PURPOSE: The objective of this study was to assess attenuation correction algorithms with the 137Cs point source for the brain positron emission tomography (PET) imaging process. MATERIALS AND METHODS: Four different types of phantoms were used in this study for testing various types of the attenuation correction techniques. Transmission data of a 137Cs point source were acquired after infusing the emission source into phantoms and then the emission data were subsequently acquired in 3D acquisition mode. Scatter corrections were performed with a background tail-fitting algorithm. Emission data were then reconstructed using iterative reconstruction method with a measured (MAC), elliptical (ELAC), segmented (SAC) and remapping (RAC) attenuation correction, respectively. Reconstructed images were then both qualitatively and quantitatively assessed. In addition, reconstructed images of a normal subject were assessed by nuclear medicine physicians. Subtracted images were also compared. RESULTS: ELAC, SAC, and RAC provided a uniform phantom image with less noise for a cylindrical phantom. In contrast, a decrease in intensity at the central portion of the attenuation map was noticed at the result of the MAC. Reconstructed images of Jaszack and Hoffan phantoms presented better quality with RAC and SAC. The attenuation of a skull on images of the normal subject was clearly noticed and the attenuation correction without considering the attenuation of the skull resulted in artificial defects on images of the brain. CONCLUSION: the complicated and improved attenuation correction methods were needed to obtain the better accuracy of the quantitative brain PET images.
Brain ; Noise ; Nuclear Medicine ; Positron-Emission Tomography ; Skull

PURPOSE: Dedicated animal PET is useful equipment for the study of new PET tracer. Recently, microPET R4 was installed in the Korea institute of radiology and medical science. In this study, we measured the characteristics of scanner. MATERIALS AND METHODS: Resolution was measured using a line source (F-18: 65 micro Ci, inner diameter: 0.5 mm). The line source was put in the axial direction and was moved from the center of field of view to outside with 1 mm interval. PET images were reconstructed using a filtered back-projection and ordered subset expectation maximization. Line source (16.5 micro Ci, 78 mm) was put on the center of axial direction to measure the sensitivity when the deadtime was under 1%. Images were acquired during 4 minutes respectively from center to 39 mm outward. Delayed count was subtracted from total count and then decay was corrected for the calculation of sensitivity. Noise equivalent count ratio and scatter fraction were calculated using cylindrical phantom. RESULTS: Spatial resolution of reconstructed image using filtered back-projection was 1.86 mm (radial), 1.95 mm (tangential), 1.95 mm (axial) in the center of field of view, and 2.54 mm, 2.8 mm, 1.61 mm in 2 cm away from the center respectively. Sensitivity was 2.36% at the center of transaxial field of view. Scatter fraction was 20%. Maximal noise equivalent count ratio was 66.4 kcps at 242 kBq/mL. Small animal images were acquired for confirmation of performance. CONCLUSION: Performance characteristics of microPET R4 were similar with reported value. So this will be a useful tool for small animal imaging.
Animals* ; Korea ; Noise

PURPOSE: Ethylenediamine-tetramethylenephosphonic acid (EDTMP) has widely used chelator for the labeling of bone seeking radiopharmaceuticals complexed with radiometals. 153Sm can be produced by the HANARO reactor at the Korea Atomic Energy Research Institute, Taejon, Korea. 153Sm has favourable radiation characteristics T1/2=46.7 h, beta max=0.81 MeV (20%), 0.71 MeV (49%), 0.64 MeV (30%) and gamma=103 keV (30%) emission which is suitable for imaging purposes during therapy. We investigated the labeling condition of 153Sm-EDTMP and imaging of 153Sm-EDTMP in normal rats. MATERIALS AND METHODS: EDTMP 20 mg was solved in 0.1 mL 2 M NaOH. 153SmCl3 was added to EDTMP solution and pH of the reaction mixtures was adjusted to 8 and 12, respectively. Radiochemical purity was determined with paper chromatography. After 30 min. reaction, reaction mixtures were neutralized to pH 7.4, and the stability was estimated upto 120 hrs. Imaging studies of each reaction were perfomed in normal rats (37 MBq/0.1 mL). RESULTS: The labeling yield of 153Sm-EDTMP was 99%. The stability of pH 8 reaction at 60, 96 and 120 hr was 99%, 95%, 89% and that of pH 12 at 36, 60, 96 and 120 hr was 99%, 95%, 88%, 66%, respectively. The 153Sm-EDTMP showed constantly higher bone uptake from 2 to 48 hr after injection. CONCLUSION: 153Sm-EDTMP, labeled at pH 8 reaction condition, has been stably maintained. Image of 153Sm-EDTMP at 2, 24, 48 hr after injection, demonstrate that 153Sm-EDTMP is a good bone seeking radiopharmaceuticals.
Academies and Institutes ; Animals* ; Chromatography, Paper ; Daejeon ; Hydrogen-Ion Concentration ; Korea ; Nuclear Energy ; Radiopharmaceuticals ; Rats

