Journal of nuclear medicine : official publication, Society of Nuclear Medicine
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Comparative Study
Comparison of various requirements of the quality assurance procedures for (18)F-FDG injection.
The quality assurance (QA) requirements (i.e., test procedure, acceptance criteria, and testing schedule) for fludeoxyglucose (18)F ((18)F-FDG) injection listed in the U. S. Pharmacopeia (USP); the draft Chemistry, Manufacturing, and Controls (CMC) issued by the U. ⋯ However, the "sunset" clause of the PET section within the FDA Modernization Act of 1997 stipulates that all PET drug products, in due course, must meet the requirements for drug approval procedures and current good manufacturing practice, and the FDA has issued a draft CMC that includes QA specifications for (18)F-FDG injection. The purpose of this article is to discuss the pros and cons of each of the QA tests stated in the USP, CMC, and EP and to propose a practical testing method for each required test, thereby helping end users to ensure the quality of the (18)F-FDG injection product. It is hoped that this article will stimulate further cooperation among various countries worldwide in the development of a set of harmonized and sensible QA standards for all PET drug products.
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Monoamine oxidase (MAO) regulates neurotransmitter concentration in the brain and is also an important detoxifying enzyme in peripheral organs. It occurs in 2 subtypes, MAO A and MAO B. Their relative ratios in different organs are variable, depending on the particular organ and species, making it difficult to extrapolate measures from animals to humans. The purpose of this study was to investigate the feasibility of imaging MAO B in peripheral organs in humans with PET. ⋯ This study demonstrates that (a) the deuterium isotope effect is useful in assessing the binding specificity of labeled deprenyl to peripheral MAO B; (b) MAO B can be visualized and quantified in the heart, lungs, kidneys, and spleen but not in the liver; (c) with the exception of the liver, which cannot be measured, MAO B activity is highest in the kidneys and heart; and (d) quantitation in organs having high levels of MAO B is improved by the use of 11C-L-deprenyl-D2, similar to prior studies on the brain. This study indicates that 11C-L-deprenyl-D2 will be useful for measuring the effects of different variables, including tobacco smoke exposure on MAO B activity in peripheral organs in humans.
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Double-phase single-tracer scintigraphy with (99m)Tc-sestamibi is now generally used for parathyroid imaging but, at least in endemic goiter areas, complementary thyroid scintigraphy is recommended. Although (123)I-sodium iodide is considered to be the optimal thyroid agent, it is hardly ever used because of high costs and logistic difficulties. Our study presents the results of using the (99m)Tc-sestamibi/(123)I subtraction technique in a region with a high goiter prevalence. Special attention was paid to the changes in sensitivity and specificity and their relationship to thyroid volume as well as to autonomous and nodular thyroid disease. ⋯ The sensitivity of parathyroid imaging with (99m)Tc-sestamibi/ (123)I subtraction depends mainly on the thyroid and parathyroid volumes rather than on the presence of nodular or autonomous thyroid disease.
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Multicenter Study
Brain perfusion follow-up in Alzheimer's patients during treatment with acetylcholinesterase inhibitors.
Transient cognitive and behavioral stabilization of patients with Alzheimer's disease (AD) is the main goal of long-term acetylcholinesterase inhibitor (AChEI) therapy, but response to treatment is variable and, indeed, only some of the patients are stabilized. This is usually assessed by means of clinical and neuropsychologic scales, whereas functional neuroimaging could allow objective evaluation of the topographic correlates of the effect of therapy on brain functioning. The aim of this study was to evaluate brain perfusion changes by SPECT in AD patients during chronic AChEI therapy in relation to their cognitive evolution. ⋯ The regional cerebral blood flow decreases in several cortical regions in AD patients with cognitive deterioration despite long-term AChEI therapy, similar to that observed in untreated patients, whereas it remains stable in AD patients with stabilized cognitive performance during therapy.
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The aim of this study was to investigate the effect of deep-brain stimulation of the subthalamic nucleus (STN) on regional cerebral blood flow (rCBF) throughout the entire brain volume in patients with Parkinson's disease and to evaluate which of the brain areas showing an rCBF increase during STN stimulation related significantly to the improvement in motor function. ⋯ According to the topographic organization of the primate STN, our study shows that stimulation of the STN leads to rCBF increases in the motor (pre-SMA), associative, and limbic territories (anterior cingulate) in the frontal cortex. The significant correlation between motor improvement and rCBF increase in the pre-SMA and the anterior cingulate motor area reinforces the hypothesis that STN stimulation in parkinsonian patients can potentiate the cortical areas participating in higher-order aspects of motor control.