• Journal of radiological science and technology
• /
• v.43 no.1
• /
• pp.9-14
• /
• 2020

Commercial plate bolus is generally used for treatment of surface tumor and required surface dose. We fabricated 3D-printed bolus by using 3D printing technology and usability of 3D-printed bolus was evaluated. RT-structure of contoured plate bolus in the TPS was exported to DICOM files and converted to STL file by using converting program. The 3D-printed bolus was manufactured with rubber-like translucent materials using a 3D printer. The dose distribution calculated in the TPS and compared the characteristics of the plate bolus and the 3D printed bolus. The absolute dose was measured inserting an ion chamber to the depth of 5 cm and 10 cm from the surface of the blue water phantom. HU and ED were measured to compare the material characteristics. 100% dose was distributed at Dmax of 1.5 cm below the surface when was applied without bolus. When the plate bolus and 3D-plate bolus were applied, dose distributed at 0.9 cm and 0.8 cm below the surface of the bolus. After the comparative analysis of the radiation dose at the reference depth, differences in radiation dose of 0.1 ~ 0.3% were found, but there was no difference dose. The usability of the 3D-printed bolus was thus confirmed and it is considered that the 3D-printed bolus can be applied in radiation therapy.

• Journal of the Korean Society of Radiology
• /
• v.9 no.5
• /
• pp.287-293
• /
• 2015

Because of esophageal cancer has the long length of the lesion and also inhomogeneous in depth. So, the radiation dose distribution was inhomogeneous in radiation therapy. To overcomes the dose distribution uniformity using half beam method. Patient's CT image was used radiation treatment planning. We used two planning methods that one is the using normal beam and another is using half beam. Than comparing the two radiotherapy planning using target coverage, dose volume histogram, conformity index, homogeneity index and normal tissues - heart, spinal cord, lung -. In results, Treatment planning using half beam is little more than normal beam in target coverage, dose volume histogram, conformity index, homogeneity index and normal tissues covering. However, If the patient is not correct position patients may arise a side effect. Thus, the using in Half beam involving the geometrically exact under lung cancer is considered to advantage.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.397.1-397.1
• /
• 2014

최근 방사선 진단 영역에 이용되고 있는 증감지는 입사된 방사선의 감도를 증가시키기 위해 형광체를 사용하고 있으며, 외부의 에너지를 흡수하여 빛으로 방출하는 역할을 한다. 이는 방사선 검출기, 디스플레이, 의료기기 등 다양한 분야에 활용되고 있다. 필름에 X선을 노출 할 경우 형광체의 사용 유무에 따라 방사선 흡수 효율에 영향을 미치며, 이는 발광 효율 및 감도에 주요한 인자로 작용한다. 현재 상용화되어 있는 형광체는 낮은 발광 효율로 인한 한계를 가지므로, 발광 효율 향상을 위하여 제작 구조에 대한 연구가 진행되고 있다. 이 중 반사막을 활용하는 연구가 활발히 진행되고 있다. 일반적으로 형광체의 제조를 위하여 보편적으로 이용하고 있는 스크린프린팅 방법에서 건조 공정을 수행 시 균일도가 감소하는 현상이 발생한다. 이러한 현상은 반사막의 증착을 불균일하게 만드는 원인으로 작용하고 빛의 산란을 초래하는 현상을 초래한다. 이에 본 연구에서는 증착 시 투명도 저하에 따라 반사율이 증가되는 반사막 성질을 가지며, 방수성 및 절연성과 같은 보호층 특성을 지닌 유기성 투명 박막 페를린에 대하여 연구하고자 한다. 본 연구에서는 화학적 증기 증착법(Chemical Vapor Deposition, CVD)을 이용하여 투명 필름의 상단에 페를린을 코팅한 시편과 코팅하지 않은 시편으로 구분하여 제작하였고, 상단에 스크핀프린팅 방법을 활용하여 형광체를 도포 하였다. 시편 제작 후 실험은 시편을 필름 상단에 위치시키고, 일반진단에너지 대역(Model-SF 80)의 X선을 조사하였다. 이 후 현상기(model-pro14)를 통해 현상된 필름에 나타난 광학적 농도(Optical Density, O.D)를 농도계(Fluke Biomedical Nuclear Associates Densitometer)로 측정하였는데, 불확실성을 줄이기 위하여 총 5회를 측정하여 그 중 2번째로 높은 값을 도출하였다. 측정 결과, 페를린을 코팅한 형광체에서는 1.71의 O.D 값이 측정되었고, 페를린을 코팅하지 않은 형광체에서는 1.43의 O.D 값이 측정되었다. 이를 이용하여 투명도를 산출한 결과 상대적으로 약 1.76% 차이가 나타났다. 이러한 결과는 페를린 활용 시 환자의 피폭 선량 저감화 및 해상력 개선을 도모할 수 있을 것으로 사료된다.

