• Journal of Radiation Protection and Research
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• v.20 no.1
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• pp.45-52
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• 1995

This study is to compare A point doses in human pelvic phantom by film dosimetry, computer planning and manual calculation by using of along-away table. We developed tissue equivalent human pelvic phantom composed of four pieces of cylindrical acryl tubes with water, to simulate intracavitary radiation (ICR) in patients with cervix cancer. When the phantom assembled from 4 pieces, it has a small space for inserting Fletcher-Suit-Delclos applicator like a human vagina. Fletcher-Suit-Delclos applicator inserted into the space was packed tightly with furacin gauzes, and three $^{137}Cs$ sources with radioactivity of $15.7mg\;Ra-eq$ were inserted into the tandem. For the film dosimetry, two pieces of X-OMAT V film (Kodak Co.) of which planes include point A, were arranged orthogonally in the slits between phantoms. A point dose and iso-dose curves were measured by means of optical densitometer. A point doses by film dosimetry, RTP system and manual calculation by using of along-away table were compared, and iso-dose curves by film dosimetry and computer planning were also compared. The dose of A point was 51.2cGy/hr by film dosimetry, 46.7cGy/hr by RTP system and 47.9 cGy/hr by along-away table. A point dose by computer planning was similar to the dose by calculation using of along-away table with acceptable accuracy $({\pm}3%)$, however, the dose by film dosimetry was different from two others with about 10% error. Since most clinical beams contains a scatter component of low energy photons, the correlation between optical density and dose becomes tenuous. In addition, film suffers from several potential errors such as changes in processing conditions, interfilm emulsion differences, and artifacts caused by air pockets adjacent to the film. For these reasons, absolute dosimetry with film is impractical, however, it is very useful for checking qualitative patterns of a radiation distribution. In future, solid state dosimeter such as TLD must be used for the dosimetry of ionizing radiation. When considerable care is used, precision of approximately 3% may be obtained using TLD.

• Journal of Gastric Cancer
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• v.9 no.4
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• pp.172-176
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• 2009

Purpose: The rapid urease test is a rapid and reliable method for diagnosing Helicobacter pylori infection. However it requires gastric mucosal biopsies during endoscopy, and the test is not covered by national health insurance for patients with gastric cancer. So, we introduced an alternative method for a rapid urease test using back-table gastric mucosal biopsies from gastrectomy specimen. Materials and Methods: Ninety gastric cancer patients underwent an anti H. pylori IgG ELISA test and gastrectomy. Just after gastrectomy, two gastric mucosal biopsies from the prepyloric antrum and lower body of the gastrectomy specimen were taken from the back table in the operative room, and these were fixed immediately with the rapid urease test kit, and the color change was monitored for up to 24 hours. In this study, H. pylori infection was defined as positive when the serology or rapid urease test showed positive results. Results: The positive rate of the rapid urease test and serology was 91.1% and 77.8%, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the rapid urease test and serology were 94.3 and 80.5%, 100 and 100%, 100 and 100%, and 37.5 and 15%, respectively. The accuracy of the rapid urease test was higher than that of serology (94.4 vs. 81.1%, respectively). The rapid urease test showed a higher rate of detecting H. pylori infection than that of serology (McNemar's test, P=0.019). Conclusion: The result of the rapid urease test using back-table gastric mucosal biopsies from a gastrectomy specimen is comparable to the reference data of the conventional rapid urease test using gastric mucosal endoscopic biopsies. Therefore, it can be an alternative diagnostic method for H. pylori infection.

• Journal of Gastric Cancer
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• v.9 no.3
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• pp.136-142
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• 2009

