PURPOSE: In prior study, we synthesized 99mTc-galactosylated chitosan (GC) and performed in vivo biodistribution study, showed specific targeting to hepatocyte. The aim of this study is to evaluate the labeling efficiency and cytotoxicity of modified galactosylated chitosan compounds, galactosyl methylated chitosan (GMC) and HYNIC-galactosylated chitosan (GCH). MATERIALS AND METHODS: GC, GMC and GCH were synthesized and radiolabeled with 99mTc. Then, they were incubated for 6 hours at room temperature and human serum at 37 degrees C. Labeling efficiencies were determined at 15, 30 m, 1, 2, 3 and 6 h after radiolabeling. To evaluate cytotoxicity, MTT assay was performed in HeLa and HepG2 cells. RESULTS: In comparison with them of 99mTc-GC, labeling efficiencies of 99mTc-GMC were significantly improved (100, 97 and 89% in acetone and 96.3, 95.8 and 75.6% in saline at 15 m, 1 and 6 h, respectively). Moreover, 99mTc-GCH showed more improved labeling efficiencies (> 95% in acetone and human serum and > 90% in saline at 6 h). In MTT assay, cytotoxicity was very low and not different from that of controls. CONCLUSION: These results represent that these compounds are radiochemically compatible radiopharmaceuticals, can be used in hepatocyte specific imaging study and in vivo gene or drug delivery monitoring.
Acetone ; Chitosan* ; Hep G2 Cells ; Hepatocytes ; Humans ; Radiopharmaceuticals

PURPOSE: The thyroglossal duct runs from the base of the tongue to the thyroid. Rarely the thyroid completely fails to migrate and results in ectopic thyroid tissue, which can be demonstrated scintigraphically. A 31-year old female patient was referred for thyroid scintigraphy due to protruding mass at the base of the tongue. She was mildly hypothyroid. Tc-99m pertechnetate thyroid scan was performed to rule out ectopic thyroid gland. There showed a focal area of intense tracer uptake in sublingual area, suggesting the sublingual thyroid. In addition there noted diffusely increased tracer uptake in both breasts. The patient delivered a baby 6 months prior to the scan and was on breast-feeding. Free Tc-99m pertechnetate physiologically secrets into the salivary glands, the stomach, the gastrointestinal tract, the genitourinary tract and the mammary glands and sodium-iodide symporter plays a role in the accumulation of free Tc-99m pertechnetate. We report simultaneous visualization of lactating breasts and ectopic thyroid gland in the base of the tongue.
Adult ; Breast* ; Female ; Gastrointestinal Tract ; Humans ; Ion Transport ; Mammary Glands, Human ; Radionuclide Imaging* ; Salivary Glands ; Sodium Pertechnetate Tc 99m* ; Stomach ; Thyroid Dysgenesis ; Thyroid Gland* ; Tongue

