• Journal of Radiation Protection and Research
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• 제39권4호
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• pp.159-167
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• 2014

국내에서는 2012년 천연방사성핵종이 포함된 가공제품의 규제를 위해 생활주변방사선 안전관리법이 시행되었지만, 해당 가공제품 사용에 대한 인체 피폭선량을 평가할 수 있는 기초자료나 피폭선량 평가기술이 미비하다. 따라서 본 연구는 사용자 피폭선량을 정량적으로 평가하기 위한 방법을 제안하고, 방사선의 종류 및 에너지에 따른 피폭선량 특성의 확인을 목적으로 한다. 피폭선량 평가를 위해서 몬테칼로 방법을 사용한 Monte Carlo N-Particle Extended (MCNPX) 코드를 통해 International Commission on Radiological Protection (ICRP)의 기준팬텀이 전산모사 되었으며, 대표적 천연방사성핵종인 우라늄 계열에서 발생되는 알파선, 베타선, 감마선의 최소, 중간, 최대 에너지가 선원항으로 사용되었다. 연간 유효선량은 가공제품 사용시간 및 사용위치를 고려한 피폭시나리오를 기반으로 평가되었다. 짧은 비정의 알파선 및 베타선은 대부분의 선량을 피부에 전달한 반면, 감마선은 대부분의 장기에 유사한 선량을 전달하였다. 방사능이 $1Bq{\cdot}g^{-1}$ 인 돌침대에 포함된 천연방사성핵종의 함유율이 10%라고 가정하고 한국인 평균 수면시간인 7시간 50분간 돌침대를 사용하였을 때 최대 연간 유효선량은 알파선, 베타선, 감마선에 대해서 각각 0.0222, 0.0836, $0.0101mSv{\cdot}y^{-1}$로 평가되었다.

• 한국의학물리학회지:의학물리
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• 제1권1호
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• pp.23-29
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• 1990

In order to explane the stereotactic procedure, the three steps of the procedure (target localization, dose planning, and radiation treatment) must be examined separately. The ultimate accuracy of the full procedure is dependent on each of these steps and on the consistancy of the approach The concern in this article was about dose planning, which is a important factor to the success of radiation treatment. The major factor in dose planning is a dosimetry system to evaluate the dose delivered to the target and normal tissues in the patient, while it generates an optimal dose distribution that will satisfy a set of clinical criteria for the patient. A three-dimensional treatment planning program is a prerequisite for treatment plan optimization. It must cover 3-D methods for representing the patient, the dose distributions, and beam settings. The major problems and possible modelings about 3-D factors and optimization technique were discussed to simplify and solve the problems associatied with 3-D optimization, with relative ease and efficiency. These modification can simplify the optimization problem while saving time, and can be used to develop reference dose planning system to prepare standard guideline for the selection of optimum beam parameters, such as the target position, collimator size, arc spacing, the variation in arc length and weight. The method yields good results which can then be simulated and tailored to the individual case. The procedure needed for dose planning in stereotactic radiosurgery is shown in figure 1.

• 상하수도학회지
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• 제26권4호
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• pp.521-533
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• 2012

Interest in application of ultraviolet light technology for primary disinfection that used for the treatment of water for consumption and wastewater has increased significantly in recent years. Analysis of these systems has been carried out using Computational Fluid Dynamics (CFD) procedure. It offers advantages over other techniques in specific circumstances. CFD has emerged as a powerful tool to aid design of a UV reactor by providing the UV dose delivered by the proposed reactor design and allowing engineers to evaluate alternative designs in much less time and at a reasonable cost. In this study, five different configurations of the apparatus depending on the location of the exit are evaluated in terms of maximum dose, minimum dose, flow patterns, particle tracks and transient dose. The configuration 3 results have higher minimum UV dose value and uniform particle distribution of the UV dose on the outlet than other's.

• Radiation Oncology Journal
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• 제35권4호
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• pp.380-384
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• 2017

Massive chylous leakage is a rare postoperative complication that can prolong hospital stay and cause secondary morbidities. Conservative management strategies are the treatment of choice; however, radiation therapy (RT) can be used as an alternative for cases that are refractory to conservative treatment. Herein, we report a 69-year-old female patient who suffered from massive chylous leakage after subtotal gastrectomy. Due to persistent massive chylous leakage, she was scheduled to undergo low-dose RT. Radiation was delivered with a daily dose of 1 Gy, using an anterior-posterior and posterior-anterior beam arrangement. The clinical target volume encompassed the entire lymph node area of the D2 dissection. RT was completed at the total dose of 8 Gy because the amount of chylous leakage declined rapidly. Percutaneous drainage tube was removed after 3 days of RT. The patient did not complain of any symptoms related to massive chylous leakage 2 years after the completion of RT.