• Journal of the Korean Society of Radiology
• /
• v.12 no.7
• /
• pp.919-927
• /
• 2018

The purpose of this study was to present simulation training model for general X-ray examinations and to analyze the errors that occur during the simulation training. From 2012 to 2018, a total of 183 students (77 men and 106 women) participated. The simulated X-ray system used computed radiography (CR) system. The contents of simulation training were patient's care, X-ray examinations accuracy, images stability, etc. As a result, it were found that the patient's position setting error, the accuracy error of the X-ray beam central ray, the image receptor's size and setting error, the error of the grid use, the marking error, and the error of X-ray exposure technical factors. It is expected that improved practical general X-ray examinations training of radiographer will be needed, focusing on these errors, so that we could contribute to the health care of the people by providing precise examinations and high quality medical service.

• Journal of Radiation Protection and Research
• /
• v.30 no.3
• /
• pp.131-148
• /
• 2005

In a nuclear emergency, protective actions for the public should be taken in time. It is internationally proposed that generic intervention levels (GILs) and generic action levels, determined based on cost-benefit analyses, be used as the decision criteria for protective actions. Operational intervention levels (OILs) are directly or easily measurable quantities corresponding to these generic levels. To assess the necessity of protective actions in a nuclear emergency, it is important that the environmental monitoring data required for applying and revising OILs should be promptly produced. It is discussed what and how to do for this task in the course of the emergency response. For an emergency environmental monitoring to be performed effectively, a thorough preparedness has to be made including maintenance of the organization and equipments, establishment of various procedure manuals, development of a supporting computer system and periodical training and exercises. It is pointed out that Korean legal provisions concerning GILs and OILs need to be amended or newly established.

• The Journal of Korean Society for Radiation Therapy
• /
• v.34
• /
• pp.43-50
• /
• 2022

Objective: The purpose of this study is to choose a treatment plan and equipment to maximize tangential irradiation to protect the normal brain tissues as much as possible during total scalp irradiation. Subjects and Methods: After zoning the total scalp of a phantom and selecting a target area for treatment, the study made a Helical TomoTherapy(HT) plan, a Helical TomoTherapy with a Complete Block(HTCB) plan, and a Volumetric Modulated Arc Therapy(VMAT) plan. All of these plans made sure that the volume of a treatment plan with 95% of a prescription dose(40 Gy) would not exceed 95% of the entire volume and that Dmax would not be more than 110% of the prescription dose. The therapy plans compared doses among organs at risk of damage including the brain. Doses in the brain tissues were assessed based on the volumetric criteria for normal tissues in Emami et al. Results: HT, HTCB, and VMAT had a dose of 21.68 Gy, 13.75 Gy, and 20.89 Gy, respectively, in brain tissues at D_33%, a dose of 7.06 Gy, 3.21 Gy, and 7.84 Gy, respectively, at D_67%, and a dose of 3.14 Gy, 1.75 Gy, and 3.84 Gy, respectively, at D_100%. They recorded a Dmean of 16.64 Gy, 11.78 Gy, and 16.64 Gy, respectively. These results show that the overall dose was low in the HTCB plan. When the volume of a low dose was calculated based on 5 Gy, they recorded 87%, 49%, and 96%, respectively, in V_5Gy. In addition, the maximum dose in the remaining organ(brain stem, hippocampus, and both lenses) except for the optic pathway was the lowest in HTCB Conclusion: The findings demonstrate that TomoTherapy with a complete block minimized a dose in organs at risk of damage including the brain and hippocampus on both sides and accordingly reduced the probability of side effects such as radiation-induced brain injuries and a resulting decrease in neurocognitive functions. In addition to total scalp irradiation, if additional studies on ring targets treated in various areas are conducted to establish the benefits of tangential irradiation, it is believed that TomoTherapy using Complete Block can be used to maximize tangential irradiation in treatment planning.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.6
• /
• pp.805-813
• /
• 2005

