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

A 42 years old woman underwent F-18 FDG PET because of the incidentally detected lung mass on chest X-ray. PET/CT showed hypermetabolic lesion in the lung right upper lobe and the lung cancer was suspected because of the high FDG uptake. However, pathologic diagnosis was sclerosing hemangioma. There are few reports on the evaluation of sclerosing hemangioma using FDG PET. A report showed a slightly increased uptake (standardized uptake ratio of 1.8) (1), and another report showed unsatisfactory result (2). We suggest that sclerosing hemangioma could be seen as hypermetabolic lesion on the FDG PET.
Adult ; Diagnosis ; Female ; Histiocytoma, Benign Fibrous* ; Humans ; Lung ; Lung Neoplasms ; Positron-Emission Tomography and Computed Tomography ; Thorax

A tail-on-detector (TOD) view has been used to see the symphysis pubis or sacrococcyx in skeletal scintigraphy, but it is inconvenient to acquire because a patient must sit or lean on a detector. The TOD views are still frequently performed in training hospitals in Korea, although it is becoming almost impossible to sit on a camera in this age of dual-headed cameras. The authors show cases with lateral views obtained in supine position that were acquired for the same reason; they are easier and more useful than the TOD views.
Coccyx ; Humans ; Korea ; Radionuclide Imaging* ; Sacrococcygeal Region* ; Sacrum ; Supine Position ; Technetium Tc 99m Medronate

PURPOSE: Tc-99m labeled diethylenetriaminepentaacetic acid (DTPA) -coupled galactosylated human serum albumin (GSA) is a currently used imaging agent for asialoglycoprotein receptor (ASGPR) of the liver, but, it has several shortcomings. Recently a new ASGPR imaging agent, (99m) Tc-lactosylated human serum albumin (LSA), with simple labeling procedure, high labeling efficiency, high stability was developed. In order to assess the feasibility of the (99m) Tc-LSA as a ASGPR imaging radiopharmaceuticals, we performed biodistribution study of the tracer in liver injured mice model and the results were compared with histolgic data. MATERIALS AND METHODS: To induce hepatic damage in ICR mice, diethylnitrosamine (DEN) (60 mg/kg/week X 5 time, low dose or 180 mg/kg/week X 2 times, high dose) and thioacetamide (TAA) (50 mg/kg X 1 time) were administrated intraperitoneally. Degree of liver damage was evaluated by tissue hematoxilin-eosin stain, and expression of asialoglycoprotein receptor (ASGPR) was assessed by immunohistochemistry using ASGPR antibody. (99m) Tc-LSA was intravenously administrated via tail vein in DEN or TAA treated mice, and biodistribution study of the tracer was also performed. RESULTS: DEN treated mice showed ballooning of hepatocyte and inflammatory cell infiltration in low dose group and severe hapatocyte necrosis in high dose group, and low dose group showed higher ASGPR staining than control mice in immunohistochemical staining. TAA treated mice showed severe hepatic necrosis. (99m) Tc-LSA Biodistribution study showed that mice with hepatic necrosis induced by high dose DEN or TAA revealed higher blood activity and lower liver activity than control mice, due to slow clearance of the tracer by the liver. The degree of liver uptake was inversely correlated with the degree of histologic liver damage. But low dose DEN treated mice with mild hepatic injury showed normal blood clearance and hepatic activity, partly due to overexpression of ASGPR in mice with mild degree hepatic injury. CONCLUSION: Liver uptake of (99m) Tc-LSA was inversely correlated with degree of histologic hepatic injury in DEN and TAA treated mice. These results support that (99m) Tc-LSA can be used to evaluate the liver status in liver disease patients.
Animals ; Asialoglycoprotein Receptor ; Diethylnitrosamine* ; Hepatocytes ; Humans ; Immunohistochemistry ; Liver Diseases ; Liver* ; Mice* ; Mice, Inbred ICR ; Necrosis ; Radiopharmaceuticals ; Serum Albumin* ; Thioacetamide* ; Veins

