Search results for "Organotechnetium Compounds"
showing 10 items of 10 documents
Visualizing the atherosclerotic plaque: a chemical perspective.
2014
Atherosclerosis is the major underlying pathologic cause of coronary artery disease. An early detection of the disease can prevent clinical sequellae such as angina, myocardial infarction, and stroke. The different imaging techniques employed to visualize the atherosclerotic plaque provide information of diagnostic and prognostic value. Furthermore, the use of contrast agents helps to improve signal-to-noise ratio providing better images. For nuclear imaging techniques and optical imaging these agents are absolutely necessary. We report on the different contrast agents that have been used, are used or may be used in future in animals, humans, or excised tissues for the distinct imaging moda…
Physico-chemical study of the radiopharmaceuticals 99mTc-DMSA, 99mTc-EDTA and 99mTc-DTPA interaction with plasmatic proteins.
1989
This report studies the binding rate of the radiopharmaceuticals 99mTc-DTPA, 99mTc-EDTA and 99mTc-DMSA to plasmatic proteins. The proteins bind to the tested radiopharmaceuticals in the following sequence: 99mTc-DTPA less than 99mTc-DMSA(C1) less than 99mTc-EDTA less than 99mTc-DMSA(C2) where C1 and C2 represent two different Tc-DMSA complexes. The thermodynamic study suggests a quantitative relationship of radiopharmaceutical:protein = 1:1 and an almost nonexistent influence of the temperature, which means that the interacting forces in this process are relatively weak.
Tc-99m HMPAO Cerebral Scintigraphy A Reliable, Noninvaslve Method for Determination of Brain Death
1993
To determine the usefulness of cerebral blood flow imaging for the diagnosis of brain death, 4 female and 12 male patients, aged 19 to 69 years and suffering from various intracranial lesions, were studied. In addition to neurologic examination, electroencephalographic recording, and cerebral angiography, tomographic brain scintigraphy was performed using a SPECT system with a LEAP collimator after the intravenous administration of 555 MBq Tc-99m HMPAO. The radioisotopic scanning procedure revealed no intracranial perfusion in 14 of the 16 patients. Only minimal cerebellar blood flow was seen in one patient. In another, residual right-sided supratentorial flow was initially present but abse…
Safety and feasibility of atropine added in patients with sub-maximal heart rate during exercise myocardial perfusion SPECT.
2006
Failure to reach 80% of maximal predicted heart rate (HR) during exercise may render a myocardial perfusion single photon emission computed tomography (SPECT) study non-diagnostic for ischemia detection. We sought to investigate the injection of atropine in patients who fail to achieve 80% of age-predicted HR during exercise performed for myocardial perfusion SPECT (MPS), defining its safety and efficacy to raise HR to adequate levels as well as its effect on MPS interpretation.Between January 2002 and December 2004, we studied 3,150 consecutive patients (2,253 men and 897 women, mean age 55 +/- 6 years) who were referred to a single office-based nuclear cardiology laboratory for MPS using …
Induction of DNA single-strand breaks by 131I and 99mTc in human mononuclear blood cells in vitro and extrapolation to the in vivo situation.
2000
The radionuclides (131)I and (99m)Tc are frequently used for therapy of benign and malignant thyroid disease ((131)I) and for diagnosis of thyroid and other diseases ((99m)Tc). However, the levels of DNA single-strand breaks (SSBs) induced in cells of patients after administration of (131)I and (99m)Tc are not known. In this study, we measured the number of SSBs per cell induced by (131)I and (99m)Tc in vitro, extrapolated the results to the clinical situation, and assessed their biological relevance by comparing levels of SSBs induced after therapeutic administration of (131)I and (99m)Tc to those induced by endogenous processes or by occupational exposure to genotoxic substances. A linear…
Influence of intravenously administered lidocaine on cerebral blood flow in a baboon model standardized under controlled general anaesthesia using si…
1993
The baboon under general anaesthesia as a model to assess drug-induced cerebral blood flow changes (delta CBF) using single-photon emission tomography (SPET) offers great in vivo possibilities but has to comply with demands on control of anaesthesia-related influencing factors, such as PaCO2 changes. The model sought in this study and described here allows control of PaCO2, in the baboon under thiopentone anaesthesia by ventilation, and was evaluated for the functional dependence of delta CBF vs delta PaCO2, using SPET technetium-99m hexamethylpropylene amine oxime (HMPAO) and the split-dose method together with controlled ventilation. During the experiment the model was validated for norma…
Prognostic value of exercise myocardial scintigraphy in patients with coronary chronic total occlusions.
2010
Objectives: To evaluate the prognostic value of exercise myocardial scintigraphy in patients undergoing incomplete revascularization by means of percutaneous coronary intervention (PCI) with at least a residual chronic total occlusion (CTO) left untreated. Methods: Of 569 consecutive patients with multivessel disease undergoing myocardial scintigraphy after incomplete revascularization by PCI between March 1997 and December 2004, 126 (79% male, 64 ± 10 years) with ≥ 1 residual CTO fulfilled the eligibility criteria and entered in the study. Hard events defined as cardiac death and myocardial infarction, soft events defined as incidence of unstable angina and PCI procedures, and their compos…
[99mTc]Ca-Phytate: Some colloidal characteristics related to the optimal preparation conditions
1983
Abstract Some physico-chemical characteristics of the colloidal radiopharmaceutical [ 99 m Tc]Ca-phytate related to optimal preparation conditions have been studied. (1,2) It is demonstrated that the Ca 2+ -phytate stoichiometry is 6:1. Two different Ca-phytate colloids seem to be formed, mainly depending on the Ca 2+ :phytate molar ratio-one of low mycelar size for a 1:1 Ca 2+ :phytate molar ratio ( cmc ∗ = 5.10 −5 M ) , and another one, with a higher mycelar size for a 6:1 molar ratio (cmc = 8.10 −5 M). This last one it probably better for providing a good quality splenic uptake.
A new principle to normalize plasma concentrations allowing single-sample clearance determinations in both children and adults.
1992
A sufficiently accurate quantification of renal function requiring only one plasma sample without an additional gamma-camera study has, until now, only been possible in adults. A new principle will be presented here allowing the universal application of known algorithms, regardless of the clearance substance used, by normalizing the plasma concentrations with respect to the individual body dimensions of the patients - for infants as well as for adults. In this respect, algorithms are developed for clearance determinations using technetium-99m mercaptoacetyltriglycine (99mTc-MAG3), which are based on steady-state studies as the reference. They allow the calculation of quantitative clearance …
Usefulness of N-terminal pro-B-type natriuretic peptide levels in predicting residual myocardial ischemia in patients with ST elevation acute myocard…
2007
N-terminal pro-b-type natriuretic peptide (NT pro-BNP) is a neurohormone synthesized predominantly in ventricular myocardium. In patients with symptoms of heart failure, elevation in NT pro-BNP accurately identifies ventricular dysfunction. However, NT pro-BNP levels are not specific for ventricular dysfunction in patients who do not have overt symptoms of heart failure, suggesting that other cardiac processes such as myocardial ischemia may also cause elevation in NT pro-BNP. The study was aimed to determine whether NT pro-BNP elevations are associated with myocardial ischemia.One hundred and thirty patients (104 males, 26 females, mean age 61+12 years), with ST elevation acute myocardial …