• Korean Journal of Head & Neck Oncology
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• v.4 no.1
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• pp.13-19
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• 1988

Brachytherapy is known to be a good modality to achieve local control as a boost treatment following limited external irradiation, which may reduce the external beam related acute radiation sickness, particularly in head and neck cancer. The authors developed iridium-192 ribbons recently to replace the radium needles. Total of 13 head and neck cancer patients had been treated with Ir-192 ribbons during last one year from October 1986 to September 1987, and the results were analysed to assess the applicability of the fabricated sources. The conclusion is as follows; 1) Iridium implant achieved 54% (7/13) of complete response and 69% (9/13) of overall response rate in head and neck cancer. 2) Iridium is superior to radium and cecium in brachytherapy because of easier to use and lesser exposure to the personnel. 3) Afterloading technique is useful to modify dose distribution, to expand treatment site and method, and to develop interstitial hyperthermia.

• The Journal of the Korean bone and joint tumor society
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• v.15 no.1
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• pp.81-86
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• 2009

An extraskeletal osteosarcoma is a rare malignancy. A small number of cases and studies have been reported in the world and only two cases have been reported in Korea. We experienced an extraskeletal osteosarcoma around the knee joint of 91-year-old male who was the oldest case in the literatures. It was developed without history of trauma, irradiation, myositis ossificans, and heterotopic ossification of dermatomyositis. This patient was treated with excision alone, however he was alive and there were no sign of local recurrence or distant metastasis and functional loss during 1-year follow-up.

• Applied Microscopy
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• v.45 no.3
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• pp.107-114
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• 2015

Two-dimensional (2D) materials containing hole defects are a promising substitute for conventional nanopore membranes like silicon nitride. Hole defects on 2D materials, as atomically thin nanopores, have been used in nanopore devices, such as DNA sensor, gas sensor and purifier at lab-scale. For practical applications of 2D materials to nanopore devices, researches on characteristics of hole defects on graphene, hexagonal boron nitride and molybdenum disulfide have been conducted precisely using transmission electron microscope. Here, we summarized formation, features, structural preference and stability of hole defects on 2D materials with atomic-resolution transmission electron microscope images and theoretical calculations, emphasizing the future challenges in controlling the edge structures and stabilization of hole defects. Exploring the properties at the local structure of hole defects through in situ experiments is also the important issue for the fabrication of realistic 2D nanopore devices.

• Korean Journal of Materials Research
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• v.30 no.12
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• pp.701-708
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• 2020

Irradiation of the metal nanoparticles causes local plasmon resonance in a specific wavelength band, which can improve the absorption and scattering properties of a structure. Since noble metal nanoparticles have better resonance effects than those of other metals, it is easy to identify plasmonic reactions and this is advantageous to find the optical tendency. Compared to having a particle gap or randomly arranged particle structures, densely and evenly packed structures can exhibit more uniform optical properties. Using the uniform properties, the structure can be applied to optical filtering applications. Therefore, in this paper, validation tests about metal nanoparticles and thin film structures are conducted for more accurate analysis. The optical properties of monolayer and bilayer noble metal nanoparticle structures with different diameters, packed in a uniform array, are investigated and their optical trends are analyzed. In addition, a thin film structure under identical conditions as metal nanoparticle structure is evaluated to confirm the improved optical characteristics.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.213-225
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• 1989