PURPOSE: In order to obtain better quantitation of kidney uptake, this study is to evaluate a conjugate view method (CVM) using a geometric mean attenuation correction for kidney uptake and to compare it to Gate's method. MATERIALS AND METHODS: We used a Monte Carlo code, SIMIND and a Zubal phantom, to simulate kidney uptake. SIMIND was both simulated with or without scatter for the Zubal phantom. Also, a real phantom test was carried out using a dual-head gamma camera. The activity of 0.5 mCi was infused into two small cylinder phantoms of 5 cm diameter, and then, they were inserted into a cylinder phantom of 20 cm diameter. The results by the CVM method were compared with ideal data without both of attenuation and scatter and with Gate's method. The CVM was performed with or without scatter correction. The Gate's method was performed without scatter correction and it was evaluated with regards to 0.12 cm (-1) and 0.15 cm (-1) attenuation coefficients. Data were analyzed with comparisons of mean counts in the regions of interest (ROI), profiles drawn over kidney images and linear regression. Correlation coefficients were calculated with ideal data, as well. RESULTS: In the case of the computer simulation, mean counts measured from ideal data, the CVM and the Gate's method were (right: 998 +/- 209, left: 896 +/- 249), (right: 911 +/- 207, left: 815 +/- 265), and (right: 1065 +/- 267, left: 1546 +/- 267), respectively. The ideal data showed good correlation with the CVM and the correlation coefficients of the CVM, Gate's method were (right: 0.91, left: 0.93) and (right: 0.85, left: 0.90), respectively. CONCLUSION: The conjugate view method using geometric mean attenuation correction resulted in better accuracy than the Gate's method. In conclusion, the conjugate view method independent of renal depths may provide more accurate kidney uptake.
Computer Simulation ; Gamma Cameras ; Kidney* ; Linear Models

PURPOSE: There are differences between Standard Uptake Value (SUV) of CT attenuation corrected PET and that of 137Cs. Since various causes lead to difference of SUV, it is important to know what is the cause of these difference. Since only the X-ray CT and 137Cs transmission data are used for the attenuation correction, in Philips GEMINI PET/CT scanner, proper transformation of these data into usable attenuation coefficients for 511 keV photon has to be ascertained. The aim of this study was to evaluate the accuracy in the CT measurement and compare the CT and 137Cs-based attenuation correction in this scanner. METHODS: For all the experiments, CT was set to 40 keV (120 kVp) and 50 mAs. To evaluate the accuracy of the CT measurement, CT performance phantom was scanned and Hounsfield units (HU) for those regions were compared to the true values. For the comparison of CT and 137Cs-based attenuation corrections, transmission scans of the elliptical lung-spine-body phantom and electron density CT phantom composed of various components, such as water, bone, brain and adipose, were performed using CT and 137Cs. Transformed attenuation coefficients from these data were compared to each other and true 511 keV attenuation coefficient acquired using 68Ge and ECAT EXACT 47 scanner. In addition, CT and 137Cs-derived attenuation coefficients and SUV values for 18F-FDG measured from the regions with normal and pathological uptake in patients' data were also compared. RESULTS: HU of all the regions in CT performance phantom measured using GEMINI PET/CT were equivalent to the known true values. CT based attenuation coefficients were lower than those of 68Ge about 10% in bony region of NEMA ECT phantom. Attenuation coefficients derived from 137Cs data was slightly higher than those from CT data also in the images of electron density CT phantom and patients' body with electron density. However, the SUV values in attenuation corrected images using 137Cs were lower than images corrected using CT. Percent difference between SUV values was about 15%. CONCLUSION: Although the HU measured using this scanner was accurate, accuracy in the conversion from CT data into the 511 keV attenuation coefficients was limited in the bony region. Discrepancy in the transformed attenuation coefficients and SUV values between CT and 137Cs-based data shown in this study suggests that further optimization of various parameters in data acquisition and processing would be necessary for this scanner.
Brain ; Fluorodeoxyglucose F18 ; Positron-Emission Tomography and Computed Tomography* ; Water

