• The Journal of Korean Society for Radiation Therapy
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• v.21 no.2
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• pp.67-74
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• 2009

Purpose: To evaluate the results of absorbed and effective doses using two different modes, standard mode (A-mode) and low-dose mode (B-mode) settings for prostate cancer IGRT from CBCT. Materials and Methods: This experimental study was obtained using Clinac iX integrated with On Board Imager (OBI) System and CBCT. CT images were obtained using a GE Light Speed scanner. Absorbed dose to organs from ICRP recommendations and effective doses to body was performed using A-mode and B-mode CBCT. Measurements were performed using a Anderson rando phantom with TLD-100 (Thermoluminescent dosimeters). TLD-100 were widely used to estimate absorbed dose and effective dose from CBCT with TLD System 4000 HAWSHAW. TLD-100 were calibrated to know sensitivity values using photon beam. The measurements were repeated three times for prostate center. Then, Evaluations of effective dose and absorbed dose were performed among the A-mode and B-mode CBCT. Results: The prostate absorbed dose from A-mode and B mode CBCT were 5.5 cGy 1.1 cGy per scan. Respectively Effective doses to body from A mode and B-mode CBCT were 19.1 mSv, 4.4 mSv per scan. Effective dose from A-mode CBCT were approximately 4 times lower than B-mode CBCT. Conclusion: We have shown that it is possible to reduce the effective dose considerably by low dose mode(B-mode) or lower mAs CBCT settings for prostate cancer IGRT. Therefore, we should try to select B-mode or low condition setting to decrease extra patient dose during the IGRT for prostate cancer as possible.

• Progress in Medical Physics
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• v.19 no.1
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• pp.63-72
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• 2008

With recent advancement of the medical imaging systems and picture archiving and communication system (PACS), installation of digital radiography has been accelerated over past few years. Moreover, Computed Radiography (CR) which was well established for the foundation of digital x-ray imaging systems at low cost was widely used for clinical applications. This study analyzes imaging characteristics for two systems with different pixel sizes through the Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE). In addition, influence of radiation dose to the imaging characteristics was also measured by quantitative assessment. A standard beam quality RQA5 based on an international electro-technical commission (IEC) standard was used to perform the x-ray imaging studies. For the results, the spatial resolution based on MTF at 10% for Agfa CR system with I.P size of $8{\times}10$ inches and $14{\times}17$ inches was measured as 3.9 cycles/mm and 2.8 cycles/mm, respectively. The spatial resolution based on MTF at 10% for Fuji CR system with I.P size of $8{\times}10$ inches and $14{\times}17$ inches was measured as 3.4 cycles/mm and 3.2 cycles/mm, respectively. There was difference in the spatial resolution for $14{\times}17$ inches, although radiation dose does not effect to the MTF. The NPS of the Agfa CR system shows similar results for different pixel size between $100{\mu}m$ for $8{\times}10$ inch I.P and $150{\mu}m$ for $14{\times}17$ inch I.P. For both systems, the results show better NPS for increased radiation dose due to increasing number of photons. DQE of the Agfa CR system for $8{\times}10$ inch I.P and $14{\times}17$ inch I.P resulted in 11% and 8.8% at 1.5 cycles/mm, respectively. Both systems show that the higher level of radiation dose would lead to the worse DQE efficiency. Measuring DQE for multiple factors of imaging characteristics plays very important role in determining efficiency of equipment and reducing radiation dose for the patients. In conclusion, the results of this study could be used as a baseline to optimize imaging systems and their imaging characteristics by measuring MTF, NPS, and DQE for different level of radiation dose.

• Radiation Oncology Journal
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• v.19 no.1
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• pp.27-33
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• 2001

