• 한국콘텐츠학회논문지
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• 제11권3호
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• pp.302-308
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• 2011

혈관 조영 검사 및 중재적 방사선 시술을 통한 환자에게 주어지는 피폭선량에 대해 대뇌를 중심으로 환자 체형을 표준화하여 검사 및 시술 차이에 따른 투시시간, 면적 선량률(kerma area product rate)을 관측하고 참고 기준치를 비교하고자 하였다. 그 결과 질병 분류에 따른 면적 선량률은 지주막하출혈(subarachnoid hemorrhage)이 가장 높았고, 뇌동맥류가 가장 낮았다. 또한 검사 및 시술에 따른 면적 선량률은 양쪽 내경동맥, 양쪽 총경동맥 및 추골동맥으로 하는 방법이 가장 높았으며, guglielmi detachable coil(GDC)이 가장 낮게 나타났다. 따라서 이를 혈관 조영 검사 및 중재적 방사선 시술시 환자 피폭 선량에 대한 참고 기준치로 이용할 수 있을 것이며 향후 환자 피폭 선량 교육과 관리에 유용할 것이라 사료된다.

• Journal of Radiation Protection and Research
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• 제41권1호
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• pp.1-6
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• 2016

Background: It is very difficult to set a regulatory guidance or criteria for the protection of non-human species from the ionizing radiation, because there are no generally or internationally accepted methods for demonstrating the compliance with such criteria. It is needed that Korea develop the primary dose rate standards for the protection of both aquatic and terrestrial biota in the near future. Materials and Methods: The potential dose rates due to both external and internal radiation exposures to marine organisms such as plaice/flounder, gray mullet, and brown seaweed collected within territorial seas around the Korean Peninsula were estimated. Results and Discussion: The total dose rates to plaice/flounder, gray mullet and brown seaweed due to $^{40}K$, a primordial radionuclide in marine environment, were found to be 0.2%, 0.08% and 0.3% of approximately the values of the Derived Consideration Reference Levels (DCRLs, i.e. $1-10mGy{\cdot}d^{-1}$), respectively, as suggested by the International Commission on Radiological Protection (ICRP) publication 124. The total dose rates to marine fishes and brown seaweed due to anthropogenic radionuclides such as $^{90}Sr$, $^{137}Cs$ and $^{239+240}Pu$ were considered to be negligible compared to the total dose rate due to $^{40}K$. The external exposure to benthic fish due to all radionuclides was much higher than that of pelagic fish. Conclusion: From this study, it is recommended that the further study is required to develop a national regulatory guidance for the evaluation of doses to non-human species.

• Radiation Oncology Journal
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• 제31권1호
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• pp.18-24
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• 2013

Purpose: The purpose of this study was to assess the clinical outcomes of hypofractionated radiotherapy (HFRT) with three-dimensional conformal technique for medically inoperable patients with early stage non-small-cell lung cancer (NSCLC) and to evaluate prognostic factors. Materials and Methods: We performed a retrospective review of 26 patients who underwent HFRT for early stage NSCLC between September 2005 and August 2011. Only clinical stage T1-3N0 was included. The median RT dose was 70 Gy (range, 60 to 72 Gy) and the median biologically equivalent dose (BED) was 94.5 Gy (range, 78.0 to 100.8 Gy). In 84.6% of patients, 4 Gy per fraction was used. Neoadjuvant chemotherapy with paclitaxel and cisplatin was given to 2 of 26 patients. Results: The median follow-up time for surviving patients was 21 months (range, 13 to 49 months). The overall response rate was 53.9%, and the initial local control rate was 100%. The median survival duration was 27.8 months. Rates of 2-year overall survival, progression-free survival (PFS), local control (LC), and locoregional-free survival (LRFS) were 54.3%, 61.1%, 74.6%, and 61.9%, respectively. Multivariate analysis showed that BED (>90 vs. ${\leq}90$ Gy) was an independent prognostic factor influencing PFS, LC, and LRFS. Severe toxicities over grade 3 were not observed. Conclusion: Radical HFRT can yield satisfactory disease control with acceptable rates of toxicities in medically inoperable patients with early stage NSCLC. HFRT is a viable alternative for clinics and patients ineligible for stereotactic ablative radiotherapy. BED over 90 Gy and 4 Gy per fraction might be appropriate for HFRT.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2004년도 제29회 추계학술대회 발표논문집
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• pp.136-139
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• 2004

본 연구에서는 직장풍선을 사용하여 전립선의 내부 움직임을 최소화함으로써 계획용표적체적 내에 정상장기의 포함을 최소화고, 직장체적의 일정부분을 고선량 분포 영역에서 떨어뜨림으로써 방사선치료의 선량한계를 극복하고자 하였다. 이를 위해 직장풍선을 사용하여 환자 Setup 시 직장풍선의 위치 재현성을 분석하였고 세기조절방사선치료계획수립을 통해 임상치료에서의 유용성을 연구하였다.