Purpose: This clinical study was conducted to evaluate the predictive value of tumor markers for recurrence and the clinical significance of false positive findings after curative gastrectomy in patients with gastric cancer. Materials and Methods: Two hundred ninety patients with gastric cancer who underwent gastrectomy with curative intent were evaluated retrospectively. We analyzed the correlations between changes in tumor markers (CEA, CA 19-9, AFP, and CA-125) and clinicopathologic data, and basis for changes in tumor markers without recurrence during the follow-up period. Results: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of tumor markers for recurrence were 75.0%, 64.6%, 23.1%, 94.8%, and 65.9% respectively. Among 36 patients with recurrences, 10 patients (27.8%) had elevated tumor markers prior to positive findings on imaging studies, while 13 patients (36.1%) had concomitant elevation in tumor markers. At least 1 of the 4 tumor markers increased in 90 of 290 patients during the follow-up period; however, there was no evidence of tumor recurrence. Twenty patients had persistently elevated tumor markers, while the tumor marker levels in 70 patients returned to normal level within $9.08\pm7.2$ months. The patients with pulmonary disease, hepatobiliary disease, diabetes, hypertension, or herbal medication users had elevated tumor markers more frequently than patients without disease (P<0.001). Conclusion: Although detecting recurrence of gastric cancer with tumor markers may be useful, false positive findings of tumor markers are common, so surgeons should consider other chronic benign diseases and medical conditions when tumor markers increase without evidence of recurrence.

• Journal of Gastric Cancer
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• v.8 no.2
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• pp.91-96
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• 2008

Purpose: The early detection of gastric cancer and accuracy of preoperative staging has currently been on the increase due to the development of endoscopy and imaging techniques, but there are still many cases of advanced gastric cancer detected at the first diagnosis and there are also many cases of stage IV gastric cancer diagnosed after a postoperative pathological examination. Although the prognosis of stage IV gastric cancer is very poor, this study was performed to determine the value of the use of aggressive treatment determined after a clinical analysis. Materials and Methods: We retrospectively analyzed 150 patients that were diagnosed with stage IV gastric cancer among 1376 patients who underwent a laparotomy for gastric cancer from January 1994 to December 2006. Results: Of the 150 patients with stage IV gastric cancer who underwent a laparotomy, there were 104 men and 46 women. The mean patient age was 57.8 years (age range, 28~93 years). A subtotal gastrectomy or total gastrectomy was performed in 119 patients and 31 patients underwent an explorative laparotomy. The mean survival time of patients that underwent a gastrectomy and patients that did not undergo a gastrectomy was 722 days (range, 14~4,559 days) and 173 days (range, 16~374 days), respectively this result was statistically significant. When patients that underwent a gastrectomy were classified according to the TNM stage, the mean survival time of 33 patients with stage T4 disease was 534 days (range, 17~3,378 days) and the mean survival time of 63 patients with stage N3 disease was 521 days (range, 14~4,190 days), but there was no statistical significance. Chemotherapy was administered to 98 patients and 52 patients did not receive chemotherapy. The mean survival time of patients that received chemotherapy was 792 days (range, 36~4,559 days) and the mean survival time of patients that did not receive chemotherapy was 243 days (range, 14~2,413 days), with statistical significance. Conclusion: If there is no evidence of distant metastasis in stage IV gastric cancer, one can expect improvement of the survival rate by the use of aggressive treatment, including curative gastric resection with radical lymph node dissection and chemotherapy.

• Journal of the Korean earth science society
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• v.21 no.2
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• pp.137-158
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• 2000

The correlation and Empirical Orthogonal Function (EOF) analyses over the globe have been applied to intercompare lower-stratospheric (${\sim}$70hPa) temperature obtained from satellite data and two model reanalyses. The data is the19 years (1980-98) Microwave Sounding Unit (MSU) channel 4 (Ch4) brightness temperature, and the reanalyses are GCM (NCEP, 1980-97; GEOS, 1981-94) outputs. In MSU monthly climatological anomaly, the temperature substantially decreases by ${\sim}$21k in winter over southern polar regions, and its annual cycle over tropics is weak. In October the temperature and total ozone over the area south of Australia remarkably increase together. High correlations (r${\ge}$0.95) between MSU and reanalyses occur in most global areas, but they are lower (r${\sim}$O.75) over the 20-3ON latitudes, northern America and southern Andes mountains. The first mode of MSU and reanalyses for monthly-mean Ch4 temperature shows annual cycle, and the lower-stratospheric warming due to volcanic eruptions. The analyses near the Korean peninsula show that lower-stratospheric temperature, out of phase with that for troposphere, increases in winter and decreases in summer. In the first mode for anomaly over the tropical Pacific, MSU and reanalyses indicate lower-stratospheric warming due to volcanic eruptions. In the second mode MSU and GEOS present Quasi-Biennial Oscillation (QBO) while NCEP, El Ni${\tilde{n}}$o. Volcanic eruption and QBO have more impact on lower-stratospheric thermal state than El Ni${\tilde{n}}$o. The EOF over the tropical Atlantic is similar to that over the Pacific, except a negligible effect of El Ni${\tilde{n}}$o. This study suggests that intercomparison of satellite data with model reanalyses may estimate relative accuracy of both data.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.210-219
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• 2017

