Research Interests: Nuclear medicine, Nuclear, Humans, Male, Fibrosis, and 12 moreCoefficient of Variation, Left Ventricular Dysfunction, Dilated cardiomyopathy, Clinical Sciences, Middle Aged, Adult, Reproducibility of Results, Biological markers, Indexation, Sensitivity and Specificity, Heart Ventricles, and Statistics as Topic
A varying degree of interstitial and perivascular fibrosis is a common finding in idiopathic dilated cardiomyopathy (DCM). The perfusable tissue index (PTI), obtained with PET, is a noninvasive tool for assessing myocardial fibrosis on a... more
A varying degree of interstitial and perivascular fibrosis is a common finding in idiopathic dilated cardiomyopathy (DCM). The perfusable tissue index (PTI), obtained with PET, is a noninvasive tool for assessing myocardial fibrosis on a regional level. Measurements of the PTI in DCM, however, have not been performed yet. This study was undertaken to test the hypothesis that the PTI is reduced in patients with DCM. Fifteen patients with an advanced stage of DCM (New York Heart Association class III or IV and left ventricular ejection fraction [LVEF] < 35%) and 11 healthy control subjects were studied. PET was performed using H(2)(15)O and C(15)O to obtain the perfusable tissue fraction (PTF) and the anatomic tissue fraction (ATF), respectively. The PTI (=PTF/ATF) was reduced in DCM compared with control subjects (0.91 +/- 0.12 vs. 1.12 +/- 0.10; P < 0.01). Heterogeneity of the PTI, expressed as the coefficient of variation, was increased in DCM versus that of healthy control s...
Research Interests: Nuclear medicine, Nuclear, Humans, Male, Fibrosis, and 12 moreCoefficient of Variation, Left Ventricular Dysfunction, Dilated cardiomyopathy, Clinical Sciences, Middle Aged, Adult, Reproducibility of Results, Biological markers, Indexation, Sensitivity and Specificity, Heart Ventricles, and Statistics as Topic
PURPOSE: The aim was to assess the value of tumor lesion glycolysis (TLG) and tumor lesion proliferation (TLP) determined by FDG and 3'-deoxy-3'-F-fluorothymidine (FLT) PET for response prediction and prognostic differentiation in... more
PURPOSE: The aim was to assess the value of tumor lesion glycolysis (TLG) and tumor lesion proliferation (TLP) determined by FDG and 3'-deoxy-3'-F-fluorothymidine (FLT) PET for response prediction and prognostic differentiation in patients with advanced non-small cell lung cancer (NSCLC) treated with erlotinib. PATIENTS AND METHODS: FDG-PET and FLT-PET were performed in 30 patients with untreated Stage IV NSCLC before start of therapy, 1 (early) and 6 (late) weeks after erlotinib treatment. Functional tumor volume parameters including TLG in FDG-PET and TLP in FLT-PET were measured in the sum of up to 5 lesions per scan. Metabolic response was assessed using different cutoff values for percentage changes of TLG and TLP. Absolute baseline and residual levels of TLG and TLP were used for dichotomizing the patients into 2 groups. Kaplan-Meier analysis and the log-rank test were performed to analyze the association with progression-free survival (PFS). RESULTS: Patients with a metabolic response measured by early changes of TLP and late changes of TLG and TLP showed a significantly better PFS than metabolically nonresponding patients. A lower cutoff value of 20% or 30% for definition of metabolic response showed better differentiation between metabolically responding and nonresponding patients in cases where the 45% cutoff value revealed no significant results. Furthermore, patients with lower absolute early and late residual TLG and TLP levels had a significantly prolonged PFS. In contrast, absolute baseline TLG and TLP levels showed no significant association with PFS. CONCLUSIONS: In patients with advanced NSCLC, percentage changes of TLG and TLP and absolute residual TLG and TLP levels under erlotinib treatment emerged as strong predictive factors for PFS. Our findings indicate that a cutoff value of 20% or 30% for definition of metabolic response measured by percentage changes of TLG and TLP provides suitable results for response prediction, which should be further validated.
