• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.484-492
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• 1996

To detect ischemic tissue in experimental model of cerebral ischemia made by middle cerebral artery(MCA)-occlusion, we acquired triple image of $^{99m}Tc$-glucarate, [$^{18}F$]fluoro-deoxyglucose (FDG), and 2,3,5- triphenyltetrazolium (TTC) staining. We made cerebral infarction either with reperfusion (after occlusion of 2 hours) or without reperfusion in 10 Sprague-Dawley rats by inserting thread to MCA through internal carotid artery. After 22 hours, we injected 740 MBq of $^{99m}Tc$-glucarate and 55.5 MBq of [$^{18}F$]FDG through tail vein. Each 1 mm slice of rat brains was frozen and exposed to imaging plate for 20 minutes in freezer to get an [$^{18}F$]FDG image. After 20 hours enough to fade radioactivity of [$^{18}F$]FDG, the slices were again imaged by BAS1500 for $^{99m}Tc$-glucarate uptake. Finally, these brain tissues were stained with TTC. Semi-quantitative visual analysis was done by grading 0 to 3 points according to the degree of uptakes($^{99m}Tc$-glucarate) and decreased uptakes([$^{18}F$]FDG and TTC). Ten rats survived with neurologic symptoms. TTC staining confirmed the development of infarction. The size of the infarction was relatively larger in the group without reperfusion. [$^{18}F$]FDG images were similar to TTC-stained images. However, we found regions with intermediate uptake which were not stained with TTC. We found regions with intermediate [$^{18}F$]FDG uptake where TTC staining was normal. $^{99m}Tc$-glucarate uptake was round only in TTC non-stained region. In the TTC stained regions, there were no uptake of $^{99m}Tc$-glucarate. We could not find clear relation between $^{99m}Tc$-glucarate uptake with [$^{18}F$]FDG uptake. This was partly because percent uptake of $^{99m}Tc$-glucarate was so small (less than 1 percent of injected dose) and because there were quite heterogeneity of patterns of [$^{18}F$]FDG uptake and TTC. With these findings, we could conclude that $^{99m}Tc$-glucarate were taken up only in part of ischemic tissues which were proven to be nonviable. The establishment of MCA-occluded rat model with or without reperfusion and triple imaging for $^{99m}Tc,\;^{18}F$ and TTC helped the characterization of $^{99m}Tc$-glucarate uptakes. Further work is needed to clarify the meaning or diversities or [$^{18}F$]FDG and TTC and their relation with $^{99m}Tc$-glucarate.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.3
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• pp.155-164
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• 1997

A comprehensive and systematic field monitoring program was initiated since October 1989, in order to investigate the temporal and spatial variation of shoreline position at northern part of Pea Island, North Carolina. Aerial photographs were taken every two months on the shoreline extending from the US Coast Guard Station at the northern end of Pea Island to a point 6 miles to the south. Aerial photographs taken were digitized initially to obtain the shoreline position data. in which a wet-dry line visible on the beach was used to identify the position of shoreline. Since the wet-dry line does not represent the “true" shoreline .position but includes the errors due to the variations of wave run-up heights and tidal elevations at the time the photos taken, it is required to eliminate the tide and wave runup effects from the initially digitized shoreline .position data. Runup heights on the beach and tidal elevations at the time the aerial photographs taken were estimated using tide data collected at the end of the FRF pier and wave data measured from wave-rider gage installed at 4 km offshore, respectively A runup formula by Hunt (1957) was used to compute the run-up heights on the beach from the given deepwater wave conditions. With shoreline position data corrected for .wave runup and tide, both spatial and temporal variations of the shoreline positions for the monitoring shoreline were analyzed by examining local differences in shoreline movement and their time dependent variability. Six years data of one-mile-average shoreline indicated that there was an apparent seasonal variation of shoreline, that is, progradation of shoreline at summer (August) and recession at winter (February) at Pea Island. which was unclear with the uncorrected shoreline position data. Determination of shoreline position from aerial photograph, without regard to the effects of wave runup and tide, can lead to mis-interpretation for the temporal and spatial variation of shoreline changes.nges.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.438-447
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• 2000

