• The Journal of the Korea Contents Association
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• v.14 no.8
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• pp.225-232
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• 2014

Underwent on modified radical mastectomy(MRM) and radiation therapy, it affects increasing rates of chronic morbidity, because of including chest wall and internal mammary nodes(IMNs). It causes the high absorbed dose on heart and ipsilateral lung. Thus in this study, we compared dose distributions through utilizing the intensity modulated radiation therapy(IMRT) and the volumetric modulated arc therapy(VMAT). We selected 10 breast cancer patients at random who took MRM and radiation therapy. Treatment plannings were done by using IMRT and VMAT from each patient ranging supraclavicular lymphnodes(SCL) and IMNs. After that we analysed the planning target volume(PTV)'s conformity and absorbed doses on heart and lungs. As a results, PTV conformities were indicated the same patten(p<0.05) in both plans. In case of Lt breast cancer patients, the dose maximum regions of the heart were more lesser in VMAT technique rather than the IMRT(p<0.05). Also, the maximum dose areas of lungs were lesser in VMAT technique rather than the IMRT(p<0.05). Therefore, it would be safe to say that it is more effective way to adapt the VMAT technique than IMRT in such cases like involve IMNs in breast cancer patients.

• Journal of radiological science and technology
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• v.39 no.4
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• pp.565-570
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• 2016

Radioactive iodine($^{131}I$) treatment reduces recurrence and increases survival in patients with differentiated thyroid cancer. However, it is important in terms of radiation safety management to measure the radiation dose rate generated from the patient because the radiation emitted from the patient may cause the exposure. Research methods, it measured radiation dose-rate according to the elapsed time from 1 m from the upper abdomen of the patient by intake of radioactive iodine. Directly comparing the changes over time, high dose rate sensitivity and efficiency is statistically significant, and higher chamber than GM counter(p<0.05). Low dose rate sensitivity and efficiency in the chamber had lower levels than gm counter, but not statistically significant(p>0.05). In this study confirmed the characteristics of calibrated ionization chamber and GM counter according to the radiation intensity during high-dose radioactive iodine therapy by measuring the accurate and rapid radiation dose rate to the patient explains, discharged patients will be reduced to worry about radiation hazard of family and others person.

• 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.30 no.1_2
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• pp.129-138
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• 2018

Purpose : An aim of this study was to compare the effect of multi leaf collimator(MLC) types for high dimension radiotherapy in treatment sites used clinically. Material and Method : 70 patients with lung cancer, spine cancer, prostate cancer, whole pelvis, head and neck, breast cancer were included in this study. High definition(HD) MLC of TrueBeam STx (Varian Medical system, Palo Alto, CA) and millenium(M) MLC of VitalBeam (Varian Medical system, Palo Alto, CA) were used. Radiotherapy plans were performed for each patient under same treatment goals with Eclipse (Version 13.7, Varian Palo Alto USA, CA). To compare the indicators of the radiotherapy plans, planning target volume(PTV) coverage, conformity index(CI), homogeneity index(HI), and clinical indicators for each treatment sites in normal tissues were evaluated. To evaluate low dose distribution, $V_{30%}$ values were compared according to MLC types. Additionally, length and volume of targets for each treatment sites were investigated. Result : In stereotatictic body radiotherapy(SBRT) plan for lung, the average value of PTV coverage was reduced by 0.52 % with HD MLC. With SBRT plan using HD MLC for spine, the average value of PTV coverage decreased by 0.63 % and maximum dose decreased by 1.13 %. In the test of CI and HI, the values in SBRT plan with HD MLC for spine were 1.144, 1.079 and the values using M MLC were 1.160, 1.092 in SBRT plan for lung, The dose evaluation of critical organ was reduced by 1.48 % in the ipsilateral lung mean dose with HD MLC. In prostate cancer volumetric modulated arc therapy(VMAT) with HD MLC, the mean dose and the $V_{30}$ of bladder and the mean dose and the $V_{25}$ of rectum were reduced by 0.53 %, 1.42 %, 0.97 %, and 0.69 %, respectively (p<0.05). The average value of heart mean dose was reduced by 0.83 % in breast cancer VMAT with M MLC. Other assessment indices for treatment sites showed no significant difference between treatment plans with two types of MLC. Conclusion : Using HD MLC had a positive impact on the PTV coverage and normal tissue sparing in usually short or small targets such as lung and spine SBRT and prostate VMAT. But, there was no significant difference in targets with long and large such as lung, head and neck, and whole pelvis for VMAT.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.813-818
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• 2014

Aims: To describe our institutional experience with high dose rate (HDR) interstitial brachytherapy (IBT) compared with previously reported results on the low dose rate (LDR) practice for head and neck cancer. Materials and Methods: Eighty-four patients with oral cavity (n=70) or oropharyngeal cancer (n=14) were treated with 192Ir HDR-IBT. Seventy-eight patients had stage I or II tumour. The patients treated with IBT alone (n=42) received 39-42 Gy/10-14 fractions (median=40 Gy/10 fractions). With respect to the combination therapy group (n=42), prescription dose comprised of 12-18 Gy/3-6 fractions (median=15 Gy/5 fractions) for IBT and 40-50 Gy/20-25 fractions (median=50 Gy/25 fractions) for external radiotherapy. Brachytherapy was given as 2 fractions per day 6 hours apart with 4 Gy per fraction for monotherapy and 3 Gy per fraction for combination therapy. Results: Four patients were not evaluable in the analysis of outcome. The primary site relapse rates were 23.8% (10/42) and 68.4% (26/38) in patients treated with IBT alone and combination therapy, respectively (p<0.001). Salvage surgery was performed in 19 patients. The 5-year local control rate was estimated at 62% and the disease-free survival (DFS) rate at 52% for all patients. Local control with respect to T1 and T2 tumours was 84% and 42%, respectively. Conclusions: Our present series on HDR-IBT and the previous report on LDR-IBT for head and neck cancer demonstrated similar DFS rates at 5 years (52%). The rate of regional failure in node-negative patients was <20% in both of our series. HDR-IBT offers similar results to LDR-IBT for head and neck cancer.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1999.04a
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• pp.53-61
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• 1999