PURPOSE: Functional imaging of dopamine transporter (DAT) defines integrity of the dopaminergic system, and DAT is the target site of drugs of abuse such as cocaine and methamphetamine. Functional imaging the DAT may be a sensitive and selective indicator of neurotoxic change by the drug. The aim of the present study is to evaluate the clinical implications of qualitative/quantitative analyses of dopamine transporter imaging in methamphetamine abusers. MATERIALS AND METHODS: Six detoxified methamphetamine abusers (abuser group) and 4 volunteers (control group) were enrolled in this study. Brain MRI was performed in all of abuser group. Abuser group underwent psychiatric and depression assessment using brief psychiatric rating scale (BPRS) and Hamilton depression rating scale (HAMD), respectively. All of the subjects underwent I-123 IPT SPECT (IPT SPECT). IPT SPECT image was analysed with visual qualitative method and quantitative method using basal ganglia dopamine transporter (DAT) specific/non-specific binding ratio (SBR). Comparison of DAT SBR between abuser and control groups was performed. We also performed correlation tests between psychiatric and depression assessment results and DAT SBR in abuser group. RESULTS: All of abuser group showed normal MRI finding, but had residual psychiatric and depressive symptoms, and psychiatric and depressive symptom scores were exactly correlated (r=1.0, p=0.005) each other. Five of them showed abnormal finding on qualitative visual I-123 IPT SPECT. Abuser group had lower basal ganglia DAT SBR than that of control (2.38+/-0.20 vs 3.04+/-0.27, p=0.000). Psychiatric and depressive symptoms were negatively well correlated with basal ganglia DAT SBR (r=-0.908, p=0.012, r=-0.924, p=0.009). CONCLUSION: These results suggest that dopamine transporter imaging using I-123 IPT SPECT may be used to evaluate dopaminergic system of the basal ganglia and the clinical status in methamphetamine abusers.
Basal Ganglia* ; Brain ; Brief Psychiatric Rating Scale ; Cocaine ; Depression ; Dopamine Plasma Membrane Transport Proteins* ; Dopamine* ; Magnetic Resonance Imaging ; Methamphetamine* ; Street Drugs ; Tomography, Emission-Computed, Single-Photon* ; Volunteers

PURPOSE: Adenosine myocardial perfusion SPECT has proven to be useful in the detection of coronary artery disease, in the follow up the success of various therapeutic regimens and in assessing the prognosis of coronary artery disease. The purpose of this study is to define the reproducibility of myocardial perfusion SPECT using adenosine stress testing between two consecutive Tc-99m sestaMIBI (MIBI) SPECT studies in the same subjects. METHODS: Thirty patients suspected of coronary artery disease in stable condition underwent sequential Tc-99m MIBI SPECT studies using intravenous adenosine. Gamma camera, acquisition and processing protocols used for the two tests were identical and no invasive procedures were performed between two tests. Mean interval between two tests were 4.1 days (range: 2-11 days). The left ventricular wall was divided into 18 segments and the degree of myocardial tracer uptake was graded with four-point scoring system by visual analysis. Images were interpretated by two independent nuclear medicine physicians and consensus was taken for final decision, if segmental score was not agreeable. RESULTS: Hemodynamic responses to adenosine were not different between two consecutive studies. There were no serious side effects to stop infusion of adenosine and side effects profile was not different. When myocardial uptake was divided into normal and abnormal uptake, 481 of 540 segments were concordant (agreement rate 89%, Kappa index 0.74). With four-grade scoring system, exact agreement was 81.3% (439 of 540 segments, tau b=0.73). One and two-grade differences were observed in 97 segments (18%) and 4 segments (0.7%) respectively, but three-grade difference was not observed in any segment. Extent and severity scores were not different between two studies. The extent and severity scores of the perfusion defect revealed excellent positive correlation between two test (r value for percentage extent and severity score is 0.982 and 0.965, p< 0.001) CONCLUSION: Hemodynamic responses and side effects profile were not different between two consecutive adenosine stress tests in the same subjects. Adenosine Tc-99m sestaMIBI SPECT is highly reproducible, and could be used to assess temporal changes in myocardial perfusion in individual patients.
Adenosine* ; Consensus ; Coronary Artery Disease* ; Coronary Vessels* ; Diagnosis* ; Exercise Test ; Follow-Up Studies ; Gamma Cameras ; Hemodynamics ; Humans ; Nuclear Medicine ; Perfusion ; Prognosis ; Tomography, Emission-Computed, Single-Photon*

