A 60-year-old woman, who had non-small-cell lung cancer (NSCLC) in left lower lobe underwent brain F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for evaluation of cerebral metastasis. On follow-up FDG-PET/CT, only hypometaolic lesion was detected and progressed in right frontal lobe at 6 months and 10 months, later. Hypermetabolic metastasis was not detected even at last scan time of FDG-PET/CT. Brain MRI showed brain metastasis in right frontal lobe. As might be expected, the physician should take cerebral metastasis into consideration even though there is only hypometabolic change on subsequent FDG-PET/CT in patients with NSCLC.
Brain ; Electrons ; Female ; Follow-Up Studies ; Frontal Lobe ; Humans ; Lung ; Lung Neoplasms ; Middle Aged ; Neoplasm Metastasis

F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET/CT) plays an important role in diagnosis of malignant tumors and adds to conventional imaging in the staging of pertoneal carcinomatosis. However, false positive cases resulting from benign disease such as tuberculosis may occur. We report two cases of peritoneal tuberculosis on F-18 FDG PET/CT which showed multiple hypermetabolic foci in the mesentery and peritoneum with increased serum cancer antigen 125 (CA 125). Subsequent F-18 FDG PET/CT showed a disappearance of pathologic uptake following treatment with anti-tuberculosis drugs.
Carcinoma ; Mesentery ; Peritoneum ; Peritonitis, Tuberculous ; Positron-Emission Tomography ; Tuberculosis

Brown tumor is the benign bone lesion consists of woven bone and fibrous tissue without matrix, which develop due to chronic excessive osteoclastic activity such as hyperparathyroidism. Usually they appear with normal uptake or occasionally focally increased uptake on bone scan. We present a case with brown tumor shown more increased uptake and more number of lesions on bone scan after parathyroidectomy, and lesser increased uptake on serial bone scans without any other treatment through several months. This finding is thought to be similar to 'flare phenomenon' which is occasionally seen after treatment of metastatic bone lesions of malignant cancer, and may represent curative process of brown tumor with rapid normal bone formation.
Hyperparathyroidism ; Osteoclasts ; Osteogenesis ; Parathyroidectomy

PURPOSE: Small size of recombinant scFv antibody has many advantages such as rapid blood clearances and improved targeting antibodies to tumor region. On the other hand owing to small size, number of amino group is insufficient in conjugation with chelator and fluorescence labeling. This study is to introduce poly lysine tag to the C-terminal end of scFv lym-1 sequence for fluorescence chelator conjugation. MATERIALS AND METHODS: Poly lysine scFv lym-1 gene, cloned into pET-22b (+) vector, was expressed in E. coli BL21 (DE3) strain. Antibody purification was performed with Ni-NTA column and then size exclusion column chromatography. Expression and purification levels of poly lysine tagged scFv lym-1 antibody were confirmed by western blot analysis. I-124, I-125, I-131 and Tc-99m were used for radiolabeling of purified poly lysine scFv lym-1. Flow cytometry analysis of FITC conjugated poly lysine scFv lym-1 was performed for confirmation of immunoreactivity of human Burkitt`s lymphoma cells. RESULTS: Poly lysine scFv lym-1 antibody was purified through two steps and identified as molecular weight of 48 KDa. Radiolabeling yields of I-124, I-125, I-131 and Tc-99m into poly lysine scFv lym-1 were >99%, >99%, >95% and >99%, respectively. Flow cytometry analysis of poly lysine scFv and scFv lym-1 was showed similar immunoreactivity to human Burkitt`s lymphoma cells. CONCLUSION: Poly lysine tag was useful for the sufficient number of amino groups to scFv lym-1 antibody for chelator conjugation with minimizing loss of immunoreactivity.
Antibodies ; Blotting, Western ; Chromatography ; Clone Cells ; Flow Cytometry ; Fluorescein-5-isothiocyanate ; Fluorescence ; Hand ; Humans ; Lymphoma ; Lysine ; Molecular Weight ; Sprains and Strains

