• Journal of Korean Society of Environmental Engineers
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• v.30 no.3
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• pp.323-330
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• 2008

The study presents the results of 1,4-dioxane degradation using zero valent (Fe$^0$) or Fe$^{2+}$ ions with and without UV. During the reaction, the change of [Fe$^{2+}$] and [Fe$^{2+}$]/[Fe(t)], the concentration ratio of ferrous ion to total iron ion in solution was measured. Less than 10% degradation of 1,4-dioxane was observed by UV-only, Fe$^0$-only, and Fe$^{2+}$-only conditions, and also the changes of [Fe$^{2+}$] and [Fe$^{2+}$]/[Fe(t)] were minimal in each reaction. However, the oxidation of Fe$^0$ was enhanced with the irradiation of UV by approximately 25% and the improvement of 1,4-dioxane degradation was observed. Fenton reaction ($Fe^{2+}+H_2O_2$) showed higher degradation efficiency of 1,4-dioxane until 90 min, which of the degradation was stopped after that time. In the reaction of Fe$^{2+}$ and UV, the ratio of [Fe$^{2+}$]/[Fe(t)] decreased then slowly increased after a certain time indicating the reduction of Fe3+ to Fe$^{2+}$. In case of Fe$^0$ in the presence of UV, the first-order rate constant was found to be 1.84$\times$10$^{-3}$ min$^{-1}$ until 90 min, and then changed to 9.33$\times$10$^{-3}$ min$^{-1}$ when the oxidation of Fe$^{2+}$ mainly occurred. In this case [Fe$^{2+}$]/[Fe(t)] kept decreasing for the reaction. However, the addition of perchlortae (ClO$_4^-$) in the reaction of Fe$^0$ and UV induced the continuous increase of [Fe$^{2+}$]/[Fe(t)] ratio. The results mean the primary degradation factor of 1,4-dioxane is the oxidation by the radicals generated from the redox reaction between Fe$^{2+}$ and Fe$^{3+}$. Also, both UV and ClO$_4^-$ played the role inducing the reduction of Fe$^{3+}$, which is important to degrade 1,4-dioxane by enhancing the generation of radicals.

• Microbiology and Biotechnology Letters
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• v.15 no.6
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• pp.388-395
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• 1987

In order to obtain a regulatory mutant strain with high cellulase activity, a newly isolated Penicillium verrculosum, strain F-3 was used as parental strain since it was proved to be an efficient cellulase producer. A number of experiments were conducted to determine the optimum conditions to in-duce mutagenesis and isolate the desirable mutant strains. Out of several restriction compounds tested, 1.5% oxgall was found to be most effective to restrict the colony size by suppressing overgrowth. Derepression of catabolites was employed as a criterion in selecting mutant strains with high cellulase productivity. Production of cellulase by Penicillium venculosum F-3 was suppressed when cultured on the media with more than 1% of glucose or glycerol. It was found that either irradiation with UV light for 19 mins or treatment with nitrosoguanidine at 200$\mu\textrm{g}$/m1 for 60 mins, induced mutagenesis at desired level, when the survival rate of the spore was 0.2% and 48%, respectively. Three mutant strains of F-3, UV-9, UV-10, and NTG-3 that had the highest cellulase productivity were finally selected, based on filter paper degradation rate, size of clearing zone on the screening plate and cellulase activity in the medium containing cellulose powder. When the mutant strains were compared with parental strain F-3, on the KC-M-W medium containing cellulose powder, the filter paper activities of UV-9, UV-10, and NTG-3 were increased by 34%, 55%, and 41%, respectively. However, the assimilation of cellobiose octaacetate by UV-9 or NTG-3 was markedly reduced. When the mutant UV-10 was grown on cellobiose octaacetate medium (CCA-4) in shaking flasks, the cellulase activities of the mutant increased by 20 to 50% compared to the parental strain. Excreation of soluble protein from the mutant also elevated up to 30%. The mutant also constitutively produced both CMCase and $\beta$-glucosidase, though at relatively low level, in the presence of glucose or cellobiose as carbon sources.