An analysis has been made of two hundred seven patients who were treated at the department of Radiation Oncology of Korea University Hospital for lung cancer from January 1981 through December 1986. There were 137 patients of nonsmall cell carcinoma (137/207, 66%), 26 patients of small cell carcinoma (26/207, 12.5%) and 44 patients of unproven histology. By aims of treatment, there were 104 patients (104/207, 50%) treated for cure, 89 patients (89/207, 42.9%) for palliation and 14 patients treated postoperatively. In 22 out of 207 patients, chemotherapy was done with radiotherapy, 12 of which were patients with small cell carcinoma. Stage II patients were 49 (49/207, 23.6%), stage III patients were 157 (157/207, 75.8%) and one patient had an occult cancer The tumor was initial Iy measured by CAT scan and chest X-rays in the 165 (165/207, 79.7%) patients, among which 117 patients had tumor diameter more than 5cm and 48 patients less than 5cm. Radiation therapy was given with Cobalt 60 teletherapy unit and the treatment volume encompassed primary tumor and the mediastinum. For curative aim, daily tumor dose of 180 cGy was given up to the range of 5,400~6,120cGy/30~34F/6~7 week period and for palliative aim, daily tumor dose of 300 cGy was given up to the range of 3,600~4,500 cGy/12~15F/2~3 week period. Postoperatively, mediastinum was treated for total dose of 5,040 cGy/28F/5.5 week period. 123 patients (123/207, 59%) were followed up after completion of radiotherapy for 14 months to 7 years. Local tumor response to the irradiation was measured by chest X-ray taken at one month follow up and was evaluated for response rate, if they were regressed more than 50% or less than 50% of the initial tumor size. The treatment results were as follows; 1. The median survival time was 8.5 months and survival rates for 1 year, 2 year and 5 year was 25%, 3.5% and 1% of nonsmall cell lung ca of 74 evaluable patients. 2. More than 50% of local tumor response rate was obtained in about half of overall cases; 90.5% for small cell ca, 50% for squamous cell ca, 25% for adenoca and 57% for large cell ca. 3. Response rate more than 50% was seen in the 50% of the patient group with tumor diameter more than 5cm and in the 55% of those with tumor diameter less than 5cm. 4. By total raidation dose given, patient group which was given 5,400~6,120 cGy equivalent dose or higher showed tumor response rate more than 50% in 53% of the patients, whereas the group with dose less than 5,400cGy equivalent, in 25% of the patients. 5. Survival rate for 6 month, 1 year and 2 year was compared between the group of local tumor response rate more than 50% vs. group with response rate less than 50%; 74% vs. 43%, 33% vs, 23%, 10% vs. 1%, respectively. 6. Local failure was seen in 21%(44/207) of the patients, which occured mostly within 15 months after completion of radiation therapy. Distant metastases were seen in 49.7%(103/207) of the patients, of which 43 cases were found before initiation of radiotherapy. The most common metastatic sites were bone and brain. In this sutdy, 1 year,2 year and S year survival rates were somewhat poor compared to the other studies. It mainly seems to be due to the poor general status of the patients and the far-advanced stage of the disease. In nonsmall cell cancer patients who had limited local disease and had small primary tumor size, we observed better local response. In addition, dose higher than 6,000 cGy group showed better tumor control than lower dose group. Survival rate was better for the local control group. For imporvement of local control of the lung cancer and hence, the survival of the patients with lung cancer, proper radical radiotherapy with high dose for localized disease is needed. New modality of treatment such as high LET beam in radiation therapy or drugs for the advanced disease as well as early diagnosis is also needed.

• Radiation Oncology Journal
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• v.17 no.4
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• pp.269-274
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• 1999

Purpose : To evaluate the Possibility of decreasing the radiation dose and to determine optimum treatment volume in intracranial germinomas. Materials and Methods : Forty five patients with pathologically-verified or presumed germinomas by a radiosensitivity test who had been treated with radiotherapy (RT) alone between 1971 and 1992 were retrospectively analyzed. The average age was 17.2 years with 68.9$\%$ of the patients being between the ages of 10$\~$20. The male and female ratio was 2.2:1. The locations of the primary tumors were at the pineal regions in 14 patients; the suprasellar regions in 12 patients; and multiple sites in 12 patients. Treatment volumes varied from a small local field (10) to the whole brain (7) or entire neuroaxis irradiation(28). All the cases after 1982 received craniospinal irradiation (CSI). Radiation doses were 41-59 Gy (median 48.5 Gy) to the primary tumor site and 19.5$\~$36 Gy (median 24 Gy) to the neuroaxis. The median follow-up period was 82 months with a range of 2$\~$260 months. Results : All the patients showed complete response after RT. Four patients sufferred from recurrence 14, 65, 76, and 170 months after RT, respectively, and two patients died with intercurrent disease. One of four recurrent cases was salvaged by re-irradiation. Therefore, a 5 and 10 year overall suNival was 95.3$\%$ and 84.7 $\%$ respectively. Five and ten year disease-free survival was 97.6 $\%$ and 88.8 $\%$ respectively. All the recurrences occurred in the patients who received local RT (3/10) or whole brain RT (1/7) with a radiation dose of 48-50 Gy. None of the patients who received CSI suffered recurrence. There was no recurrence among the 15 patients who received $\leq$45 Gy to the primary site and the 18 patients who received $\leq$24 Gy (6 patients received 19.5 Gy) to the neuroaxis. Conclusion : CSI is recommended for the treatment of intracranial germinomas. The radiation dose can be safely decreased to $\leq$45 Gy on a primay tumor site and 19.5 Gy on the spine.

