) in the untreated mesocosms which were not observed under high fCO2 conditions. Consequently, it can be hypothesized that the relationship between PP formation and phytoplankton growth changed with CO2 elevation. It can be deduced from the results, that visible effects of CO2 on P pools are coupled to phytoplankton growth when the transformation of PO4 into POP was stimulated. The transformation of PO4 into DOP on the other hand does not seem to be affected. Additionally, there were some indications that cellular mechanisms of P regulation might be modified under CO2 elevation changing the relationship between cellular constituents.
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Aperia, A., A. Bertorello, and I. Seri. "Dopamine causes inhibition of Na+-K+-ATPase activity in rat proximal convoluted tubule segments." American Journal of Physiology-Renal Physiology 252, no. 1 (January 1, 1987): F39—F45. http://dx.doi.org/10.1152/ajprenal.1987.252.1.f39.
Abstract:
We studied the effect of dopamine (DA) on Na+-K+-ATPase activity in proximal convoluted tubule (PCT) segments dissected from perfused rat kidneys. DA inhibited Na+-K+-ATPase activity in a dose-dependent manner. Inhibition was significant with 10(-7) M DA and maximal with 10(-4) M DA. The inhibition was reversible. Enzyme inhibition occurred in the presence of DA and a DA antagonist, metoclopramide, but not when 10(5) M of the DA1 and DA2 agonists fenoldopam mesylate and LY 171555 were added in the absence of DA. In PCT segments incubated with the DA precursor dopa, Na+-K+-ATPase activity was also inhibited. However, dopa did not inhibit the sodium pump if dopa decarboxylase activity was blocked with benserazide. These findings suggest an intracellular site of action of DA. In tubules incubated in different K concentrations, 10(-5) DA decreased the maximal activity (Vmax) and increased the Km. DA 10(-5) M caused an almost immediate swelling of PCT segments. Swelling did not occur in the presence of both DA and 10(-5) M amiloride. The DA-induced tubular swelling was probably due to inhibition of Na+-K+-ATPase-mediated Na+-transport. We conclude that in rat PCT segments, DA causes a rapid and reversible inhibition of apparent Na+-K+-ATPase activity and an apparent reduction in the affinity for K. The site of action appears to be intracellular.
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Sonnier, Rodolphe, Belkacem Otazaghine, Christelle Vagner, Frédéric Bier, Jean-Luc Six, Alain Durand, and Henri Vahabi. "Exploring the Contribution of Two Phosphorus-Based Groups to Polymer Flammability via Pyrolysis–Combustion Flow Calorimetry." Materials 12, no. 18 (September 12, 2019): 2961. http://dx.doi.org/10.3390/ma12182961.
Abstract:
From a set of around 100 phosphorus-containing polymers tested in pyrolysis–combustion flow calorimetry, the contributions to flammability of two phosphorus-containing pendant groups (called 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and PO3) were calculated using an advanced method previously proposed and validated. The flammability properties include total heat release (THR) and heat release capacity (HRC) measured in standard conditions, i.e., anaerobic pyrolysis and complete combustion. The calculated contributions are in good agreement with the main modes of action of both phosphorus groups, i.e., flame inhibition for DOPO and char promotion for PO3. Moreover, the results provide first conclusions about the cooperative interaction between phosphorus and nitrogen, as well as the influence of the architecture of tested co-polymers.
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Schneider, B., A. Kraft, E. Moser, E. U. Nitzsche, and S. Hoegerle. "Imaging of a Metastatic Gastrointestinal Carcinoid by F-18-DOPA Positron Emission Tomography." Nuklearmedizin 38, no. 04 (1999): 127–30. http://dx.doi.org/10.1055/s-0038-1632205.
Abstract:
SummaryThe localization of carcinoids in the gastrointestinal tract is frequently difficult if not impossible with the imaging procedures used to date. It is reported on a patient with metastasizing carcinoid in whom various imaging procedures were not successful in detecting the primary tumor. Due to the importance of primary tumor proof for potential curative surgical therapy, a whole-body positron emission tomography with F-18-DOPA was performed. PET enabled localization of a potential primary tumor in the ileum. Moreover, in addition to the known abdominal lymph node and liver metastases, it detected a mediastinal lymph node metastasis and a pulmonary metastasis. F-18-DOPA whole-body PET may be a very promising imaging approach to the localization and staging of gastrointestinal carcinoids.
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Pretze, M., C. Wängler, and B. Wängler. "6-[18F]Fluoro-L-DOPA: A Well-Established Neurotracer with Expanding Application Spectrum and Strongly Improved Radiosyntheses." BioMed Research International 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/674063.
