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  • 1
    Electronic Resource
    Electronic Resource
    Characterization of Radioiodinated TISCH: A High-Affinity and Selective Ligand for Mapping CNS D1 Dopamine Receptor (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 58 (1992), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: In developing CNS D1 dopamine receptor-imaging agents with improved specificity and longer brain retention, an iodinated D1 ligand was synthesized. In vitro and in vivo radiolabeling studies of a new iodinated benzazepine, TISCH [7-chloro-8-hydroxy-1-(3′-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1 H-3-benzazepine], an analog of SCH 23390 (7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine), were investigated. After an intravenous injection, the R(+) isomer of TISCH showed high brain uptake in rats (2.20 and 0.57% dose per whole brain at 2 and 60 min, respectively). The striatum/cerebellum ratio increased progressively with time (12 at 60 min). Ex vivo autoradiography of rat brain sections, after intravenous injection of R(+)-[125I]TISCH, displayed the highest uptake in striatum and substantia nigra, regions known to have a high concentration of D1 receptors, whereas the S(–) isomer displayed no specific uptake. Furthermore, the specific uptake can be blocked by pretreatment with SCH 23390. In vitro binding studies using the rat striatum tissue preparation showed high specific and low nonspecific bindings (KD= 0.21 ± 0.03 nM). The rank order of potency exhibiting high specificity to the D1 receptor was SCH 23390 〉 (±)-TISCH 〉 (+)-butaclamol = (±)-FISCH [7-chloro-8-hydroxy-1-(4′-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1 H-3-benzazepine] ≥ WB4101 = spiperone 〉 dopamine, serotonin, (±)-propranolol, and naloxone. Imaging studies in a monkey with the resolved isomer, R(+)-[123I]TISCH, demonstrated a high uptake in the basal ganglia and prolonged retention. The preliminary data suggest that R(+)-TISCH is selective for the CNS D1 receptor and is potentially useful for in vivo and in vitro pharmacological studies. When labeled with iodine-123, it may be suitable for noninvasive imaging in humans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1992.tb09300.x
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  • 2
    Electronic Resource
    Electronic Resource
    Active Macromolecule Uptake by Lymph Node Antigen-Presenting Cells: A Novel Mechanism in Determining Sentinel Lymph Node Status (2000)
    Springer
    Annals of surgical oncology 7 (2000), S. 98-105 
    Details
    ISSN: 1534-4681
    Keywords: Sentinel lymph node ; 99mTechnetium-human serum albumin ; 99mTechnetiumsulfur colloid ; Antigen uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Although sentinel lymph node (SLN) biopsy is a powerful staging tool for patients with melanoma and breast cancer, controversy remains regarding specific aspects of technique. We examined particle uptake by antigen-presenting cells (APCs) to determine if this mechanism is responsible for the differential retention of radioactivity in SLNs relative to nonsentinel lymph nodes (NSLNs). Methods: Mapping was conducted in pigs injected with vital blue dye, fluoroscein isothiocyanate- labeled human serum albumin (FITC-HSA), and one of two99mtechnetium-labeled tracers, i.e., human serum albumin, a small macromolecule, or unfiltered sulfur colloid, a mixture of small and large particles. Macromolecule uptake by APCs was studied in vitro by using FITC-HSA and measured by fluorescence-activated cell sorting (FACS). SLNs and NSLNs were analyzed by fluorescence microscopy or FACS, with counterstaining for leukocyte cell surface markers. Results: Both radiotracers were effective. Cultured APCs rapidly took up FITC-HSA. Microscopy showed FITC-HSA in the subcapsular sinus of SLNs shortly after injection and subsequent distribution to interfollicular areas. FACS revealed increasing amounts of FITC-HSA in SLNs over time. Cells responsible for uptake were APCs, expressing major histocompatibility (locus) class II. Conclusions: This report establishes active macromolecule uptake as a mechanism that determines SLN status. This mechanism has important implications for performing SLN biopsy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10434-000-0098-6
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  • 3
    Electronic Resource
    Electronic Resource
    Incidence of Sentinel Node Metastasis in Patients With Thin Primary Melanoma (#1 mm) With Vertical Growth Phase (2000)
    Springer
    Annals of surgical oncology 7 (2000), S. 262-267 
    Details
    ISSN: 1534-4681