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The purpose of this study was to evaluate the relevance for the prediction of clinical benefit of first-line treatment with erlotinib using different quantitative parameters for PET with both (18)F-FDG and... more
The purpose of this study was to evaluate the relevance for the prediction of clinical benefit of first-line treatment with erlotinib using different quantitative parameters for PET with both (18)F-FDG and 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) in patients with advanced non-small cell lung cancer. METHODS: Data were used from a prospective trial involving patients with untreated stage IV non-small cell lung cancer. (18)F-FDG PET and (18)F-FLT PET were performed before and 1 (early) and 6 (late) weeks after erlotinib treatment. Several quantitative standardized uptake values (SUVs) using different definitions of volumes of interest with varying isocontours (maximum SUV [SUV(max)], 2-dimensional peak SUV [SUV(2Dpeak)], 3-dimensional [3D] peak SUV [SUV(3Dpeak)], 3D isocontour at 50% of the maximum pixel value [SUV(50)], 3D isocontour at 50% adapted for background [SUV(A50)], 3D isocontour at 41% of the maximum pixel value adapted for background [SUV(A41)], 3D isocontour at 70% of the maximum pixel value [SUV(70)], 3D isocontour at 70% adapted for background [SUV(A70)], and relative SUV threshold level [SUV(RTL)]) and metabolically active volume measurements were obtained in the hottest single tumor lesion and in the sum of up to 5 lesions per scan in 30 patients. Metabolic response was defined as a minimum reduction of 30% in each of the different SUVs and as a minimum reduction of 45% in metabolically active volume. Progression-free survival (PFS) was compared between patients with and without metabolic response measured with each of the different parameters, using Kaplan-Meier statistics and a log-rank test. RESULTS: Patients with a metabolic response on early (18)F-FDG PET and (18)F-FLT PET in the hottest single tumor lesion as well as in the sum of up to 5 lesions per scan had a significantly longer PFS, regardless of the method used to calculate SUV. However, the highest significance was obtained for SUV(max), SUV(50), SUV(A50), and SUV(A41.) Patients with a metabolic response measured by SUV(max) and SUV(3Dpeak) on late (18)F-FDG PET in the hottest single tumor lesion had a significantly longer PFS. Furthermore, Kaplan-Meier analyses showed a strong association between PFS and response seen by metabolically active volume, measured either in early (18)F-FLT or in late (18)F-FDG. CONCLUSION: Early (18)F-FDG PET and (18)F-FLT PET can predict PFS regardless of the method used for SUV calculation. However, SUV(max), SUV(50), SUV(A50), and SUV(A41) measured with (18)F-FDG might be the best robust SUV to use for early response prediction. Metabolically active volume measurement in early (18)F-FLT PET and late (18)F-FDG PET may have an additional predictive value in monitoring response in patients with advanced non-small cell lung cancer treated with erlotinib.
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3'-deoxy-3'-[(18)F]fluoro-L-thymidine (FLT) and 2'-deoxy-2'-[(18)F]fluoro-D-glucose (FDG) are used to visualize proliferative and metabolic activity of tumors. In this study we aimed at evaluating the prognostic value of FLT and FDG... more
3'-deoxy-3'-[(18)F]fluoro-L-thymidine (FLT) and 2'-deoxy-2'-[(18)F]fluoro-D-glucose (FDG) are used to visualize proliferative and metabolic activity of tumors. In this study we aimed at evaluating the prognostic value of FLT and FDG uptake measured by positron emission tomography (PET) in patients with metastatic non-small cell lung cancer (NSCLC) prior to systemic therapy with erlotinib. FLT and FDG maximum standardized uptake (SUVmax) values per patient were analyzed in 40 chemotherapy naive patients with advanced NSCLC (stage IV) before treatment with erlotinib. Prior therapy median SUVmax was 6.6 for FDG and 3.0 for FLT, respectively. In univariate analysis, patients with an FDG SUVmax <6.6 had a significantly better overall survival (16.3 months [95% confidence interval [CI] 7.1-25.4 months]) compared to patients with an FDG SUVmax ≥6.6 (3.1 months [95% CI 0.6-5.5 months]) (p<0.001, log rank). Similarly, low FLT uptake (SUVmax <3.0) was associated with significantly longer survival (10.3 months (0-23.3 months, 95% CI) compared to high FLT uptake (3.4 months (0-8.1 months, 95% CI) (p = 0.027). The independent prognostic value of baseline FDG uptake was demonstrated in multivariate analysis (p = 0.05, Cox regression). These data suggest that baseline SUVmax values for both FDG and FLT PET might be further developed as markers for prognostic stratification of patients in advanced NSCLC treated with tyrosine kinase inhibitors (TKI) directed against the epidermal growth factor receptor (EGFR). TRIAL REGISTRATION: Clinicaltrials.gov, Identifier: NCT00568841.