• 대한방사선기술학회지:방사선기술과학
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• 제34권2호
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• pp.105-116
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• 2011

두경부(Head & Neck) CT(Computed Tomography)검사에서 환자가 받는 피폭선량 측정을 위하여 인체등가물질로 만든 Rando phantom과 유리선량계를 이용하여 두경부 검사에 따른 환자의 흡수선량의 변화를 실험을 통하여 연구하였다. 인체두부모형을 안와신경(optic nerve), 교뇌(pons), 소뇌(cerebellum), 갑상선(thyroid)으로 나누어, 두경부(Head & Neck) 부위의 검사를 단독검사(Brain, 3D Facial, Temporal, Brain Angiography, 3D Cervical Spine)와 복합검사(Brain+Brain Angiography, Brain+3D Facial, Brain+Temporal, Brain+3D Cervical spine, Brain+3D Facial+Temporal, Brain+3D Cervical Spin+Angiography)로 구분하여 유효선량의 변화를 실험한 후 결과를 측정하였다. 단순 Brain검사와 Brain Angio검사에는 optic nerve에 유효 선량이 높게 분석되었으며, 또한 Temporal검사에는 Pons에, 3D facial 검사와 3D Cervical Spin검사에는 thyroid의 유효선량 값이 높게 나타났다. 복합적으로 이루어는 검사 중 두경부의 Brain+Brain Angio의 검사는 cerebellum의 부위, Brain+3D facial 검사와 Brain+3D Cervical Spin의 복합검사는 thyroid의 부위, Brain+Temporal의 검사에는 pon's 부위 유효 선량 값이 높게 나타났다. Brain +3D facial +Temporal의 복합검사와 Brain+3D Cervical Spin+Angio의 복합검사는 thyroid의 부위에 유효 선량 값이 높게 분석 되었다. 본 연구 결과 Brain+3D Cervical Spin+Brain Angio 복합검사인 경우의 유효 선량은 2.51858 mSv로 일반인의 연간 유효선량한도 1 mSv의 피폭을 초과하는 결과가 나왔다. 또한, Brain 단순 검사 시 optic nerve는 0.31312 mSv의 유효선량으로 향후 방사선학 검사가 이루어질 경우, 두경부의 일반인의 연간 유효선량을 훨씬 초과할 것이라 사료된다. 따라서 진료의 필요성에 의해서 시행되는 CT검사일지라도 질환 병변의 특성에 맞게 CT촬영조건 변화를 주면서 환자의 피폭선량을 최소한으로 할 수 있는 다양한 검사방법의 연구가 필요하다고 사료된다.

• 한국의학물리학회지:의학물리
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• 제9권4호
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• pp.259-266
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• 1998

코발트-60 근접조사선원을 대체할 Ir-l92 선원주변의 2차원적 선량분포를 얻기 위하여, 조사선량률과, 조직감쇠계수를 구하였다. 조직감쇠계수는 선원에서 20 cm 지점까지 실험식을 구하였다. ？보기 방사능은 조사선량상수를 사용하여 결정하였으며, 2.5mm 직경에 두께 2.5 mm 의 선원은 조직선량을 정하기 위해 선원을 4401 개로 분할하여 선원 자체의 흡수효과와 ？슐벽의 차폐 효과와 조직감쇠계수를 적용하였다. 조직감쇠계수는 4차식을 사용하여 1% 오차범위내에서 실험값을 얻을 수 있었으며, Meisberger 상수는 선원에서 많이 떨어질수록 오차가 커서, 10 cm 위치서 7%, 20 cm 에서 33%의 오차를 발견할 수 있었으나, 겉보기방사능과 선원모양 및 크기가 달라 다른 결과를 가져올 수 있다고 본다. 발표된 Ir-192 선원의 에너지스펙트럼을 이용한 선량률상수는 절삭에너지 10 keV인 경우 4.69 R$cm^2$/mCi-hr을 얻었으며 Air Kerma는 0.973 을 구하였다. 이 실험에서 고안 선원의 분할선원에 의한 선원자체흡수와 ？슐벽에 의한 감쇠는 실선원의 54.6%가 겉보기방사능으로 나타남을 알 수 있었으며, 선량계획에 이용하기 위해 단위 ？보기 방사능에 대한 2차원적 선량표를 준비함으로써 기하학적선량과 선량 비등방성을 쉽게 이용할 수 있도록 하였다.

• 대한방사선치료학회지
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• 제6권1호
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• pp.146-153
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• 1994

A modified irradiation technique utilizing a linear accelerator for radiation surgery within the brain was performed in 41 cases of patients with anteriovenous malformation(AVM), astrocytoma, meningioma. etc. The treatment planning and dosimetry of small field for stereotactic radiosurgery with 10 MV X-ray isocentically mounted linear accelerator will be presented dose with field size, the central axis persent depth dose and the combined moving beam dose distribution. The three dimensional dose planning of stereotactic focusing irradiation on small size tumor region was perfomed with dose planning computer system(Therac 2300) and was verified with film dosimetry. The more the number of strip and the wider the angle of arc rotation, the larger were the dose delivered on tumor and the less the dose to surrounding the normal tissues. In this study, the using machine and method was as fellowing. 1) Apparatus : NELAC-1018 10MV X-ray 2) Strip No. : Select the 5-7 strips 3) Cone and field size are from $1{\times}1cm^2$ to $3.5{\times}3.5cm^2$, and special circular cone designed for the purpose of minimized the risk to normal tissue and those size are $0.7{\~}3.6cm{\phi}$.