PURPOSE: SPECT using a fan-beam collimator improves spatial resolution and sensitivity. For the reconstruction from fan-beam projections, it is necessary to implement direct fan-beam reconstruction methods without transforming the data into the parallel geometry. In this study, various fan-beam reconstruction algorithms were implemented and their performances were compared. MATERIALS AND METHODS: The projector for fan-beam SPECT was implemented using a ray-tracing method. The direct reconstruction algorithms implemented for fan-beam projection data were FBP (filtered backprojection), EM (expectation maximization), OS-EM (ordered subsets EM) and MAP-EM OSL (maximum a posteriori EM using the one-step late method) with membrane and thin-plate models as priors. For comparison, the fan-beam projection data were also rebinned into the parallel data using various interpolation methods, such as the nearest neighbor, bilinear and bicubic interpolations, and reconstructed using the conventional EM algorithm for parallel data. Noiseless and noisy projection data from the digital Hoffman brain and Shepp/Logan phantoms were reconstructed using the above algorithms. The reconstructed images were compared in terms of a percent error metric. RESULTS: For the fan-beam data with Poisson noise, the MAP-EM OSL algorithm with the thin-plate prior showed the best result in both percent error and stability. Bilinear interpolation was the most effective method for rebinning from the fan-beam to parallel geometry when the accuracy and computation load were considered. Direct fan-beam EM reconstructions were more accurate than the standard EM reconstructions obtained from rebinned parallel data. CONCLUSION: Direct fan-beam reconstruction algorithms were implemented, which provided significantly improved reconstructions.
Brain ; Membranes ; Noise ; Tomography, Emission-Computed, Single-Photon*

PURPOSE: we often find variable degrees of FDG uptake and patterns in stomach, which can make difficult to distinguish physiologic uptake from pathologic uptake on FDG PET. The purpose of this study was to find out the significant findings of stomach on FDG PET. MATERIALS AND METHODS: Thirty-eight patients who underwent both FDG PET and endoscopy within one week from Jun. 2003, to Aug. 2004 were included in this study. We reviewed 38 patients (18 for medical check up, 15 for work up of other malignancies, and 5 for the evaluation of stomach lesion). Their mean age was 56 years old (range: 32~79), men and women were 28 and 10, respectively. Two nuclear physicians evaluated five parameters on FDG PET findings of stomach with a consensus: 1) visual grades 2) maximum SUV (max.SUV) 3) focal 4) diffuse and 5) asymmetric patterns. We correlated the lesions of FDG PET findings of stomach with those of endoscopy. We considered more than equivocal findings on FDG PET as positive. RESULTS: The six of 38 patients were proven as malignant lesions by endoscopic biopsy and others were inflammatory lesions (ulcer in 3, chronic atrophic gastritis in 12, uncommon forms of gastritis in 5), non-inflammatory lesions (n=3), and normal stomach (n=9). By the visual analysis, malignant lesions had higher FDG uptake than the others. The max.SUV of malignant lesions was 7.95 4.83 which was significantly higher than the other benign lesions (2.9 0.69 in ulcer, 3.08 1.2 in chronic atrophic gastritis, 3.2 1.49 in uncommon forms of gastritis (p=0.044) ). In the appearance of stomach on FDG PET, malignant lesions were shown focal (5 of 6) and benign inflammatory lesions were shown diffuse (9 of 20) and asymmetric (14 of 20). Benign lesions and normal stomach were shown variable degrees of uptake and patterns. Some cases of benign inflammatory lesions such as ulcer and gastritis were shown focal and mimicked cancerous lesion (4 of 15). CONCLUSION: Gastric malignant lesions had higher FDG uptake and focal pattern. However, benign inflammatory lesions had moderate degrees of uptake and diffuse and asymmetric patterns rather than focal. It is difficult to differentiate between benign lesions including normal.
Biopsy ; Consensus ; Electrons* ; Endoscopy ; Female ; Gastritis ; Gastritis, Atrophic ; Humans ; Male ; Middle Aged ; Positron-Emission Tomography* ; Stomach* ; Ulcer

