• Imaging Science in Dentistry
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• 제41권1호
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• pp.1-6
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• 2011

Purpose : The purpose of this review is to evaluate the possibility of panoramic radiography as a national oral examination tool. Materials and Methods : This report was carried out by review of the literatures. Results : Panoramic radiography has sufficient diagnostic accuracy in dental caries, periodontal diseases, and other lesions. Also, the effective dose of panoramic radiography is lower than traditional full-mouth periapical radiography. Conclusion : Panoramic radiography will improve the efficacy of dental examination in national oral examination. However, more studies are required to evaluate the benefit, financial cost, and operation time and also to make selection criteria and quality management program.

• 대한두개안면성형외과학회지
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• 제20권6호
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• pp.416-420
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• 2019

Reconstruction method choice in recurrent head and neck cancer depends on surgical history, radiation therapy dosage, conditions of recipient vessels, and general patient condition. Furthermore, when defects are multiple or three dimensional in nature, reconstruction and flap choice aimed at rebuilding the functional structure of the head and neck are difficult. We experienced successful reconstruction of recurrent laryngeal cancer requiring reconstruction of esophageal and tracheostomy stroma defects using a chimeric two-skin anterolateral thigh flap with a single pedicle.

• Radiation Oncology Journal
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• 제8권2호
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• pp.241-253
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• 1990

1980.6.부터 1985.12.까지 고신의료원 치료방사선과에서 방사선 단독 치료한 병기 IIb 자궁경부암 환자 331명에 대하여 후향적으로 생존율 치료 실패 및 합병증 등에 영향을 미칠 수 있는 방사선 치료요소들을 분석조사 하였다. 5년 생존율과 무병생존율은 각각 $82.8{\%}$와 $82.4{\%}$였다. 방사선 치료 6주 경과에 분석한 골반내 관해율은 전골반 외부 조사후 강내조사한 예에서는 $98.6{\%}$였고 축소조사한 추가 치료한 예에서는 $71.6{\%}$였다. 전골반 방사선 조사후 완전관해를 보였던 예에서의 5년 생존율은 $98.9{\%}$였지만 국소치료실패 및 원격전이한 예에서는 $12.9{\%}$였다. Point A에 $7500{\~}8500$ cGy를 조사한 예에서는 $88.5{\%}$의 5년 생존율을 보였고 합병증은 $4.9{\%}$였지만 그 이상의 조사량에서는 생존율은 증가한지 않았고 합병증만 증가하였다. $18.7{\%}$(62예)에서 치료실패를 보였는데, 이중국소치료실패가 $72.6{\%}$(45예), 국소 및 골반임파 치료실패가 $3.2{\%}$(2예)였으며 원격전이 실패는 $24{\%}$(15)였다. 합병증은 $15.1{\%}$(50예)였는데 이중 $42{\%}$가 직장 출혈 및 협착이였다. Point A의 조사량은 8500 cGy가 합병증 유발의한계 조사량 이였으며 합병증의 $70{\%}$가 그 이상의 조사양에서 발생하였다. 직장 합병증은 6500 cGy이상에서 발생하였고 방광합병증은 7500 cGy이상에서 발생하였다. 사망의 원인으로는 국소치료실패로 인한 전신쇠약이 대다수였으며 전체 사망원인으로는 국소치료 실패로 인한 전신쇠약이 대다수였으며 전체 사망원인의 $73.7{\%}$였고 그외 폐, 간, 뼈 전이순이였으며 방사선합병증으로 인한 사망은 3예에 지나지 않았다. 상기와 같은 결과에 대한 결론으로 크기가 아주 큰 종양이나 Barrel형태의 종양의 방사선 치료에는 지금 많이 사용되고 있는 4000 cGy이상의 외부 조사량이 강내조사전에 골반관해를 성취하기 위해 필요한 것을 알 수 있었다.

• 대한방사선치료학회지
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• 제19권2호
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• pp.107-112
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• 2007