Background : Transbronchial lung biopsy (TBLB) is a relatively simple and convenient procedure to obtain lung tissue from a patient with diffuse or localized lesion on chest radiographs, whose disease cannot be diagnosed through routine tests. The authors tried to evaluate the diagnostic value of TBLB, especially, the concordance between CT scan and TBLB with respect to the location of the lesion and diagnostic yield according to tumor-bronchus relationship. Method : We reviewed the medical records, plain chest films, and chest CT scans of 278 patients who underwent TBLB at Kyungpook National University Hospital between January 1996 and June 1998. Results : One hundred and sixteen (41.7 %) patients were diagnosed by TBLB. Diagnostic yield of TBLB of malignant tumors tended to be higher than that of benign diseases (64.7% versus 53.9%, p=0.09). Of primary lung cancers, TBLB was more diagnostic in adenocarcinoma and small-cell carcinoma than other cell types (p<0.01) and, of benign diseases, more diagnostic in tuberculosis than in non-tuberculous diseases (p<0.05). There was no significant difference in the diagnostic rate according to the location of the tumor. The diagnostic rate tended to increase with the size of tumor (p=0.06). The diagnootic rate of TBLB did not differ according to the pattern of lesion in benign diseases. However, in malignant diseases TBLB was more diagnostic in diffuse/multiple nodular lesions than in localized lesions(p<0.05). According to the tumor-bronchus relationship, TBLB was more diagnootic in type I/II groups than in other types. CT scan and TBLB showed a strong correlation with respect to the localization of the lesion (r=0.994, p<0.01). Conclusion : The above results show that TBLB is useful in the diagnosis of lung disease. CT scan and TBLB showed a strong correlation in determining the location of the lesion. Diagnostic yield of TBLB is higher in lesions with 'bronchus sign' (type I and II). TBLB and other diagnootic methods such as transthoracic needle aspiration are expected to complement one another in the diagnosis of lung diseases.

• Radiation Oncology Journal
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• v.22 no.2
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• pp.91-97
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• 2004

Propose: To Analyze the survival outcomes and prognostic factors In glioblastoma patients treated with surgery and radiation therapy. Materials and Methods : One hundred twenty glloblastoma patients treated with postoperative radiation therapy from 1994 to 2003 at Samsung Medical Center were retrospectively reviewed. Surgical extents were gross total resection in 22 patients (18$\%$), subtotal resection in 69 (58$\%$), and biopsy only in 29 (24$\%$). The median radiation dose was 50 Gy, ranging from 45 Gy to 72 Gy The median follow-up period was 12 months ranging from 2 to 52 months. Results The overall 1- and 2-year survival rates were 52$\%$ and 14$\%$, respectively, and the median survival duration was 13 months. Favorable prognostic factors by Uunivarlate analyses of prognostic factors on 1-year survival rate were revealed that age under 50 (p<0.01), ECOG performance status 0 or 1 (p=0.03), single lesion (p=0.02), and gross total resection (p=0.04), were the favorable prognostic (actors. and by Mmultlvarlate analyses were revealed that female (p<0.01), age under 50 (p<0.01), ECOG performance status 0 or 1 (p=0.05) and gross total resection (p=0.05) were the favorable prognostic factors. Conclusions : The results of our study were comparable with those previously reported. To Improve treatment outcome, various modifications, Including radiation dose escalation through newer radiation therapy techniques and use of effective chemotherapy regimen, should be further Investigated. Investigated. Also Furthermore, the application of Individualized treatment strategy based on 4he patient's prognostic factors might be needed.

• Radiation Oncology Journal
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• v.14 no.3
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• pp.201-209
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• 1996