PURPOSE: Reduction of respiratory motion artifacts in PET images was studied using respiratory-gated PET (RGPET) with moving phantom. Especially a method of generating simulated helical CT images from 4D-CT datasets was developed and applied to a respiratory specific RGPET images for more accurate attenuation correction. MATERIALS AND METHODS: Using a motion phantom with periodicity of 6 seconds and linear motion amplitude of 26 mm, PET/CT (Discovery ST; GEMS) scans with and without respiratory gating were obtained for one syringe and two vials with each volume of 3, 10, and 30 ml respectively. RPM (Real-Time Position Management, Varian) was used for tracking motion during PET/CT scanning. Ten datasets of RGPET and 4D-CT corresponding to every 10% phase intervals were acquired. From the positions, sizes, and uptake values of each subject on the resultant phase specific PET and CT datasets, the correlations between motion artifacts in PET and CT images and the size of motion relative to the size of subject were analyzed. RESULTS: The center positions of three vials in RGPET and 4D-CT agree well with the actual position within the estimated error. However, volumes of subjects in non-gated PET images increase proportional to relative motion size and were overestimated as much as 250% when the motion amplitude was increased two times larger than the size of the subject. On the contrary, the corresponding maximal uptake value was reduced to about 50%. CONCLUSION: RGPET is demonstrated to remove respiratory motion artifacts in PET imaging, and moreover, more precise image fusion and more accurate attenuation correction is possible by combining with 4D-CT.
Artifacts* ; Dataset ; Periodicity ; Positron-Emission Tomography and Computed Tomography ; Syringes ; Tomography, Spiral Computed

PURPOSE: Abutted scatter energy windows used for a triple energy window (TEW) method may provide wrong estimation of scatter. This study is to propose an extended TEW (ETEW) method, which doesn't require abutted scatter energy windows and overcomes the shortcomings of TEW method. MATERIALS AND METHODS: The ETEW is a modification of the TEW which corrects for scatter by using abutted scatter rejection windows, which can overestimate or underestimate scatter. The ETEW is compared to the TEW using Monte Carlo simulated data for point sources as well as hot and cold spheres in a cylindrical water phantom. Various main energy window widths (10 %, 15 % and 20 %) were simulated. Both TEW and ETEW improved image contrast, % recovery coefficients and normalized standard deviation. RESULTS: Both of TEW and ETEW improved image contrast and % recovery coefficients. Estimated scatter components by the TEW were not proportional to the true scatter components over the main energy windows when ones of 10 %, 15 %, and 20 % were simulated. The ETEW linearly estimated scatter components over the width of the main energy windows. CONCLUSION: We extended the TEW method into the method which could linearly estimate scatter components over the main energy windows.
Tomography, Emission-Computed, Single-Photon* ; Water

Hemangioma is the most common benign tumor of the liver, with a prevalence estimated as high as 7%. Tc-99m red blood cell (RBC) hepatic blood pool scan with single photon emission computed tomography (SPECT) imaging is extremely useful for the confirmation or exclusion of hepatic hemangiomas. The classic finding of absent or decreased perfusion and increased blood pooling ("perfusion/blood pool mismatch") is the key diagnostic element in the diagnosis of hemangiomas. The combination of early arterial flow and delayed blood pooling ("perfusion/blood pool match") is shown uncommonly. In giant hemangioma, filling with radioactivity appears first in the periphery, with progressive central fill-in on sequential RBC blood pool scan. However, the reverse filling pattern, which begins first in the center with progressive peripheral filling, is also rarely seen. Studies with false-positive blood pooling have been reported infrequently in nonhemangiomas, including hemangiosarcoma, hepatocellular carcinoma, hepatic adenoma, and metastatic carcinomas (adenocarcinoma of the colon, small cell carcinoma of the lung, neruroendocrine carcinoma). False-negative results have been also reported rarely except for small hemagniomas that are below the limits of spatial resolution of gamma camera.
Adenoma ; Carcinoma, Hepatocellular ; Carcinoma, Small Cell ; Colon ; Diagnosis ; Erythrocytes* ; Gamma Cameras ; Hemangioma* ; Hemangiosarcoma ; Liver ; Lung ; Perfusion ; Prevalence ; Radioactivity ; Tomography, Emission-Computed, Single-Photon

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