Abstract:
For many years, the main application of [18F]F-DOPA has been the PET imaging of neuropsychiatric diseases, movement disorders, and brain malignancies. Recent findings however point to very favorable results of this tracer for the imaging of other malignant diseases such as neuroendocrine tumors, pheochromocytoma, and pancreatic adenocarcinoma expanding its application spectrum. With the application of this tracer in neuroendocrine tumor imaging, improved radiosyntheses have been developed. Among these, the no-carrier-added nucleophilic introduction of fluorine-18, especially, has gained increasing attention as it gives [18F]F-DOPA in higher specific activities and shorter reaction times by less intricate synthesis protocols. The nucleophilic syntheses which were developed recently are able to provide [18F]F-DOPA by automated syntheses in very high specific activities, radiochemical yields, and enantiomeric purities. This review summarizes the developments in the field of [18F]F-DOPA syntheses using electrophilic synthesis pathways as well as recent developments of nucleophilic syntheses of [18F]F-DOPA and compares the different synthesis strategies regarding the accessibility and applicability of the products for humanin vivoPET tumor imaging.
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Abramov, V. G., A. A. Khoroshavina, K. O. Tutsenko, M. G. Sadovsky, E. A. Karlova, and D. V. Pokhabov. "Determination of Parameter Reference Values for 18F-DOPA PET Imaging of the Brain (Based on Using Data from Healthy Subjects)." Doctor.Ru 19, no. 9 (2020): 13–19. http://dx.doi.org/10.31550/1727-2378-2020-19-9-13-19.
Abstract:
Study Objective: To determine, based on data from examination of apparently healthy subjects, parameter reference values for 18F-DOPA positron emission tomography (PET) of the brain. Study Design: This was a prospective study. Materials and Methods: Apparently healthy subjects (n = 33) underwent 18F-DOPA PET of the brain using a Discovery PET/CT 600 scanner. Data were processed using standard statistical methods. The Shapiro-Wilk test was used to test data distribution for normality, and Pearson and Spearman covariance and correlation matrices were calculated. The key components were analyzed to assess combined scattering (explained variance). Study Results: For absolute parameters, the following reference levels were determined for radioactivity concentration (median [1st quartile; 3rd quartile]): 2.24 [2.02; 2.80] kBq/mL in the right putamen, 2.26 [2.02; 2.75] kBq/mL in the left putamen, 2.11 [1.78; 2.55] kBq/mL in the right caudate nucleus (CN), 2.01 [1.74; 2.49] kBq/mL in the left caudate nucleus, and 0.81 [0.71; 1.00] and 0.81 [0.74; 1.02] kBq/mL in the right and left occipital cortices (OC), respectively. For relative parameters, the following reference values were determined (mean ± standard deviation): 2.66 ± 0.52 for the right corpus striatum/OC, 2.68 ± 0.53 for the left corpus striatum/OC, 2.36 ± 0.48 for the right CN/OC, 2.34 ± 0.47 for the left CN/OC, 1.09 ± 0.21 for the right corpus striatum/CN, and 1.11 ± 0.21 for the left corpus striatum/CN. Conclusion: The paper presents reference values for radioactivity concentration in 18F-DOPA PET of the brain. This is the first report of such data. Keywords: neurodegenerative disorders, dopamine metabolism, population norm.
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Pichon, Baptiste, Caroline Rousseau, Audrey Blanc-Lapierre, Gregory Delpon, Ludovic Ferrer, Vincent Libois, Matthieu Le Turnier, et al. "Targeting Stereotactic Body Radiotherapy on Metabolic PET- and Immuno-PET-Positive Vertebral Metastases." Biomedicines 8, no. 12 (November 28, 2020): 548. http://dx.doi.org/10.3390/biomedicines8120548.
Abstract:
(1) Background: Stereotactic body radiotherapy (SBRT) for vertebral metastases (VM) allows the delivery of high radiation doses to tumors while sparing the spinal cord. We report a new approach to clinical target volume (CTV) delineation based on anti-carcinoembryonic antigen (CEA) positron emission tomography (pretargeted immuno-PET; “iPET”) in patients with metastatic breast cancer (BC) or medullary thyroid cancer (MTC). (2) Methods: All patients underwent iPET, spine magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT) using 18F-deoxyglucose (FDG) for BC or 18F-dihydroxy-phenylalanine (F-DOPA) for MTC. Vertebrae locations and vertebral segments of lesions were recorded and the impact on CTV delineation was evaluated. (3) Results: Forty-six VM eligible for SBRT following iPET were evaluated in eight patients (five BC, three MTC). Eighty-one vertebral segments were detected using MRI, 26 with FDG or F-DOPA PET/CT, and 70 using iPET. iPET was able to detect more lesions than MRI for vertebral bodies (44 vs. 34). iPET-based delineation modified MRI-based CTV in 70% (32/46) of cases. (4) Conclusion: iPET allows a precise mapping of affected VM segments, and adds complementary information to MRI in the definition of candidate volumes for VM SBRT. iPET may facilitate determining target volumes for treatment with stereotactic body radiotherapy in metastatic vertebral disease.