Purpose : To evaluate interim results in terms of failure, cosmetic results and survival after breast conserving operation and radiation therapy in early breast cancer. Material and Methods : From January 1992 through December 1997, seventy two patients with early stage 0, I and II breast cancer were treated with conservative surgery plus radiotherapy at Keimyung University Dongsan Medical Center. Age distribution was 25 to 77 years old with median age of 43. According to TNM stage, five patients had stage 0, thirty three were stage I, twenty five were IIa, and nine were IIb. Most patients underwent excision of all gross tumor and ipsilateral axillary dissection. Breast was irradiated through medial and lateral tangential fields of 6 MV photons to 50.4 Gy in 28 fractions over 5.5 weeks. We delivered a boost irradiation dose of 10 to 16 Gy in 1 to 2 weeks to excision site. Adjuvant chemotherapy was administered in forty one patients with CMF (cyclophosphamide, methotrexate, 5-fluorouracil) regimens of 6 cycles concurrently or before radiation. Cosmetic results were assessed by questionnaire to patients grading of excellent, good, fair, poor. Follow-up periods were 22 to 91 months with median 40 months. Results : Five year disease free survival rate (5YDFS) was $95.8\%$. According to stage, 5YDFS was $100\%,\;96.9\%,\;96\%\;and\;88.9\%$ in stage 0, I, IIa and IIb, respectively. Two patients had distant metastasis and one had local and distant failure. One patient with distant failure had bone and liver metastasis at 14 months after treatment and the other had lung and both supraclavicular metastasis at 21 months after treatment. Patient with local and distant failure had local recurrence on other quadrant in same breast and then salvaged with total mastectomy and chemotherapy but she died due to brain metastasis at 55 months. Complications were radiation pneumonitis in five patients (four patients of asymptomatic, one patients of symptomatic) and hand or arm edema(4 patients). Fifty nine patients answered our cosmetic result questionnaire and cosmetic results were good to excellent in fifty one patients $(86\%)$. Conclusion : We considered that conservative surgery and radiation for the treatment of early stage invasive breast cancer was safe and had excellent survival and cosmetic results. We need to assess about prognostic factors with longer follow up and with large number of patients.

• Radiation Oncology Journal
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• v.27 no.3
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• pp.153-162
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• 2009

Purpose: To evaluate the long-term results after breast-conserving surgery and radiation therapy in early breast cancer in terms of failure, survival, and cosmesis. Materials and Methods: One hundred fifty-four patients with stage I and II breast cancer were treated with conservative surgery plus radiotherapy between January 1992 and December 2002 at the Keimyung University Dongsan Medical Center. According to TNM stage, 93 patients were stage I, 50 were IIa, and 11 were IIb. The affected breasts were irradiated with 6 MV photons to 50.4 Gy in 28 fractions over 5.5 weeks with a boost irradiation dose of 10~16 Gy to the excision site. Chemotherapy was administered in 75 patients and hormonal therapy in 92 patients with tamoxifen. Follow-up periods were 13~179 months, with a median of 92.5 months. Results: The 5- and 10-year overall survival rates were 97.3% and 94.5%, respectively. The 5- and 10-year disease-free survival (5YDFS and 10YDFS, respectively) rates were 92.5% and 88.9%, respectively; the ultimate 5YDFS and 10YDFS rates after salvage treatment were 93.9% and 90.2%, respectively. Based on multivariate analysis, only the interval between surgery and radiation therapy ($\leq$6 weeks vs. >6 weeks, p=0.017) was a statistically significant prognostic factor for DFS. The major type of treatment failure was distant failure (78.5%) and the most common distant metastatic site was the lungs. The cosmetic results were good-to-excellent in 96 patients (80.7%). Conclusion: Conservative surgery and radiation for early stage invasive breast cancer yielded excellent survival and cosmetic results. Radiation therapy should be started as soon as possible after breast-conserving surgery in patients with early breast cancer, ideally within 6 weeks.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.249-260
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• 2007

Purpose: In order to enhance the quality of IMRT as employed in Korea, we developed a remote monitoring system. The feasibility of the system was evaluated by conducting a pilot study. Materials and Methods: The remote monitoring system consisted of a head and neck phantom and a user manual. The phantom contains a target and three OARs (organs at risk) that can be detected on CT images. TLD capsules were inserted at the center of the target and at the OARs. Two film slits for GafchromicEBT film were located on the axial and saggital planes. The user manual contained an IMRT planning guide and instructions for IMRT planning and the delivery process. After the manual and phantom were sent to four institutions, IMRT was planed and delivered. Predicted doses were compared with measured doses. Dose distribution along the two straight lines that intersected at the center of the axial film was measured and compared with the profiles predicted by the plan. Results: The measurements at the target agreed with the predicted dose within a 3% deviation. Doses at the OARs that represented the thyroid glands showed larger deviations (minimum 3.3% and maximum 19.8%). The deviation at OARs that represented the spiral cord was $0.7{\sim}1.4%$. The percentage of dose distributions that showed more than a 5% of deviation on the lines was $7{\sim}27%$ and $7{\sim}14%$ along the horizontal and vertical lines, respectively. Conculsion: Remote monitoring of IMRT using the developed system was feasible. With remote monitoring, the deviation at the target is expected to be small while the deviation at the OARs can be very large. Therefore, a method that is able to investigate the cause of a large deviation needs to be developed. In addition, a more clinically relevant measure for the two-dimensional dose comparison and pass/fail criteria need to be further developed.