• The Journal of Korean Society for Radiation Therapy
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• v.15 no.1
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• pp.67-77
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• 2003

I. Purpose Uniform dose distribution of the whole body is essential factor for the total body irradiation(TBI). In order to achieved this goal, we used to compensation filter to compensate body contour irregularity and thickness differences. But we can not compensate components of body, namely lung or bone. The purpose of this study is evaluation of dose attenuation in bone tissue when TBI using diode detectors and TLD system. II. Materials and Methods The object of this study were 5 patients who undergo TBI at our hospital. Dosimetry system were diode detectors and TLD system. Treatment method was bilateral and delivered 10MV X-ray from linear accelerator. Measurement points were head, neck, pelvis, knees and ankles. TLD used two patients and diode detectors used three patients. III. Results Results are as followed. All measured dose value were normalized skin dose. TLD dosimetry : Measured skin dose of head, neck, pelvis, knees and ankles were $92.78{\pm}3.3,\;104.34{\pm}2.3,\;98.03{\pm}1.4,\;99.9{\pm}2.53,\;98.17{\pm}0.56$ respectably. Measured mid-depth dose of pelvis, knees and ankles were $86{\pm}1.82,\;93.24{\pm}2.53,\;91.50{\pm}2.84$ respectably. There were $6.67\%{\sim}11.65\%$ dose attenuation at mid-depth in pelvis, knees and ankles. Diode detector : Measured skin dose of head, neck, pelvis, knees and ankles were $95.23{\pm}1.18,\;98.33{\pm}0.6,\;93.5{\pm}1.5,\;87.3{\pm}1.5,\;86.90{\pm}1.16$ respectably. There were $4.53\%{\sim}12.6\%$ dose attenuation at mid-depth in pelvis, knees and ankles. IV. Conclusion We concluded that dose measurement with TLD or diode detector was inevitable when TBI treatment. Considered dose attenuation in bone tissue, We must have adequately deduction of compensator thickness that body portion involved bone tissue.

• 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.19 no.1
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• pp.40-44
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• 2001

Purpose : To evaluate effect and tolerance of external beam radiotherapy for carcinoma of the prostate and define the optimal radiotherapeutic regimen. Materials and methods : We retrospectively analyzed the records of 60 patients with prostate cancer who were treated with external beam radiotherapy with curative intent in our institution between September, 1987 and March, 2000. Histologic diagnosis was established by transurethral resection or ultrasonography guided biopsy. The major presenting symptoms were a nodule at routine prostatic examination and frequency and urgency of urination, along with dysuria. The median age was 63 years with range of 51 to 87 years. There were 6 patients in Stage A, 20 in Stage 8, 26 in Stage C, and 8 in Stage Dl. All patients were treated with megavoltage equipment producing 10 MV photons. The 4 field pelvic brick technique was used to a dose of 45 Gy or 50.4 Gy at 1.8 Gy per day in 5 to 6 weeks, after which a small boost field was delivered 2.0 Gy per day to a total dose of 66 to 70 Gy. The follow-up period ranged from 1 to 8 years. Results : Actuarial 5-year and 7-year survival rates for Stage A, B, C, and D1 were $100\%\;and\;84\%$, $83\%\;and\;72\%$, $67\%\;and\;54\%$, and $v$, respectively. The corresponding 5-year and 7-year relapse free survival rates were $84\%\;and\;84\%$, $77\%\;and\;67\%$, $48\%\;and\;40\%$, and $33\%\;and\;25\%$, respectively. Relapse free 5-year survival rates for Stage B were $80\%,\;80\%,\;and\;50\%$ for well, moderately, and poorly differentiated tumors, respectively. These were $64\%,\;44\%,\;and\;33\%$ for Stage C, respectively. The local control rates at 5 years were $84\%,\;85\%,\;78\%,\;and\;60\%$ for Stage A, B, C, and D1, respectively. Mild to moderate complications were observed in $22\%$ of patients. Severe complications requiring surgical procedures were documented in only $3\%$ of patients. Conclusion : This study confirms that external beam irradiation is an effective and safe treatment for prostatic cancer, providing long-term local control and good survival with acceptable complications.

• Radiation Oncology Journal
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• v.19 no.1
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• pp.74-80
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• 2001