• Tuberculosis and Respiratory Diseases
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• 제68권5호
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• pp.286-289
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• 2010

A 55-year old woman with advanced stage non-small cell lung cancer was admitted to hospital for the management of severe chest pain, which measured 7 out of 10 on a numerical rating scale (NRS). Despite palliative radiation and the application of multiple epidural blocks, she continued to experience severe cancer pain. We gradually increased the dose of transdermal fentanyl patches from $500{\mu}g/hr$ to $3,650{\mu}g/hr$, for 3 months without any significant side effects. Concomitantly, adjuvant therapy with antidepressants and anticonvulsants were added, decreasing the patient's pain to NRS 3~4 down from 7. After being transferred to a hospice clinic, her chest pain was well-controlled below NRS 4 by means of strong opioid medications, including the highest dose of transdermal fentanyl $4,050{\mu}g/hr$ for more than 16 months.

• 대한핵의학회지
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• 제33권2호
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• pp.163-171
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• 1999

목적 : 혈관 재협착을 막기 위하여 풍선에 용액 형태의 베타 방출 핵종을 넣어 사용하는 방법이 연구되고 있다. 이 연구에서는 Re-188-DTPA를 풍선에 넣어 사용하는 경우 주위 혈관에 대한 에너지 분포와 용액이 풍선에서 누출되는 경우 주요 장기와 전신에의 흡수 선량을 계산하였다. 대상 및 방법: 전자와 광자의 물에서의 운반은 몬테카를로 EGS4 코드를 사용하였으며 풍선은 직경 3 mm, 길이 20 mm의 원기둥으로 대체하였다. 개에게 Re-188-DTPA 370MBq를 주사하여 감마카메라로 영상을 얻어 주요장기의 잔류 시간을 구하였고 전신과 주요 장기에의 흡수 선량은 MIRDOSE3와 ICRP Dynamic Bladder모델을 사용하여 계산하였다. 결과: 3,700 MBq/1ml을 100초 동안 조사하였을 때 풍선 표면에 전달된 에너지는 17.6 Gy, 표면으로부터 0.5 mm 떨어진 곳에서 9.5 Gy이었다. 풍선에서 용액이 누출되었을 경우 전신에 0.005 mGy/MBq, 방광에 2.39 mGy/MBq의 흡수 선량이 전달되었다. 결론: 관상동맥 풍선 성형술용 풍선에 Re-188-DTPA를 주입하여 사용하는 방법이 목표선량을 조사하는 데 적절하고 방사선 안전의 관점에서 사용 가능한 방법이라고 생각한다.

• 한국의학물리학회지:의학물리
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• 제24권4호
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• pp.253-258
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• 2013

본 연구의 목적은 electronic portal imaging device (EPID)를 통하여 방사선 치료를 받는 환자로부터 투과해 나오는 선량으로 외부적인 선량 재구성과 몬테카를로 전산모사로부터 도출되는 내부 선량 계측과의 관계를 도출하고 이를 분석하기 위한 연구로 진행되었다. 본 연구는 전산모사 연구로써 두 가지의 경우를 비교 분석하고 이와 비슷한 연구에 대한 기본적인 지표를 제공하고자 시행되었다. 실험에 관한 기하학적 정보와 방사선 소스에 대한 정보를 몬테카를로 전산모사 툴인 Monte Carlo n-particle (MCNPX)에 입력하였고 EPID 이미지 도출을 위하여 MCNPX 내에 tally카드를 이용하여 선량정보를 도출하고 이를 영상화 할 수 있도록 하였다. 또한 내부적인 계측을 위하여 물 팬텀을 소스와 표면의 거리(source to surface distance, SSD)가 100 cm이 되도록 설정하였으며, 그보다 10 cm 아래에 EPID를 위치시켰다. 내부 계측은 물팬텀 자체에서 흡수되는 흡수 선량을 mesh tally로 수집하였고, 4문 조사를 통하여 중첩된 선량에 대한 데이터를 획득하였다. 그와 동시에 EPID에서 물을 투과해 나오는 선량을 획득 한 뒤 역 투사 방법을 사용하여 선량 재구성을 하였다. 이둘의 경우를 비교하기 위해 자체적인 교정(calibration)을 통하여 투과해 나온 선량과 흡수된 선량과의 관계를 비교하고 4문 조사를 통하여 물 팬텀 내의 특정 부분에 대한 중첩된 선량 데이터와 EPID를 통해 재구성한 선량 데이터를 분석하였다. 물 팬텀과 EPID에서 획득한 누적 선량의 합은 각각 평균 3.4580 MeV/g과 3.4354 MeV/g이었다. 이는 앞서 계측된 물 팬텀 내부의 누적 선량과 0.6536% 선량 오차를 보였다.

