The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform
Francis D Moore - One of the best experts on this subject based on the ideXlab platform.
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parathyroid reoperation with use of technetium 99m sestamibi radiolocalization and an intraoperative Gamma Counter
Endocrine Practice, 1996Co-Authors: Sandy Feng, Francis D MooreAbstract:Objective: To describe a new intraoperative technique for localization of abnormal parathyroid tissue. Methods: We report a case and discuss the difficulties enCountered in reexploration of the neck area. Results: Parathyroid reoperation remains a formidable challenge to even the most experienced endocrine surgeon. Despite the advances in radiographic imaging and localization techniques, accurate intraoperative identification of abnormal parathyroid tissue in a scarred field with obliterated anatomic planes is frequently tedious and occasionally unsuccessful. In a 48-year-old woman with hyperparathyroidism, extensive exploration of the area identified (on the basis of preoperative magnetic resonance imaging and technetium 99m sestamibi scans) as suspicious for the presence of abnormal parathyroid tissue revealed only an aberrant vein. With use of a handheld Gamma Counter to provide intraoperative guidance during parathyroid reexploration after preoperative intravenous injection of technetium 99m sestamibi, quick identification of a small, intrathyroidal, fifth gland adenoma responsible for persistent primary hyperparathyroidism was facilitated. Conclusion: Because of suboptimal precision and specificity, current preoperative localization studies can occasionally provide misleading information. Particularly in difficult cases of parathyroid reexploration, an instrument capable of localizing abnormal parathyroid tissue, which can be used intraoperatively with ease, can be an invaluable tool to ensure a safe, expedient, and successful surgical outcome. (Endocr Pract. 1996; 2:382-384)
June Kee Yoon - One of the best experts on this subject based on the ideXlab platform.
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Survey Result of the Counting Efficiency of Gamma Counter by Certified Reference Materials
Nuclear Medicine and Molecular Imaging, 2018Co-Authors: Ji In Bang, Jeong Mi Park, June Kee YoonAbstract:Purpose In radioimmunoassay (RIA), the Gamma Counter is the important instrument for the accurate measurement. To manage quality assurance of RIA, the counting efficiency of Gamma Counter is one of the important parameters. The aim of this study was to evaluate the counting efficiency of Gamma Counters in multiple institutes on the base of traceability by using the certified reference materials (CRMs). Methods Twenty-three institutes that perform RIA were enrolled in this study. I-125 CRMs that were certified by National Institute of Standards and Technology (NIST) were used. Each institute was asked to count the activity of I-125 CRMs at most twice on all Gamma Counters in use. The counting efficiency of each well of Counter was calculated on the base of NIST-certified information, corrected for I-125 decay for date of testing. Results From 23 institutes, 44 Gamma Counters were evaluated. The average counting efficiency of all wells was 85.9% and the standard deviation was 13.5%. As a mean value of each Gamma Counter, three Gamma Counters showed poor counting efficiency (less than 70%). The poorest counting efficiency was 7%. The counting efficiency of seven Gamma Counters was between 70 and 75%. Eight Counters had the counting efficiency between 75 and 90%. More than half of Counter (26 Gamma Counters) showed excellent counting efficiency (more than 90%). The standard deviation variation range of inter-well efficiency was from 0 to 11.2. Conclusion The first survey on the counting efficiency of Gamma Counter was performed in South Korea. Most of the RIA laboratories have well managed the quality assurance of Gamma Counter.
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survey result of the counting efficiency of Gamma Counter by certified reference materials
Nuclear Medicine and Molecular Imaging, 2018Co-Authors: Ji In Bang, Jeong Mi Park, June Kee YoonAbstract:Purpose In radioimmunoassay (RIA), the Gamma Counter is the important instrument for the accurate measurement. To manage quality assurance of RIA, the counting efficiency of Gamma Counter is one of the important parameters. The aim of this study was to evaluate the counting efficiency of Gamma Counters in multiple institutes on the base of traceability by using the certified reference materials (CRMs).
