• Radiation Oncology Journal
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• v.27 no.4
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• pp.194-200
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• 2009

Purpose: This aim of this study was to evaluate changes in gastric volume and organ position as a result of delayed gastric emptying after a subtotal gastrectomy performed as part of the treatment of stomach cancer. Materials and Methods: The medical records of 32 patients who underwent concurrent chemoradiotherapy after a subtotal gastrectomy from March 2005 to December 2008 were reviewed. Of these, 5 patients that had more than 50 cc of residual gastric food detected at computed tomography (CT) simulation, were retrospectively enrolled in this study. Gastric volume and organ location was measured from CT images obtained before radiotherapy, twice weekly. In addition, authors evaluated the change of radiation dose distribution to planning the target volume and normal organ in a constant radiation therapy plan regardless of gastric volume variation. Results: A variation in the gastric volume was observed during the radiotherapy period (64.2~340.8 cc; mean, 188.2 cc). According to the change in gastric volume, the location of the left kidney was shifted up to 0.7 - 2.2 cm (mean, 1.2 cm) in the z-axis. Under-dose to planning target volume (V43, 79.5${\pm}$10.4%) and over-dose to left kidney (V20, 34.1${\pm}$12.1%; Mean dose, 23.5${\pm}$8.3 Gy) was expected, given that gastric volume change due to delayed gastric emptying wasn't taken into account. Conclusion: This study has shown that a great change in gastric volume and left kidney location may occur during the radiation therapy period following a subtotal gastrectomy, as a result of delayed gastric emptying. Detection of patients who experienced delayed gastric emptying and the application of gastric volume variation to radiation therapy planning will be very important.

• The Korean Journal of Nuclear Medicine
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• v.34 no.6
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• pp.465-477
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• 2000

Purpose: Thallim-201 ($^{201}Tl$) brain SPECT and proton ($^1H$) magnetic resonance spectroscopy (MRS) have been used to evaluate tumor grade and viability of glioma. We assessed the correlations between $^{201}Tl$ brain index or spectrum of metabolites of $^1H$ MRS and grade of glioma or histopathologic findings. Materials and Methods: We studied 17 patients (4 astrocytoma, 7 anaplastic astrocytoma and 6 glioblastoma). On $^{201}Tl$ Brain SPECT, $^{201}Tl$ index was measured as the ratio of average counts for region of interest to those for the contralateral normal brain. On $^1H$ MRS, we calculated choline (Cho) /creatine (Cr) ratio and N-acetylaspartate (NAA)/Cr ratio in ROI defined as tumor center. Histopathologic findings were graded by Ki-67 index, cellularity, mitosis, pleomorphism, necrosis and endothelial proliferation. An unpaired t test and statistical correlations were performed to evaluate these data. Results: Tl-index showed the best correlation with Ki-67 index (p<0.01), less correlations with cellularity, mitosis, and endothelial proliferation, but no correlation with results of MRS, pleomorphism, or necrosis. The findings of MRS did not correlate with all of the above. The cases of glioblastoma demonstrated a higher Tl-index, Cho/cr ratio, Ki-67 index and lower NAA/Cr ratio, albeit without statistical significance. Conclusion: Even though $^{201}Tl$ brain SPECT did not correlate directly with grade of malignancy, it may still be useful in determining biological aggressiveness of tumor and prognosis of patients because it correlated well with Ki-67 index, a growth fraction of glioma, cellularity, mitosis and endothelial proliferation.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.238-249
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• 1998

Purpose: To localize and compare the neural basis of verbal and visual human working memory, we performed functional activation study using $H_2^{15}O$ PET. Materials and Methods: Repeated $H_2^{15}O$ PET scans with one control and three different activation tasks were performed on six right-handed normal volunteers. Each activation task was composed of 13 match-ing trials. On each trial, four targets, a fixation dot and a probe were presented sequentially and subject's task was to press a response button to indicate whether or not the probe was one of the previous targets. Short meaningful Korean words, simple drawings and monochromic pictures of human faces were used as matching objects for verbal or visual memory. All the images were spatially normalized and the differences between control and activation states were statistically analyzed using SPM96. Results: Statistical analysis of verbal memory activation with short words showed activation in the left Broca's area, promoter cortex, cerebellum and right cingulate gyrus. In verbal memory with simple drawings, activation was shown in the larger regions including where activated with short words and left superior temporal cortex, basal ganglia, thalamus, prefrontal cortex, anterior portion of right superior temporal gyrus and right infero-lateral frontal cortex. On the other hand, the visual memory task activated predominantly right-sided structures, especially inferior frontal cortex, supplementary motor cortex and superior parietal cortex. Conclusion: The results are consistent with the hypothesis of the laterality and dissociation of the verbal and visual working memory from the invasive electrophysiological studies and emphasize the pivotal role of frontal cortex and cingulate gyrus in working memory system.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.401-409
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• 2008