• Radiation Oncology Journal
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• 제38권1호
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• pp.35-43
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• 2020

Purpose: This retrospective study compares higher-dose whole-brain radiotherapy (hdWBRT) with reduced-dose WBRT (rdWBRT) in terms of clinical efficacy and toxicity profile in patients treated for primary central nervous system lymphoma (PCNSL). Materials and Methods: Radiotherapy followed by high-dose methotrexate (HD-MTX)-based chemotherapy was administered to immunocompetent patients with histologically confirmed PCNSL between 2000 and 2016. Response to chemotherapy was taken into account when prescribing the radiation dose to the whole brain and primary tumor bed. The whole brain dose was ≤23.4 Gy for rdWBRT (n = 20) and >23.4 Gy for hdWBRT (n = 68). Patients manifesting cognitive disturbance, memory impairment and dysarthria were considered to have neurotoxicity. A median follow-up was 3.62 years. Results: The 3-year overall survival (OS) and progression-free survival (PFS) were 70.0% and 48.9% with rdWBRT, and 63.2% and 43.2% with hdWBRT. The 3-year OS and PFS among patients with partial response (n = 45) after chemotherapy were 77.8% and 53.3% with rdWBRT, and 58.3% and 45.8% with hdWBRT (p > 0.05). Among patients with complete response achieved during follow-up, the 3-year freedom from neurotoxicity (FFNT) rate was 94.1% with rdWBRT and 62.4% with hdWBRT. Among patients aged ≥60 years, the 3-year FFNT rate was 87.5% with rdWBRT and 39.1% with hdWBRT (p = 0.49). Neurotoxicity was not observed after rdWBRT in patients aged below 60 years. Conclusion: rdWBRT with tumor bed boost combined with upfront HD-MTX is less neurotoxic and results in effective survival as higher-dose radiotherapy even in partial response after chemotherapy.

• Nuclear Engineering and Technology
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• 제40권7호
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• pp.527-532
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• 2008

As therapeutic uses of radionuclides in nuclear medicine increases, the use of patient-specific methods for calculation of radiation dose becomes more important. In this manuscript basic methods and resources for internal dose calculations are outlined, with a focus on how current changes and advances are making more accurate and detailed, patient-individualized dose calculations possible. Most current resources make use of standardized models of the human body representing median individuals, but the use of image-based and more realistic models will soon take their place, and will permit adjustments to represent individual patients and tailor therapy planning uniquely for each subject.

• Korean Journal of Radiology
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• 제24권7호
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• pp.681-689
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• 2023

Objective: Three-dimensional rotational angiography (3D-RA) is increasingly used for the evaluation of intracranial aneurysms (IAs); however, radiation exposure to the lens is a concern. We investigated the effect of head off-centering by adjusting table height on the lens dose during 3D-RA and its feasibility in patient examination. Materials and Methods: The effect of head off-centering during 3D-RA on the lens radiation dose at various table heights was investigated using a RANDO head phantom (Alderson Research Labs). We prospectively enrolled 20 patients (58.0 ± 9.4 years) with IAs who were scheduled to undergo bilateral 3D-RA. In all patients' 3D-RA, the lens dose-reduction protocol involving elevation of the examination table was applied to one internal carotid artery, and the conventional protocol was applied to the other. The lens dose was measured using photoluminescent glass dosimeters (GD-352M, AGC Techno Glass Co., LTD), and radiation dose metrics were compared between the two protocols. Image quality was quantitatively analyzed using source images for image noise, signal-to-noise ratio, and contrast-to-noise ratio. Additionally, three reviewers qualitatively assessed the image quality using a five-point Likert scale. Results: The phantom study showed that the lens dose was reduced by an average of 38% per 1 cm increase in table height. In the patient study, the dose-reduction protocol (elevating the table height by an average of 2.3 cm) led to an 83% reduction in the median dose from 4.65 mGy to 0.79 mGy (P < 0.001). There were no significant differences between dose-reduction and conventional protocols in the kerma area product (7.34 vs. 7.40 Gy·cm², P = 0.892), air kerma (75.7 vs. 75.1 mGy, P = 0.872), and image quality. Conclusion: The lens radiation dose was significantly affected by table height adjustment during 3D-RA. Intentional head off-centering by elevation of the table is a simple and effective way to reduce the lens dose in clinical practice.