• Radiation Oncology Journal
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• 제16권4호
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• pp.399-408
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• 1998

목적 : 본 연구는 비인강암 환자의 방사선치료에서 기존의 2차원적 치료계획과 3차원 입체조형 치료계획을 비교 분석하여 3차원적 치료계획의 우월성을 입증하고자 하였다. 대상 및 방법 : 병기가 T4인 환자를 대상으로 하였으며, 두 치료계획 모두 기존의 2차원적 치료방법으로 50.4Gy가 조사된 후 추가조사하는 과정을 2차원적 치료계획과 3차원적 치료계획으로 구분하여 수립하였다. 치료계획의 비교는 선량통계, 선량체적히스토그람, 국소제어율, 그리고 정상조직손상확률을 이용하여 시행하였다. 결과 : 3차원적 치료계획에서 2차원적 치료계획과 비교하여 계획용표적체적의 선량균일성이 더욱 향상되었으며 평균선량도 15.2$\%$의 증가를 보였다. 또한 종양 주위의 정상 장기인 측두엽, 뇌간, 이하선 및 측두하악골관절에 조사되는 평균선량은 3차원적 치료계획에서 낮았다. 종양제어확률은 3차원적 치료계획에서 2차원적 치료계획에서보다도 6$\%$ 증가하였으나 정상조직손상확률은 측두엽, 뇌간, 이하선, 측두하악골관절, 그리고 시신경교차 등 대부분의 정상장기에서 낮았다. 결론 : 3차원 입체조형치료계획은 2차원적 치료계획에 비교하여 종양의 국소제어율을 증가시킬수 있는 우월한 치료법임이 증명되었으나 임상적으로도 같은 결과를 가져올 지는 향후 전향적인 임상 연구가 요구된다.

• Journal of Preventive Medicine and Public Health
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• 제33권2호
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• pp.165-173
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• 2000

Objectives : To assess the availability of the glycophorin A (GPA) assay to detect the biological effect of ionizing radiation in workers exposed to low-doses of radiation. Methods : Information on confounding factors, such as age and cigarette smoking was obtained on 144 nuclear power plant workers and 32 hospital workers, by a self-administered questionnaire. Information on physical exposure levels was obtained from the registries of radiation exposure monitoring and control at each facility. The GPA mutant assay was performed using the BR6 method with modification by using a FACScan flow cytometer. Results : As confounders, age and cigarette smoking habits showed increasing trends with GPA variants, but these were of no statistical significance. Hospital workers showed a higher frequency of the GPA variant than nuclear power plant workers in terms of the NO variant. Significant dose-response relationships were obtained from in simple and multiple linear regression models. The slope of the regression equation for nuclear power plant workers was much smaller than that of hospital workers. These findings suggest that there may be apparent dose-rate effects. Conclusion : In population exposed to chronic low-dose radiation, the GPA assay has a potential to be used as an effective biologic marker for assessing the bone marrow cumulative exposure dose.

• The Plant Pathology Journal
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• 제32권2호
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• pp.157-161
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• 2016

Gamma irradiation was evaluated for its in vitro and in vivo antibacterial activity against a postharvest bacterial pathogen, Erwinia carotovora subsp. carotovora (Ecc). Gamma irradiation in a bacteria cell suspension resulted in a dramatic reduction of the viable counts as well as an increase in the amounts of DNA and protein released from the cells. Gamma irradiation showed complete inactivation of Ecc, especially at a dose of 0.6 kGy. In addition, scanning electron microscopy of irradiated cells revealed severe damage on the surface of most bacterial cells. Along with the morphological changes of cells by gamma irradiation, it also affected the membrane integrity in a dose-dependent manner. The mechanisms by which the gamma irradiation decreased the bacterial soft rot can be directly associated with the disruption of the cell membrane of the bacterial pathogen, along with DNA fragmentation, results in dose-dependent cell inactivation. These findings suggest that gamma irradiation has potential as an antibacterial approach to reduce the severity of the soft rot of paprika.