Purpose: Recently multi-modal imaging system has become widely adopted in molecular imaging. We tried to fabricate animal-specific positioning molds for PET/MR fusion imaging using easily available molding clay and rapid foam. The animal-specific positioning molds provide immobilization and reproducible positioning of small animal. Herein, we have compared fiber-based molding clay with rapid foam in fabricating the molds of experimental animal. Materials and Methods: The round bottomed-acrylic frame, which fitted into microPET gantry, was prepared at first. The experimental mice was anesthetized and placed on the mold for positioning. Rapid foam and fiber-based clay were used to fabricate the mold. In case of both rapid foam and the clay, the experimental animal needs to be pushed down smoothly into the mold for positioning. However, after the mouse was removed, the fabricated clay needed to be dried completely at $60^{\circ}C$ in oven overnight for hardening. Four sealed pipet tips containing $[^{18}F]FDG$ solution were used as fiduciary markers. After injection of $[^{18}F]FDG$ via tail vein, microPET scanning was performed. Successively, MRI scanning was followed in the same animal. Results: Animal-specific positioning molds were fabricated using rapid foam and fiber-based molding clay for multimodality imaging. Functional and anatomical images were obtained with microPET and MRI, respectively. The fused PET/MR images were obtained using freely available AMIDE program. Conclusion: Animal-specific molds were successfully prepared using easily available rapid foam, molding clay and disposable pipet tips. Thanks to animal-specific molds, fusion images of PET and MR were co-registered with negligible misalignment.

• Radiation Oncology Journal
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• v.20 no.4
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• pp.381-390
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• 2002

Purpose : To develop a dose calibration program for the IAEA TRS-277 and AAPM TG-21, based on the air kerma calibration factor (or the cavity-gas calibration factor), as well as for the IAEA TRS-398 and the AAPM TG-51, based on the absorbed dose to water calibration factor, so as to avoid the unwanted error associated with these calculation procedures. Materials and Methods : Currently, the most widely used dosimetry Protocols of high energy photon beams are the air kerma calibration factor based on the IAEA TRS-277 and the AAPM TG-21. However, this has somewhat complex formalism and limitations for the improvement of the accuracy due to uncertainties of the physical quantities. Recently, the IAEA and the AAPM published the absorbed dose to water calibration factor based, on the IAEA TRS-398 and the AAPM TG-51. The formalism and physical parameters were strictly applied to these four dose calibration programs. The tables and graphs of physical data and the information for ion chambers were numericalized for their incorporation into a database. These programs were developed user to be friendly, with the Visual $C^{++}$ language for their ease of use in a Windows environment according to the recommendation of each protocols. Results : The dose calibration programs for the high energy photon beams, developed for the four protocols, allow the input of informations about a dosimetry system, the characteristics of the beam quality, the measurement conditions and dosimetry results, to enable the minimization of any inter-user variations and errors, during the calculation procedure. Also, it was possible to compare the absorbed dose to water data of the four different protocols at a single reference points. Conclusion : Since this program expressed information in numerical and data-based forms for the physical parameter tables, graphs and of the ion chambers, the error associated with the procedures and different user could be solved. It was possible to analyze and compare the major difference for each dosimetry protocol, since the program was designed to be user friendly and to accurately calculate the correction factors and absorbed dose. It is expected that accurate dose calculations in high energy photon beams can be made by the users for selecting and performing the appropriate dosimetry protocol.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.459-467
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• 2009

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 see, 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 see, 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.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.349-353
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• 2013

This study was performed to evaluate the bactericidal efficacy of Fumagari OPP$^{(R)}$, fumigation disinfectant, containing 20% ortho-phenylphenol against Staphylococcus aureus (S. aureus). In this research, efficacy test of fumigant against S. aureus was carried out according to French standard NF T 72-281. S. aureus working culture suspension number (N value), all of the colony numbers on the carriers exposed with the fumigant (n1, n2, and n3), the number of bacterial test suspentions by pour plate method (N1), the number of bacterial test suspentions by filter membrane method (N2) and the mean number of bacteria recovered on the control-carriers (T value) were obtained from the preliminary test. In addition, the reduction number of S. aureus exposed with the fumigant (d value) was calculated using T value, the mean number of bacteria in recovery solution (n'1) and the mean number of bacteria on carriers plated in agar (n'2). N value was $4.0{\times}10^8$ CFU/mL, and n1, n2, and n3 were higher than 0.5N1, 0.5N2 and 0.5N1, respectively. Additionally, T value was $3.4{\times}10^6$ CFU/mL. In the bactericidal effect of the fumigant, the d value was 6.43 logCFU/mL. According to the French standard for the fumigant, the d value for the effective bactericidal fumigant should be over than 5 logCFU/mL. The results indicated that Fumagari OPP$^{(R)}$ had an effective bactericidal activity against S. aureus, then the fumigant can be applied to disinfect food materials and kitchen appliances contaminated with pathogenic bacteria.

