• Progress in Medical Physics
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• v.24 no.1
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• pp.1-24
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• 2013

As image-guided radiation therapy (IGRT) has been commonly used for more accurate patient setup and monitoring tumor movement during radiation therapy, the necessity for management of imaging dose is increased. However, it has not been an interest issue to radiation therapy communities because the imaging dose is much lower than the therapeutic dose. However, since the cumulative dose from 4DCT and repeated imaging for daily setup verificationin would not be ignorable, appropriate dose management based on ALARA (As Low As Reasonably Achievable) principle is required. In this study, we aimed that (1) survey on imaging equipments and modalities used for IGRT, (2) estimation of IGRT imaging dose depending on treatment types and equipments, (3) collecting data of effective dose on treatment sites from each equipment and imaging protocol, and thus finally provide guideline for imaging dose reduction and optimization.

• Clinical and Experimental Pediatrics
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• v.48 no.2
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• pp.165-173
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• 2005

Purpose : We performed the study to evaluate the value of the follow-up echocardiogram performed 6 months to 1 year after the onset of Kawasaki disease(KD), as recommended by American Heart Association(AHA) guidelines, when echocardiograms in the convalescent period were normal. Methods : Patients were selected from 147 cases diagnosed with KD at Pusan Paik hospital from January 2000 to October 2003. A total of 45 KD patients belonged to AHA risk level I and II were performed follow-up echocardiography. The patient's medical records and echocardiogram were reviewed. Additionally, we sought the opinion of pediatric cardiologists on the subject by means of a multiple-choice survey. Results : 37 children were belonged to AHA risk level I and the remaining 8 patients were belonged to risk level II. Of these 45 children, none were noted to have abnormalities on later follow-up echocardiogram. In the results of questionnaire, 37 percent of the participants advocate no follow-up after convalescent period for risk level I, and 33.3 percent favor periodic follow-up with echocardiography for risk level II up to one year. But there were no consensus about the diagnostic criteria of coronary abnormalities and how to follow-up these patients. Conclusion : All children with KD should have an echocardiogram at present and a follow-up study 6 to 8 weeks after the onset of fever. However, additional echocardiographies are not justified if the 6- to 8-week follow-up echocardiogram is normal. We would recommend that the more reasonable diagnostic criteria for coronary abnormalities and the Korean guidelines for long-term cardiovascular management and follow-up of KD need to be established.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1558-1566
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• 2015

The purpose of this study was to examine dietitians' perception of importance about standards of foodservice management associated with long-term care hospital accreditation. This study was carried out through a postal survey consisting of 500 questionnaires, and 157 returned questionnaires were used in the statistical analysis. The results were summarized as follows. Average scores of perception of importance were 4.54/5 points in foodservice production management domain, 4.56/5 points in foodservice facilities management domain, and 4.70/5 points in foodservice sanitation domain. The average scores of importance of long-term care hospitals without accreditation were significantly (P<0.05) lower than those of hospitals with accreditation in items of 'establishment of ventilation equipment in kitchen', 'establishment of hand-washstand in toilet (warm-water, soap)', 'setup of sterilizing foothold in entrance of kitchen and toilet', 'division and use of knife, chopping board, gloves, and utensils before and after cook', 'establishment of cleaning plan and cyclic practice', and 'recording of receiving diary'. Results indicate that there is a need to supplement a casebook of regulations by suggesting detailed and critical limits in the case of below average points of importance. A manual, including HACCP standards for foodservice management of long-term care hospitals, is needed, along with education and webpage for comparing notes on accreditation of long-term care hospitals.

• Korean Journal of Psychosomatic Medicine
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• v.27 no.2
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• pp.130-137
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• 2019

Objectives : When a patient who attempts suicide visits the emergency room, it is important that the departments of emergency medicine, internal medicine, and psychiatry communicate with each other and prioritize treatment. This study was conducted to verify the effectiveness of the multidisciplinary emergency consultation system (ECS) for drug intoxicated patients. Methods : We retrospectively analyzed the data from medical records prior to the ECS, from July 2017 to May 2018, and after the ECS, from July 2018 to May 2019, to verify the effectiveness of the system. Results : After the ECS, admission to open wards was significantly higher than to the intensive care units (χ²=8.567, p=0.014). In addition, the proportion of consultations to the department of psychiatry among patients admitted to other departments tended to increase (χ²=4.202, p=0.053), and the time required for consultation response decreased (Z=-2.031, p=0.042). As a result of the consultation, the proportion of the patients who had been transferred to the department of psychiatry was increased (χ²=4.692, p=0.043), and the time spent to transfer tended to decrease (Z=-1.941, p=0.052). Conclusions : After implementing the ECS for drug intoxicated patients, unnecessary intensive care unit admissions, consultation response time, and the time spent to transfer were reduced, and the rate of consultation referrals and transfer rates increased. This means that the multidisciplinary consultation system rapidly provided essential medical services to patients at lower medical costs.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.1
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• pp.1-5
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• 2006