Purpose : To assess the efficacy of high dose rate - intracavitary radio-therapy (HDR-ICR) in the radiotherapy of FIGO stage IB squamous cell carcinoma of uterine cervix and to determine the optimum dose combination scheme of external radiotherapy and ICR to achieve acceptable local control without severe complication. Materials and Methods : One hundred and sixty two patients with FIGO stage Ib squamous cell carcinoma of uterine cervix who received definitive radiotherapy between May 1979 and December 1990 were retrospectively analyzed. All the patients received external radiotherapy combined with HDR-ICR. External dose of 40-46 Gy in 4.5-5 weeks was given to whole pelvis(median 45 Gy) and ICR dose of 30-39 Gy in 10-13 times was given to the point A. Midline shielding was done after 20-45 Gy of external radiotherapy(median 40 Gy) Summation of external dose Plus ICR dose to the point A range were 64.20-95.00 Gy. and mean was 83.94 Gy. We analyzed the local control rate, survival rate, and late complication rate. Rusults : Initial complete response rate was $99.4\%$ for all patients. Overall 5-year survival rate was $91.1\%$ and 5-year disease free survival rate was $90.9\%$. Local failure rate was $4.9\%$ and distant failure rate was $4.3\%$. Tumor size was the only significant prognostic factor. When tumor size greater than 3cm, 5-rear survival rate was $92.6\%$ and less than 3cm, that was $79.6\%$. Late complication rate was $23.5\%$ with $18.5\%$ of rectal complication and $4.9\%$ of bladder complication. Mean rectal dose summation of external midline dose plus ICR rectal point dose was lower in the patients without rectal complication(74.88 Gr) than those with rectal complication (78.87 Gy). Complication rate was increased with low rate of improvement of survival rate when summation of external midline dose plus point A or point R dose by ICR was greater than 70-75 Gy. Conclusion : The definitive radiation therapy using high dose rate ICR in FIGO stage IB uterine cervical cancer is effective treatment modality with good local control and survival rate without severe complication.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.226-232
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• 2000

Purpose :This study was performed to find out the prognostic factors affecting local control in early glottic cancer treated with radiation therapy alone. Materials and Methods :We analysed 37 patients of histologically confirmed early glottic cancer treated at Chonnam National University Hospital between July Im and December 1995, retrospectively. Age of patients ranged from 30 to 73 years (median; 59 years). Thirty-five (95$\%$) patients were male. Histological type was all squamous cell carcinoma. According to the staging system of 1997 American Joint Committee on Cancer, 37 patients were restaged as follows: Tla; U (73$\%$), Tlb; 3 (8$\%$), 72: 7 (19$\%$). Radiation therapy was done using 6 MV X-ray of linear accelerator The range of total radiation dose delivered to the glottic lesion was between 5,040 cGy and 7,020 cGy (median; 6,600 cGy). Median follow-up period was U months. local control rates were calculated by Kaplan-Meier method. Generalized Wilcoxon test was used to evaluate the difference of control rates between comparable groups. Multivariate analysis using Cox proportional hazard model was done to find out prognostic factors affecting local control. Results:5 year survival rate of 37 patients was 89$\%$. Local control rate of 37 patients was 74$\%$ in 5 years. We included age, 7-stage, anterior commissure involvement, fraction size, total radiation dose, treatment time of radiotherapy as potential prognostic factors in univariate and multivariate analysis. As a result, treatment time had statistical significance in local control rate in both univariate (p=0.026) and multivariate (p=0.017) analysis. Complication was not recorded except one patient with hypothyroidism. Conclusion :This study revealed that overall treatment time of radiation was a significant factor affecting local control rate.

• Progress in Medical Physics
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• v.25 no.4
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• pp.218-224
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• 2014

The small field dosimetry is very important in modern radiotherapy because it has been frequently used to treat the tumor with high dose hypo-fractionated radiotherapy or high dose single fraction stereotactic radiosurgery (SRS) with small size target. But, the dosimetry of a small field (< $3{\times}3cm^2$) has been great challenges in radiotherapy. Small field dosimetry is difficult because of (a) a lack of lateral electronic equilibrium, (b) steep dose gradients, and (c) partial blocking of the source. The objectives of this study were to measure and verify with the various detectors the output factors in a small field (<3 cm) for the 6 MV photon beams. Output factors were measured using the CC13, CC01, EDGE detector, thermoluminescence dosimeters (TLDs), and Gafchromic EBT2 films at the sizes of field such as $0.5{\times}0.5$, $1{\times}1$, $2{\times}2$, $3{\times}3$, $5{\times}5$, and $10{\times}10cm^2$. The differences in the output factors with the various detectors increased with decreasing field size. Our study demonstrates that the dosimetry for a small photon beam (< $3{\times}3cm^2$) should use CC01 or EDGE detectors with a small active volume. And also, Output factors with the EDGE detectors in a small field (< $3{\times}3cm^2$) coincided well with the Gafchromic EBT2 films.

