• 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.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.2
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• pp.168-175
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• 2003

Fracture about proximal humerus may be classified as the articular segment or the anatomical neck, the greater tuberosity, the lesser tuberosity, and the shaft or surgical neck. Now, usually used, Neer's classification is based on the number of segments displaced, over 1cm of displaced or more than 45 degrees of angulation , rather than the number of fracture line . Absolute indication of a operative treatment a open fracture, the fracture with vascular injury or nerve injury , and unreductable fracture-dislocation . Inversely, the case that are severe osteoporosis, and eldly patient who can't be operated by strong internal fixation is better than arthroplasty used by primary prosthetic replacement and early rehabilitation program than open reduction and internal fixation. The operator make a decision for the patient who should be taken the open reduction and internal fixation, because it's different that anatomical morphology, bone density, condition of patient. The operator decide operation procedure. For example, percutaneous pinning, open reduction, plate & screws, wire tension bands combined with some intramedullary device are operation procedure that operator can decide . The poor health condition for other health problem, fracture with unstable vital sign and severe osteoporosis , are the relative contraindication. The stable fracture without dislocation is not the operative indication . The radiologic film of the prokimal humerus before the operation can not predict for fracture evaluation. It's necessary to good radiologic film for evaluation of fracture form. The trauma serise is better than the other radiologic film for evaluation. The accessary radiologic exam is able to help for evaluation of bone fragment and anatomy. The CT can be helpful in evaluating these injury, especially if the extract fracture type cannot be determined from plain roenterogram of the proximal humerus, bone of humerus head. If the dislocation is severe anatomically , we could consider to do three dimentional remodelling. The MRI doing for observing of bony morphology before the operation is not better than CT If we were suspicious of vascular injury, we could consider the angiography.

• Radiation Oncology Journal
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• v.21 no.2
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• pp.167-173
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• 2003

Purpose: The purpose of this study was to evaluate whether a GafChromic film applied to stereotactic radiosurgery with a linear accelerator could provide information on the value for acceptance testing and quality control on the absolute dose and relative dose measurements and/or calculation of treatment planning system. Materials and methods: A spherical acrylic phantom, simulating a patient's head, was constructed from three points. The absolute and relative dose distributions could be measured by inserting a GafChromic film into the phantom. We tested the use of a calibrated GafChromic film (MD-55-2, Nuclear Associate, USA) for measuring the optical density. These measurements were achieved by irradiating the films with a dose of 0-112 Gy employing 6 MV photon. To verify the accuracy of the prescribed dose delivery to a target isocenter using a five arc beams (irradiated in 3 Gy per one beam) setup, calculated by the Linapel planning system the absolute dose and relative dose distribution using a GafChromic film were measured. All the irradiated films were digitized with a Lumiscan 75 laser digitizer and processed with the RIT113 film dosimetry system. Results: We verified the linearity of the Optical Density of a MD-55-2 GafChromic film, and measured the depth dose profile of the beam. The absolute dose delivered to the target was close to the prescribed dose of Linapel within an accuracy for the GafChromic film dosimetry (of $\pm$3$\%$), with a measurement uncertainty of $\pm$1 mm for the 50$\~$90$\%$ isodose lines. Conclusion: Our results have shown that the absolute dose and relative dose distribution curves obtained from a GafChromic film can provide information on the value for acceptance. To conclude the GafChromic flim is a convenient and useful dosimetry tool for linac based radiosurgery.