This study aimed to establish an optimal extraction process and high-performance liquid chromatography (HPLC)-photodiode array (PDA) analytical method for determination of marker compounds, dihydrokaempferol (DHK) and 3-O-methylquercetin (3-MeQ), as a part of materials standardization for the development of health functional foods from stems of Opuntia ficus-indica var. saboten (OFS). The quantitative determination method of marker compounds was optimized by HPLC analysis, and the correlation coefficient for the calibration curve showed very good linearity. The HPLC-PDA method was applied successfully to quantification of marker compounds in OFS after validation of the method in terms of linearity, accuracy, and precision. Ethanolic extracts from stems of O. ficus-indica var. saboten (OFSEs) were evaluated by reflux extraction at 70 and $80^{\circ}C$ with 50, 70, and 80% ethanol for 3, 4, 5, and 6 h. Among OFSEs, OFS70E at $80^{\circ}C$ showed the highest contents of DHK and 3-MeQ of $26.42{\pm}0.65$ and $3.88{\pm}0.29mg/OFS100g$, respectively. Furthermore, OFSEs were determined for their antioxidant activities by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and lipid peroxidation (LPO) inhibitory activities in rat liver homogenate. OFS70E at $70^{\circ}C$ showed the most potent antioxidant activities with $IC_{50}$ values of $1.19{\pm}0.11$ and $0.89{\pm}0.09mg/mL$ in the DPPH radical scavenging and LPO inhibitory assays, respectively. To identify active components of OFS, various chromatographic separation of OFS70E led to isolation of 11 flavonoids: dihydrokaempferol, dihydroquercetin, 3-O-methylquercetin, quercetin, isorhamnetin 3-O-glucoside, isorhamnetin 3-O-galactoside, narcissin, kaempferol 7-O-glucoside, quercetin 3-O-galactoside, isorhamnetin, and kaempferol 3-O-rutinoside. The results suggest that standardization of DHK in OFSEs using HPLC-PDA analysis would be an acceptable method for the development of health functional foods.

• Tuberculosis and Respiratory Diseases
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• v.62 no.4
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• pp.276-283
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• 2007

Background: A national health care initiative recommends routine spirometry screening of all smokers over age 45 or patients with respiratory symptoms. In response to the recommendation, new, simple, and inexpensive desktop spirometers for the purpose of promoting widespread spirometric screening were marketed. The performance of these spirometers was evaluated in vivo testing with healthy subjects. However, the clinical setting allows spirometric assessment of various pathologic combinations of flow and volume. Objective: The aim of this study was to compare the accuracy of a desktop spirometer to a standard laboratory spirometer, in a clinical setting with pathologic pulmonary function. Method: In a health check-up center, where screening pulmonary funct test was performed using the HI-801 spirometer. Subjects who revealed the ventilation defect in screening spirometry, performed the spirometry again using the standard Vmax spectra 22d spirometer in a tertiary care hospital pulmonary function laboratory. Pulmonary function test with both spirometer was performed according to the guidelines of the American Thoracic Society. Results: 109 patients were enrolled. Pulmonary function measurements (FVC, $FEV_1$, PEFR, FEF25%-75%) from the HI-801 correlated closely (r=0.94, 0.93, 0.81, 0.84, respectively) with those performed with the Vmax spectra 22d and showed the good limits of agreement and differences between the 2 devices; FVC +0.35 L, $FEV_1$ +0.16 L, PEFR +1.85 L/s, FEF25%-75%-0.13 L/s. With the exception of $FEV_1$, FEF25%-75%, these differences were significant(p<0.05) but small. Conclusion: The HI-801 spirometer is comparable to the standard laboratory spirometer, Vmax spectra 22d, with high accurary for $FEV_1$ and FVC and acceptable differences for clinical use.