    Keywords: Vertical growth phase—Thin melanoma—Sentinel node—Metastasis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Patients with thin primary melanomas (#1 mm) generally have an excellent prognosis. However, the presence of a vertical growth phase (VGP) adversely impacts the survival rate. We report on the rate of occurrence of nodal metastasis in patients with thin primary melanomas with a VGP who are offered sentinel lymph node (SLN) biopsy. Methods: Among 235 patients with clinically localized cutaneous melanomas who underwent successful SLN biopsy, 71 had lesions 1 mm or smaller with a VGP. The SLN was localized by using blue dye and a radiotracer. If negative for tumor by using hematoxylin and eosin staining, the SLN was further examined by immunohistochemistry. Results: The rate of occurrence of SLN metastasis was 15.2% in patients with melanomas deeper than 1 mm and 5.6% in patients with thin melanomas. Three patients with thin melanomas and a positive SLN had low-risk lesions, based on a highly accurate six-variable multivariate logistic regression model for predicting 8-year survival in stage I/II melanomas. The fourth patient had a low- to intermediate-risk lesion based on this model. At the time of the lymphadenectomy, one patient had two additional nodes with metastasis. Conclusions: VGP in a melanoma 1 mm or smaller seems to be a risk factor for nodal metastasis. The risk of nodal disease may not be accurately predicted by the use of a multivariate logistic regression model that incorporates thickness, mitotic rate, regression, tumor-infiltrating lymphocytes, sex, and anatomical site. Patients with thin lesions having VGP should be evaluated for SLN biopsy and trials of adjuvant therapy when stage III disease is found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10434-000-0262-z
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  • 4
    Electronic Resource
    Electronic Resource
    Scintigraphic demonstration of acute gastrointestinal bleeding (1980)
    Springer
    Abdominal imaging 5 (1980), S. 205-208 
    Details
    ISSN: 1432-0509
    Keywords: Acute gastrointestinal bleeding ; Abdominal scintigraphy ; Technetium-99m sulfur colloid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acute gastrointestinal bleeding may be localized using noninvasive radionuclide methods. We have favored the use of technetium-99m sulfur colloid with sequential imaging because of the rapid clearance of background activity. Definition of the site of upper gastrointestinal bleeding, however, may be obscured by intense uptake of radioactivity by liver and spleen. The sensitivity of the method is such that the bleeding rates of 0.05–0.1 ml/min can be detected compared to a sensitivity of 0.5 ml/min for angiography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01888631
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of aging on the cerebral distribution of technetium-99m hexamethylpropylene amine oxime in healthy humans (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 754-761 
    Details
    ISSN: 1619-7089
    Keywords: Aging ; Regional cerebral blood flow ; Single-photon emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Some brain functions decline at a linear rate throughout adulthood. Others remain relatively stable until very late in the life cycle. This study characterized the effects of aging on the regional cerebral distribution of hexamethylpropylene amine oxime (HMPAO) in healthy human volunteers. The sample consisted of 26 men and 18 women with a mean age of 41.6±14.9 years (range: 19–73). Their past medical histories, physical examinations, and laboratory screening tests were normal. Single-photon emission tomography (SPET) scans of the brain were performed with a standardized acquisition and processing protocol on a triple-headed camera equipped with fan beam collimators. A 3-D restorative filter and a correction for uniform attenuation were applied before the images were reinterpolated in planes parallel to the line connecting the frontal and occipital poles. Mean counts per pixel were measured in multiple regions of interest (ROIs) within each hemisphere by custom fitting a set of templates to the images. The mean activity in each ROI was compared with the mean activity per pixel in the whole brain. Regression analyses were used to relate the activity ratios to age with both linear and nonlinear models. The relative concentration of radioactivity decreased significantly with age in most, but not all, gray matter structures. It increased in the white matter regions. The nonlinear model of aging fit the data significantly better than a straight line did. Most of the changes with age occurred during young adulthood. No further changes were detectable after the onset of middle age. The median breakpoint age at which the rate of change became negligible was 36.6 years. Aging significantly affects the relative uptake of HMPAO in healthy humans. It decreases in many gray matter regions and increases in most white matter regions. However, the changes do not appear to be linear. Most seem to occur during young adulthood before people reach their late thirties. The distribution then appears to remain relatively stable throughout middle age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00879663
