No abstract available.

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

No abstract available.
Glucose* ; Humans* ; Hyperglycemia* ; Monocytes*

Primary gallbladder cancer is a highly malignant tumor and is characterized by early metastasis and rapid progression of disease. Since the majority of patients have unresectable disease, laparotomy, instead of providing relief of symptoms, often adds to the morbidity and needs to be avoided in patients with advanced disease. Clinical features, peritoneoscopic findings, and comparison of peritoneoscopy with radiologic studies were reviewed in 29 patients, who underwent peritoneoscopy, with primary gallbladder cancer at Severaace Hospital, College of Medicine, Yonsei University between Aug. 1982 and Mar. 1994. (continue...)
Gallbladder Neoplasms* ; Gallbladder* ; Humans ; Laparoscopy* ; Laparotomy ; Neoplasm Metastasis

PURPOSE: Radiotracers that bind to the central benzodiazepine receptor are useful for the investigation of various neurological and psychiatric diseases. [C-11]Flumazenil, a benzodiazepine antagonist, is the most widely used radioligand for central benzodiazepine receptor imaging by PET. We synthesized 3-(2-[F- 18]fluoro)flumazenil, a new fluorine-18 (t1/2=110 min) labeled analogue of benzodiazepine receptor imaging agent, and evaluated in vivo for biodistribution in mice. MATERIALS AND METHODS: Flumazenil (Ro 15-1788) was synthesized by a modification of the reported method. Precursor of 3-(2-[F-18]fluoro)flumazenil, the tosylated flumazenil derivative was prepared by the tosylation of the ethyl ester by ditosylethane. [F-18] labeling of tosyl substitued flumazenil precursor was performed by adding F-18 ion at 85 degree C in the hot cell for 20 min. The reaction mixture was trapped by C18 cartridge, washed with 10% ethanol, and eluted by 40% ethanol. Bidistribution in mice was determined after intravenous injection. RESULTS: The total chemical yield of tosylated flumazenil derivative was ~40%. The efficiency of labeling 3-(2-[F-18]fluoro)flumazenil was 66% with a total synthesis time of 50 min. Brain uptakes of 3-(2-[F-18]fluoro)flumazenil at 10, 30, 60 min after injection, were 2.5+/-0.37, 2.2+/-0.26, 2.1+/-0.11 and blood activities were 3.7+/-0.43, 3.3+/-0.07, 3.3+/-0.09%ID/g, respectively. CONCLUSION: We synthesized a tosylated flumazenil derivative which was successfully labeled with no-carrier-added F-18 by nucleophilic substitution.
Animals ; Benzodiazepines* ; Brain ; Ethanol ; Flumazenil* ; Injections, Intravenous ; Mice ; Receptors, GABA-A*

PURPOSE: The purpose of this study was to evaluate the diagnostic accuracy of Tc-99m labeled antigranulocyte antibody immunoscintigrapy in the diagnosis of osteomyelitis and compare with the results of triphasic bone scan. MATERIALS AND METHODS: The study population was 39 patients (22 male, 17 female) who had uncertain diagnoses of osteomyelitis. Fifteen patients had history of orthopedic surgery, and 5 had previous fracture. One milligram of monoclonal antibody against NCA-95 was labeled with 370 MBq of Tc-99m, injected intravenously, and 4 hour images were obtained. Triphasic bone scan images were obtained in 30 p;tients. The final diagnosis was confirmed by bacteriologic culture, biopsy or long term clinical follow up. RESULTS: Twenty one patients were confirmed to have osteomyelitis (1 acute, 20 chronic). Eighteen patients were without osteomyelitis. Antigranulocyte antibody immunoscintigraphy had a sensitivity of 71% (15/21), and a specificity of 89% (16/18), while the sensitivity and specificity of triphasic bone scan was 93% (13/14) and 38% (6/16), respectively. Antigranulocyte antibody scan showed higher specificity of 100% (11/11) in comparison with 33% (3/9) of triphasic bone scan in patients with history of orthopedic surgery or fracture. CONCLUSION: Antigranulocyte antibody immunoscintigraphy is more specific than that of triphasic bone scan and may be helpful in patients with history of surgery or fracture. However, sensitivity is lower than triphasic bone scan in the detection of chronic osteomyelitis.
Biopsy ; Diagnosis ; Follow-Up Studies ; Humans ; Male ; Orthopedics ; Osteomyelitis ; Sensitivity and Specificity

OBJECTIVE: It is still the important subject that 3D visualizing of medical images to help patient diagnose. There were many challenges for fast 3D visualization but it has some limitations that volume rendering without high price's hardware and software. Some techniques through the web were suggested to construct high quality's 3D visualization even though it was an only poor personal computer. This technique could share the volume rendering board and diagnose 3D images together. However there are some problems to construct web based 3D visualization. These are network delay, optimized visualization and security etc. The purpose of this paper was to visualize and control the 3D medical image having a high quality on the web. METHODS: To construct this system, we used mainly three tools which were VolumePro1000 board, WMV9(Windows Media Video 9 Codec) and socket functions based on TCP(Transmission Control Protocol). VolumePro1000 board could calculate quickly heavy matrixes of 3D images using phong's shading and shear-warp factorization. WMV9 was able to compress efficiently live images and to apply image streaming technique. Socket functions based on TCP transmitted messages to control the 3D images. RESULTS: We developed 3D visualization system and evaluated about image qualities and transmission conditions of different compression rates on unfixed network condition. CONCLUSION: It was big advantages that WMV9 encoder could decode automatically in many platforms(desk top, PDA, notebook, cellular phone, etc) without installing specific decoding programs if they only have Windows Media player. We expect 3D visualization system to be utilized various biomedical fields such as IIGS(Interactive Image Guided Surgery), CAD(Computer Aided Diagnosis) and Tele-medicine technologies.
Cellular Phone ; Humans ; Microcomputers ; Rivers*