• Journal of agricultural medicine and community health
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• v.28 no.1
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• pp.67-77
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• 2003

Objectives: This study is designed to suggest the health service goals necessary for providing the more efficient services relevant to the requests of the community, through the evaluation on the operating status of the unified health subcenters. Methods: We visited total 5 unified health subcenters comprising 3 ones located in Gyeongsangbuk-do and 2 ones located in Gyeongsangnam-do from December 2000 to January 2001, and interviewed about the pre- and post-unified status related to manpower, facilities, equipment, medical service and health service quality, and the problems and improvement plans of the unified management. Results: According to the evaluation on the manpower before and after the unification of the health subcenters, the total employees increased by 2.8 persons on average from 6.8 to 9.6 persons in the investigated subjects. The numbers of doctors, dentists and nurses were almost the same as before. There were no clinical pathologic technician and radiological technician before but they were appointed to duty in 3 unified health subcenters later. The unification of the health subcenters has produced slight increases in the frequency of the medical service and dental treatment and considerable increases in that of the physical therapy and laboratory tests. In relating to the changes of the health service, the cases of visiting health care and ambulatory medical service, and the total number of health education participants were greatly increased after the unification. The number of cases undergoing the vaccination and cervical cancer screening was similar to that of the pre-unification while the patient number of the registration to hypertension or diabetes showed a tendency to increase a little. Since the unification of the health subcenters, the frequency of laboratory tests has been increased, but the quality of health service has not been improved yet. Nevertheless, the unification seems to be positive according to the result of the great improvement in visiting health care, ambulatory medical service and health education service. The problems of the unification of the health subcenters were indicated in indefiniteness of the service details between the workers; excessively large building hard to be effectively managed; insufficient medical instruments, inappropriation of working expenses, lack of professional training for the health education, etc. Conclusions: For further active functions of the unified health subcenters, the minimal allocation basis to appoint doctors, nurses and administrative workers to do the duty should be differentiated from the basis for a health subcenter, and the fundamental instruments needs to be expanded to improve the quality of the medical service and visiting health care service. Moreover, the unified health subcenter needs to have definite service details between the workers, and should improve the working efficiency through the development of service-related guidelines.

• 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.

• Radiation Oncology Journal
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• v.24 no.1
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• pp.44-50
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• 2006

Puroose: This study evaluated the late rectal complications in cervix cancer patients following treatment with external beam radiotherapy (EBRT) and high dose rate intracavitary radiation (HDR ICR). The factors affecting the risk of developing late rectal complications and its incidence were analyzed and discussed. Materials and Methods: The records of 105 patients with cervix cancer who were treated with radical radiotherapy using HDR ICR between July, 1995 and December, 2001 were retrospectively reviewed. The median dose of EBRT was 50.4Gy $(41.4{\sim}56.4 Gy)$ with a daily fraction size of 1.8Gy. A total of $5{\sim}7$ (median: 6) fractions of HDR ICR were given twice weekly with a fraction size of $4{\sim}5 Gy$ (median: 4Gy) to A point using an Ir (Iridium)-192 source. The median dose of ICR was 24 Gy $(20{\sim}35 Gy)$. During HDR ICR, the rectal dose was measured in vivo by a semiconductor dosimeter. The median follow-up period was 32 months, ranging from 5 to 84 months. Results: Of the 105 patients, 12 patients (11%) developed late rectal complications: 7 patients with grade 1 or 2, 4 patients with grade 3 and 1 patient with grade 4. Rectal bleeding was the most frequent chief complaint. The complications usually began to occur $5{\sim}32$ (median: 12) months after the completion of radiotherapy. Multivariate analysis revealed that the measured cumulative rectal BED over 115 Gy3 (Deq over 69 Gy) and the depth (D) of a 5 Gy isodose volume more than 50 mm were the independent predictors for late rectal complications. Conclusion: With evaluating the cumulative rectal BED and the depth of a 5 Gy isodose volume as predictors, we can individualize treatment planning to reduce the probability of late rectal complications.