PURPOSE: 5-iododeoxyuridine analogues have been exclusively developed for the potential antiviral and antitumor therapeutic agents. In this study, we synthesized carbocyclic radioiododeoxyuridineanalogue (ddIVDU) and carbocyclic intermediate as efficient carbocyclic radiopharmaceuticals. MATERIALS AND METHODS: The synthesis is LAH reduction, hetero Diels-Alder reaction as key reactions including Pd(0)-catalyzed coupling reaction together with organotin. MCA-RH7777 (MCA) and MCA-tk (HSV1-tk positive) cells were treated with various concentration of carbocyclic ddIVDU, and GCV. Cytotoxicity was measured by the MTS methods. For in vitro uptake study, MCA and MCA-tk cells were incubated with 1uCi of [(125)I]carbocyclic ddIVDU. Accumulated radioactivity was measured after various incubation times. RESULTS: The synthesis of ddIVDU and precursor for radioiodination were achieved from cyclopentadiene in good overall yield, respectively. The radioiododemetallation for radiolabeling gave more than 80% yield with > 95% radiochemical purity. GCV was more toxic than carbocyclic ddIVDU in MCA-tk cells. Accumulation of [(125)I]carbocyclic ddIVDU was higher in MCA-tk cells than MCA cells. CONCLUSION: Biological data reveal that ddIVDU is stable in vitro, less toxic than ganciclovir (GCV), and selective in HSV1-tk expressed cells. Thus, this new carbocyclic nucleoside, referred to in this paper as carbocyclic 2',3'-didehydro-2',3'-dideoxy-5- iodovinyluridine (carbocyclic ddIVDU), is a potential imaging probe for HSV1-tk.
Cycloaddition Reaction ; Ganciclovir ; Herpesvirus 1, Human ; Idoxuridine ; Radioactivity ; Radiopharmaceuticals

PURPOSE: Hydrodynamic-based procedure is a simple and effective gene delivery method to lead a high gene expression in liver tissue. Non-invasive imaging reporter gene system has been used widely with herpes simplex virus type 1 thymidine kinase (HSV1-tk) and its various substrates. In the present study, we investigated to image the expression of HSV1-tk gene with 5-(2-iodovinyl)-2'-deoxyuridine (IVDU) in mouse liver by the hydrodynamicbased procedure. MATERIALS AND METHODS: HSV1-tk or enhanced green fluorescence protein (EGFP) encoded plasmid DNA was transferred into the mouse liver by hydrodynaminc injection. At 24 h post-injection, RT-PCR, biodistribution, fluorescence imaging, nuclear imaging and digital wholebody autoradiography (DWBA) were performed to confirm transferred gene expression. RESULTS: In RT-PCR assay using mRNA from the mouse liver, specific bands of HSV1-tk and EGFP gene were observed in HSV1-tk and EGFP expressing plasmid injected mouse, respectively. Higher uptake of radiolabeled IVDU was exhibited in liver of HSV1-tk gene transferred mouse by biodistribution study. In fluorescence imaging, the liver showed specific fluorescence signal in EGFP gene transferred mouse. Gamma-camera image and DWBA results showed that radiolabeled IVDU was accumulated in the liver of HSV1-tk gene transferred mouse. CONCLUSION: In this study, hydrodynamic-based procedure was effective in liver-specific gene delivery and it could be quantified with molecular imaging methods. Therefore, co-expression of HSV1-tk reporter gene and target gene by hydrodynamic-based procedure is expected to be a useful method for the evaluation of the target gene expression level with radiolabeled IVDU.
Animals ; Autoradiography ; DNA ; Fluorescence ; Gene Expression ; Genes, Reporter ; Herpes Simplex ; Herpesvirus 1, Human ; Idoxuridine ; Liver ; Methylmethacrylates ; Mice ; Molecular Imaging ; Optical Imaging ; Plasmids ; Polystyrenes ; RNA, Messenger ; Simplexvirus ; Thymidine Kinase

PURPOSE: The maximum likelihood-expectation maximization (ML-EM) is the statistical reconstruction algorithm derived from probabilistic model of the emission and detection processes. Although the ML-EM has many advantages in accuracy and utility, the use of the ML-EM is limited due to the computational burden of iterating processing on a CPU (central processing unit). In this study, we developed a parallel computing technique on GPU (graphic processing unit) for ML-EM algorithm. MATERIALS AND METHODS: Using Geforce 9800 GTX+ graphic card and CUDA (compute unified device architecture) the projection and backprojection in ML-EM algorithm were parallelized by NVIDIA's technology. The time delay on computations for projection, errors between measured and estimated data and backprojection in an iteration were measured. Total time included the latency in data transmission between RAM and GPU memory. RESULTS: The total computation time of the CPU- and GPU-based ML-EM with 32 iterations were 3.83 and 0.26 sec, respectively. In this case, the computing speed was improved about 15 times on GPU. When the number of iterations increased into 1024, the CPU- and GPU-based computing took totally 18 min and 8 sec, respectively. The improvement was about 135 times and was caused by delay on CPU-based computing after certain iterations. On the other hand, the GPU-based computation provided very small variation on time delay per iteration due to use of shared memory. CONCLUSION: The GPU-based parallel computation for ML-EM improved significantly the computing speed and stability. The developed GPU-based ML-EM algorithm could be easily modified for some other imaging geometries.
Hand ; Image Processing, Computer-Assisted ; Memory ; Models, Statistical ; Tomography, Emission-Computed, Single-Photon