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  • 6
    Electronic Resource
    Electronic Resource
    Dual time point fluorine-18 fluorodeoxyglucose positron emission tomography: a potential method to differentiate malignancy from inflammation and normal tissue in the head and neck (1999)
    Springer
    European journal of nuclear medicine 26 (1999), S. 1345-1348 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Positron emission tomography ; Fluorine-18 fluorodeoxyglucose ; Head and neck cancer ; Inflammation ; Standardised uptake value
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) studies imaging FDG PET imaging is used to detect and stage head and neck cancers. However, the variable physiologic uptake of FDG in different normal structures as well as at inflammatory sites may either obscure a tumor focus or be falsely interpreted to represent tumor activity. Twenty-one patients (9 men, 12 women, median age 59) were scanned serially at two time points, one at 70 min (range 47–112) and the second at 98 min (77–142) after the intravenous injection of 4.3 MBq/kg of FDG. The mean interval between emission scans was 28 min (13–49). Transmission scans were performed and regions of interest (ROIs) were overlayed on the fully corrected images. Standardiued uptake values (SUVs) were generated for the cerebellum, tongue, larynx, every lesion, and a matched contralateral site. Follow-up and pathologic studies revealed 18 squamous cell carcinomas and nine inflammatory or infectious lesions. Tumor SUVs were 4.0±1.6 (mean ± SD) for the first scan and 4.5±2.2 for the second scan. Contralateral SUVs were 1.2±0.5 and 1.1±0.5 for the two scans. Tumor SUVs increased by 12%±12% as compared with a 5%±17% decrease for contralateral sites (P〈0.05). SUVs for inflammatory sites (2.0±0.7 and 2.0±0.9), cerebellum (4.2±1.3 and 4.3±1.4), tongue (1.8±0.4 and 1.9±0.5) and larynx (1.5±0.6 and 1.5±0.6) remained constant over time (+0.6%, +2.8%, +1.4%, and –2.4%; P〈0.05 when compared with tumor SUV changes). The ratio tumor/contralateral SUV increased by 23%±29% over time while this ratio for inflamed sites increased by only 5%±15% (P=0.07). The time interval between scans correlated with increase in SUV for tumors (r=0.55, P〈0.05) but not for any of the other ROIs. Separation was superior when studies were performed more than 30 min apart (P〈0.05). These preliminary data suggest that dual time point imaging compatible with a clinical study protocol is helpful in differentiating malignant lesions from inflammation and normal tissues, especially when separated by a sufficient time interval.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590050593
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  • 7
    Electronic Resource
    Electronic Resource
    Automated calculation of gallbladder ejection fraction (1983)
    Springer
    European journal of nuclear medicine 8 (1983), S. 307-311 
    Details
    ISSN: 1619-7089
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have developed a computer method which by automatically locating the border of the gallbladder in each image and subtracting a varying location-dependent background corresponding to the gallbladder border overcomes the difficulties associated with quantitating gallbladder contraction. These difficulties are attributable to significant and changing background activity, imprecise manual delineation of the gallbladder, and the changing position and shape of the gallbladder. Validation studies using a gallbladder phantom showed the method to be very accurate. No significant difference (P〉0.05) was observed between the expected and calculated ejection fractions. Ten patient studies were analyzed, with a resulting range of gallbladder ejection fractions of 22–79%. Excellent reproducibility was obtained with an average intraobserver coefficient of variation of 3.5%, and no statistically significant difference in interobserver measurements (P〉0.05). The regression line for interobserver measurements had a slope of 0.96±0.08, an intercept of 1.6±4.0%, and a correlation coefficient of 0.99. From these preliminary results we conclude that this method offers a reliable means of quantitating gallbladder contraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00253757
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  • 8
    Electronic Resource
    Electronic Resource
    Can the standardized uptake value characterize primary brain tumors on FDG-PET? (1999)
    Springer
    European journal of nuclear medicine 26 (1999), S. 1501-1509 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Brain tumor ; Fluorine-18 fluorodeoxyglucose ; Positron emission tomography ; Standardized uptake value