PURPOSE: 99mTc-sestamibi (MIBI) and 99mTc-tetrofosmin have been used as substrates for P-glycoprotein (Pgp) and multidrug resistance associated protein (MRP), which are closely associated with multidrug resistance of the tumors. To understand different handling of radiotracers in cancer cell lines expressing Pgp and MRP, we compared cellular uptakes of 99mTc-MIBI and 99mTc-tetrofosmin. The effects of cyclosporin A (CsA), well-known multidrug resistant reversing agent, on the uptake of both tracers were also compared. MATERIALS AND METHODS: HCT15/CL02 human colorectal cancer cells for Pgp expressing cells, and human non-small cell lung cancer A549 cells for MRP expressing cells, were used for in vitro and in vivo studies. RT-PCR, western blot analysis and immunohistochemistry were used for detection of Pgp and MRP. MDR-reversal effect with CsA was evaluated at different drug concentrations after incubation with MIBI or tetrofosmin. Radioactivities of supernatant and pellet were measured with gamma well counter. Tumoral uptake of the tracers were measured from tumor bearing nude mice treated with or without CsA. RESULTS: RT-PCR, western blot analysis of the cells and immunochemical staining revealed selective expression of Pgp and MRP for HCT15/CL02 and A549 cells, respectively. There were no significant difference in cellular uptakes of both tracers in HCT15/CL02 cells, but MIBI uptake was slightly higher than that of tetrofosmin in A549 cells. Co-incubation with CsA resulted in a increase in cellular uptakes of MIBI and tetrofosmin. Uptake of MIBI or tetrofosmin in HCT15/CL02 cells was increased by 10- and 2.4-fold, and by 7.5 and 6.3-fold in A549 cells, respectively. Percentage increase of MIBI was higher than that of tetrofosmin with CsA for both cells (p< 0.05). In vivo biodistribution study showed that MIBI (114% at 10 min, 257% at 60 min, 396% at 240 min) and tetrofosmin uptake (110% at 10 min, 205% at 60 min, 410% at 240 min) were progressively increased by the time, up to 240 min with CsA. But increases in tumoral uptake were not significantly different between MIBI and tetrofosmin for both tumors. CONCLUSION: MIBI seems to be a better tracer than tetrofosmin for evaluating MDR reversal effect of the modulators in vitro, but these differences were not evident in vivo tumoral uptake. Both MIBI and tetrofosmin seem to be suitable tracers for imaging Pgp- and MRP-mediated drug resistance in tumors.
Animals ; Blotting, Western ; Carcinoma, Non-Small-Cell Lung ; Cell Line ; Colorectal Neoplasms ; Cyclosporine ; Drug Resistance ; Drug Resistance, Multiple* ; Humans ; Immunohistochemistry ; Mice ; Mice, Nude ; Multidrug Resistance-Associated Proteins* ; P-Glycoprotein* ; Radioactivity ; Technetium Tc 99m Sestamibi