• Journal of Radiation Protection and Research
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• 제29권1호
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• pp.9-15
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• 2004

방사선에 의해 유도되는 사람 말초혈액 림프구 미소핵 관찰빈도를 높이면서 생물학적 선량평가법으로서 활용 가능성을 확인하고자 본 연구를 수행하였다. 우선 5명의 건강한 사람으로부터 혈액을 제공 받아 선량영역을 0에서 800cGy로 하여 감마선$(^{137}Cs)$을 조사 한 후 김사와 아크리딘 오렌지 형광 염색하고 미소핵 출현빈도를 비교하였다. 아크리딘 오렌지 염색법을 이용하여 미소핵을 관찰하였을 때, 김사 염색법에 비교하여 적갈색의 비특이성 과립과 녹황색의 DNA가 붉은색의 세포질을 배경으로 명확히 구별되었을 뿐만 아니라 선량이 증가하면서 검출율도 높았다. 아울러, 말초혈액 T와 B-림프구에 대하여 선량영역을 0에서 50cGy로 하여 방사선을 조사한 후 미소핵 출현빈도를 아크리딘 오렌지 염색하여 김사염색과 비교한 바, B-림프구에서 선량이 증가하면서 적어도 2배 이상 높게 관찰되었다. 본 실험 결과, 사람 말초 혈액 B-림프구를 대상으로 한 아크리딘 오렌지 형광염색 미소핵 분석법은 저선량 방사선 인체영향 평가나 과피폭 선량추정시 활용이 가능 할 것으로 생각된다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권1호
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• pp.319-323
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• 2012

Objective: To explore the feasibility of shrinking field technique after 40 Gy radiation through 18F-FDG PET/CT during treatment for patients with stage III non-small cell lung cancer (NSCLC). Methods: In 66 consecutive patients with local-advanced NSCLC, 18F-FDG PET/CT scanning was performed prior to treatment and repeated after 40 Gy. Conventionally fractionated IMRT or CRT plans to a median total dose of 66Gy (range, 60-78Gy) were generated. The target volumes were delineated in composite images of CT and PET. Plan 1 was designed for 40 Gy to the initial planning target volume (PTV) with a subsequent 20-28 Gy-boost to the shrunken PTV. Plan 2 was delivering the same dose to the initial PTV without shrinking field. Accumulated doses of normal tissues were calculated using deformable image registration during the treatment course. Results: The median GTV and PTV reduction were 35% and 30% after 40 Gy treatment. Target volume reduction was correlated with chemotherapy and sex. In plan 2, delivering the same dose to the initial PTV could have only been achieved in 10 (15.2%) patients. Significant differences (p<0.05) were observed regarding doses to the lung, spinal cord, esophagus and heart. Conclusions: Radiotherapy adaptive to tumor shrinkage determined by repeated 18F-FDG PET/CT after 40 Gy during treatment course might be feasible to spare more normal tissues, and has the potential to allow dose escalation and increased local control.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6251-6255
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• 2012

Radiation proctitis and radiation cystitis are major complications for patients with cervical carcinoma following radiotherapy. In the present study, we aimed to determine the potential risk factors for the development of radiation proctitis and radiation cystitis after irradiation. A total of 1,518 patients with cervical carcinoma received external beam radiotherapy (EBRT) followed by high-dose-rate intracavitary brachytherapy (HDRICB) in our hospital. The incidences of radiation proctitis and radiation cystitis were recorded and associations with different factors (age, time period, tumor stage) were analyzed with ${\chi}^2$ (chi-squared) and Fisher exact tests. We found that 161 and 94 patients with cervical carcinoma were diagnosed with radiation proctitis and radiation cystitis, respectively, following radiotherapy. The prevalence of Grade I-II radiation proctitis or radiation cystitis was significantly lower than that of Grade III (radiation proctitis: 3.82% vs. 6.76%, P < 0.05; radiation cystitis: 2.31% vs. 3.87%, P < 0.05) and was significantly enhanced in patients with late stage (IIIb) tumor progression compared to those in early stage (Ib, IIa) (P < 0.05). Moreover, the incidence of radiation proctitis and cystitis was not correlated with age or, time period following radiation, for each patient (P > 0.05). These observations indicate that a late stage of tumor progression is a potential risk factor for the incidence of radiation proctitis and cystitis in cervical carcinoma patients receiving radiotherapy.