Radiation therapy has been used for the cancer treatment and radiation synovectomy$\^$1-3)/. There are two kinds of radiation therapy; the external radiation therapy and the internal radiation therapy. Hitherto, the external radiation therapy has been widely used, but for the lack of its selectivity it requires strong radiation dose and causes the irritation and damage of the normal tissue or organ. Therefore many researchers give their interests to the internal radiation therapy in which the radioactive materials are injected directly into the target organ or tissue. Many ${\beta}$-emitting radionuclides have been studied for the application of the internal radiation theraily. Among them, Holmium-166 has the many beneficial physical characteristics for the internal radiation therapy such as appropriate half life (26.8hr), high ${\beta}$ energy (max. 1.85 MeV(51%), 1.77 MeV (48%), mean 0.67MeV), and low ${\gamma}$ energy (0.081MeV) easily detected by ${\gamma}$-camera. In the internal radiation therapy, the administered radioactive materials should be retained in the target long enough to increase the therapeutic effects and avoid the damage in the normal tissue or organ. For this purpose, radionuclides are used as complex form with carriers. Carriers should have a high affinity with radionuclides in vivo and in vitro, so the complex can be evenly distributed in the lesion but can not be leaked out from the lesion.

• Journal of Yeungnam Medical Science
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• v.28 no.2
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• pp.173-179
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• 2011

Polymyositis is diffuse, inflammatory myopathy with proximal-muscle weakness due to lymphocyte infiltration to the muscle layer. The exact cause of the muscle weakness is unclear but may be related with an immunologic mechanism. Using high-dose steroid is the treatment of choice for polymyositis. It is difficult to distinguish steroid-resistant polymyositis from steroid myopathy, however, in the course of high-dose steroid therapy. These authors encountered a steroid myopathy patient during polymyositis treatment with high-dose steroid. A 57-year-old woman was diagnosed with polymyositis and was treated with high-dose steroid. Her condition was initially improved, but in the course of the treatment, her symptom was aggravated without increasing the muscle enzymes. Her muscle weakness was improved by reducing the steroid dosage.

• The Journal of Korean Society for Radiation Therapy
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• v.9 no.1
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• pp.106-112
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• 1997

The present study was undertaken to investigate the effects of cultured MDCK cell line on the cell viability and the activities of superoxide dismutase(SOD). catalase, change of FOX 1 with low dose radiation. When MDCK cells were irradiated low dose (less than 50 cGy), the cell viability remains high after 2 hrs, but few changes after 24 hrs. In the low dose irradiated MDCK cells, the activities of SOD and catalase were increased with compared to control group and high dose. But the content of $H_2O_2$(FOX 1) was decreased. These results suggest that the cultured MDCK cells probably were induced expression of defense mechanism.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.199-201
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• 2002

Cancer therapy using high-energy $^{12}$ C ions is successfully under way at HIMAC, Japan. An alternative beam to $^{12}$ C is $^{11}$ C ions. The merit of $^{11}$ C over $^{12}$ C is its capability for monitoring spatial distribution of the irradiated $^{11}$ C by observing the $\beta$$^{+}$ decay with a good position resolution. One of the several problems to be solved before its use for therapy is the amount of nuclear interaction that deteriorates the dose concentration owing to the Bragg curve. Utilizing the dedicated secondary beam course for R&D studies at HIMAC, we measured the total energy loss of $^{11}$ C ions in a scintillator block that simulates the soft tissue in human bodies. In addition to the total absorption $^{11}$ C peak, non-negligible bump-shaped contribution is observed in the energy spectrum. The origin of the bump contribution can be nuclear interaction of the incident $^{11}$ C ions with hydrogen and carbon atoms. Further studies to reduce the ambiguity in dose distribution are mentioned.

• Clinical and Experimental Pediatrics
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• v.53 no.7
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• pp.741-744
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• 2010

Purpose: To evaluate the long-term safety of polyethylene glycol (PEG) 4000 in children with constipation, particularly the biochemical aspects of safety. Methods: Medical records were evaluated, and 100 children, who had been taking PEG 4000 for more than 6 months, and who had been under clinical and biochemical monitoring, were enrolled. Ages; $6.11{\pm}3.12$ years, Duration of therapy; $16.93{\pm}7.02$ months, dose of PEG 4000; $0.72{\pm}0.21g/kg/d$. Results: None of the children complained of clinical adverse effect. The first biochemical test was performed at 8.05 months after beginning of PEG 4000. Serum phosphate (SP) value was high in 10 children, and leucopenia was noted in one child. The second test was performed in 44 children at 7.57 months after the first test. The SP value was high in four children, including the three children whose initial SP value was high and one new child. Six out of 10 children with high initial SP value became normal and one was lost. Hypernatremia was noted in one child. The third test was done in 15 children at 7.5 months after the second test. The SP value of the new child from the second test was high, but became normal after finishing treatment. Two out of 3 children with high SP value at the second test became normal and one was lost. The fourth test was done in 2 children few months after the third test. All of the results were normal. There were no relation between duration of therapy and hyperphosphatemia, or between dose of PEG 4000 and hyperphosphatemia. Conclusions: PEG 4000 is safe for long-term therapy in children with constipation with respect to biochemical parameters.