목 적: 본원에서 시행하고 있는 전립선암의 세기조절 방사선치료시 직장 내에 존재하는 불균질부에 의한 선량변화를 전산화 치료계획 선량과 자체 제작한 전립선암 환자형 골반 팬톰을 이용하여 측정한 선량을 비교하고자 한다. 대상 및 방법: 전립선암 환자형 골반 팬톰(타원형의 물 팬톰: $30\times20\times20cm^3$, 방광, 직장, 정낭을 묘사하는 팬톰)을 제작하였으며, 전산화단층촬영으로 3차원 영상을 획득하였다. 전산화치료계획장치(ECLIPSE, Varian, USA), 6 MV X선(Clinac 6EX, Varian, USA)을 이용하여 세기조절 방사선치료계획을 수립한 후, 전립선암 환자형 골반 팬톰을 이용하여 직장벽, 방광벽, 정낭 부위에 TLD를 삽입하고, 전산화치료계획 선량과 비교하였다. 결 과: 전산화치료계획에 의한 선량은 직장벽 100%, 방광벽 52%, 우측 정낭 86%, 좌측 정낭 87%, 표면 18%였으나, TLD로 측정 한 선량은 직장벽 89%, 방광벽 54%, 우측 정낭 85%, 좌측 정낭 84%, 표면 17%로 측정되었다. 직장벽은 11%, 방광벽은 2%, 우측 정낭은 1%, 좌측 정낭 3%, 표면 1%의 선량차이를 확인하였다. 결 론: 본원에서 개발한 전립선암 환자형 골반 팬톰으로 전산화치료계획에서 구현하는 불균질부 선량계산의 오차를 확인할 수 있었으며, 다양한 선량 측정 장치(TLD, film)를 이용하여 쉽고 간편하게 선량 검증을 할 수 있을 것으로 사료된다.

• Journal of Radiation Protection and Research
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• 제35권2호
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• pp.63-68
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• 2010

방사선치료의 최대 목표는 정상조직을 보호하고 종양부위에 방사선량을 충분히 조사하는 것이다. 그 중에서 환자호흡에 의한 문제점을 보안하기 위해 환자호흡에 따른 주기적 움직임을 분석하여 안정된 일정영역에서만 방사선이 조사되도록 하는 호흡동조방사선치료 방법이 임상에서 활용되고 있다. 본 논문은 특히 호흡에 의해 움직임 영향을 많이 받는 간암 환자 40명을 대상으로 실제 방사선 치료 계획에 이용되는 4D-CT와 호흡동조방사선 치료에 사용하는 RPM을 이용하여 간암의 움직임을 환자의 나이, 성별 및 움직임 방향으로 나누어 분석하였다. 움직임의 변화는 방향으로는 right-left($3.19{\pm}1.29$), anteroposterior($5.44{\pm}2.07$), craniocaudal($12.54{\pm}4.70mm$)이었고, 이는 성별과 관련이 없고 나이가 고령일수록 움직임이 크다는 것을 알 수 있다. 따라서 호흡에 의해 움직임으로 인한 치료부위의 방향이 변화가 생김으로 RPM 호흡동조방사선 치료로 움직임에 대한 보정을 실시하여 간암 치료에서 치료효과를 높일 수 있다.

• Imaging Science in Dentistry
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• 제30권4호
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• pp.275-279
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• 2000

Purpose: Radiation damage is produced and viable cell number is reduced. We need to know the type of cell death by the ionizing radiation and the amount and duration of cell cycle arrest. In this study, we want to identified the main cause of the cellular damage in the oral cancer cells and normal keratinocytes with clinically useful radiation dosage. Materials and Methods: Human gingival tissue specimens obtained from healthy volunteers were used for primary culture of the normal human oral keratinocytes (NHOK). Primary NHOK were prepared from separated epithelial tissue and maintained in keratinocyte growth medium containing 0.15 mM calcium and a supplementary growth factor bullet kit. Fadu and Hep-2 cell lines were obtained from KCLB. Cells were irradiated in a /sup 137/Cs γ-irradiator at the dose of 10 Gy. The dose rate was 5.38 Gy/min. The necrotic cell death was examined with Lactate Dehydrogenase (LDH) activity in the culture medium. Every 4 day after irradiation, LDH activities were read and compared control group. Cell cycle phase distribution and preG1-incidence after radiation were analyzed by flow cytometry using Propidium Iodine staining. Cell cycle analysis were carried out with a FAC Star plus flowcytometry (FACS, Becton Dickinson, USA) and DNA histograms were processed with CELLFIT software (Becton Dickinson, USA). Results: LDH activity increased in all of the experimental cells by the times. This pattern could be seen in the non-irradiated cells, and there was no difference between the non-irradiated cells and irradiated cells. We detected an induction of apoptosis after irradiation with a single dose of 10 Gy. The maximal rate of apoptosis ranged from 4.0% to 8.0% 4 days after irradiation. In all experimental cells, we detected G2/M arrest after irradiation with a single dose of 10 Gy. Yet there were differences in the number of G2/M arrested cells. The maximal rate of the G2/M ranges from 60.0% to 80.0% 24h after irradiation. There is no significant changes on the rate of the G0/G1 phase. Conclusion: Radiation sensitivity was not related with necrosis but cell cycle arrest and apoptosis. These data suggested that more arrested cell is correlated with more apoptosis.

