Browsing by Author "Gümüser, G"

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    The evaluation of urine activity and external dose rate from patients receiving radioiodine therapy for thyroid cancer
    Demir, M; Parlak, Y; Çavdar, I; Yeyin, N; Tanyildizi, H; Gümüser, G; Sayit, E; Erees, S; Sayman, H
    The aim of this study was to determine the external dose rate of iodine retention as a function of time in the bodies of thyroid cancer patients during their isolation period in the hospital. Urine samples were collected at 6th, 12th, 18th, 24th h and 2nd, 3rd, 4th, 5th d from 83 patients after oral administration of I-131 and counted. The external dose rates were also simultaneously determined at the same time points. Then, it was expressed as retained radioiodine body activity versus dose rate. Effective half life calculated from urine sample measurements was found as 18.41.8 h within the first 24 h and 642.7 h between 48 and 120 h. According to this results, the external dose rate (20 Sv h(1)), which patients could be discharged, was achieved after 48 h for 3700 and 5550 MBq, and after 72 h for 7400 MBq of I-131 treatments.
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    Pulmonary Epithelial Permeability and Radioaerosol Penetration in Pulmonary Tuberculosis
    Sayit, E; Erer, OF; Bekis, R; Tasci, C; Konya, A; Gümüser, G; Kaya, GÇ; Özkan, SA; Durak, H
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    Unexpected Metastatic Localizations of Prostate Cancer Determined by 68Ga PSMA PET/CT: Series of Four Cases
    Mütevelizade, G; Sezgin, C; Gümüser, G; Sayit, E
    Prostate-specific membrane antigen (PSMA) is a transmembrane protein with overexpression in most prostate cancer cells. Gallium-68-(Ga-68) PSMA positron emission tomography/computed tomography (PET/CT) imaging is a game-changer in the management of prostate cancer. 68Ga PSMA PET/CT scan is advanced and a promising radioligand has high sensitivity in determining lesions of prostate cancer with a high tumor to background ratio. The most common areas of metastasis are the bone and pelvic lymph nodes. The prognosis of prostate cancer is mainly determined by the status of metastases. The presence and the localization of metastases affects treatment planning. In our cases, we presented some examples of uncommon sites of metastases such as the brain, adrenal glands, penis and orbit. Improvements in imaging techniques, such as Ga-68 PSMA PET/CT have led to the possibility to make more determination of rare metastase sites in prostate cancer patients.
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    Baseline SUV Range for Liver and Blood Pool in Patients Undergoing F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography
    Parlak, Y; Göksoy, D; Mütevelizade, G; Gümüser, G; Sayit, E
    Introduction: The aim of the study was to define the baseline SUVmax range in the liver and blood pool of patients undergoing fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) imaging. Methods: Five hundred and thirty-one patients (264 females, 267 males; mean age: 59.6 dagger 13.4 years) who were admitted to our department for PET/CT imaging before treatment were included in the study. Patient preparation, acquisition parameters and reconstruction protocols were standardized for all patients prior to PET/CT imaging. The mean serum glucose levels and mean age of the patients were calculated. These patients were divided into 10 groups as esophagus, stomach, colon, rectum, larynx, lung, breast, endometrium, ovarian cancers and lymphoma. 2D region of interests were plotted to calculate the mean SUV values in the right lobe of the liver and the aortic arch for the blood pool. Results: Normal Gaussian distributions of mean SUV changes for liver and blood pool were obtained. Mean SUVmax and SUVmean values for liver were 2.73 +/- 0.22 and 2.34 +/- 0.16, respectively, and 1.80 +/- 0.2 and 1.57 +/- 0.14 for blood pool, respectively. Conclusion: It was concluded that the obtained SUV ranges may provide ease of application in the clinic in evaluating qualitative tumor response and comparing tumor/background ratios in cancer patients.