• Applied Biological Chemistry
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• v.26 no.2
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• pp.82-89
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• 1983

In order to develop a commercial storage method of onions by irradiation combined with natural low temperature, two local varieties of onions, precocious species and late ripening, were stored at natural low temperature storage room ($450{\times}650{\times}250cmH.$; year-round temperature change, $2{\sim}17^{\circ}C$; R.H., $80{\sim}85%$) on batch scale following irradiation with optimum dose level. Precocious and late varieties were all sprouted after five to seven months storage, whereas $10{\sim}15$ Krad irradiated precocious variety was $2{\sim}4%$ sprouted after nine months storage, but sprouting was completly inhibited at the same dose for late variety. The extent of loss due to rot attack after ten months storage were $23{\sim}49%$ in both control and irradiated group of precocious variety but those of late variety were only $4{\sim}10%$. The weight loss of irradiated precocious variety after ten months storage was $13{\sim}16$, while that of late variety was $5.3{\sim}5.9%$ after nine months storage. The moisture content, during whole storage period, of two varieties were $90{\sim}93$ with negligible changes. The total sugar content differed little with varieties and doses immediatly after irradiation, but decreased by the elapse of storage period. 33.6% of its content was decreased in control and 12.5% in irradiated group but $20{\sim}26$ decreased in both control and irradiated group of late variety after nine months storage. No appreciable change was observed immediately after irradiation irrespective of variety and dose, but decreased slightly with storage. Ascorbic acid content of precocious variety was increased slightly with dose immediately after irradiation, but those of late variety decreased slightly. Ascorbic acid content were generally decreased during whole storage period. An economical preservation method of onions appliable to late variety, would be to irradiate onion bulbs at dost range of $10{\sim}15$ Krad followed by storage at natural low temperature storage room.

• Radiation Oncology Journal
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• v.13 no.1
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• pp.55-61
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• 1995

Purpose : Despite a development of therapeutic machines and advance in modern radiation therapy techniques, locally advanced cervical carcinoma has shown high rate of local failure and poor survival rate, Combination of chemotherapy and radiotherapy demonstrated benefit in improving local control and possibly the overall survival. Our study was performed to evaluate effect of concurrent chemoradiation on locally advanced uterine cervical cancer. Methods and Materials : Twenty six patients with locally advanced stage(FIGO stage IIB with ${\geq}5cm$ in diameter, III, IVA) were treated with combination of radiation therapy and concurrent cisplatinum between May of 1988 and September of 1993 at our hospital. Radiation therapy consisted of external irradiaton and 1-2 sessions of intracavitary irradiation. Cisplatinum was administered in bolus injection of 25mg/$m^2$ at weekly intervals during the course of external radiation therapy. Results : Of the 26 Patients, twenty-five patients were evaluable for estimation of response. Median follow-up period was 25 months with ranges from 3 to 73 months. Stage IIB, III, and IVA were 16, 5, 4 patients, respectively, Twenty patients were squamous cell carcinoma. Response was noted in all 25 patients: complete response(CR) in 17/25($68\%$), Partial response(PR) in 8/25($32\%$). Of the 24 patients except one who died of sepsis at 3 months follow-up, seventeen patients($70.8\%$) maintained local control in the pelvis: 16/17($94.1\%$) in CR, 1/17($14.3\%$) in PR. Fourteen of the 17 patients with CR are alive disease free on the completion of follow-up. Median survival is 28 months for CR and 15 months for PR. Analysis of 5-year survival by stage shows 11/16($59.8\%$) in IIB, 3/5($60.0\%$) in III, and 1/4($25.0\%$) in IVA. Overall 5-year survival rate was $55.2\%$. Ten patients recurred: 4 at locoregional, 3 in distant metastasis and 3 with locoregional and distant site. Toxicity by addition of cisplatinum was not excessive. Conclusion : Although the result of this study was obtained from small number of patients, it is rather encouraging in view of markedly improved response rate compared with the results of historical group.