• Progress in Medical Physics
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• v.26 no.4
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• pp.258-266
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• 2015

The modern radiotherapy technique which delivers a large amount of dose to patients asks to confirm the positions of patients or tumors more accurately by using X-ray projection images of high-definition. However, a rapid increase in patient's exposure and image information for CT image acquisition may be additional burden on the patient. In this study, by introducing structural similarity (SSIM) index that can effectively extract the structural information of the image, we analyze the differences between daily acquired x-ray images of a patient to verify the accuracy of patient positioning. First, for simulating a moving target, the spherical computational phantoms changing the sizes and positions were created to acquire projected images. Differences between the images were automatically detected and analyzed by extracting their SSIM values. In addition, as a clinical test, differences between daily acquired x-ray images of a patient for 12 days were detected in the same way. As a result, we confirmed that the SSIM index was changed in the range of 0.85~1 (0.006~1 when a region of interest (ROI) was applied) as the sizes or positions of the phantom changed. The SSIM was more sensitive to the change of the phantom when the ROI was limited to the phantom itself. In the clinical test, the daily change of patient positions was 0.799~0.853 in SSIM values, those well described differences among images. Therefore, we expect that SSIM index can provide an objective and quantitative technique to verify the patient position using simple x-ray images, instead of time and cost intensive three-dimensional x-ray images.

• Progress in Medical Physics
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• v.22 no.3
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• pp.107-116
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• 2011

Respiratory gated radiation therapy and stereotactic body radiation therapy require identical tumor motions during each treatment with the motion detected in treatment planning CT. Therefore, this study developed a tumor motion monitoring and analysis system during the treatments employing RPM data, gated setup OBI images and a data analysis software. A respiratory training and guiding program which improves the regularity of breathing was used to patients. The breathing signal was obtained by RPM and the recorded data in the 4D console was read after treatment. The setup OBI images obtained gated at 0% and 50% of breathing phases were used to detect the tumor motion range in crenio-caudal direction. By matching the RPM data recorded at the OBI imaging time, a factor which converts the RPM motion to the tumor motion was computed. RPM data was entered to the institute developed data analysis software and the maximum, minimum, average of the breathing motion as well as the standard deviation of motion amplitude and period was computed. The computed result is exported in an excel file. The conversion factor was applied to the analyzed data to estimate the tumor motion. The accuracy of the developed method was tested by using a moving phantom, and the efficacy was evaluated for 10 stereotactic body radiation therapy patients. For the sine wave motion of the phantom with 4 sec of period and 2 cm of peak-to-peak amplitude, the measurement was slightly larger (4.052 sec) and the amplitude was smaller (1.952 cm). For patient treatment, one patient was evaluated not to qualified to SBRT due to the usability of the breathing, and in one patient case, the treatment was changed to respiratory gated treatment due the larger motion range of the tumor than treatment planed motion. The developed method and data analysis program was useful to estimate the tumor motion during treatment.

• Progress in Medical Physics
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• v.20 no.3
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• pp.132-138
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• 2009

Studies on target motion in 4-dimensional radiotherapy are being world-widely conducted to enhance treatment record and protection of normal organs. Prediction of tumor motion might be very useful and/or essential for especially free-breathing system during radiation delivery such as respiratory gating system and tumor tracking system. Neural network is powerful to express a time series with nonlinearity because its prediction algorithm is not governed by statistic formula but finds a rule of data expression. This study intended to assess applicability of neural network method to predict tumor motion in 4-dimensional radiotherapy. Scaled Conjugate Gradient algorithm was employed as a learning algorithm. Considering reparation data for 10 patients, prediction by the neural network algorithms was compared with the measurement by the real-time position management (RPM) system. The results showed that the neural network algorithm has the excellent accuracy of maximum absolute error smaller than 3 mm, except for the cases in which the maximum amplitude of respiration is over the range of respiration used in the learning process of neural network. It indicates the insufficient learning of the neural network for extrapolation. The problem could be solved by acquiring a full range of respiration before learning procedure. Further works are programmed to verify a feasibility of practical application for 4-dimensional treatment system, including prediction performance according to various system latency and irregular patterns of respiration.