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    Effects of simvastatin on bone mineral density and remodeling parameters in postmenopausal osteopenic subjects
    Tikiz, C; Tikiz, H; Taneli, F; Gümüser, G; Tüzün, Ç
    Observational studies suggest that statin use may be associated with lower incidence of fracture. However, there are conflicting data for their effects on bone remodeling parameters and bone mineral density (BMD). In the present study, we aimed to investigate the effects of simvastatin on bone metabolism and BMD in subjects with hypercholesterolemia (> 240 mg/dl). For this purpose, 32 postmenopausal osteopenic subjects who were given simvastatin treatment (20 mg/day) and not on osteoporosis treatment were included in the study. During the 1-year follow-up period, the total cholesterol level decreased from 262.1 +/- 30.9 to 202.2 +/- 30.1 mg/dl (p < 0.0001). At a period as early as the 3rd month, levels of the anabolic markers, e.g., bone-specific alkaline phosphatase (BSAP) and osteocalcin (OCL), were found to be significantly increased (from 120.8 +/- 56.6 to 149.5 +/- 57.6 IU/l, p = 0.008, and from 20.8 +/- 12.6 to 34.7 +/- 118.4 mu g/l, p = 0.015, respectively) while no significant change was observed in the resorptive marker of serum N-telopeptide of type I collagen (CTX). At the 6th and 12th month, BSAP and OCL were both found to be decreased below the pretreatment values. While a significant reduction was found in BSAP levels (from 120.8 +/- 56.6 to 55.9 +/- 18.8 IU/l, p < 0.001), no significant change was observed in CTX levels after the 6-month treatment period. Parathyroid hormone showed a gradual profound increase during the follow-up period (from 62.7 +/- 41.5 to 108.4 +/- 51.7 pg/ml, p < 0.001). No significant change was found in BMD levels at the spine, femoral neck, Ward's triangle, and trochanter at the end of the 1-year follow-up period. In conclusion, simvastatin treatment showed a short-lasting anabolic effect on bone metabolism. However, this effect was lost by prolongation of therapy. The decrease in both anabolic and resorptive markers at the 6th and 12th month suggests that simvastatin affects bone metabolism mostly in favor of inhibition of the bone turnover in a long-term observation period although this inhibitory effect was not reflected in BMD.
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    Effects of Different Intensity Resistance Exercise Programs on Bone Turnover Markers, Osteoprotegerin and Receptor Activator of Nuclear Factor Kappa B Ligand in Post-Menopausal Women
    Karaarslan, S; Büyükyazi, G; Taneli, F; Ulman, C; Tikiz, C; Gümüser, G; Sahan, P
    Objective: To investigate the effects of 12-week two-different intensity resistance training programs on bone turnover markers, bone mineral density (BMD), osteoprotogerin (OPG), and soluble receptor activator of nuclear factor kappa p ligand (sRANKL) in postmenopausal women. Material and Methods: Forty healthy women (aged 45-60 years) participated in the study. High-intensity group (HIG; n=14) worked 4 days a week and performed two sets of 8-10 repetitions at similar to 70-80% of I repeat maximum (RM). Low-intensity group (LIG; n=13) worked in the same duration, with 13-17 repetitions, at similar to 40-50% of IRM. Control group (CG; n=13) did not perform any exercises. Body composition, I RM value for 10 exercises, repetitions of sit-ups for 30 seconds, bone formation and resorption markers, serum osteocalcine (OC). bone alkaline phosphatase (BAP), beta CrossLabs. OPG, and sRANKL levels were measured before and after the training program. BMD was measured via dual energy X-ray absorptiometry. Results: Resistance training caused increases in spine BMD in HIG and LIG (p<0.05). and OC levels increased in the HIG (p<0.05). We observed a significant difference between the percent change in HIG versus the percent change in CC in the spine BMD values (p<0.01). sRANKL levels decreased significantly in all three groups. Strength measures increased in both exercise groups (p<0.001), favoring the HIG. Conclusion: High-intensity resistance training may be more effective for increasing muscle strength and protecting against osteoporosis and fractures. Due to insignificant changes in OPG levels and significant reductions in sRANKL in all groups, measures of circulating OPG and sRANKL levels seem not to be so useful to predict BMD or bone turnover status after resistance training programs. Therefore, these parameters remain to be determined directly in the bone microenyironments together with BMD measures and bone turnover markers.
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    Can Urinary Gamma Glutamyl Transferase be Used as a Bone Resorption Marker in Postmenopausal Osteoporosis?