In our previous study, a novel herb mixture (HIM-I) of Angelim gigas radix, Cnidium officinale rhizoma, and Paeonia japonica radix was developed to protect the intestinal and immune systems and promote its recovery against radiation damage. In this study, a new herbal preparation (HemoHIM) with the high immune modulating activity was developed from HIM-I. HIM-I was fractionated into ethanol fraction (HIM-I-E) and polysaccharide fraction (HIM-I-P). And HemoHIM was prepared by adding HIM-I-P to HIM-I. The protective activities against $\gamma$ -irradiation were compared among HemoHIM, HIM-I and the fractions. HemoHIM and HIM-I significantly decreased the radiation-induced DNA damage in vitro, and scavenged hydroxyl radicals in a dose-dependent manner. HemoHIM showed similar activity to HIM-I. In vitro proliferation assay with mouse lymphocytes and bone marrow cells showed that HIM-I-P was remarkably higher than HIM-I and HIM-I-E in cell proliferating activity. HemoHIM showed higher activity than HIM-I and this might be associated with the higher polysaccharide content. The in vivo protective effects of HemoHIM and HIM-I were investigated in $\gamma$-irradiated mice. HemoHIM increased the surviving intestinal crypts to a similar extent compared with HIM-I. In contrast, HemoHIM appeared to be more effective than HIM-I in endogenous spleen colony formation assay. The recovery of white blood cells and lymphocytes in irradiated mice were significantly enhanced by the administration of HemoHIM. Also HemoHIM administration prolonged the survival of irradiated mice. These results showed that the novel herbal preparation, HemoHIM, effectively protected the self-renewal tissues and immune system, and promoted the survival of irradiated mice. Moreover, in comparison with HIM-I, HemoHIM maintained similar activity in the reduction of oxidative damage of self-renewal tissue but exhibited the higher activity in protection and proliferation of immune and hematopoietic cells. These results suggested that HemoHIM might be more effective than HIM-I in immune modulation as well as radioprotection.

• Journal of Radiation Protection and Research
• /
• v.24 no.2
• /
• pp.93-99
• /
• 1999

The alkaline single-cell gel electrophoresis (SCGE) assay, called the comet assay, has been applied to the detection of DNA damage from a number of chemical and biological factors in vivo and in vitro. The comet assay is a novel method to assess DNA single-strand breaks, alkali-labile sites in individual cells. The effect of peach kernel extracts on radiation-induced DNA damage in human blood lymphocytes was evaluated by the SCGE assay. The lymphocytes, with or without pretreatment of the extracts, were exposed to 0, 0.1, 0.3, 0.5, 1.0 and 2.0 Gy of $^{60}Co$ gamma ray. Significantly increased tail moment, which was a marker of DNA strand breaks in the comet assay, showed an excellent dose-response relationship. The treatment of the peach kernel extracts reduced the DNA damage by 30 % in irradiated groups as compared to that in non-treated control groups. The result indicates that the extracts shows radioprotective effect on lymphocyte DNA when assessed by the comet assay.

• Korean Journal of Environmental Biology
• /
• v.29 no.1
• /
• pp.61-67
• /
• 2011

N-acetyl-L-cysteine (NAC) having a thiol, a precursor for glutathione (GSH), is known as one of the antioxidants. NAC used as a radioprotector against ionizing radiation (IR)-induced injury and damage. The aim of this study was to evaluate the radioprotective effects of NAC against IR-induced cell damage in Saccharomyces cerevisiae and the antioxidative effect of NAC on transcriptional level of yeast antioxidant enzyme genes such as superoxide dismutase (SOD) and catalase. In the present study, yeast cells were pretreated with various concentrations of NAC and/or irradiated with various doses of gamma rays. The cell viability was measured by counting the cell forming unit (CFU). The quantitative real-time PCR was performed for analysis of gene expression of SOD and catalase. The viability of irradiated cells was not improved by pretreatment with NAC. Ionizing radiation with 100 Gy highly induced the gene expression of antioxidant enzymes. In the irradiated group with NAC pretreatment, the gene expression of SOD and catalase was gradually reduced with the increased concentrations of NAC. These results indicate that NAC can act as a useful antioxidant to scavenge reactive oxygen species in vivo, but does not protect cells against IR-induced cell death in S. cerevisiae.

• Korean Journal of Breeding Science
• /
• v.42 no.3
• /
• pp.222-225
• /
• 2010

'Seoritae' is a very famous variety of black soybean for mixed cooking with rice in Korea. However, it has a couple of bad traits such as late flowering and maturity. To improve these characteristics, seeds of original 'Seoritae' were irradiated using a 250 Gy gamma ray in 1994. Some mutants were identified and finally a new soybean variety 'Josaengseori' was developed in 2005. This variety has a few distinguishable characteristics such as smaller grain size, early maturity and high yielding compared to the 'Seoritae'. The flowering period of 'Josaengseori' is 57 days after seeding (DAS), which is 10 days earlier than that of 'Seoritae' (67 DAS). The maturation period of 'Josaengseori' is 130 DAS, which is 34 days earlier than 'Seoritae' (164 DAS). And the total yield of the new variety with 179 kg/10a is 2.4 times higher than that of 'Seoritae' with 74 kg/10a. 100 grain weight of 'Josaengseori' is 32.8 g, which is 20% lower than that of 'Seoritae' with 40.1 g.