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This article reviews positron emission tomography (PET) studies of labeled enantiomers of different PET-tracers from the early 1980s. Comparative studies on stereoselective behavior of the transport of tracers across the blood-brain... more
This article reviews positron emission tomography (PET) studies of labeled enantiomers of different PET-tracers from the early 1980s. Comparative studies on stereoselective behavior of the transport of tracers across the blood-brain barrier (BBB) are discussed. Tracers are transported through the BBB into the brain, via diffusion or via several transport systems. These transport systems are able to transport endogenous and exogenous compounds from the blood into the brain, and visa versa. A clear difference exists in BBB transport of the enantiomers of several tracers. In addition, in most cases, binding of these labeled enantiomers to receptors/transporters is stereoselective. Finally, use of the biological inactive labeled enantiomer for the measurement of nonspecific binding is discussed.Given the differences in transport and binding, it is concluded that quantitative PET studies can only be performed using pure enantiomers.
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In patients with acute myocardial infarction (AMI), coronary vasomotor function is impaired in the myocardial territory supplied by the culprit artery and in remote myocardium supplied by angiographically normal vessels. The aim was to... more
In patients with acute myocardial infarction (AMI), coronary vasomotor function is impaired in the myocardial territory supplied by the culprit artery and in remote myocardium supplied by angiographically normal vessels. The aim was to investigate the temporal evolution of coronary vasodilatory reserve in patients with AMI by use of [(15)O]H2O positron emission tomography, after successful percutaneous coronary intervention. 44 patients with AMI and successful revascularisation by percutaneous coronary intervention were included. Subjects were examined 1 week and 3 months after AMI with [(15)O]H2O positron emission tomography to assess the coronary flow reserve (CFR). CFR was defined as the ratio of myocardial blood flow (MBF) during hyperaemia and rest. Additionally, 45 age-matched and sex-matched subjects underwent similar scanning procedures and served as controls. At baseline, CFR averaged 1.81±0.66 in infarcted myocardium versus 2.51±0.81 in remote myocardium (p<0.01). In co...
Research Interests: Treatment Outcome, Positron Emission Tomography, Humans, Female, Male, and 13 moreHeart, Aged, Middle Aged, Percutaneous Coronary Intervention, Myocardial Infarction, Adult, Time Factors, Radiopharmaceuticals, Myocardial Perfusion Imaging, Vasodilation, Predictive value of tests, Case Control Studies, and Vascular Resistance
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Mismatch between areas of reduced myocardial blood flow (MBF) and reduced myocardial innervation ('defect' areas) may be used to estimate the risk for ventricular arrhythmias. The presence of a mismatch zone can be derived using a... more
Mismatch between areas of reduced myocardial blood flow (MBF) and reduced myocardial innervation ('defect' areas) may be used to estimate the risk for ventricular arrhythmias. The presence of a mismatch zone can be derived using a combined protocol consisting of both an MBF and (11)C-meta-hydroxyephedrine ((11)C-HED) scans. The rate of influx from blood to myocardium (K1) of (11)C-HED is proportional to MBF and could potentially be used as an index for defining MBF defects. The aim of this study was to assess whether K1 derived from a (11)C-HED scan can be used as an index of MBF, potentially allowing for an assessment of MBF-innervation mismatch areas from a single (11)C-HED scan METHODS: 17 patients with known ischemic cardiomyopathy underwent dynamic (15)O-water and (11)C-HED scans. Discrete arterial blood samples were taken during (11)C-HED scans for metabolite correction of the image derived input function. (11)C-HED influx rate was obtained using a single tissue compar...