PURPOSE: The purpose of this study is to evaluate migration of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labeled immature and mature dendritic cells (DC) in the mouse. METHODS: DC were collected from bone marrow (BM) of tibiae and femurs of mice. Immature and mature DC from BM cells were radiolabeled with 99mTc-HMPAO. To evaluate the functional and phenotypic changes of DC from radiolabeling, the allogeneic mixed lymphocyte reaction (MLR) and fluorescence-activated cell sorting (FACS) analysis were performed before and after labeling with 99mTc-HMPAO. Migration of intravenously injected DC (iv-DC) was assessed by serial gamma camera images of mice with or without subcutaneous tumor. Percent injected dose per gram (%ID/g) was calculated in lungs, liver, spleen, kidneys, and tumor through dissection of each mice after 24 hours of injection. RESULTS: Labeling efficiency of immature and mature DC were 60.4 +/- 5.4% and 61.8 +/- 6.7%, respectively. Iv-DC initially appeared in the lungs, then redistributed mainly to liver and spleen. Migration of mature DC to spleen was significantly higher than that of immature DC (38.3 +/- 4.0 % vs. 32.2 +/- 4.1 % in control group, 40.4 +/- 4.1% vs. 35.9 +/- 3.8 % in tumor group; p< 0.05). Migration to tumor was also significantly higher in mature DC than in immature DC (2.4 +/- 0.3% vs 1.7 +/- 0.2%; p=0.034). CONCLUSION: Assessment of migration pattern of DC in mice was possible using 99mTc-HMPAO labeled immature and mature DC. Migration of mature DC to spleen and tumor was higher than that of immature DC when they were i.v. injected.
Animals ; Bone Marrow ; Dendritic Cells* ; Femur ; Flow Cytometry ; Gamma Cameras ; Kidney ; Liver ; Lung ; Lymphocyte Culture Test, Mixed ; Mice* ; Radionuclide Imaging ; Spleen ; Technetium Tc 99m Exametazime ; Tibia

PURPOSE: 14C-urea breath test (UBT) is a non-invasive and reliable method for the diagnosis of Helicobacter pylori (HP) infection. In this study, we evaluated the diagnostic performance of a new and rapid 14C-UBT (Heliprobe method), which was equipped with Geiger-Muller counter and compared the results with those obtained by using the conventional method. MATERIALS AND METHODS: Forty-nine patients with dyspepsia underwent gastroduodenoscopy and 14C-UBT. A 37 KBq 14C-urea capsule was administered to patients and breath samples were collected. In Heliprobe method, patients exhaled into a Heliprobe BreathCard for 10 min. And then the activities of the BreathCard were countered using Heliprobe analyzer. In the conventional method, results were countered using liquid scintillation counter. During gastroduodenoscopy, 18 of 49 patients were underwent biopsies. According to these histologic results, we evaluated the diagnostic performance of two different methods and compared them. Also we evaluated the concordant and disconcordant rates between them. RESULTS: In all 49 patients, concordant rate of both conventional and Heliprobe methods was 98% (48/49) and the discordant rate was 2% (1/49). Thirteen of 18 patients to whom biopsies were applied, were found to be HP positive on histologic results. And both Heliprobe method and conventional method classified 13 of 13 HP-positive patients and 5 of 5 HP-negative patients correctly (sensitivity 100%, specificity 100%, accuracy 100%). CONCLUSION: The Heliprobe method demonstrated the same diagnostic performance compared with the conventional method and was a simpler and more rapid technique.
Biopsy ; Breath Tests* ; Diagnosis* ; Dyspepsia ; Helicobacter pylori* ; Helicobacter* ; Humans ; Scintillation Counting ; Sensitivity and Specificity

PURPOSE: Physiologic intestinal FDG uptake is frequently observed in asymptomatic individuals for cancer screening FDG PET. Colonic FDG accumulation is a well-known confusing findings that interfere true cancer detection or cause false positive. The aim of this study was to evaluate the pattern and intensity of colonic uptake in whole body FDG PET in asymptomatic healthy adults and to correlate them with colonoscopic findings. MATERIALS AND METHODS: We reviewed retrospectively 64 subjects (age: 27-87, M: F = 31: 33 ) who underwent both FDG PET and colonoscopy for cancer screening. FDG uptake patterns were classified as focal, segmental and diffuse. Maximum SUV were measured. The PET results were compared with colonoscopic and histologic findings. RESULTS: In 13 patients FDG bowel uptake was interpreted as focal, in 17 patients as segmental and in 34 patients as diffuse uptake. Six adenomas (17.6%, average diameter =5.0 mm) were found in diffuse pattern, 7 adenomas (41.1%, 5.6 mm) in segmental and 4 adenomas and 1 adenocarcinoma (38.5%, 16.4 mm) in focal uptake pattern. In patients with focal uptake, four were non-adenomatous pathologic lesions (30.8%, 2 intestinal tuberculosis, 2 mucosal ulcer). There is no difference of mean SUV between patients with adenoma and with negative colonoscopic results in each group of intestinal FDG pattern (Diffuse: 1.7 +/- 0.1 vs. 1.9 +/- 0.5, Segmental: 4.8 +/- 3.6 vs. 4.2 +/- 1.2, Focal: 6.5 +/- 4.7 vs. 3.5 +/- 1.3). Large adenomas (> 1 cm) can be detected more in the focal uptake pattern (4 out of 5) rather than in segmental (1 out of 7) or diffuse uptake (none) and had higher SUV (6.3 +/- 4.8) than small adenomas (3.5 +/- 3.0) (statistically insignificant). CONCLUSION: Focal FDG uptake is associated more often with large adenoma and other pathologic findings in colonoscopy. Segmental uptake cannot discriminate presence of adenoma from negative results, while diffuse pattern may have more chance to be normal.
Adenocarcinoma ; Adenoma ; Adult* ; Colon* ; Colonoscopy ; Early Detection of Cancer ; Humans ; Retrospective Studies ; Tuberculosis