Purpose: IMRT quality assurance(Q.A) is consist of the absolute dosimetry using ionization chamber and relative dosimetry using the film. We have in general used 0.015 cc ionization chamber, because small size and measure the point dose. But this ionization chamber is too small to give an accurate measurement value. In this study, we have examined the degree of calculated to measured dose difference in intensity modulated radiotherapy(IMRT) based on the observed/expected ratio using various kinds of ion chambers, which were used for absolute dosimetry. Materials and Methods: we peformed the 6 cases of IMRT sliding-window method for head and neck cases. Radiation was delivered by using a Clinac 21EX unit(Varian, USA) generating a 6 MV x-ray beam, which is equipped with an integrated multileaf collimator. The dose rate for IMRT treatment is set to 300 MU/min. The ion chamber was located 5cm below the surface of phantom giving 100cm as a source-axis distance(SAD). The various types of ion chambers were used including 0.015cc(pin point type 31014, PTW. Germany), 0.125 cc(micro type 31002, PTW, Germany) and 0.6 cc(famer type 30002, PTW, Germany). The measurement point was carefully chosen to be located at low-gradient area. Results: The experimental results show that the average differences between plan value and measured value are ${\pm}0.91%$ for 0.015 cc pin point chamber, ${\pm}0.52%$ for 0.125 cc micro type chamber and ${\pm}0.76%$ for farmer type 0.6cc chamber. The 0.125 cc micro type chamber is appropriate size for dose measure in IMRT. Conclusion: IMRT Q.A is the important procedure. Based on the various types of ion chamber measurements, we have demonstrated that the dose discrepancy between calculated dose distribution and measured dose distribution for IMRT plans is dependent on the size of ion chambers. The reason is small size ionization chamber have the high signal-to-noise ratio and big size ionization chamber is not located accurate measurement point. Therefore our results suggest the 0.125 cc farmer type chamber is appropriate size for dose measure in IMRT.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.113-122
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• 2010

Purpose: To evaluate the accuracy of a target position at static and dynamic state by using Dynamic phantom for the difference between tumor's actual movement during respiratory gated radiation therapy and skin movement measured by RPM (Real-time Position Management). Materials and Methods: It self-produced Dynamic phantom that moves two-dimensionally to measure a tumor moved by breath. After putting marker block on dynamic phantom, it analyzed the amplitude and status change depending on respiratory time setup in advance by using RPM. It places marker block on dynamic phantom based on this result, inserts Gafchromic EBT film into the target, and investigates 5 Gy respectively at static and dynamic state. And it scanned investigated Gafchromic EBT film and analyzed dose distribution by using automatic calculation. Results: As a result of an analysis of Gafchromic EBT film's radiation amount at static and dynamic state, it could be known that dose distribution involving 90% is distributed within margin of error of 3 mm. Conclusion: As a result of an analysis of dose distribution's change depending on patient's respiratory cycle during respiratory gated radiation therapy, it is expected that the treatment would be possible within recommended margin of error at ICRP 60.

• Journal of radiological science and technology
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• v.40 no.3
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• pp.461-468
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• 2017

This study measured and compared the protective clothing using Pb used for shielding in a diagnostic X-ray energy range, and the shielding rates of X-ray fusion shielding materials using Si and $TiO_2$. For the experiment, a pad type shielding with a thickness of 1 mm was prepared by mixing $Si-TiO_2$, and the X-ray shielding rate was compared with 0.5 mmPb plate of The shielding rate of shielding of 0.5 mmPb plate 95.92%, 85.26 % based on the case of no shielding under each 60 kVp, 100 kVp tube voltage condition. When the shielding of $Si-TiO_2$ pad was applied, the shielding rate equal to or greater than 0.5 mmPb plate was obtained at a thickness of 11 mm or more, and the shielding rate of 100% or more was confirmed at a thickness of 13 mm in 60 kVp condition. When the shielding of $Si-TiO_2$ pad was applied, the shielding rate equal to or greater than 0.5 mmPb plate was obtained at a thickness of 17 mm or more, and a shielding rate of 0.5 mmPb plate was observed at a thickness of 23 mm in 100 kVp condition. Through the results of this study, We could confirm the possibility of manufacturing radiation protective materials that does not contain lead hazard using various metalic compound and liquid Si. This study shows that possibility of liquid Si and other metalic compound can harmonize easily. Beside, It is flexible and strong to physical stress than Pb obtained radiation protective closthes. But additional studies are needed to increase the shielding rate and reduce the weight.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.213-218
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• 2007