• Radiation Oncology Journal
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• v.13 no.1
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• pp.19-26
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• 1995

Purpose : Surgery is the treatment of choice for resectable non-small cell lung cancer. For patients who are medically unable to tolerate a surgical resection or who refuse surgery, radiation therapy is an acceptable alternative. A retrospective analysis of Patients with stage I non-samll cell lung cancer treated with curative radiation therapy was performed to determine the results of curative radiation therapy and patterns of failure, and to identify factors that may influence survival. Materials and Methods : From 1986 through 1993, 39 Patients with T2N0M0 non-small cell lung cancer were treated with curative radiation therapy at department of radiation oncology, Kyungpook national university hospital. All Patients were not candidates for surgical resection because of either Patient refusal (16 patients), poor pulmonary function (12 patients), old age (7 patients), Poor Performance (2 patients) or coexisting medical disease (2 patients). Median age of patients was 67 years. Histologic cell type was squamous cell carcinoma in 36, adenocarcinoma in 1, large cell carcinoma in 1 and mucoepidermoid carcinoma in 1. All patients were treated with megavoltage irradiation and radiation dose ranged from 5000cgy to 6150cGy with a median dose of 6000cGy. The median follow-up was 17 months with a range of 4 to 82 months, Survival was measured from the date therapy initiated. Results : The overall survival rate for entire Patients was $40.6\%$ at 2 years and $27.7\%$ at 3 years, with a median survival time of 21 months. The disease-free survival at 2 and 3 years was $51.7\%$ and $25.8\%$, respectively. Of evaluable 20 patients with complete response, 15 patients were considered to have failed. Of these, 13 patients showed local failure and 2 patients failed distantly. Response to treatment (p=0.0001), tumor size (p=0.0019) and age (p=0.0247) were favorably associated with overall survival. Only age was predictive for disease-free survival (p = 0.0452). Conclusion : Radiation therapy is an effective treatment for small (less than 3cm) tumors, and should be offered as an alternative to surgery in elderly or infirm patients. Since local failure is the prominent Patterns of relapse, potential methods to improve local control with radiation therapy are discussed.

• Radiation Oncology Journal
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• v.12 no.3
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• pp.307-313
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• 1994

Purpose : Maxillary sinus cancers usually are locally advanced and involve the structures around sinus. It is uncommon for this cancer to spread to the regional lymph-nodes. For this reason, local control is of paramount important for cure. A policy of combined treatment is generally accepted as the most effective means of enhancing cure rartes. This paper reports our experience of a retrospective study of 31 Patients treated with radiation therapy alone and combination therapy of surgery and radiation. Materials and Methods: Between July 1974 and January 1992, 47 Patients with maxillary sinus cancers underwent either radiation therpay alone or combination therapy of surgery and radiation. Of these, only 31 patients were eligible for analysis. The distribution of clinical stage by the AJCC system was $26\%$(8/31) for T2 and $74\%$(23/31) for T3 and T4. Eight patients had palpable lymphadenopathy at diagnosis. Primary site was treated by Cobalt-60 radiation therapy using through a $45^{\circ}$ wedge-pair technique. Elective neck irradiation was not routinely given. Of these 8 patients, the six who had clinically involved nodes were treated with definite radiation therapy. The other two patients had received radical neck dissection. The twenty-two patients were treated with radiation alone and 9 patients were treated with combination radiation therapy, The RT alone patients with RT dose less than 60 Gy were 9 and those above 60 Gy were 13. Results : The overall 5 year survival rate was $23.8\%$. The 5 year survival rate by T-stage was $60.5\%$ and $7.9\%$ for T2 and T3,4, respectively. Statistical significance was found by T-stage(p<0.005). The 5 year survival rate by N-stage was $30\%$ for N (-) and $8.3\%$ for N(+), but statistically no significant difference was seen(p${\geq}$0.1). The 5 year survival rate for RT alone and combination RT was $22.5\%$ and $27.4\%$, respectively. The primary local control rate was $65\%$ (20/31). Conclusion : This study did not show significant difference in survival between RT alone and combination RT. There is still much controversy with regard to which treatment is optimum. Improved RT technique and development of multimodality treatment are essential to improve the local control and the survival rate in patients with advanced maxillary sinus cancer.