• Progress in Medical Physics
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• v.9 no.2
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• pp.77-88
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• 1998

Wedge shaped isodoses are desired in a number of clinical situations. Hard wedge filters have provided nominal angled isodoses with dosimetric consequences of beam hardening, increased peripheral dosing, nonidealized gradients at deep depths along with the practical consequendes of filter handling and placement problems. Dynamic wedging uses a combination of a moving collimator and changing monitor dose to achieve angled isodoses. The segmented treatment tables(STT) that monitor unit setting by every distance of moving collimator, was induced by numerical formular. The characteristics of dynamic wedge by STT compared with real dosimetry. Methods and Materials : The accelerator CLINAC 2100C/D at Yonsei Cancer Center has two photon energies (6MV and 10MV), currently with dynamic wedge angles of 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$ and 60$^{\circ}$. The segmented treatment tables(STT) that drive the collimator in concert with a changing monitor unit are unique for field sizes ranging from 4.0cm to 20.0cm in 0.5cm steps. Transmission wedge factors were measured for each STT with an standard ion chamber. Isodose profiles, isodose curves, percentage depth dose for dynamic wedge filters were measured with film dosimetry. Dynamic wedge angle by STT was well coincident with film dosimetry. Percent depth doses were found to be closer to open field but more shallow than hard wedge filter. The wedge transmission factor were decreased by increased the wedge angle and more higher than hard wedge filters. Dynamic wedging probided more consistent gradients across the field compared with hard wedge filters. Dynamic wedging has practical and dosimetric advantages over hard filters for rapid setup and keeping from table collisions. Dynamic wedge filters are positive replacement for hard filters and introduction of dynamic conformal radiotherapy and intensity modulation radiotherapy in a future.

• Radiation Oncology Journal
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• v.24 no.1
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• pp.37-43
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• 2006

Purpose: We wanted to determine the clinical characteristics and prognosis according to the VEGF expression in stage II cervical carcinoma patients treated with definitive radiotherapy. Materials and Methods: We enrolled 31 patients who were diagnosed with cervical cancer from 1995 to 2003 at Samsung Medical Center and their paraffin block tissue samples were available for study. The median age of the patients was 65 years. The mean tumor size was 4.1 cm $(range:\;1.2{\sim}8.2cm)$. Seven patients (22.6%) were suspected of having pelvic lymph node metastasis. An external beam irradiation dose of 45-56.4 Gy was administered to the whole pelvis with a 15 MV linear accelerator, and an additional 24 Gy was given to point A by HDR intracavitary brachytherapy. VEGF staining was defined as positive when more than 10% of the tumor cells were stained. The median follow-up duration was 58 months. Results: A positive VEGF expression was observed in 21 patients (67.7%), There was no significant correlation between the VEGF expression and pelvic lymph node metastasis, tumor size and the response of radiotherapy. During follow-up, 7 patients had recurrence. The complete response rate was not significant between the VEGF(-) and VEGF(+) tumors. However, the VEGF(+) tumors showed a significantly higher recurrence rate in comparison with the VEGF(-) tumors (p=0.040), The three year disease-free survival rates were 100% and 66.7%, respectively, for patients with VEGF(-) or VEGF(+) tumor (p=0.047), Conclusion: The VEGF expression was a significant factor for recurrence and disease-free survival. However, the significance of the VEGF expression is still controversial because of the various definitions of VEGF expression and the mismatches of the clinical data in the previous studies.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.325-331
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• 2015

Skin is exposed to sunlight or artificial indoor light on a daily. The reached solar light on the earth surface consist of 50% visible light and 45% infrared (IR) except for ultra violet (UV). The negative effects of UV including UVB and UVA have been steadily investigated within the last decades. However, little is known about the effects of visible or IR light. In this study, we irradiated human dermal fibroblasts using light emitting diode (LED) to investigate the optimal parameter for enhancing cell growth and collagen synthesis. We found that red of 630 nm and green of 520 nm enhance the cell proliferation, but irradiation with purple and blue light exerts toxic effects. To examine the response of irradiation time and light intensity on the fibroblasts, cells were exposed to red or green light with intensities from 0.05 to $0.75mW/cm^2$. Procollagen secretion was increased of 1.4 fold by 10 min irradiation, while 30 min treatment decreased the collagen synthesis of dermal fibroblasts. Treatment with red of $0.3mW/cm^2$ and green of 0.15 and $0.3mW/cm^2$ resulted in enhancement of collagen mRNA. Lastly, we investigated the combinatorial effect of red and green light on dermal fibroblasts. The sequential irradiation of red and green light is an efficient way for the purpose of the increase in the number of fibroblasts than single light treatment. On the other hand, the exposure of red light alone was more effective method for enhancing of collagen secretion. Our study showed that specific light parameters accelerated cell proliferation, gene expression and collagen secretion on human dermal fibroblasts. In conclusion, we demonstrate that light exposure with specific parameter has beneficial effects on the function of dermal fibroblasts, and suggests the possibility of its cosmetically and clinical application.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.147-157
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• 1998