• The Korean Journal of Air & Space Law and Policy
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• v.28 no.2
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• pp.63-96
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• 2013

Recently, U.S. Department of Transportation (DOT) expanded the "Enhancing Airline Passenger Protections" on August 23, 2011 and October 24, 2011. The Rule regulates tarmac delays, denied boarding compensation, customer service plans, and fare advertising. The adopted rule is to protect passengers by improving passenger service requirements on U.S. national or domestic carriers and foreign air carriers as well. The major issues are as follows: First, regarding to so called Tarmac Delay, carriers must establish a Tarmac Delay Contingency Plan setting forth the number of hours the carrier will permit an aircraft to remain on the tarmac at U.S. airports before allowing passengers to deplane. Carriers also must provide passengers with food and water in the event the aircraft remains on the tarmac for two or more hours and must provide operable lavatories and medical attention while the aircraft remains on the tarmac, irrespective of the length of the delay. Carriers also must create and retain records regarding tarmac delays lasting more than three hours. Also they need to update passengers every 30 minutes during a tarmac delay of the status of the flight and the reason for the delay, allow passengers to deplane if the aircraft is at the gate or another disembarkation area with the door open. Second, carriers now must adopt a "Customer Service Plan" that addresses offering customers the lowest fares available, notifying customers about delays, cancellations, and diversions; timely delivery of baggage; accommodating passengers' needs during tarmac delays and in "bumping cases"; and ensuring quality customer service. Third, the new regulations also increase minimum denied boarding compensation limits to $650 / $1,300 or 200% / 400% of the fare, whichever is less. Last, the DOT also has modified its policies related to enforcement of Rules pertaining to full fare advertising. The Rule states that the advertised price for air transportation must be the entire price to be paid by the customer. Similarly, Korea revised the passenger protection clauses within Aviation Act. However, it seems to be required to include various more issues such as Tarmac Delay, oversales of air tickets, involuntary denied boarding passengers, advertisements, etc.

• Journal of the Economic Geographical Society of Korea
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• v.8 no.1
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• pp.91-105
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• 2005

The assessment (or the evaluation) of spatial disparity is the main concern for the study of spatial disparities or spatial inequalities. In order to evaluate the spatial disparity, the regional differences have to be counted quantitatively. Several measurements have been introduced for evaluating the development potentials of each region. Most of them are the composite indices of the socio-economic variables rather than the real potentials of the region. This study attempts to investigate the spatial disparity in Korea. For the purpose, the levels of opportunity potentials of the cities have been calculated by the Potential Model redefined by Lee(1995). The opportunity potentials have been calculated for the educational, cultural, medical service, environmental sectors, income, and consumption sectors, and the spatial patterns of various opportunity potentials have been analyzed. The spatial patterns of opportunity potentials show the severe concentration on the Metropolitan Seoul area through all sectors. The next level concentration appears at the other end of the Keuyng-Bu axis. And the cities relatively high opportunity potential values are distributed along the Keuyng-Bu axis. Remain parts of the country show quietly low opportunity potential values. In particular, the southern-west and the northern-east parts show relatively very low values. This pattern appears for all sectors except for the opportunity potential of the environmental sector. It means that the spatial disparity in Korea have been promoted and enhanced by the national development policies concentrated the investment on the large cities along the Keuyng-Bu axis during the last 40 years.

• Journal of Chest Surgery
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• v.36 no.6
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• pp.397-403
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• 2003

Background: The research sought to identify the clinical features of pleomorphic carcinoma of the lung generally known as a rare subtype in accordance with the lung cancer classification done in 1999 by WHO. Material and Method: 250 cases of surgically resected lung cancers were collected in this hospital from January 1992 to December 2001. This study included 42 cases of pleomorphic carcinoma diagnosed through light microscope and immunohistochemistry. Result: Out of 42 cases, males represented 31, and females 11, the age ranged from 26 to 77. Main clinical symptoms included coughing, hemoptysis, sputum. Diagnoses disclosed the stage as stage la in 3 cases (7%), Ib in 16 (38%), IIa in 1 (2%), IIb in 8 (19%), IIIa in 15 (35%), and IIIb in 1 (2%). Out of these, no lymph node metastasis was represented in 23 cases (54%), while N1 and N2 involving lymph node metastasis was shown 19 cases (46%). A total of 19 patients developed metastasis, comprising the brain in 5 cases (26%), bone in 4 (21%), muscle in 4 (21%), Lymph node in 2 (10%), and 1 liver, ovary, contralateral lung, and adrenal gland, respectively. The size of the tumor ranged from 1 cm to 11 cm, averaging 5.85 cm. Out of the 42 patients, the total two-year and five-year survival rates in accordance with the Kaplan-Meier method represented 26% and 13%, respectively, These figures compared to the corresponding 44% and 34% in cases other than pleomorphic carcinoma from the survey target of 256 cases, proved to be significantly low (p<0.002). No significant difference was found in the survival rates compared between age and tumor size, between stage I and above stage II, and between N0 and above N1. Patients who developed postoperative metastasis all died, and showed significantly low survival rates (p<0.002) compared to those patients without metastasis. Conclusion: With the new diagnosis method of f999 WHO's lung cancer classification applied, pleomorphic carcinoma showed a higher prevalence rate than under previous classifications, their postoperative survival rate was significantly low compared to histologic type of non small cell lung carcinomas.