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Overexpression of the multidrug efflux transport P-glycoprotein may play an important role in pharmacoresistance. (11)C-laniquidar is a newly developed tracer of P-glycoprotein expression. The aim of this study was to develop a... more
Overexpression of the multidrug efflux transport P-glycoprotein may play an important role in pharmacoresistance. (11)C-laniquidar is a newly developed tracer of P-glycoprotein expression. The aim of this study was to develop a pharmacokinetic model for quantification of (11)C-laniquidar uptake and to assess its test-retest variability. Two (test-retest) dynamic (11)C-laniquidar PET scans were performed in eight healthy subjects. Plasma input functions were obtained using on-line arterial blood sampling with metabolite corrections derived from manual samples. Co-registered T1 MRI scans were used for region of interest definition. Time-activity curves were analysed using various plasma input compartmental models. (11)C-Laniquidar was metabolised rapidly with a parent plasma fraction of 50% at ten minutes post tracer injection. In addition, its first pass extraction was low. Using conventional models, (11)C-laniquidar time-activity curves were best fitted to an irreversible single tis...
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Overexpression of P-glycoprotein (Pgp) is thought to be an important mechanism of pharmacoresistance in epilepsy. Recently, (11)C-Phenytoin has been evaluated preclinically as a tracer for Pgp. The aim of the present study was to assess... more
Overexpression of P-glycoprotein (Pgp) is thought to be an important mechanism of pharmacoresistance in epilepsy. Recently, (11)C-Phenytoin has been evaluated preclinically as a tracer for Pgp. The aim of the present study was to assess the optimal plasma kinetic model for quantification of (11)C-Phenytoin studies in humans. Dynamic (11)C-Phenytoin PET scans of six healthy volunteers with arterial sampling were acquired twice on the same day, and analysed using single and two tissue compartment models with and without a blood volume parameter. Global and regional test-retest (TRT) variability was determined for both K1 and VT. According to the Akaike Information Criterion, the reversible single tissue compartment model with blood volume parameter was the preferred plasma input model. Mean TRT variability ranged from 1.5 to 16.9% for K1 and from 0.5% to 5.8% for VT, respectively. Larger volumes of interest showed better repeatabilities than smaller regions. A 45 minutes scan provided...
Research Interests: Algorithms, Biomarkers, Nuclear medicine, Positron Emission Tomography, Molecular Imaging, and 13 moreHumans, Computer Simulation, Female, Male, P-glycoprotein, Young Adult, Clinical Sciences, Image Enhancement, Adult, Reproducibility of Results, Sensitivity and Specificity, Phenytoin, and Reference Values
3′-Deoxy-3′-fluorothymidine (FLT), a thymidine analog, is a relative new PET tracer for imaging proliferation. Thymidine is transported into the cell, and after several phosphorylation steps, it will be incorporated into DNA. FLT is... more
3′-Deoxy-3′-fluorothymidine (FLT), a thymidine analog, is a relative new PET tracer for imaging proliferation. Thymidine is transported into the cell, and after several phosphorylation steps, it will be incorporated into DNA. FLT is transported into the cell by the same mechanism but is then trapped in the cell after the first phosphorylation step. The cell cycle-dependent enzyme TK1 is responsible for the first phosphorylation step of thymidine and FLT. Consequently, FLT labeled with 18F is a PET tracer of TK1 activity, and as such an indirect marker of DNA synthesizing activity and cell proliferation. Potential applications of FLT are in detecting and staging tumors.
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In idiopathic pulmonary arterial hypertension (IPAH), increased right ventricular (RV) power is required to maintain cardiac output. For this, RV O2 consumption (MVO2) must increase by augmentation of O2 supply and/or improvement of... more
In idiopathic pulmonary arterial hypertension (IPAH), increased right ventricular (RV) power is required to maintain cardiac output. For this, RV O2 consumption (MVO2) must increase by augmentation of O2 supply and/or improvement of mechanical efficiency-ratio of power output to MVO2. In IPAH with overt RV failure, however, there is evidence that O2 supply (perfusion) reserve is reduced, leaving only increase in either O2 extraction or mechanical efficiency as compensatory mechanisms. We related RV mechanical efficiency to clinical and hemodynamic parameters of RV function in patients with IPAH and associated it with glucose metabolism. The patients included were in New York Heart Association (NYHA) class II (n=8) and class III (n=8). They underwent right heart catheterization, MRI, and H2(15)O-, (15)O2-, C(15)O-, and 18FDG-PET. RV power and O2 supply were similar in both groups (NYHA class II versus class III: 0.54±0.14 versus 0.47±0.12 J/s and 0.109±0.022 versus 0.128±0.026 mL O2/...