Purpose: To analyze retrospectively the outcome of postoperative radiation therapy with or without concurrent chemotherapy for curatively resected stage II pancreatic cancer with T3 or N1 disease. Materials and Methods: Between January 1996 and December 2005, twenty-eight patients completed adjuvant radiation therapy at Ajou University Hospital. The patients had either pathologic T3 stage or N1 stage. The radiation target volume encompassed the initial tumor bed identified preoperatively, resection margin area and celiac nodal area. In the case of N1 patients, the radiation field extended to the lower margin of the L3 vertebra for covering both para-aortic lymph nodes bearing area. The median total radiation dose was 50 Gy. Ten patients received concurrent chemotherapy. Results: Thirteen patients (46%) showed loco-regional recurrences. The celiac axis nodal area was the most frequent site (4 patients). Five patients showed both loco-regional recurrence and a distant metastasis. Patients with positive lymph nodes had a relatively high probability of a distant metastasis (57.1%). Patients that had a positive resection margin showed a relatively high local failure rate (57.1%). The median disease-free survival period of all patients was 6 months and the 1-and 2-year disease free survival rates were 27.4% and 8.2%, respectively. The median overall survival period was 9 months. The 2-and 3-year overall survival rates were 31.6% and 15.8%, respectively. Conclusion: The pancreatic cancer patients with stage II had a high risk of local failure and a high risk of a distant metastasis. We suggest the concurrent use of an effective radiation-sensitizing chemotherapeutic drug and adjuvant chemotherapy after postoperative radiation therapy for the treatment of patients with stage II pancreatic cancer.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.619-627
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• 2016

The purpose of this study is to investigate the effect of CT contrast agent and MRI contrast agent on the area dose in the body when using automatic exposure control system in general radiography. After making rectangular holes in the center of the abdominal thickness paraffin phantom, CT contrast agent and MRI contrast agent were respectively diluted with physiological saline solution for contrast medium dilution ratio of 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, 0:10%. Each experiment was set to 78 kVp, 320 mA, which is the proper condition for KUB photography, and thereafter a total of 30 inspections were made for each dilution ratio using an automatic exposure control device, and the area dose corresponding to the dilution ratio of each contrast agent, Average comparison and correlation analysis were performed on the exposure index. As a result, the CT contrast agent and the MRI contrast agent appeared different in area dose according to the dilution ratio(p<0.05), and as the dilution ratio increased, the area dose increased for CT contrast agent and MRI contrast agent(P<0.05). In each test, the exposure index showed the manufacturer's recommendation of 200-800 EI value, and the exposure index and area dose increased as the area dose increased(p<0.05). In conclusion, CT contrast agent and MRI contrast agent confirmed to increase the area dose by general imaging test using all automatic exposure control device. Therefore, it is considered that it is necessary to perform it after the contrast medium has been excreted sufficiently when using usual imaging test after using the contrast agent in CT and MRI examination.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.597-602
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• 2016

Recent clinical field utilizes the aluminium filter in order to reduce the low-energy photons. However, the usage of the filter can cause adverse effect on the image quality because of the scattered dose that is generated by X-ray hardening phenomenon. Further, usage of filter with improper thickness can be a reason of dose creep phenomenon where unnecessary exposure is generated towards the patient. In this study, the author evaluated the RMS and the RSD analysis in order to have a quantitative evaluation for the effect of forward scattering dose by the filter on the image. as a result of the study, the FSR and the RSD was increased together with the increasing of thickness of the filter. In this study the RSD means the standard deviation of the mean value is relatively size. It can be understood that the signal-to-noise ratio decreases when the average value is taken as a signal and the standard deviation is judged as a noise. The signal-to-noise ratio can understanding as index of resolution at image. Based on these findings, it was quantitatively verified that there is a correlation of the image quality with the FSR by using an additional filter. The results, a 2.5 mmAl which is as recommended by NCRP in the tube voltage of 70 kVp or more showed the 14.6% on the RSD when the filter was not in used. these results are considered able to be utilized as basic data for the study about the filter to improve the quality of the image.