Purpose : The aim of this retrospective study is to assess the necessity of s1aging laparotomy in the management of supradiaphragmatic CS I-II Hodgkin's disease. Prognostic factors and the usefulness of prognostic factor groups were also analyzed. Materials and Methods : From 1985 to 1995, fifty one Patients who were diagnosed as supradiaphragmatic CS I-II Hodgkin's disease at Yonsei Cancer Center in Seoul, Korea were enrolled in this study Age range was 4 to 67 with median age of 30. The number of patients with each CS IA, II A, and IIB were 16, 25, and 10, respectively. Radiotherapy(RT) was delivered using 4 or 6 MV photon beam to a total dose of 19.5 to 55.6Gy (median dose : 45Gy) with a 1.5 to 1.BGy per fraction. Chemotherapy(CT) was given in 2-12 cycles(median : 6 cycles). Thirty one Patients were treated with RT alone, 4 patients with CT alone and 16 patients with combined chemoradiotherapy. RT volumes varied from involved fields(3), subtotal nodal fields(18) or mantle fields(26). Results : Five-year disease-free survival rate(DFS) was $78.0\%$ and overall survival rate(05) was $87.6\%$. Fifty Patients achieved a complete remission after initial treatment and 8 patients were relapsed. Salvage therapy was given to 7 patients, 1 with RT alone, 4 with CT alone, 2 with RT+CT. Only two patients were successfully salvaged. Feminine gender and large media-stinal adenopathy were significant adverse prognostic factors in the univariate analysis for DFS. The significant adverse prognostic factors of OS were B symptom and clinical stage. When patients were analyzed according to European Organization for Research and Treatment of Cancer(EORTC) prognostic factor groups, the DFS in Patients with very favorable, favorable and unfavorable group was 100, 100 and $55.8\%$(p<0.05), and the 05 in each patients' group was 100, 100 and $75.1\%$(p<0.05), respectively. In very favorable and favorable groups, the DFS and 05 were all $100\%$ by RT alone, but in unfavorable group, RT with CT had a lesser relapse rate than RT alone. The subtotal nodal irradiation had better OFS than mantle RT in patients treated with RT. Conclusion : In present study, the DFS and OS in patients who did not undergo s1aging laparotomy were similar with the results in the literatures of which patients were surgically staged. Therefore, we may suggest that staging laparotomy would not influence the outcome of treatments. In univariate analysis, gender, large mediastinal adenopathy. B symptoms and clinical stage were significant prognostic factors for the survival rate. We confirm the usefulness of EORTC prognostic factor groups which may be a good.

• Journal of Food Hygiene and Safety
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• v.27 no.3
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• pp.233-246
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• 2012