• Radiation Oncology Journal
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• v.22 no.1
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• pp.33-39
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• 2004

Purpose : A tumor registry system for the patients treated by radiotherapy at Samsung Medical Center since the opening of a hospital at 1994 was employed. In this study, the tumor registry system was introduced and the validity of the tumor registration was analyzed. Materials and Methods: The tumor registry system was composed of three parts: patient demographic, diagnostic, and treatment Information. All data were input in a screen using a mouse only. Among the 10,000 registered cases in the tumor registry system until Aug, 2002, 199 were randomly selected and their registration data were compared with the patients' medical records. Results : Total input errors were detected on 15 cases (7.5%). There were 8 error items In the part relating to diagnostic Information: tumor site 3, pathology 2, AJCC staging 2 and performance status 1. In the part relating to treatment information there were 9 mistaken items: combination treatment 4, the date of initial treatment 3 and radiation completeness 2. According to the assignment doctor, the error ratio was consequently variable. The doctors who 010 no double-checks showed higher errors than those that 010 (15.6%:3.7%). Conclusion: Our tumor registry had errors within 2% for each Item. Although the overall data qualify was high, further improvement might be achieved through promoting sincerity, continuing training, periodic validity tests and keeping double-checks. Also, some items associated with the hospital Information system will be input automatically In the next step.

• Journal of Life Science
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• v.27 no.4
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• pp.383-389
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• 2017

This study intends to analyze the contents of rutin, procyanidin B3, quercetin, kaempferol, known to have antioxidant, anti-inflammatory and anti-carcinogenic effects, among the polyphenol type contained in the grape pruning stem extracts (GPSE), utilizing grape stems being discarded after harvest, measure the effects on the skin moisture, inhibition of skin cell proliferation, anti-inflammatory on the damaged skin of a HR-1 mice induced with UVB, and verify the applicability as a material for functional food and functional cosmetics. The results of verifying the photoprotection effects through the skin proliferation control through of GPSE showed similar result to suncream was achieved at the GPSE concentration of 2,000 mg/kg on the epidermis (p<0.05). The results showed anti-inflammatory effects on all groups applied with GPSE as compared to the control group irradiated with UVB, but at the GPSE concentration of 1,000 mg/kg, a lower COX-2 protein expression at 8%, lower than the 22% of suncream, was observed to achieve an excellent anti-inflammatory effect (p<0.05). The results of this study confirmed the existence of active polyphenol type, such as rutin, kaempferol, querocetin and procyanidin B3, within the GPSE, and GPSE has improvement effects on moisturizing effects, skin proliferation control effect, inflammatory control effect and improvement effects on the skin barrier function through UV ray damage. GPSE is a functional ingredient with a potential for skin protection effects, and has high utilization as an ingredient for functional food and functional cosmetics.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.1
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• pp.77-84
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• 2017

Purpose: To evaluate the image quality improvement and dosimetric effects on virtual monochromatic images of a Dual Source-Dual Energy CT(DS-DECT) for radiotherapy planning. Materials and Methods: Dual energy(80/Sn 140 kVp) and single energy(120 kVp) scans were obtained with dual source CT scanner. Virtual monochromatic images were reconstructed at 40-140 keV for the catphan phantom study. The solid water-equivalent phantom for dosimetry performs an analytical calculation, which is implemented in TPS, of a 10 MV, $10{\times}10cm^2$ photon beam incident into the solid phantom with the existence of stainless steel. The dose profiles along the central axis at depths were discussed. The dosimetric consequences in computed treatment plans were evaluated based on polychromatic images at 120 kVp. Results: The magnitude of differences was large at lower monochromatic energy levels. The measurements at over 70 keV shows stable HU for polystyrene, acrylic. For CT to ED conversion curve, the shape of the curve at 120 kVp was close to that at 80 keV. 105 keV virtual monochromatic images were more successful than other energies at reducing streak artifacts, which some residual artifacts remained in the corrected image. The dose-calculation variations in radiotherapy treatment planning do not exceed ${\pm}0.7%$. Conclusion: Radiation doses with dual energy CT imaging can be lower than those with single energy CT imaging. The virtual monochromatic images were useful for the revision of CT number, which can be improved for target coverage and electron densities distribution.