Purpose : Irradiation cones by using backscatter electrons are made for the treatment of superficial small lesions of skin, oral cavity, and rectum where a significant dose gradient and maximum surface dose is desired. Methods and Materials : Backscatter electrons are produced from the primary electron beams from the linear accelerators. The design consists of a cylindrical cone that has a thick circular plate of high atomic number medium (Pb or Cu) attached to the distal end, and the plate can be adjusted the reflected angle. Primary electrons strike the metal plate perpendicularly and produce backscatter electrons that reflect through the lateral hole for treatment. Using film and a parallel plate ion chamber, backscatter electron dose characteristics are measured. Results : The depth dose characteristic of the backscatter electron is very similar to that of the hard x-ray beam that is commonly used for the intracavitary and superficial lesions. The basckscatter electron energy is nearly constant and effectively about 1.5 MeV from the clinical megavoltage beams. The backscatter electron dose rate of $35\~85\;cGy/min$ could be achieved from modern accelerators without any modification. and the depth in water of $50\%$ depth dose from backscatter electron located at 6mm for $45^{\circ}$ angled lead scatter. The beam flatness is dependent on the slit size and the depth of treatment, but is satisfactory to treat small lesions. Conclusions : The measured data for backscatter electron energy, depth dose flatness dose rate and absolute dose indicates that the backscatter electrons are suitable for clinical use.

• Radiation Oncology Journal
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• v.12 no.1
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• pp.59-66
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• 1994

Seventy-five patients with tumors of the head and neck treated with either radiation therapy alone or combined with surgery or chemotherapy were studied prospectively to evaluate the effects of radiation therapy to the neck on thyroid gland between September 1986 and October 1992. All patients were serially monitored for thyroid function tests before and after radiation therapy. Radiation dose to the thyroid gland ranged from 35 to 60 Gy with a median dose of 50 Gy. Median follow-up time was 30 months with a range of 11 to 85 months. The incidence of thyroid dysfunction was 40$ \% $: forty-five patients(60$ \% $) euthyroid, 2 patients(3$ \% $) clinical hypothyroidism, 27 patients(36$ \% $) subclinical hypothyroidism and 1 patient(1$ \% $) hyperthyroidism. No thyroid nodules or thyroid cancer were detected in any patients. Thyroid dysfunction appeared earlier in patients who underwent surgery than in those patients treated with radiation therapy alone or combination of chemotherapy and radiation therapy(P=0.0013). By multivariate analysis, risk factors that significantly influenced a higher incidence of thyroid dysfunction were female sex(p=0.0293) and combination of total laryngectomy and radiation therapy(p : 0.0045). In conclusion, evaluation of thyroid function before and after radiation therapy with periodic thyroid function tests are recommended to detect thyroid dysfunction in time and thyroid hormone replacement therapy is recommended whenever thyroid dysfunction develops.

• Radiation Oncology Journal
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• v.15 no.2
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• pp.113-119
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• 1997

Purpose : Radical gastrectomy is main treatment of gastric cancer. But the result is not satisfactory with surgery alone. Most of pattern of failure remain locoregional recurrence. To improve 5 year survival postoperative chemotherapy with or without radiotherapy has been used. We analyzed patients with stage III and IV stomach cancer who had radical operation and received postoperative radiation therapy combined with or without chemotherapy retrospectively. Material and Method : From March 1985 to June 1993, 68 patients treated with curative resection and received postoperative adiuvant radiotherapy with 36Gy or more were evaluated. Median age was 60 years(range 28-66 yrs) . Patients were followed from 3 to 133 months with median follow up of 48 months. Thirty seven patients had non signet ring adenocarcinoma, 29 signet ring cell, 2 other cell. Patients with stage IIIA, IIIB, IV disease were 19, 25 and 24 respectively Chemotherapy was given to all patients except two. Results : Five-year overall survival and disease-free survival rate were 36.6% and 33.6%, respectively. Prognostic factor affecting survival were assessed. High ratio of jnvolved/dissected Iymph node, signet ring histology showed Poor Prognosis with statistical significance. Presence of residual tumor after surgery, stageIV. split course of radiation therapy, age, number of involved Iymph node, number of Iymph node dissection and grade of tumor affected survival without statistical significance, Type of chemotherapy did not affect survival. Recurrence was documented in 34 patients. High recurrence was seen in omentum and peritoneum with 23.5%, and remnant stomach, anastomosis site, A-loop and I-loop had also high recurrence with 13.2%. In field locoregional recurrence was 20.7% and total distant metastases were 39.7%. Total intraabdominal failure was 47.1% and extraabdominal failure was 13.2%. Treatment toxicity was considered to be acceptable. 22.1% of patients had grade 3 and only 1 patient had grade 4 leukopenia. Six Patients(8.8%) had weigh loss more than 10%. Conclusion : Treatment toxicity was acceptable with combined treatment with chemotherapy and radiotherapy. Locoregional recurrence was relatively low compared to distant failure with addition of irradiation. Peritoneal and omental seeding was high Five-rear surival was increased with combined modality. Radiation may eradicate minimal residual disease and improve survival, To evaluate role of radiation Prospective randomized study employing chemotherapy alone and chemotherapy plus radiation is necessary. Futhermore to reduce intraabdominal failure, role of intraabdominal chemotherapy in addition to combined chemotherapy plus radiation has to be explored.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.136-140
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• 1999