• 대한방사선치료학회지
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• 제20권1호
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• pp.11-15
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• 2008

목 적: 방사선치료계획에 있어서 정상조직과 치료부위의 선량 분포는 매우 중요하다. 이에 본원에서는 유방암 환자를 대상으로 Three-dimensional conformal radiation therapy (3D-CRT), Helical tomotherapy (TOMO)의 방법으로 방사선치료계획을 세웠으며 이에 선량분포를 분석하여 실제 임상에서의 적용여부를 알아보고자 한다. 대상 및 방법: 20명의(좌측: 10명, 우측: 10명) 유방보존절제술 환자를 대상으로 시행하였으며 방법으로는 같은 조건에서 3D-CRT는 Philips사의 Pinnacle을, TOMO는 TomoTherapy사의 TOMO Planning System을 이용해 치료계획을 세웠다. Dose-Volume Histogram (DVH)의 prescribed dose (PD)에 대한 PTV의 Homogeneity index (HI)와 Conformity index (CI)를 구하였고, 정상조직의 dose- volume 관계를 비교하였다. 결 과: Homogeneity index (HI)와 Conformity, index (CI)는 TOMO에서 우수한 결과를 나타났다. $V_{-50-IB-NPTV}$ (the percentage ipsilateral non-PTV breast volume that was delivered 50% of the prescribed dose)는 3D-CRT: 40.4%, TOMO: 18.3%, $V_{20-IL}$ (the average ipsilateral lung volume percentage receiving 20% of the prescribed dose)는 3D-CRT: 4.8%, TOMO: 14.2%, $V_{20-10H}$ (the average heart volume percentage delivered 20% and 10% of the prescribed dose in left breast cancer)는 3D-CRT: 1.6%, 3% TOMO: 9.7%, 26.3%의 결과를 보여준다. 결 론: 유방암 환자의 방사선치료계획 방법들은 PTV에서 원하는 선량분포를 보여줬다. 그러나 TOMO는 좋은 Homogeneity index (HI), Conformity index (CI)와 Breast를 보호하는 장점이 있는 반면에 Lung과 Heart에서는 많은 피폭선량이 있음을 알 수 있기에 TOMO의 방사선치료계획시 주의해야 할 점으로 사료된다.

• Journal of Korean Neurosurgical Society
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• 제29권8호
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• pp.1024-1029
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• 2000

Objectives : With recent improvements in neuroimaging and the development of third and fourth-generation radiosurgical dose-planning soft ware, came a renewed interest in using radiosurgery for the treatment of movement disorders. Radiosurgery involves no opening of the cranium and no incisions, eliminating both the risk of hemorrhage from passing an electrode to the depths of meningitis from operative infection. It is for these reasons stereotactic radiosurgical treatment of movement disorders has value in a small subgroup of patients. The authors report four cases of Parkinson's disease and one case of dystonia that were treated by Gamma knife. Methods : Radiosurgical nucleus ventralis intermedius thalamotomy using the gamma knife unit was performed to make lesion in two Parkinson's disease patients. A radiation dose of 120Gy was delivered to nucleus using a single 4-mm collimator plug pattern following classic anatomical landmarks. Patients were followed for a median of 10.5 months(range 9-12 months). An independent neurological evaluation of tremor, based on the change in the United Parkinson's Disease Rating Scale tremor score(UPDRS), was correlated with a subjective evaluation. Gamma knife ventrolateral(V.O.P) thalamotomy was performed in one case of dystonia. A central dose of 150Gy was delivered and the patient was followed for 18 months. Gamma knife globus pallidus interna pallidotomy was performed in two Parkinson's disease patients. A radiation dose of 130Gy(range 120-140Gy) was delivered. Patients were followed for a median of 13 months(range 9-14 months). Result : Ventrolateral thalamotomy in dystonia produced regained left hand usage in order to be able to use the telephone. Ventralis intermedius thalamotomy produced an excellent improvement of the tremor in one case, mild improvement of the tremor in the other case of Parkinson's disease. A globus pallidus internalis(GPi) pallidotomy produced improvement of rigidity and dyskinesia : one other showed no change. There were no neurological complications. Conclusion : Gamma Knife thalamotomy considered a safe and effective technique for the treatment of tremor in Parkinson's disease. Although the results from Longer follow-up is not available yet, the short-term results seem to be encouraging.

• Nuclear Engineering and Technology
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• 제46권2호
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• pp.255-262
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• 2014

During image-guided radiation therapy, the patient is exposed to unwanted radiation from imaging devices built into the medical LINAC. In the present study, the effective dose delivered to a patient from a cone beam computed tomography (CBCT) machine was measured. Absorbed doses in specific organs listed in ICRP Publication 103 were measured with glass dosimeters calibrated with kilovolt (kV) X-rays using a whole body physical phantom for typical radiotherapy sites, including the head and neck, chest, and pelvis. The effective dose per scan for the head and neck, chest, and pelvis were $3.37{\pm}0.29$, $7.36{\pm}0.33$, and $4.09{\pm}0.29$ mSv, respectively. The results highlight the importance of the compensation of treatment dose by managing imaging dose.