It has been emphasized that the treatment of choice for the trochanteric fracture of the femur is open reduction and rigid internal fixation. Regarding the stability of the fracture, most reports were focused on the comminution of the medial cortex, but few reports were paid attention to the additional fracture of the greater trochanter. This paper was aimed to evaluate the fragment of the greater trochanter on the maintenance of reduction. We treated 23 cases of unstable trochanteric fractures in which 16 cases were treated with Dynamic Hip Screw (DHS) alone, and 7 cases were treated with DHS and additional DHS Trochanter Stabilizing Plate (TSP). We compared the two groups and the results were as follows: 1. The average lag screw slipping distance was 17.1mm in DHS Group and 10.0mm in TSP Group. 2. The average distance of lateral displacement of greater trochanter over the trochantric fractures was 11.5mm in DHS Group and no change in TSP Group. The above results suggested that the comhined use of DHS Trochanter Stabilizing Plate with Dynamic Hip Screw provided good results in the treatment of uristable intertrochanteric fractures with completely detached greater trochanter and reverse oblique fracture.
Femur* ; Hip Fractures* ; Hip*

The purpose of this study was to estimate average radiation exposure from 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) examinations and to analyze possible factors affecting the radiation dose. A nation-wide questionnaire survey was conducted involving all institutions that operate PET/CT scanners in Korea. From the response, radiation doses from injected FDG and CT examination were calculated. A total of 105 PET/CT scanners in 73 institutions were included in the analysis (response rate of 62.4%). The average FDG injected activity was 310 +/- 77 MBq and 5.11 +/- 1.19 MBq/kg. The average effective dose from FDG was estimated to be 5.89 +/- 1.46 mSv. The average CT dose index and dose-length product were 4.60 +/- 2.47 mGy and 429.2 +/- 227.6 mGycm, which corresponded to 6.26 +/- 3.06 mSv. The radiation doses from FDG and CT were significantly lower in case of newer scanners than older ones (P < 0.001). Advanced PET technologies such as time-of-flight acquisition and point-spread function recovery were also related to low radiation dose (P < 0.001). In conclusion, the average radiation dose from FDG PET/CT is estimated to be 12.2 mSv. The radiation dose from FDG PET/CT is reduced with more recent scanners equipped with image-enhancing algorithms.
Child ; Child, Preschool ; Fluorodeoxyglucose F18/chemistry ; Humans ; Infant ; *Positron-Emission Tomography ; *Radiation Dosage ; Surveys and Questionnaires ; *Tomography, X-Ray Computed ; *Whole Body Imaging

PURPOSE: Radiolabeled CEA79.4 antibody has a possibility to be used in radioimmunoscintigraphy or radioimmunotheraphy of cancer. We investigated the in vitro properties and biodistribution of CEA79.4 antibody labeled with Re-188 or Tc-99m. MATERIALS AND METHODS: CEA79.4 was reduced by 2-mercaptoethanol to produce-SH reside, and was labeled with Re-188 or Tc-99m. For direct labeling of Tc-99m, methylene-diphosphonate was used as transchelating agent. CEA79.4 in 50 mM Acetate Buffered Saline (ABS, pH 5.3) was labeled with Re-188, using stannous tartrate as reducing agent. In order to measure immunoreactivity and the affinity constant of radiolabeled antibody, cell binding assay and Scatchard analysis using human colon cancer cells SNU-C4, were performed. Biodistribution study of labeled CEA79.4 was carried out at 1, 14 and 24 hr in ICR mice. RESULTS:. Labeling efficiencies of Tc-99m and Re-188 labeled antibodies were 92.4+/-5.9% and 84.7+/-4.6%, respectively. In vitro stability of Tc-99m-CEA79.4 in human serum was higher than Re-188-CEA79.4. Immunoreactivity and affinity constant of Tc-99m-CEA79.4 were 59.2% and 6.59x109 M-1, respectively, while those of Re-188-CEA79.4 were 41.6% and 4.2x109 M-1, respectively. After 24 hr of administrations of Re-188 and Tc-99m labeled antibody, the remaining antibody, the remaining antibodies in blood were 6.32 and 9.35% ID/g respectively. The biodistribution of each labeled antibody in other organs was similar because they did not accumulate in non-targeted organs. CONCLUSION: In vitro properties and biodistribution of Re-188-CEA79.4 were similar to those of Tc-99m-CEA79.4. It appears that Re-188-CEA79.4 can be used as a suitable agent for radioimmunotherapy.
Animals ; Antibodies ; Colonic Neoplasms ; Humans ; Hydrogen-Ion Concentration ; Mercaptoethanol ; Mice ; Mice, Inbred ICR ; Radioimmunodetection ; Radioimmunotherapy