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to evaluate the usefulness of measuring the standardized uptake value (SUV) in primary brain tumors on fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) scans. Two groups of patients were studied. Whole-brain glucose cerebral metabolic rates (wCMRs) and SUVs were obtained in 20 normal subjects. Twenty-seven patients with histology-proven malignant primary CNS tumors (high-grade gliomas n=22, primitive neuroectodermal tumors n=3, ependymomas n=2) were also studied. The degree of FDG uptake was assessed by visual inspection and thereafter regions of interest were placed over the lesion, the contralateral cortex and white matter and the whole brain. Average (avg) and maximum (max) pixel values were determined in each site. Based on these measurements, SUV, tumor to cortex (T/C) and tumor to white matter (T/WM) activity ratios were calculated. There was no correlation between wCMRs (4.55±0.36 mg min–1 100 g–1) and wSUVs (5.41±0.43) in the normal subjects (r=0.18, P=0.45). In the second group,17 lesions were described as definitely and seven as probably malignant. However, SUVs in these tumors and in the contralateral cortex were not significantly different. Although the SUVs were generally higher in the tumor than in the contralateral white matter, there was a significant overlap between the values. The range of the SUVs was wide: 2.54–11.8 for the tumors, 2.98–9.96 for the cortex and 1.87–6.76 for the white matter. SUVs in the normal cortex were negatively correlated with blood glucose level at the time of the injection. SUVs in the whole brain and in the cortex were lower in patients previously treated by irradiation, even months after completion of the treatment. No correlation was detectable between any of the SUVs and the age of the patients, tumor type, time post injection, use of dexamethasone, patient weight, dose injected and visual score. With cutoff levels of 1.5 for T max/WM and 0.6 for T max/C, the sensitivity of the activity ratios was 74% and 96% respectively. In conclusion, SUVs do not correlate with CMRs across subjects and appear to be of limited value in characterizing brain tumors. Visual assessment and measurement of the activity ratios currently remain the most reliable methods of analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590050487
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  • 9
    Electronic Resource
    Electronic Resource
    Impact of attenuation correction on the accuracy of FDG-PET in patients with abdominal tumors: a free-response ROC analysis (2000)
    Springer
    European journal of nuclear medicine 27 (2000), S. 1365-1371 
    Details
    ISSN: 1619-7089
    Keywords: Positron emission tomography Fluorine-18 fluorodeoxyglucose Attenuation correction ROC analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to evaluate image quality and lesion detectability with and without attenuation correction in patients with abdominal tumors, using a free-response receiver operating characteristic (FROC) methodology. Thirty-four patients with various abdominal tumors were evaluated (11 men, 23 women, median age 48 years). Whole-body emission scans were performed 68 min (35–102 min) after intravenous injection of 4.3 MBq/kg fluorine-18 fluorodeoxyglucose (FDG). Images were reconstructed using the OS-EM algorithm and corrected for attenuation either using postinjection singles transmission (n=27) or by calculation and body outline (n=7). Total scan duration did not exceed 70 min. Studies were read independently by four observers unaware of any clinical data. The uncorrected (UC) images were systematically read before the attenuation-corrected (AC) images. All studies were given an image quality score ranging from 1 (unreadable) to 5 (excellent). Each focus of increased activity was then localized and given a probability of malignancy using a five-point scale. The average image quality score was similar for both UC and AC images. At the time of the positron emission tomography (PET) scans, 127 lesions (63 liver metastases, 9 retroperitoneal lesions, 50 peritoneal or bowel lesions, and 5 pancreatic carcinomas) were revealed by pathological or correlative studies. The areas under the FROC curves were consistently greater for AC images (range 0.8663–0.8867) than for UC images (range 0.7774–0.8613). Overall, the difference between the AC images and the UC images was significant (P=0.019). In particular, correction for attenuation increased the sensitivity regardless of the location of the lesions. In conclusion, correction for attenuation significantly improves the diagnostic accuracy of FDG-PET for abdominal staging of neoplasms, without impairing the image quality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590000287
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  • 10
    Electronic Resource
    Electronic Resource
    Lung scanning in patients with suspected pulmonary embolism: a decade of PIOPED (1996)
    Springer
    European journal of nuclear medicine 23 (1996), S. 731-734 
    Details
    ISSN: 1619-7089
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00834542
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