    Tikiz, C; Ulman, C; Taneli, F; Acar, EY; Gümüser, G; Horasan, GD
    Objectives: To evaluate whether gamma-glutamyl transferase can be used as a new novel bone resorption marker in postmenopusal osteoporotic subjects. Design and methods: 156 postmenopausal subjects were divided into three groups according to their lumbar spine T-score measured by dual-energy X-ray absorptiometry as normal, (control group, n=56), osteopenic (n=50) and osteoporotic (n=50). Deoxypyridinoline and gamma-glutamyl transferase from urine samples and osteocalcin and bone specific alkaline phosphates from blood samples were assessed. Results: Osteocalcin and bone specific alkaline phosphates levels were increased in osteoporotic group (p<0.05). Although there is a tendency to increase in deoxypyridinoline values in osteoporotic group, this difference did not reach to a statistical significance. No significant differences were observed in urinary gamma-glutamyl transferase levels between the three groups (p>0.05). No significant correlation was found between urinary gamma-glutamyl transferase and deoxypyridinoline, bone specific alkaline phosphates and osteocalcin (p>0.05). Urinary gamma-glutamyl transferase levels showed no significant correlation with neither bone mineral density nor T scores in all subjects (r=0.058 p=0.625, r=-0.074 p=0.533 respectively). Conclusions: Our primary findings did not support the suggestion that urinary g-glutamyl transferase could be used as a potential marker for bone resorption in postmenopusal osteoporotic subjects.
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    Bone mineral density, vitamin D status, and calcium intake in healthy female university students from different socioeconomic groups in Turkey
    Ersoy, B; Kizilay, DÖ; Yilmaz, SK; Taneli, F; Gümüser, G
    Peak bone mass is reached in late adolescence. Low peak bone mass is a well recognized risk factor for osteoporosis later in life. Our data do not support a link between vitamin D status, bone mineral density (BMD), and socioeconomic status (SES). However, there was a marked inadequacy of daily calcium intake and a high presence of osteopenia in females with low SES.PurposeOur aims were to (1) examine the effects of different SES on BMD, vitamin D status, and daily calcium intake and (2) investigate any association between vitamin D status and BMD in female university students.Subjects and methodsA questionnaire was used to obtain information about SES, daily calcium intake, and physical activity in 138 healthy, female university students (age range 18-22years). Subjects were stratified into lower, middle, and higher SES according to the educational and occupational levels of their parents. All serum samples were collected in spring for 25-hydroxyvitamin D concentration (25OHD). Lumbar spine and total body BMD was obtained by dual-energy X-ray absorptiometry (DXA) scan (Lunar DPX series). Osteopenia was defined as a BMD between -1.0 and -2.5 standard deviations (SDs) below the mean for healthy young adults on lumbar spine DXA.ResultsNo significant difference was found between the three socioeconomic groups in terms of serum 25OHD concentration, BMD levels, or BMD Z scores (p>0.05). Both the daily intake of calcium was significantly lower (p=0.02), and the frequency of osteopenia was significantly higher in girls with low SES (p=0.02). There was no correlation between serum 25OHD concentration and calcium intake and BMD values and BMD Z scores (p>0.05). The most important factor affecting BMD was weight (=0.38, p<0.001).ConclusionsLow SES may be associated with sub-optimal bone health and predispose to osteopenia in later life, even in female university students.
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    Contribution of Open Mouth Technique in 18F-FDG PET/CT Imaging in Patients with Malignant Lip Neoplasm
    Mütevelizade, G; Sezgin, C; Parlak, Y; Gümüser, G; Sayit, E
    Objectives: F-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) plays an important role in evaluating head and neck cancers. However, localization and size evaluation in this region can be rough due to the multitude of the anatomic structures and physiologic uptakes. The aim of this study was to evaluate malignant lip lesions with the contribution of open mouth (OM) imaging technique at PET/CT. Methods: Fifty-six patients with malignant lip neoplasm underwent F-18-FDG PET/CT imaging. Each patient was imaged twice as whole-body PET/CT with routine closed mouth (CM) position; and OM head and neck image, standardized with a special device. Lesion maximum standard uptake value (SUVmax), localization, size, and involvement of lymph nodes were evaluated. Results: Lesion localization was correctly detected in 100% of the OM images. Lesion size in PET/CT was compared with clinical, radiological (magnetic resonance imaging and CT) and/or histopathological results and the size measurement was coherent at 47.1% and 95.6% for CM and OM images, respectively. It was observed that OM acquisition did not contribute additionally in detecting regional lymph node metastasis. Forty-one PET/CT scans with CT artifacts due to dental amalgams were evaluated and 46.3% dimensional and 53.7% localization errors were detected in the CM position. There was no statistically significant difference between OM and CM SUVmax (p>0.05). Conclusion: We concluded that additional OM head and neck imaging is useful and necessary to accurately determine the localization and size of the tumor, thus enhancing the value of PET/CT in staging, treatment response assessment, and restaging of patients with malignant lip cancer with or without dental amalgam.