PURPOSE: Abnormal myocardial perfusion may be caused by ventricular preexcitation, but its location, extent, severity and correlation with accessory pathway (AP) are not established. We evaluated perfusion patterns on myocardial perfusion SPECT and location of AP in patients with WPW (Wolff-Parkinson-White) syndrome. MATERIALS AND METHODS: Adenosine Tc-99m MIBI or Tl-201 myocardial perfusion SPECT was performed in 11 patients with WPW syndrome. Perfusion defects (PD) were compared to AP location based on ECG with Fitzpatrick's algorithm or electrophysiologic study and radiofrequency catheter ablation. RESULTS: Patients had atypical chest discomfort or no symptom. Risk of coronary artery disease (CAD) was below 0.1 in 11 patients using the nomogram to estimate the probability of CAD. Coronary angiography was performed in 4 patients (mid-LAD 50% in one, normal in others). In 4 patients, AP localization was done by electrophysiologic study and radiofrequency catheter ablation (RFCA). Small to large extent (11.0 +/- 8.5%, range: 3~35%) and mild to moderate severity (-71 +/- 42.7%, range: -217~-39%) of reversible (n=9) or fixed (n=1) perfusion defects were noted. One patient with right free wall (right lateral) AP showed normal. PD locations were variable following the location of AP. One patient with left lateral wall AP was followed 6 weeks after RFCA and showed significantly decreased PD on SPECT with successful ablation. CONCLUSION: Myocardial perfusion defect showed variable extent, severity and location in patients with WPW syndrome. Abnormal perfusion defect showed in most of all patients, but it did not seem to be correlated specifically with location of accessory pathway and coronary artery disease. Therefore myocardial perfusion SPECT should be interpreted carefully in patients with WPW syndrome.
Adenosine ; Catheter Ablation ; Coronary Angiography ; Coronary Artery Disease ; Electrocardiography ; Humans ; Nomograms ; Perfusion* ; Thorax ; Tomography, Emission-Computed, Single-Photon* ; Wolff-Parkinson-White Syndrome*

This paper is described on the development of KOTRON-13 and recent status of PET cyclotron by commercial cyclotron companies. KIRAMS has developed medical cyclotron which is KIRAMS-13. Samyoung Unitech produces KOTRON-13 with transfered technology by KIRAMS. As a part of Regional Cyclotron Installation Project, KOTRON-13 cyclotrons and [18F]FDG production modules are being installed at regional cyclotron centers in Korea. The medical concern with radiation technology has been growing for the last several years. Early cancer diagnosis through the cyclotron and PET-CT have been brought to public attention by commercial cyclotron models in the world. The new commercial cyclotron models are introduced compact low energy cyclotrons developed by CTI, GE, Sumitomo in recent. It produces different short-lived radioisotopes, such as [18F], [11C], [13N] and [15O]. For the better reliability acceleration particle is proton only. The characteristics of new model cyclotrons are changed to lower energy corresponding to less 13 MeV. New models have self-shielding and low power consumption. Design criteria for the different types of commercial cyclotrons are described with reference to hospital demands.
Acceleration ; Cyclotrons* ; Diagnosis ; Korea ; Protons ; Radioisotopes

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