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Research Interests: Magnetic Resonance Imaging, Positron Emission Tomography, Time-Delay Systems, Humans, Spatial Heterogeneity, and 25 moreFemale, Male, Magnetic Resonance, Deuterium, Risk factors, Clinical Sciences, Aged, Middle Aged, Gold Standard, White matter, Blood Flow, Risk Factors, Carotid Artery, Cerebral Blood Flow, ASL (Arterial Spin Labeling), Cerebrovascular Disorders, Neurosciences, Transit Time, Gray Matter, Blood Vessel, Middle Cerebral Artery, Internal Carotid Artery, Carotid Stenosis, Image Acquisition, and Posterior Cerebral Artery
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Research Interests: Algorithms, Mild Cognitive Impairment, Positron Emission Tomography, Humans, Cerebellum, and 13 moreThalamus, Computer Simulation, Cluster Analysis, Young Adult, Clinical Sciences, Aged, Middle Aged, Adult, Reproducibility of Results, Reference Values, Protein Binding, Alzheimer Disease, and Neurosciences
ABSTRACT To determine perfusion and coronary reserve in human myocardium without contrast agent using a spin labeling technique. Assessment of myocardial perfusion is based on T1 measurements after global and slice-selective spin... more
ABSTRACT To determine perfusion and coronary reserve in human myocardium without contrast agent using a spin labeling technique. Assessment of myocardial perfusion is based on T1 measurements after global and slice-selective spin preparation. This magnetic resonance imaging (MRI) technique was applied to 12 healthy volunteers and 16 patients with suspected coronary artery disease under resting conditions and adenosine-induced vasodilatation. In volunteers, quantitative perfusion was calculated as 2.4 +/- 1.2 mL/g/minute (rest) and 3.9 +/- 1.3 mL/g/minute (adenosine), respectively. Perfusion reserve was 2.1 +/- 0.6. In patients, when comparing perfusion reserve in the anterior and posterior myocardium, reduced values according to a stenotic supplying vessel could be seen in seven of 11 patients who underwent stress testing. In these patients, the relative difference of coronary reserve was 44% +/- 18%. Two patients without stenosis of coronary arteries showed no differences in coronary reserve (with a relative change of 2 +/- 2%). In patients with single-vessel coronary artery disease, differences in coronary reserve were clearly detectable when comparing anterior and posterior myocardium. The spin labeling method is noninvasive and easily repeatable, and it could therefore become an important tool to study changes in myocardial perfusion.
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Impaired right ventricular (RV) myocardial blood flow (MBF) has been associated with RV dysfunction and fatal RV failure in idiopathic pulmonary hypertension during stress. MBF and O(2) extraction from myocardial capillaries (O(2)... more
Impaired right ventricular (RV) myocardial blood flow (MBF) has been associated with RV dysfunction and fatal RV failure in idiopathic pulmonary hypertension during stress. MBF and O(2) extraction from myocardial capillaries (O(2) extraction fraction (OEF)) influence myocardial O(2) supply. To determine how the baseline RV OEF affects the amount of MBF increase induced by supine exercise, the authors hypothesise that higher baseline OEF (H-OEF) results in limited O(2) extraction during exercise and that MBF must therefore be increased to obtain sufficient O(2). In 18 patients with idiopathic pulmonary hypertension, baseline OEF, resting MBF and exercise-induced MBF at 40% of maximal cardiopulmonary exercise testing load were measured using positron emission tomography and [(15)O]O(2), [(15)O]H(2)O and [(15)O]CO. For the whole population, exercise increased RV MBF from 0.68±0.16 to 1.13 ± 0.38 ml/min/g (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). The MBF exercise-to-rest ratio (reserve) was 1.7 ± 0.7. The median baseline OEF was 0.73 at which the patient population was split into H-OEF and lower baseline OEF (L-OEF). Baseline MBF values (0.61 ± 0.11 and 0.74 ± 0.17 ml/min/g, respectively) were similar, and exercise induced a significant MBF increase in both groups (p = 0.0001). However, exercise-induced increase in MBF was significantly less in the H-OEF group than in the L-OEF group (0.97 ± 0.30 and 1.30 ± 0.39 ml/min/g, respectively, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Moreover, H-OEF patients had lower baseline stroke volume and cardiac output than the L-OEF group (52 ± 19 ml and 4.0 ± 1.1 l/min vs 78 ± 18 ml and 5.5 ± 0.9 l/min, respectively, both p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). H-OEF patients were hemodynamically poorer and showed a lower exercise-induced MBF increase compared to L-OEF patients, suggesting exercise-induced O(2) supply limitation.