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    The effects of lornoxicam on brain edema and blood brain barrier following diffuse traumatic brain injury in rats
    Topçu, I; Gümüser, G; Bayram, E; Aras, F; Çetin, I; Temiz, C; Çivi, M
    BACKGROUND In this experiment, the effects of lornoxicam on brain edema and the blood brain barrier (BBB) following diffuse traumatic brain injury (TBI) were studied. METHODS Twenty adult male Wistar albino rats were anesthetized, and experimental closed head trauma was induced by the Marmarou method. After head injury, the rats were randomly divided into two groups: Group I was the control group, to which 2 ml saline was administered intraperitoneally, and Group II was the lornoxicam group, to which 2 ml 1.3 mg kg(-1) lornoxicam was administered intraperitoneally. Twenty-four hours after head trauma, 99 mTc pentetate (DTPA) was injected at a dose of 37 MBq, and posterior planar images of each rat were obtained using an Infinia gamma camera. After imaging of BBB permeability, brain tissues were dissected from the cranium. The brain water content (BWC) of each sample was calculated using the wet-dry method. RESULTS The lesion/background (L/b) ratio of Group I was 3.76 +/- 0.46 and 3.02 +/- 0.66 for early (5th min) and late (60th min) imaging, respectively. In Group II, the L/b ratios were 3.52 +/- 0.96 and 2.63 +/- 0.63 for early and late imaging, respectively (p>0.05). BWC was 79.6 +/- 2.5% and 77.5 +/- 1.1% for Groups I and II, respectively (p<0.05). CONCLUSION In this rat model of TBI, lornoxicam reduced brain edema but did not affect BBB permeability.
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    Early renal parenchymal histological changes in an experimental model of vesico-ureteral reflux and the role of apoptosis
    Sencan, A; Vatansever, S; Yilmaz, Ö; Genç, A; Serter, S; Gümüser, G; Kurutepe, S; Pekindil, G; Günsar, C; Mir, E
    Objectives. To observe early renal parenchymal cellular changes in an experimental model of vesico-ureteral reflux (VUR) and to show whether the apoptotic pathway plays a role in these cellular changes. Material and methods. Fourteen New Zealand breed rabbits were used and were divided into two equal groups (control and experimental groups). Urine samples were obtained in a sterile manner and cultured. In the study group, reflux was created in the right kidneys surgically. Renal scintigraphy and voiding cystourethrography (VCUG) were performed in both groups on Day 17. The kidneys were examined in terms of histology, apoptotic activity and caspase activity. Results. No growth was observed in urine cultures in either group. VUR was manifested in only two rabbits in the experimental group on VCUG. On renal scintigraphy, no renal scarring was observed in either of the groups and renal uptake values were in the normal range. There was a greater increase in collagen in the right kidneys in the experimental group than in the control group and apoptotic activity was significantly increased in the study group: 0% in the control group, 10.8%0.7% in the experimental group (p0.001). Caspase-6 activity was strongly positive and caspase-8 and -9 activities were moderately positive in the right kidneys of the experimental group. Caspase-6 activity was moderately positive, and caspase-8 and -9 activities were weakly positive in the contralateral kidneys of the experimental group. Caspase activities in the control group were negative (p0.001). Conclusions. In this experimental model of VUR, apoptotic activity was initiated via the caspase-8 and -9 pathway and collagen tissue increased in the renal parenchyma where reflux occurred. The balance of apoptotic activity may play a key role in the occurrence of reflux nephropathy.