• Pediatric Infection and Vaccine
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• v.12 no.2
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• pp.149-156
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• 2005

Purpose : Acute septic arthritis and acute osteomyelitis are not rare diseases in pediatric population. But when the diagnosis is delayed or inappropriate treatments are given, permanent disabilities of joint or bone can be followed. We analysed clinical manifestations, laboratory findings, X-ray findings, causative microorganisms and antibiotic susceptibility results of the two diseases in children. Methods : During January 1992 and May 2002, we conducted a retrospective study of 103 children who were diagnosed as acute septic arthritis and acute osteomyelitis. We selected out 34 children who had positive culture results in the blood or involved sites. Results : 19 cases were diagnosed as acute septic arthritis and 15 cases were acute osteomyelitis. These diseases were most common in preschool children and next in neonates. Hip joints and tibia were the most common sites in each disease. X-ray findings showed abnormalities in 6 cases(36%) of acute septic arthritis and 7 cases(50%) of acute osteomyelitis on admission. The most common microorganism isolated from the involved sites was Staphylococcus aureus; 12 out of 14 cases in acute septic arthritis and 6 out of 13 cases in acute osteomyelitis. Conclusion : It is difficult to make a clear initial diagnosis of the two diseases. We could not find any differences between these two diseases on clinical manifestations such as fever, swelling, tenderness and limitation of movements in joint and bone. The most common microorganism was Staphylococcus aureus.

• Korean Journal of Veterinary Research
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• v.41 no.4
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• pp.571-578
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• 2001

To evaluate if the apoptotic fragment assay could be used to estimate the dose prediction after radiation exposure, we examined apoptotic mouse crypt cells per 1,000 cells after whole body $^{60}Co$ $\gamma$-rays and 50MeV ($p{\rightarrow}Be^+$) cyclotron fast neutron irradiation in the range of 0.25 to 1 Gy, respectively. The incidence of apoptotic cell death rose steeply at very low doses up to 1 Gy, and radiation at all doses tigger rapid changes in crypt cells in stem cell region. These data suggest that apoptosis may play an important role in homeostasis of damaged radiosensitive target organ by removing damaged cells. The curve of dose-effect relationship for the data of apoptotic fragments was obtained by the linear-quadratic model $y=0.18+(9.728{\pm}0.887)D+(-4.727{\pm}1.033)D^2$ ($r^2=0.984$) after $\gamma$-rays irradiation, while $y=0.18+(5.125{\pm}0.601)D+(-2.652{\pm}0.7000)D^2$ ($r^2=0.970$) after neutrons in mice. The dose-response curves were linear-quadratic, and a significant dose-response relationship was found between the frequency of apoptotic cell and dose. These data show a trend towards increase of the numbers of apoptotic crypt cells with increasing dose. Both the time course and the radiation dose-response curve for high and low linear energy transfer (LET) radiation modalities were similar. The relative biological effectiveness (RBE) value for crypt cells was 2.072. In addition, there were significant peaks on apoptosis induction at 4 and 6h after irradiation, and the morpholoigcal findings of the irradiated groups were typical apoptotic fragments in crypt cells that were hardly observed in the control group. Thus, apoptosis in crypt cells could be a useful in vivo model for studying radio-protective drug sensitivity or screening test, microdosimetric indicator and radiation-induced target organ injury. Since the apoptotic fragment assay is simple, rapid and reproducible in the range of 0.25 to 1 Gy, it will also be a good tool for evaluating the dose response of radiation-induced organ damage in vivo and provide a potentially valuable biodosimetry for the early dose prediction after accidental exposure.