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Research Interests: Magnetic Resonance Imaging, Nuclear medicine, Japan, Positron Emission Tomography, Humans, and 21 moreCarbon Monoxide, Movement, Chronic Disease, Female, Male, Myocardial Revascularization, ROC Curve, Left Ventricular Dysfunction, Contrast-Enhanced Ultrasound, Clinical Sciences, Aged, Middle Aged, Single Photon Emission Computed Tomography, Myocardial Infarction, Functional Recovery, Prognosis, Indexation, Myocardial Perfusion Imaging, Sensitivity and Specificity, Contrast Media, and Cohort Studies
Tumor resistance to docetaxel may be associated with reduced drug concentrations in tumor tissue. Positron emission tomography (PET) allows for quantification of radiolabeled docetaxel ([(11)C]docetaxel) kinetics and might be useful for... more
Tumor resistance to docetaxel may be associated with reduced drug concentrations in tumor tissue. Positron emission tomography (PET) allows for quantification of radiolabeled docetaxel ([(11)C]docetaxel) kinetics and might be useful for predicting response to therapy. The primary objective was to evaluate the feasibility of quantitative [(11)C]docetaxel PET scans in lung cancer patients. The secondary objective was to investigate whether [(11)C]docetaxel kinetics were associated with tumor perfusion, tumor size, and dexamethasone administration. Thirty-four lung cancer patients underwent dynamic PET-computed tomography (CT) scans using [(11)C]docetaxel. Blood flow was measured using oxygen-15 labeled water. The first 24 patients were premedicated with dexamethasone. For quantification of [(11)C]docetaxel kinetics, the optimal tracer kinetic model was developed and a noninvasive procedure was validated. Reproducible quantification of [(11)C]docetaxel kinetics in tumors was possible using a noninvasive approach (image derived input function). Thirty-two lesions (size ≥4 cm(3)) were identified, having a variable net influx rate of [(11)C]docetaxel (range, 0.0023-0.0229 mL·cm(-3)·min(-1)). [(11)C]docetaxel uptake was highly related to tumor perfusion (Spearman&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s ρ = 0.815;P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), but not to tumor size (Spearman&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s ρ = -0.140; P = 0.446). Patients pretreated with dexamethasone showed lower [(11)C]docetaxel uptake in tumors (P = 0.013). Finally, in a subgroup of patients who subsequently received docetaxel therapy, relative high [(11)C]docetaxel uptake was related with improved tumor response. Quantification of [(11)C]docetaxel kinetics in lung cancer was feasible in a clinical setting. Variable [(11)C]docetaxel kinetics in tumors may reflect differential sensitivity to docetaxel therapy. Our findings warrant further studies investigating the predictive value of [(11)C]docetaxel uptake and the effects of comedication on [(11)C]docetaxel kinetics in tumors.