PURPOSE: We developed an animal SPECT system using clinical Philips ARGUS scintillation camera and pinhole collimator with specially manufactured small apertures. In this study, we evaluated the physical characteristics of this system and biological feasibility for animal experiments. MATERIALS AND METHODS: Rotating station for small animals using a step motor and operating software were developed. Pinhole inserts with small apertures (diameter of 0.5, 1.0, and 2.0 mm) were manufactured and physical parameters including planar spatial resolution and sensitivity and reconstructed resolution were measured for some apertures. In order to measure the size of the usable field of view according to the distance from the focal point, manufactured multiple line sources separated with the same distance were scanned and numbers of lines within the field of view were counted. Using a Tc-99m line source with 0.5 mm diameter and 12 mm length placed in the exact center of field of view, planar spatial resolution according to the distance was measured. Calibration factor to obtain FWHM values in 'mm' unit was calculated from the planar image of two separated line sources. Tc-99m point source with 1 mm diameter was used for the measurement of system sensitivity. In addition, SPECT data of micro phantom with cold and hot line inserts and rat brain after intravenous injection of [I-123]FP-CIT were acquired and reconstructed using filtered back projection reconstruction algorithm for pinhole collimator. RESULTS: Size of usable field of view was proportional to the distance from the focal point and their relationship could be fitted into a linear equation (y=1.4x+0.5, x: distance). System sensitivity and planar spatial resolution at 3 cm measured using 1.0 mm aperture was 71 cps/MBq and 1.24 mm, respectively. In the SPECT image of rat brain with [I-123]FP-CIT acquired using 1.0 mm aperture, the distribution of dopamine transporter in the striatum was well identified in each hemisphere. CONCLUSION: We verified that this new animal SPECT system with the Philips ARGUS scanner and small apertures had sufficient performance for small animal imaging.
Animal Experimentation ; Animals* ; Brain ; Calibration ; Dopamine Plasma Membrane Transport Proteins ; Gamma Cameras* ; Injections, Intravenous ; Rats ; Tomography, Emission-Computed, Single-Photon*

PURPOSE: Anhedonia has been proposed to be the result of a basic neurophysiologic dysfunction and a vulnerability marker that precede and contribute to the liability of developing schizophrenia. We hypothesized that anhedonia, as a construct reflecting the decreased capacity to experience pleasure, should be associated with decreased positive hedonic affect trait. This study examined the relationship between anhedonia and positive hedonic affect trait and searched for the brain regions which correlate with anhedonia in normal subjects. MATERIALS AND METHODS: Using 18F-FDG PET scan, we investigated the brain activity of twenty one subjects during resting state. Questionnaires were administrated after the scan in order to assess the self-rated individual differences in physical/social anhedonia and positive/negative affect traits. RESULTS: Negative correlation between physical anhedonia score and positive affect trait score was significant (Pearson coefficient=-0.440, p< 0.05). The subjects' physical and social anhedonia scores showed positive correlation with metabolic rates in the cerebellum and negative correlation with metabolic rates in the inferior temporal gyrus and middle frontal gyrus. In addition, the positive affect trait score positively correlated with various areas, most prominent with the inferior temporal gyrus. CONCLUSION: These results suggest that neural substrates, such as the inferior temporal gyrus and prefrontal-cerebellar circuit, which dysfunction has been proposed to be involved with the cognitive deficits of schizophrenia, may also play a significant role in the liability of affective deficits like anhedonia.
Adult* ; Anhedonia* ; Brain* ; Cerebellum ; Fluorodeoxyglucose F18 ; Humans ; Individuality ; Pleasure ; Positron-Emission Tomography ; Schizophrenia ; Statistics as Topic* ; Surveys and Questionnaires