• The Korean Journal of Pain
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• 제24권4호
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• pp.199-204
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• 2011

Background: Although many clinicians know about the reducing effects of the pulsed and low-dose modes for fluoroscopic radiation when performing interventional procedures, few studies have quantified the reduction of radiation-absorbed doses (RADs). The aim of this study is to compare how much the RADs from a fluoroscopy are reduced according to the C-arm fluoroscopic modes used. Methods: We measured the RADs in the C-arm fluoroscopic modes including 'conventional mode', 'pulsed mode', 'low-dose mode', and 'pulsed + low-dose mode'. Clinical imaging conditions were simulated using a lead apron instead of a patient. According to each mode, one experimenter radiographed the lead apron, which was on the table, consecutively 5 times on the AP views. We regarded this as one set and a total of 10 sets were done according to each mode. Cumulative exposure time, RADs, peak X-ray energy, and current, which were viewed on the monitor, were recorded. Results: Pulsed, low-dose, and pulsed + low-dose modes showed significantly decreased RADs by 32%, 57%, and 83% compared to the conventional mode. The mean cumulative exposure time was significantly lower in the pulsed and pulsed + low-dose modes than in the conventional mode. All modes had pretty much the same peak X-ray energy. The mean current was significantly lower in the low-dose and pulsed + low-dose modes than in the conventional mode. Conclusions: The use of the pulsed and low-dose modes together significantly reduced the RADs compared to the conventional mode. Therefore, the proper use of the fluoroscopy and its C-arm modes will reduce the radiation exposure of patients and clinicians.

• Imaging Science in Dentistry
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• 제46권2호
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• pp.103-108
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• 2016

Purpose: The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. Materials and Methods: An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. Results: The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. Conclusion: A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose.

• 한국산학기술학회논문지
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• 제12권7호
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• pp.3117-3122
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• 2011

머리부 전후방향촬영은 종래의 증감지-필름 방사선촬영보다 디지털방사선촬영 시 입사표면선량(ESD)이 훨씬 높다. 따라서 본 연구의 목적은 부가필터를 사용하여 환자의 피폭선량을 줄이기 위한 것이다. 본 연구에서는 머리부 팬톰을 이용하여 머리부 전후방향촬영 시 부가여과판의 두께에 따른 선량 감소효과를 알아보았고, 동시에 부가여과판 사용에 따른 영상의 질적 저하의 평가를 위한 실험을 진행하였다. 선량측정은 머리부 팬톰을 머리부 전후방향촬영자 세로 위치시켜 입사표면선량과 투과선량을 0.1 mmAl으로부터 0.5 mmCu+2.0 mmAl까지 16종류의 부가여과판을 바꾸어 가며 측정하였다. 영상의 화질 평가를 위해서 총 17매의 영상을 촬영하였고 촬영된 영상은 영상의학과 전문의에게 평가를 의뢰하였다. 그 결과 부가여과판 중 0.2 mmCu+1.0 mmAl의 복합여과판을 사용한 부가여과판까지 진단적 가치가 있는 영상을 얻었고, 이 때 머리부 팬톰에 입사표면선량은 약 0.6 mGy이었다. 이 값은 국제원자력기구(IAEA)에서 권고하고 있는 머리부 후전방향촬영 시 입사표면선량 5 mGy의 12%에 불과하였다. 따라서 검사부위에 따라 적정한 부가여과판의 사용으로 환자의 피폭선량을 상당히 감소시키는 효과를 얻을 수 있다.

• 대한방사선기술학회지:방사선기술과학
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• 제41권2호
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• pp.141-148
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• 2018

This study examined the properties of photons and the dose distribution in a human body via a simulation where the total body irradiation(TBI) is performed on a pediatric anthropomorphic phantom and a child size water phantom. Based on this, we tried to find the optimal photon beam energy and material for beam spoiler. In this study, MCNPX (Ver. 2.5.0), a simulation program based on the Monte Carlo method, was used for the photon beam analysis and TBI simulation. Several different beam spoiler materials (plexiglass, copper, lead, aluminium) were used, and three different electron beam energies were used in the simulated accelerator to produce photon beams (6, 10, and 15 MeV). Moreover, both a water phantom for calculating the depth-dependent dosage and a pediatric anthropomorphic phantom for calculating the organ dosage were used. The homogeneity of photon beam was examined in different depths for the water phantom, which shows the 20%-40% difference for each material. Next, the org an doses on pediatric anthropomorphic phantom were examined, and the results showed that the average dose for each part of the body was skin 17.7 Gy, sexual gland 15.2 Gy, digestion 13.8 Gy, liver 11.8 Gy, kidney 9.2 Gy, lungs 6.2 Gy, and brain 4.6 Gy. Moreover, as for the organ doses according to materials, the highest dose was observed in lead while the lowest was observed in plexiglass. Plexiglass in current use is considered the most suitable material, and a 6 or 10 MV photon energy plan tailored to the patient condition is considered more suitable than a higher energy plan.