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Research Interests: Cardiovascular, Magnetic Resonance Imaging, Positron Emission Tomography, Insulin Resistance, Humans, and 13 moreGlucose, Male, Heart, Left Ventricular Dysfunction, Middle Aged, Adiponectin, Myocardium, Biological markers, Type 2 Diabetes Mellitus, Cross Sectional Studies, Aorta, Case Control Studies, and OSTEOPROTEGERIN
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Research Interests: Treatment Outcome, Positron Emission Tomography, Corticotropin Releasing Hormone, Temporal Lobe, Dexamethasone, and 18 moreHumans, Major Depressive Disorder, Female, Male, HPA axis, Depressive Disorder, Clinical Sciences, European, Major Depression, Butyric Acid, Adult, Parahippocampal Gyrus, Protein Binding, Region of Interest, Gamma-Aminobutyric Acid, Case Control Studies, Dorsolateral Prefrontal Cortex, and Flumazenil
Research Interests: Radiation Dosimetry, Nuclear medicine, Rheumatoid Arthritis, Positron Emission Tomography, Humans, and 24 morePET imaging, Female, Animals, Blood sampling, Male, Clinical Sciences, Aged, Middle Aged, Radiometry, Dynamic Panel Data, Rats, Adult, Radiation Dose, Neoplasms, Cancer Patient, Adrenal Gland, Treatment planning, Radiopharmaceuticals, X ray Computed Tomography, Residence Time, Choline, Effective Dose, Whole Body, and Region of Interest
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In this review, first principles of positron emission tomography (PET) and single photon emission tomography (SPECT) are discussed together with the relative strengths and weaknesses of both techniques. With both modalities it is possible... more
In this review, first principles of positron emission tomography (PET) and single photon emission tomography (SPECT) are discussed together with the relative strengths and weaknesses of both techniques. With both modalities it is possible to image and, especially with PET, to measure regional tissue function, the particular function being interrogated depending on the actual tracer being used. In the second part, the use of PET for neuroactivation studies is presented, illustrated with some key examples from the literature using both perfusion and metabolism tracers. It is argued that the future of PET (and SPECT) neuroactivation studies lies in the use of ligands. Possible approaches for performing ligand activation studies are discussed.
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The effects of transient regional ischemia on monovalent cation uptake and extraction by the myocardium were studied in seven open chest dogs. Following a 10-20% stenosis of the left anterior descending coronary artery to prevent reactive... more
The effects of transient regional ischemia on monovalent cation uptake and extraction by the myocardium were studied in seven open chest dogs. Following a 10-20% stenosis of the left anterior descending coronary artery to prevent reactive hyperemia, the regional myocardial uptake of the monovalent cation 82Rb (ml/min/g X extraction) was measured before, during, and at 10, 30, and 60-80 min after a 10 min total occlusion of the left anterior descending coronary artery using positron emission tomography. Regional myocardial blood flow was also measured at the same time interval using radiolabeled carbonized microspheres. The regional myocardial extraction of 82Rb was calculated as uptake/flow. In normally perfused myocardial regions there was an inverse relationship between 82Rb extraction and blood flow [extraction = -0.56 (In flow) + 0.46, r = 0.93] over a range of flow from 0.3 to 4 ml/min/g. During the prolonged recovery of 82Rb uptake in the transiently ischemic region, flow had returned to normal levels but 82Rb extraction at a given value of flow was significantly decreased at the 30 and 60-80 min times after release of the occlusion compared with normally perfused regions. Thus, prolonged abnormalities in the 82Rb uptake and extraction occur in myocardium recovering from transient ischemia.
Research Interests: Computed Tomography, Positron Emission Tomography, Cardiovascular disease, Dogs, Beta decay, and 13 moreAnimals, Alkali Metals, Clinical Sciences, Cardiovascular system, Computer Assisted Tomography, Single Photon Emission Computed Tomography, Myocardium, Coronary heart disease, Blood Flow, Computerized tomography, Radioisotopes, Computer, and Coronary artery
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Received Dec. 8,1993; revision accepted Jul. 21,1994. For correspondence or reprints contact: Hidehiro lida, DSc, Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels, 6-10 Senshu-Kubota-Machi.... more
Received Dec. 8,1993; revision accepted Jul. 21,1994. For correspondence or reprints contact: Hidehiro lida, DSc, Department of Radiology and Nuclear Medicine, Research Institute for Brain and Blood Vessels, 6-10 Senshu-Kubota-Machi. Akita City, Akita 010 Japan.