PURPOSE: The objectives of this study were - First, to determine the normal range of left ventricular end diastolic volume (EDV), end systolic volume (ESV) and ejection fraction (EF) from gated myocardial perfusion SPECT for Quantitative Gated SPECT (QGS) and 4D-MSPECT (4DM), respectively. Second, to evaluate the relationships between values produced by both software packages. MATERIALS AND METHODS: Tc-99m MIBI gated myocardial perfusion SPECT were performed for 77 patients (mean age: 49.6+/-13.7y, n=37 (M), 40 (F) ) with a low likelihood (< 10%) of coronary artery disease (CAD) using dual head gamma camera (E.CAM, Siemens, USA). Left ventricular EDV, ESV and EF were automatically measured by means of QGS (R) and 4DM, respectively. RESULTS: In QGS, the mean EDV, ESV and EF for all patients were 78.2+/-25.2ml, 27.4+/-12.9ml and 66.6+/-8.0% at stress test respectively, not different from rest test (p> 0.05). In 4DM, the mean EDV, ESV and EF for all patients were 89.1+/-26.4ml, 29.1+/-12.8ml and 68.5+/-6.7% at stress test. Most cases in 4DM, there was no significant difference statistically between stress and rest test (p> 0.05). But statistically significant difference was found in EF (68.5+/-6.7% at stress vs 70.9+/-8.0% at rest, p< 0.05). Correlation coefficients between the methods for EDV, ESV and EF were comparatively high (0.95, 0.93, 0.71 at stress test and 0.95, 0.90, 0.69 at rest test, respectively). However, Bland-Altman plots showed a large range of the limit value of agreement for EDV, ESV and EF between both methods (-30ml 10ml, -12ml 8ml, -14% 11% at stress test and -32ml 5ml, -13ml 13ml, -18% 12% at rest test). CONCLUSION: We found the normal ranges of EDV, ESV and EF for patients with a low likelihood of CAD in both methods. We expect these values will be a good reference to interpret gated myocardial perfusion SPECT. Although good correlation was observed between both methods, they should not be used interchangeably. Therefore, when both programs are used at the same site, it will be important to apply normal limits specific to each method.
Coronary Artery Disease ; Exercise Test ; Gamma Cameras ; Head ; Humans ; Perfusion* ; Reference Values* ; Stroke Volume ; Tomography, Emission-Computed, Single-Photon*

PURPOSE: It has been postulated that dopamine release in the striatum underlies the reinforcing properties of nicotine. Substantial evidence in the animal studies demonstrates that nicotine interacts with dopaminergic neuron and regulates the activation of the dopaminergic system. The aim of this study was to visualize the dopamine release by smoking in human brain using PET scan with [11C]raclopride. MATERIALS AND METHODS: Five male non-smokers or ex-smokers with an abstinence period longer than 1 year (mean age of 24.4+/-1.7 years) were enrolled in this study. [11C]raclopride, a dopamine D2 receptor radioligand, was administrated with bolus-plus- constant infusion. Dynamic PET was performed during 120 minutes (3x20s, 2x60s, 2x120s, 1x180s and 22x300s). Following the 50 minute-scanning, subjects smoked a cigarette containing 1 mg of nicotine while in the scanner. Blood samples for the measurement of plasma nicotine level were collected at 0, 5, 10, 15, 20, 25, 30, 45, 60, and 90 minute after smoking. Regions for striatal structures were drawn on the coronal summed PET images guided with co-registered MRI. Binding potential, calculated as (striatal-cerebellar) /cerebellar activity, was measured under equilibrium condition at baseline and smoking session. RESULTS: The mean decrease in binding potential of [11C]raclopride between the baseline and smoking in caudate head, anterior putamen and ventral striatum was 4.7 %, 4.0 % and 7.8 %, respectively. This indicated the striatal dopamine release by smoking. Of these, the reduction in binding potential in the ventral striatum was significantly correlated with the cumulated plasma level of the nicotine (Spearman's rho=0.9, p=0.04). CONCLUSION: These data demonstrate that in vivo imaging with [11C]raclopride PET could measure nicotine-induced dopamine release in the human brain, which has a significant positive correlation with the amount of nicotine administered by smoking.
Animals ; Basal Ganglia ; Brain ; Dopamine* ; Dopaminergic Neurons ; Head ; Humans ; Magnetic Resonance Imaging ; Male ; Nicotine ; Plasma ; Positron-Emission Tomography ; Putamen ; Receptors, Dopamine D2 ; Smoke ; Smoking ; Tobacco Products