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Laughlin, Brady, Deanna Pafundi, Matthew Buras, Jonathan Ashman, Bernard Bendok, Nadia Laack, William Breen, et al. "RADT-25. IMPACT OF 18F-DOPA PET ON RADIATION TREATMENT PLANNING FROM PHASE II STUDY OF SHORT COURSE HYPOFRACTIONATED PROTON BEAM THERAPY FOR ELDERLY PATIENTS WITH GLIOBLASTOMA." Neuro-Oncology 25, Supplement_5 (November 1, 2023): v54. http://dx.doi.org/10.1093/neuonc/noad179.0214.
Abstract:
Abstract PURPOSE 18F-DOPA is sensitive/specific for identifying areas of biologically aggressive disease for glioblastoma. We report the impact of 18F-DOPA on radiation treatment planning from a phase II study. METHODS Gross target volume (GTV) was defined by the boolean of high-risk PET (tumor/normal brain SUV > 2.0) and MRI T1 contrast enhancement (MRI-CE) including surgical cavity. The clinical target volume (CTV) included the GTV with 1cm margin. Using proton beam therapy, GTV ≤ 65 cc was treated with 25 (CTV), 30 (MRI-CE), and 35 (PET) GyE over 5 fractions with a simultaneous integrated boost. GTV > 65 cc received 30 (CTV), 35 (MRI-CE), and 40 (PET) GyE over 10 fractions. Radiation field design was compared to traditional 1.5cm CTV margin on MRI-CE. RESULTS Between May 2019 and October 2021, 39 patients were treated. The median MRI-CE tumor diameter was 5.2cm. The median PET volume was 7.9cc (range 0–64.9cc). The median MRI-CE volume was 35.1cc (range 8.6–114cc). High-risk PET was contained within: MRI-CE 18/39 (46%), MRI-CE + T2W FLAIR 13/39 (33%), MRI-CE + T2W FLAIR + outside GTV 4/39 (10%), outside GTV 2/39 (5%) and no uptake 2/39 (5%). Utilizing this planning technique, there was a 26% volume reduction in CTV to traditional 1.5 cm margin on MRI-CE. PET imaging in treatment planning allowed inclusion of high-risk disease that would have been excluded on traditional CTV in 23% of cases (range 1.6-33.8cc). PET was more predictive [HR 1.03 (95% CI 1.01, 1.05) p = 0.002] than MRI [HR 1.01 (95% CI 1.00, 1.03) p = 0.02] for death with each cc increasing risk of death by 3.1%. CONCLUSIONS The incorporation of 18F-DOPA in treatment planning yields a more targeted approach with reductions in both normal brain treated and risk of geographic miss compared to traditional CTV margins.
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Gribble, Daniel A., and Vilas G. Pol. "Polydopamine-Modified Carboxymethyl Cellulose as Advanced Polysulfide Trapping Binder." Batteries 9, no. 11 (October 24, 2023): 525. http://dx.doi.org/10.3390/batteries9110525.
Abstract:
The search for a high-energy-density alternative to lithium-ion batteries has led to great interest in the lithium sulfur battery (LSB). However, poor cycle lifetimes and coulombic efficiencies (CEs) due to detrimental lithium polysulfide (LiPS) shuttling has hindered its widespread adoption. To address this challenge, a modified sodium carboxymethyl cellulose (CMC) polymer with integrated dopamine moieties and polydopamine nanoparticles was created through a facile one-pot dopamine (DOP) amidation reaction to strengthen noncovalent interactions with LiPSs and mitigate the shuttling effect. The resulting CMC-DOP binder improved electrode wettability, adhesion, and electrochemical performance. Compared to LSBs with a standard CMC binder, CMC-DOP 5:1 (with a 5:1 weight ratio of CMC to dopamine precursor) improves the specific capacity at cycle 100 by 38% to 552 mAh g−1 and CE from 96.8 to 98.9%. LSBs show good stability, even after 500 cycles. Post-mortem electrochemical impedance spectroscopy (EIS) and energy-dispersive spectroscopy (EDS) studies confirmed the effectiveness of the CMC-DOP in confining LiPS in the cathode. This simple but effective nature-inspired strategy promises to enhance the viability of LSBs without using harmful chemicals or adding excess bulk.
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Nanni, Cristina, Domenico Rubello, and Stefano Fanti. "18F-DOPA PET/CT and neuroendocrine tumours." European Journal of Nuclear Medicine and Molecular Imaging 33, no. 5 (April 1, 2006): 509–13. http://dx.doi.org/10.1007/s00259-006-0079-5.
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Beuthien-Baumann, B. "18F-DOPA-PET bei neuroendokrinen Tumoren (NET)." Der Nuklearmediziner 32, no. 02 (June 2009): 131–34. http://dx.doi.org/10.1055/s-0028-1112124.
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Ghaemi, M., J. Rudolf, S. Schmülling, S. Bamborschke, and W. D. Heiss. "FDG- and Dopa-PET in postencephalitic parkinsonism." Journal of Neural Transmission 107, no. 11 (November 8, 2000): 1289–95. http://dx.doi.org/10.1007/s007020070018.