G. Alexander Patterson - One of the best experts on this subject based on the ideXlab platform.
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In vivo molecular imaging of transgene expression in a model of solid organ transplantation
Journal of Surgical Research, 2004Co-Authors: Sekhar Dharmarajan, M. Hayama, T. Ishiyama, Daniel P. Schuster, G. Alexander PattersonAbstract:Abstract Gene therapy is a promising strategy to prevent immune- and non-immune-mediated injury in solid organ transplantation. This study was performed to investigate the use of noninvasive molecular imaging techniques with PET to accurately characterize transgene expression in an experimental rodent model of lung transplantation. Fischer 344 rats underwent endotracheal transfection with adenovirus encoding a fusion gene of green fluorescent protein (standard reporter gene) and a mutant herpes simplex virus-1 thymidine kinase (PET imaging reporter gene). Rats were then divided into a control group ( n = 6) which underwent transfection alone and groups of rats which underwent orthotopic left lung transplantation ( n = 3 each) 24 h after transfection. Lungs were transplanted in groups representing normal transplantation, ischemia-reperfusion injury, and acute allograft rejection. PET imaging was obtained 24 h after transplantation to study reperfusion injury and 4 days after transplantation to study graft rejection. After imaging, lungs were excised, weighed, and analyzed for thymidine kinase activity and Gamma Counter tissue radioactivity. PET imaging signals were strongly and linearly correlated with postmortem ex vivo Gamma Counter activity ( r 2 = 0.82, P in vitro thymidine kinase activity ( r 2 = 0.42, P
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In vivo molecular imaging characterizes pulmonary gene expression in experimental lung transplantation
Journal of The American College of Surgeons, 2004Co-Authors: Sekhar Dharmarajan, M. Hayama, T. Ishiyama, Daniel P. Schuster, G. Alexander PattersonAbstract:Abstract Introduction: Gene therapy is effective in preventing ischemia-reperfusion injury and allograft rejection after experimental lung transplantation. Currently, no means exist to noninvasively determine the distribution, magnitude and timing of transgene expression after transplantation. This study utilizes a novel PET reporter gene system to characterize transgene expression after experimental lung transplantation. Methods: Experiments utilized a rodent orthotopic left lung transplant model. Donors underwent endotracheal transfection 24 hours before harvest with 5x1010 VPs of adenovirus encoding a fusion gene of thymidine kinase (TK, PET reporter gene) and green fluorescent protein. PET images were obtained in 4 groups of recipients: 24 hours postoperatively with and without I/R injury, and 4 days postoperatively with and without acute rejection. Rats which underwent transfection alone served as controls. Excised lungs were assessed for Gamma Counter radioactivity and TK activity. Results: Transplanted lungs displayed strong and linear correlation between PET signals and Gamma Counter radioactivity (r2 = 0.82, p Conclusions: PET imaging is a sensitive and quantitative method for characterizing pulmonary transgene expression in experimental lung transplantation. Characterization of transgene expression is not adversely affected by I/R injury or graft rejection.
Sandy Feng - One of the best experts on this subject based on the ideXlab platform.
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parathyroid reoperation with use of technetium 99m sestamibi radiolocalization and an intraoperative Gamma Counter
Endocrine Practice, 1996Co-Authors: Sandy Feng, Francis D MooreAbstract:Objective: To describe a new intraoperative technique for localization of abnormal parathyroid tissue. Methods: We report a case and discuss the difficulties enCountered in reexploration of the neck area. Results: Parathyroid reoperation remains a formidable challenge to even the most experienced endocrine surgeon. Despite the advances in radiographic imaging and localization techniques, accurate intraoperative identification of abnormal parathyroid tissue in a scarred field with obliterated anatomic planes is frequently tedious and occasionally unsuccessful. In a 48-year-old woman with hyperparathyroidism, extensive exploration of the area identified (on the basis of preoperative magnetic resonance imaging and technetium 99m sestamibi scans) as suspicious for the presence of abnormal parathyroid tissue revealed only an aberrant vein. With use of a handheld Gamma Counter to provide intraoperative guidance during parathyroid reexploration after preoperative intravenous injection of technetium 99m sestamibi, quick identification of a small, intrathyroidal, fifth gland adenoma responsible for persistent primary hyperparathyroidism was facilitated. Conclusion: Because of suboptimal precision and specificity, current preoperative localization studies can occasionally provide misleading information. Particularly in difficult cases of parathyroid reexploration, an instrument capable of localizing abnormal parathyroid tissue, which can be used intraoperatively with ease, can be an invaluable tool to ensure a safe, expedient, and successful surgical outcome. (Endocr Pract. 1996; 2:382-384)
James E Goodnight - One of the best experts on this subject based on the ideXlab platform.
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a simplified technique to resect abnormal bony radiolocalizations using a Gamma Counter
Surgical Oncology-oxford, 1992Co-Authors: David N Krag, Patrick V Ford, M Patel, Philip D Schneider, James E GoodnightAbstract:Abstract A simplified technique for localizing and verifying the correct biopsy site of lesions identified on a bone scan has been utilized. A hand-held Gamma Counter was used for localization of incision placement, determination of extent of bone to be resected, and verification that appropriate tissue was resected. This technique was used to guide biopsy of bony lesions in five patients and to guide resection of a pubic ramus chondrosarcoma. We conclude that intraoperative use of a Gamma Counter to guide biopsy of bony lesions minimizes surgery time, increases the confidence of obtaining correct tissue, and makes a frequently frustrating procedure very simple. In addition, the probe may assist with determining adequate margins at definitive resection of tumours which accumulate technetium-99m MDP.