PURPOSE: Optical molecular luminescence imaging is widely used for detection and imaging of bio-photons emitted by luminescent luciferase activation. The measured photons in this method provide the degree of molecular alteration or cell numbers with the advantage of high signal-to-noise ratio. To extract useful information from the measured results, the analysis based on a proper quantification method is necessary. In this research, we propose a quantification method presenting linear response of measured light signal to measurement time. MATERIALS AND METHODS: We detected the luminescence signal by using lab-made optical imaging equipment of animal light imaging system (ALIS) and different two kinds of light sources. One is three bacterial light-emitting sources containing different number of bacteria. The other is three different non-bacterial light sources emitting very weak light. By using the concept of the candela and the flux, we could derive simplified linear quantification formula. After experimentally measuring light intensity, the data was processed with the proposed quantification function. RESULTS: We could obtain linear response of photon counts to measurement time by applying the pre-determined quantification function. The ratio of the re-calculated photon counts and measurement time present a constant value although different light source was applied. CONCLUSION: The quantification function for linear response could be applicable to the standard quantification process. The proposed method could be used for the exact quantitative analysis in various light imaging equipments with presenting linear response behavior of constant light emitting sources to measurement time.
Animals ; Bacteria ; Cell Count ; Enzyme Multiplied Immunoassay Technique ; Imidazoles ; Light ; Luciferases ; Luminescence ; Nitro Compounds ; Optical Imaging ; Photons ; Signal-To-Noise Ratio

PURPOSE: Conventional image reconstruction uses simplified physical models of projection. However, real physics, for example 3D reconstruction, takes too long time to process all the data in clinic and is unable in a common reconstruction machine because of the large memory for complex physical models. We suggest the realistic distributed memory model of fast-reconstruction using parallel processing on personal computers to enable large-scale technologies. MATERIALS AND METHODS: The preliminary tests for the possibility on virtual manchines and various performance test on commercial super computer, Tachyon were performed. Expectation maximization algorithm with common 2D projection and realistic 3D line of response were tested. Since the process time was getting slower (max 6 times) after a certain iteration, optimization for compiler was performed to maximize the efficiency of parallelization. RESULTS: Parallel processing of a program on multiple computers was available on Linux with MPICH and NFS. We verified that differences between parallel processed image and single processed image at the same iterations were under the significant digits of floating point number, about 6 bit. Double processors showed good efficiency (1.96 times) of parallel computing. Delay phenomenon was solved by vectorization method using SSE. CONCLUSION: Through the study, realistic parallel computing system in clinic was established to be able to reconstruct by plenty of memory using the realistic physical models which was impossible to simplify
Image Processing, Computer-Assisted ; Isothiocyanates ; Memory ; Microcomputers ; Tomography, Emission-Computed

PURPOSE: We underwent this study to evaluate the diagnostic potential of I-123/I-131 metaiodobenzylguanidine (MIBG) scintigraphy alone in the initial diagnosis of pheochromocytoma, compared with biochemical test and anatomic imaging. MATERIALS & METHODS: Twenty two patients (M:F=13:9, Age: 44.3+/- 19.3 years) having the clinical evaluation due to suspicious pheochromocytoma received the biochemical test, anatomic imaging modality (CT and/or MRI) and I-123/I-131 MIBG scan for diagnosis of pheochromocytoma, prior to histopathological confirmation. MIBG scans were independently reviewed by 2 nuclear medicine physicians. RESULTS: All patients were confirmed histopathologically by operation or biopsy (incisional or excisonal). In comparison of final diagnosis and findings of each diagnostic modality, the sensitivities of the biochemical test, anatomic imaging, and MIBG scan were 88.9%, 55.6%, and 88.9%, respectively. And the specificities of the biochemical test, anatomic imaging, and MIBG scan also were 69.2%, 69.2%, and 92.3%, respectively. MIBG scan showed one false positive (neuroblastoma) and one false negative finding. There was one patient with positive MIBG scan and negative findings of the biochemical test, anatomic imaging. CONCLUSION: Our data suggest that I-123/I-131 MIBG scan has higher sensitivity, specificity, positive predictive value, negative predictive value and accuracy than those of biochemical test and anatomic imaging. Thus, we expect that MIBG scan is e tectively used for initial diagnosis of pheochromocytoma alone as well as biochemical test and anatomic imaging.
3-Iodobenzylguanidine ; Biopsy ; Humans ; Nuclear Medicine ; Pheochromocytoma ; Sensitivity and Specificity