The multidrug-resistant P-glycoprotein (Pgp), a M(r) 170,000 plasma membrane protein encoded by the mammalian multidrug resistance gene (MDR1), appears to function as an energy-dependent efflux pump. Many of the drugs that interact with Pgp are lipophilic and cationic at physiological pH. We tested the hypothesis that the synthetic gamma-emitting organotechnetium complex, hexakis(2-methoxyisobu...

BACKGROUND The physiological assessment of angiographically intermediate-severity stenoses remains problematic. Functional measurements of poststenotic intracoronary Doppler coronary flow reserve can be performed in humans but have not been correlated with hyperemic myocardial perfusion imaging or angiographic data in this patient population. METHODS AND RESULTS Thirty-three patients undergoi...

OBJECTIVE 99mTc-tetrofosmin and 99mTc-sestamibi are approved tracers for myocardial perfusion studies. Recently, a 99mTc-MIBI preparation from a different manufacturer (99mTc-cardiospect-MIBI) has been introduced to the market. Therefore, the aim of this study was the evaluation of 99mTc-tetrofosmin as well as of two different 99mTc-labeled MIBI tracers with regard to differences in imaging qua...

UNLABELLED Lung uptake of 201Tl is a reliable marker of left ventricular dysfunction. The goal of our study was to establish whether the evaluation of lung-to-heart uptake ratios (LHR) with 99mTc-sestamibi imaging may provide valuable information. METHODS We studied 72 male subjects with recent anterior myocardial infarction undergoing 99mTc-sestamibi first-pass ventriculography and SPECT per...

BACKGROUND Low-dose dobutamine stress echocardiography is specific for predicting reversible contractility dysfunction, but its sensitivity is lower than ideal. OBJECTIVE We sought to explore the predictors of myocardial contractile recovery following revascularization, in patients with no viability by low-dose dobutamine stress echocardiography. METHODS We prospectively enrolled 30 consecu...

PURPOSE This review aims to discuss the methodological aspects of dedicated molecular breast imaging (MBI) using 99mTc-sestamibi as radiotracer to guide biopsy of occult or unclear breast lesions on mammography (MG) and ultrasound (US) that are suspicious on MBI (BI-RADS criteria 4 and 5), including its advantages, limitations and future clinical applications. METHODS Literature search was pe...

OBJECTIVE Measurement of cardiac perfusion via agents such as 99mTc-sestamibi (Cardiolite; DuPont-Merck Pharmaceutical Co., Inc.) is widely used in clinical nuclear medicine for the diagnosis of coronary artery disease. The monograph for 99mTc-sestamibi recommends at least 90% radiochemical purity (RCP) for clinical use. Various factors may influence the RCP of certain reagent kits. Some of the...

BACKGROUND Thallous chloride (201Tl) and hexakis(2-methoxyisobutyl isonitrile) technetium (I) (99mTc-SESTAMIBI) are myocardial perfusion imaging agents with biological properties that also reflect tissue viability. Initial myocellular uptake rates of 201Tl reflect activity of Na,K-ATPase, whereas those of 99mTc-SESTAMIBI reflect mean plasma membrane potential. METHODS AND RESULTS To better un...

We measured the pulmonary clearance of inhaled 99mTc-diethylenetriamine penta-acetic acid (DTPA), 99mTc-sestamibi and 99mTc-dimethyliminodiacetic acid (HIDA) in normal rabbits, and rabbits with surfactant dysfunction induced by the detergent dioctyl sodium sulfosuccinate. The tracers differ widely in lipid/water partition coefficients, but have similar molecular radius and weight. Five animals ...

BACKGROUND In contrast to 201TlCl, 99mTc-sestamibi shows very slow myocardial clearance after its initial myocardial uptake. In the present study, myocardial washout of 99mTc-sestamibi was calculated in patients with non-ischemic chronic heart failure (CHF) and compared with biventricular parameters obtained from first-pass and ECG-gated myocardial perfusion SPECT data. METHODS AND RESULTS Af...