• Imaging Science in Dentistry
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• 제43권2호
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• pp.63-69
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• 2013

After over one decade development, cone beam computed tomography (CBCT) has been widely accepted for clinical application in almost every field of dentistry. Meanwhile, the radiation dose of CBCT to patient has also caused broad concern. According to the literature, the effective radiation doses of CBCTs in nowadays market fall into a considerably wide range that is from $19{\mu}Sv$ to $1073{\mu}Sv$ and closely related to the imaging detector, field of view, and voxel sizes used for scanning. To deeply understand the potential risk from CBCT, this report also reviewed the effective doses from literatures on intra-oral radiograph, panoramic radiograph, lateral and posteroanterior cephalometric radiograph, multi-slice CT, and so on. The protection effect of thyroid collar and leaded glasses were also reviewed.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1210-1217
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• 2023

The assessment of radiation fields in the lithium loop pipes and dump tank during the operation were performed for International Fusion Materials Irradiation Facility - DEMO-Oriented NEutron Source (IFMIF-DONES) in order to obtain the radiation dose-rate maps in the component surroundings. Variance reduction techniques such as weight window mesh (produced with the ADVANTG code) were applied to bring the statistical uncertainty down to a reasonable level. The biological dose was given in the study, and potential shielding optimization is suggested and more thoroughly evaluated. The MCNP Monte Carlo was used to simulate a gamma particle transport for radiation shielding purposes for the current Li Systems' design. In addition, the shielding efficiency was identified for the Impurity Control System components and the dump tank. The analysis reported in this paper takes into account the radiation decay source from and activated corrosion products (ACPs), which is created by d-Li interaction. As a consequence, the radiation (resulting from ACPs and Be-7) shielding calculations have been carried out for safety considerations.

• 대한방사선기술학회지:방사선기술과학
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• 제19권2호
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• pp.71-77
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• 1996

Studies were conducted to determine the clinical application of photodiode. We compared photodiode with ion-chamber as to change of tube potential, tube current, mAs and measured decreasing rate of penetration dose. When tube potential was changed from 60 kVp to 120 kVp, output of photodiode and ion-chamber were changed from 0.4 to 1.625, and 1.018 to 4.268, respectively. This was a good agreement to theory that $I=Kv^2it$(I is intensity, K is constant, v is tube potential, i is tube current, t is time). Characteristics for change of tube current and mAs were also a good agreement to theory. And comparison in decreasing rate of penetration dose was similar except above 6 cm in depth. Our results indicated that photodiode was a good instrument for relative measurement of radiation exposure, but we can not use the photodiode for absolute radiation dose.

• 한국산학기술학회논문지
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• 제11권6호
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• pp.2118-2123
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• 2010

국내의 경우 방사선작업종사자의 개인피폭관리는 선량한도를 초과한 피폭의 유무를 확인하여 사후 조치를 취하는 것에 초점이 맞추어져 있다. 그러나 의료기관 핵의학과의 경우 개봉선원을 사용하므로 작업환경이 방사선에 노출될 가능성이 많고, 방사성의약품 투여 후 수 시간 혹은 수 일 동안은 환자 자체가 방사선원이 되므로 방사선작업종사자나 수시출입자, 환자보호자들의 방사선 피폭 가능성이 매우 높다. 따라서 환자보호자 등 일반출입자의 방사선피폭을 방지하기 위해서는 환경방사선관리가 적절하게 실시되어야 한다. 일본에서는 "방사성동위원소등에 의한 방사선장해의 방지에 관한 법률" 등에 근거하여 방사선작업환경에 대한 환경방사선량을 정기적으로 측정, 보관하도록 하고 있다. 이에 대전시 소재 대학병원 핵의학과에서 일본에서 시행하고 있는 것과 같은 방법으로 핵의학과 내 8개소에 유리선량계를 설치하여 환경방사선을 측정한 결과 8개소 모두 "진단용 방사선 발생장치의 안전관리에 관한 규칙"에 규정된 방사선구역의 외부방사선량인 주당 0.3 mSv에는 훨씬 미치지 못하는 적은 선량이 측정되었다. 그러나 접수대에서는 3개월 누계 선량률이 0.51 mSv로서 접수대 종사자는 일반인 연간 유효선량한도인 1 mSv를 초과할 가능성이 높았으며, 환자 및 보호자 대기실에서도 0.23 mSv(3개월 누계치 0.69mSv)가 측정되어 유리선량계를 설치한 8개소 가운데 가장 높은 선량률을 보였다. 이것은 일반인의 연간 유효선량한도인 1 mSv를 초과하는 값이며, "방사선방호 등에 관한 기준 고시"에 환경상 위해방지를 위해 규정된 연간 유효선량 0.25 mSv를 초과하는 값이다. 따라서 접수대 근무자, 환자보호자 및 제3자 보호를 위해 핵의학과 내 환경방사선량 감소를 위한 적극적인 대책이 필요한 것으로 나타났다.