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    Bone mineral density in girls and boys at different pubertal stages
    Yilmaz, D; Ersoy, B; Bilgin, E; Gümüser, G; Onur, E; Pinar, ED
    Puberty has a key role in bone development. During puberty, several nutritional and hormonal factors play a major role in this process. The aim of this study was to determine the changes in areal bone mineral density (BMD), gonadal steroids, bone formation markers, and growth parameters in healthy Turkish pubertal girls and boys at different pubertal stages. In additional, we aimed to detect the relationship between BMD, sex steroids, and growth parameters, and to reveal the most important determinant of BMD in the pubertal period. BMD of the lumbar spine and total body was performed by dual-energy X-ray absorptiometry (Lunar DPX series) in 174 healthy pubertal children (91 girls, 83 boys), aged 11-15 years. Height and weight were measured. Pubertal stages were assesed. Bone formation markers and gonadal steroids were measured. BMD values significantly increased until stage IV in girls. In boys, BMD values also increased during puberty (P < 0.05), but it was significantly higher in stage IV compared with that in other pubertal stages (P < 0.01). Testosterone levels increased until stage IV in both sexes, particularly in boys. Estrogen levels significantly increased during puberty in girls, whereas it was significantly higher at stage IV in boys (P < 0.001). Bone-specific alkaline phosphatase (BAP) level was higher in early and midpuberty, and decreased in late puberty in girls (P < 0.001). BAP level was higher in stage IV in boys. Osteocalcin level was shown not to change significantly in pubertal stages. There was a modest correlation between BMD values and estrogen and testosterone levels in boys. In girls, there was a correlation between BMD values and estrogen levels only (P < 0.05). Weight was significantly associated with BMD in both sexes (P < 0.05). Estrogen had a significant influence on BMD in boys and girls. In conclusion, bone mass increased throughout puberty in both sexes. Peak bone mass was not achieved in girls, but was obtained at stage IV in boys. Bone formation markers were good predictors of bone mass in girls, but not in boys. Estrogen level made the greatest contribution to bone mineral acquisition in boys and girls. The achievement of peak bone mass was sustained by estrogen in boys. The major independent determinant of BMD in both sexes was weight.
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    F-18 FDG PET/CT imaging artifacts
    Parlak, Y; Gümüser, G; Sayit Bilgin, BE
    F-18 FDG PET/CT are being used in increasing numbers in the diagnosis of the primary lesion, disease staging and evaluation of response to therapy of various cancers due to its high accuracy. However, PET/CT have various artifacts which affected image quality including PET and CT AC (attenuation correction) artifacts. For accurate identification of malignant lesions, to characterize these artifacts is clinically important. Our aim is to identify, to characterize and to investigate the effect of PET/CT image quality of these artifacts.
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    F-18 fluorodeoxyglucose positron emission tomography in testicular cancer
    Gümüser, G; Aras, F; Bilgin, ES
    F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) is becoming a standard imaging modality in the diagnosis, staging and evaluation of therapy response for most malignant diseases. The purpose of the present review is to update existing knowledge about the value of FDG PET in testicular cancer together with a summary of the literature.
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    The Role Of 68ga Dotatate Pet/Ct In Breast Cancer Imaging; A Prospective Study Compared With 18f Fdg Pet/Ct
    Sezgin, C; Coskun, T; Parlak, Y; Mutevelizade, G; Sayit, E; Gümüser, G
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    Radiation Exposure to Nuclear Medicine Staff Working with Tc99m Radiopharmaceutical
    Hizli, Y; Parlak, Y; Göksoy, D; Mütevelizade, G; Gümüser, G; Sayit, E
    Introduction: Nuclear medicine technologists are potentially exposed to ionizing radiations while performing a variety of tasks associated with nuclear medicine procedures. We measured the external radiation doses for staff members working with Tc-99m radiopharmaceuticals to assess the annual radiation doses. Methods: Radiation doses for a nuclear medicine physician, a technologist, a nurse, a radiopharmacist, and a cleaning staff were measured by digital dosimeters. We measured the radiation exposure of these five people every day for 1 month. The dosimeters were placed at the waist levels on the anterior surfaces of the bodies. Results: After correction of natural background doses, the mean 1-month radiation dose for the physician, technologist, nurse, radiopharmacist, and cleaning staff were determined as 102.37 +/- 15.16 mu Sv, 110.8 +/- 7.5 mu Sv, 84.67 +/- 8.2 mu Sv, 111.8 +/- 7.1 mu Sv, and 106.5 +/- 12.27 mu Sv, respectively. Discussion: This study showed that effective radiation doses for nuclear medicine department staff members were within the permissible level.
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    Aneurysmal Bone Cyst in a patient with McCune-Albright Syndrome
    Aydin, N; Mütevelizade, G; Gümüser, G; Bilgin, ES
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