In this study, we investigated the applicability of the photostimulated luminescence(PSL), thermoluminescence(TL) and electron spin resonance(ESR) methods for various foods which are not allowed to be irradiated in Korea. All 15 foods including sesame, almond, peanut, cocoa powder etc. were analyzed. Samples were irradiated at 1~10 kGy using a $^{60}Co$ gamma-ray irradiator. In PSL study, the photon counts of all the unirradiated samples showed negative(lower than 700). The photon counts irradiated(1 kGy) dried shrimp, roasted peanut and seasoned peanut showed positive(higher than 5,000) and the other samples were negative or intermediate(> 700 and < 5,000). In TL analysis, results showed that it is possible to apply TL method to all foods containing minerals. In ESR measurements, the ESR signal(single-line) intensity of irradiated foods was higher than non-irradiated foods. In particular, the specific ESR signals of irradiation-induced crystalline sugar, cellulose and bone radical were detected in dried plum, raisin, dried cherry, mango(dried, frozen), rambutan, cocoa(powder), cinnamon, parsley, carrot, broccoli, dried arrow squid, dried pollack and dried shrimp. According to the results, PSL, TL and ESR methods were successfully applied to detect the irradiated foods because TL method is not able to detect the irradiated foods rarely composed of minerals. ESR is also a difficult method to detect the changes of ESR signal patterns of food. It is concluded that TL analysis or ESR assay is suitable for detection of irradiated samples and a combined method is recommendable for enhancing the reliability of detection results.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.233-243
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• 2000

Purpose : First of all, this study was performed to assess the result of curative radiotherapy and to evaluate different possible prognostic factors for squamous cell carcinoma of the supraglottic larynx treated at the Pusan National University Hospital. The second goal of this study was by comparing our data with those of other study groups, to determine the better treatment policy of supraglottic cancer in future. Methods and Material : Thirty-two patients with squamous cell carcinoma of the supraglottic larynx were treated with radiotherapy at Pusan National University Hospital, from August 1985 to December 1996. Minimum follow-up period was 29 months, Twenty-seven patients (84.4$\%$) were followed up over 5 years. Radiotherapy was delivered with 6 MV photons to the primary laryngeal tumor and regional iymphatics with shrinking field technique. Ail patients received radiotherapy under conventional fractionated schedule (once a day). Median total tumor dose was 70.2 Gy (range, 55.8 to 75.6 Gy) on primary or gross tumor lesion. Thirteen patients had Induction chemotherapy with cisplatln and 5-fluorouracil (1-3 cycles). Patient distribution, according to the different stages, were as follows: stage I, 5/32 (15.6$\%$): stage II, 10/32 (31.3$\%$); stage III, 8/32 (25$\%$): stage IV, 9/32 (28.1$\%$). Results :The 5-year overall survival rate of the whole series (32 patients) was 51.7$\%$. The overall survival rate at 5-years was 80$\%$ in stage I, 66.7$\%$ in stage II, 42.9$\%$ in stage III, 25$\%$ in stage IV (p=0.0958). The S-year local control rates after radiotherapy were as fellows: stage I, 100$\%$; stage II, 60$\%$ stage III, 62.5$\%$; stage IV, 44.4$\%$ (p=0.233). Overall vocal preservation rates was 65.6$\%$, 100% In stage I, 70% in stage II, 62.5$\%$ In stage III, 44.4$\%$ in stage IV (p=0.210). There was no statistical significance in survival and local control rate between neoadjuvant chemotherapy followed by radiotherapy group and radiotherapy alone group. Severe laryngeal edema was found in 2 cases after radiotllerapy, emergent tracheostomy was done. Four patients were died from distant metastsis, . three in lung, one in brain. Double primary tumor was found in 2 cases, one in lung (metachronous), another in thyroid (synchronous). Ulcerative lesions were revealed as unfavorable prognostic factor ( p=0.0215), and radiation dose (more or less than 70.2 Gy) was an important factor on survival (p=0.002). Conclusion : The role of radiotherapy treatment of supraglottic carcinoma is to important factor on survival and to preserve the laryngeal function. Based on our data and other studies, early and moderately advanced supragiottic carcinomas could be successfully treated with either consewative surgery or radiotherapy alone. Both modalities showed similar results in survival and vocal preservation. For the advanced cases, radiotherapy alone is Inadequate for curative aim and surgery combined with radiotherapy should be done in operable patients. When patients refuse operation or want to preserve vocal function, or for the patients with inoperable medical conditions, combined chemoradiotherapy (concurrent) or altered fractionated radiotherapy with or without radiosensitizer should be taken into consideration in future.