Purpose : Prostate specific antigen (PSA) is a useful tumor marker, which is widely used as a diagnostic index and predictor of both treatment and follow-up result in prostate cancer. A prospective analysis was carried out to obtain the period of PSA normalization and the half life of PSA and to analyze the factors influencing the period of PSA normalization. The PSA level was checked before and serially after radical radiotherapy. Materials and Method : Twen쇼 patients with clinically localized prostate cancer who underwent radical external beam radiotherapy were enrolled in this study. Accrual period was from April 1993 to May 1998. Median follow-up period was 20 months. Radiotherapy was given to whole pelvis followed by a boost to prostate. Dose range for the whole pelvis was from 45 Gy to 50 Gy and boost dose to prostate, from 14 Gy to 20 Gy. The post-irradiation PSA normal value was under 3.0 ng/ml. The physical examination and serum PSA level evaluation were performed at 3 month interval in the first one year, and then at every 4 to 6 months. Results : PSA value was normalized in nineteen patients (95%) within 12 months. The mean period of PSA normalization was 5.3 (${\pm}$2.7) months. The half life of PSA Of the nonfailing patients was 2.1 (${\pm}$0.9) month. The nadir PSA level Of the nonfailing Patients waS 0.8 (${\pm}$0.5) ng/ml. The period of PSA normalization had the positive correlation with pretreatment PSA level (R$^{2}$=0.468). The nadir PSA level had no definite positive correlation with the pretreatment PSA level (R$^{2}$=0.075). The half life of serum PSA level also had no definite correlation with pretreatment PSA level (R$^{2}$=0.029). Conclusion :The PSA level was mostly normalized within 8 months (85%). If it has not normalized within 12 months, we should consider the residual disease in prostate or distant metastasis. In 2 patients, the PSA level increased 6 months or 20 months before clinical disease was detected. So the serum PSA level can be used as early diagnostic indicator of treatment failure.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.79-84
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• 2000

Purpose : To evaluate the effectiveness and tolerance of postoperative e지ernai beam radiotherapy for patients with low grade glioma of the brain and define the optimal radiotherapeutic regimen. Materials and Methods : Between June, 1985 and May, 1998, 72 patients with low grade gliomas were treated with postoperative radiotherapy immediately following surgery. Median age was 37 years with range of 11 to 76 years. Forty one patients were male and 31 patients were female with male to female ratio of 1.3:1. Of those patients, 15 underwent biopsy alone and remaining 57 did subtotal resection. The distribution of the patients according to histologic type was as follows: astrocytomas-42 patients (58$\%$), mixed oligodendrogliomas-19 patients (27$\%$), oiigodendrogliomas-11 patients (15$\%$). Two patients were treated with whole brain irradiation followed by cone down boost and remaining 70 patients were treated with localized field with appropriate margin. Ail of the patients were treated with conventional once a day fractionation. Most of patients received total tumor dose of 5000 $\~$ 5500 cGy. Results : The overall 5 and 7 year survival rates for entire group of 72 patients were 61$\~$ and 50$\~$. Corresponding disease free survival rates for entire patients were 53$\~$ and 45$\~$, respectively. The 5 and 7 year overall survival rates for astrocytomas, mixed oligodendrogiiomas, and oligodendrogiiorras were 48$\%$ and 45$\%$, 76$\%$ and 56$\%$, and 80$\%$ and 52$\%$, respectively. Patients who underwent subtotal resection showed better survival rates than those who did biopsy alone. The overall 5 year survival rates for sub total resection patients and biopsy alone patients were 57$\%$ and 43$\%$, respectively. Forty six patients who were 40 years or younger survived batter than 26 patients who were 41 years or older (overall survival rate at 5 years, 69$\%$ vs 45$\%$). Although one patient was not able to complete the treatment because of neurological deterioration, there was no significant treatment related acute toxicities. Conclusion : Postoperative radiotherapy was safe and effective treatment for patients with low grade gliomas. However, we probably need prospective randomized trial to define optimal treatment timing and schedule for low grade gliomas and select patient group for different treatment philosophies.