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Background Ratios (background + ratio)

Distribution by Scientific Domains

Medical Sciences	83%

Selected Abstracts

Usefulness of 201TL SPECT/CT relative to 18F-FDG PET/CT in detecting recurrent skull base nasopharyngeal carcinoma

HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 6 2009
Ruoh-Fang Yen MD
Abstract Background This study was designed to compare 201Tl single photon emission computed tomography (SPECT)/CT with 18-fluoro-2-deoxyglucose (18F-FDG) PET/CT in diagnosing recurrent skull base nasopharyngeal carcinoma (NPC). Methods Twenty-seven patients were recruited. Both 201Tl SPECT/CT and 18F-FDG PET/CT for each patient were performed at least 4 months later after initial therapy. Results The sensitivity and specificity for 201Tl SPECT/CT were 66.7% and 100%, and those for 18F-FDG PET/CT were 86.7% and 75.0%. Lesion/background ratios were obtained for the 10 lesions that were both SPECT and PET true positive. For the 8 patients with recurrences in nasopharyngeal regions, PET lesion/background ratios were all higher than SPECT lesion/background ratios. For the 2 patients with intracranial metastases, SPECT lesion/background ratios were higher than PET lesion/background ratios. Conclusion 201Tl SPECT/CT is as effective as 18F-FDG PET/CT in detecting recurrent NPC. For intracranial recurrence, 201Tl SPECT, because of its high intracranial lesion/background ratio, is probably better than 18F-FDG PET. © 2009 Wiley Periodicals, Inc. Head Neck, 2009 [source]

Voltammetric Assay of Naproxen in Pharmaceutical Formulations Using Boron-Doped Diamond Electrode

ELECTROANALYSIS, Issue 11 2005
V. Suryanarayanan
Abstract The electrooxidation of naproxen was studied, for the first time, using boron-doped diamond (BDD) electrode by cyclic and differential pulse voltammetry (CV and DPV) in nonaqueous solvent supporting electrolyte system. The results were also compared with glassy carbon electrode (GC) under the same conditions. Naproxen undergoes one electron transfer resulting in the formation of cation radical for the first electrooxidation step, which follows other chemical and electrochemical steps such as deprotonation, removal of another electron and the attack of nucleophile (ECEC mechanism). BDD electrode provided higher signal to background ratio, well resolved and highly reproducible cyclic voltammograms than the GC electrode. With a scan rate of 50,mV s,1 and pulse height of 50,ms, respectively, the DPV technique was able to determine the naproxen concentrations in the range of 0.5 to 50,,M with a detection limit of 30,nM. The influence of interference compounds namely 2-acetyl-6-methoxy naphthalene (AMN) on naproxen oxidation can also be followed successfully. Moreover, the percentage of AMN present in the standard chemical form of a mixture containing naproxen can be found accurately. Rapidity, precise and good selectivity were also found for the determination of naproxen in pharmaceutical formulations. [source]

111Indium Pentetreotide Imaging in the Evaluation of Head and Neck Tumors

THE LARYNGOSCOPE, Issue 10 2005
David Myssiorek MD
Abstract Objectives/Hypothesis: Peptide receptor imaging with 111Indium pentetreotide is useful in the diagnosis of diffuse neuroendocrine system tumors (DNEST) of the head and neck. Uses of 111Indium pentetreotide scintigraphy include tumor and metastases detection, familial tumor screening, and surveillance for recurrence. Using target to background ratios (TBR) could generate a comparative scale for these tumors. Study Design: A retrospective study evaluated the size, TBR, conventional imaging, and outcomes of patients imaged with 111Indium pentetreotide scintigraphy for suspected head and neck DNEST. Methods: Patients with head and neck tumors imaged by 111Indium pentetreotide scintigraphy during a nine-year period were reviewed. Data analyzed were age, sex, scintigraphy, pathology, and conventional radiology. Tumor data included dimension, multiplicity, metastases, and tumor and brain counts. Results: Fifty-three patients underwent 58 scans. The sensitivity and specificity were 93% and 92%. Several different DNEST were successfully evaluated, including familial paragangliomas and multiple paragangliomas. TBRs were variable depending on type of DNEST. Conclusions:111Indium pentetreotide scintigraphy is accurate in determining the presence of paragangliomas, carcinoid tumors, esthesioneuroblastomas, small cell neuroendocrine tumors, andmetastases. It is an excellent surveillance tool. Screening patients for familial paragangliomas can be accomplished. No reliable comparative scale to distinguish amongst the various DNEST could be developed using TBR. [source]

Multicolor in vivo targeted imaging to guide real-time surgery of HER2-positive micrometastases in a two-tumor coincident model of ovarian cancer

CANCER SCIENCE, Issue 6 2009
Michelle Longmire
One of the primary goals of oncological molecular imaging is to accurately identify and characterize malignant tissues in vivo. Currently, molecular imaging relies on targeting a single molecule that while overexpressed in malignancy, is often also expressed at lower levels in normal tissue, resulting in reduced tumor to background ratios. One approach to increasing the specificity of molecular imaging in cancer is to use multiple probes each with distinct fluorescence to target several surface antigens simultaneously, in order to identify tissue expression profiles, rather than relying on the expression of a single target. This next step forward in molecular imaging will rely on characterization of tissue based on fluorescence and therefore will require the ability to simultaneously identify several optical probes each attached to different targeting ligands. We created a novel ,coincident' ovarian cancer mouse model by coinjecting each animal with two distinct cell lines, HER2+/red fluorescent protein (RFP), SKOV3 and HER2,/RFP+ SHIN3-RFP, in order to establish a model of disease in which animals simultaneously bore tumors with two distinct phenotypes (HER2+/RFP,, HER2,/RFP+), which could be utilized for multicolor imaging. The HER2 receptor of the SKOV3 cell line was targeted with a trastuzumab,rhodamine green conjugate to create green tumor implants, whereas the RFP plasmid of the SHIN3 cells created red tumor implants. We demonstrate that real-time in vivo multicolor imaging is feasible and that fluorescence characteristics can then serve to guide the surgical removal of disease. (Cancer Sci 2009; 100: 1099,1104) [source]