Following the previous study, the toxicity of a single subcutaneous administration of the Thyrokitty injection (I-131) and the side effects that may occur at therapeutic doses were confirmed. The Thyrokitty injection (I-131) was administered subcutaneously once at a dose of 0, 2.0, 6.0, and 18.0 mCi/kg, 5 male and female rats per group, and mortality, general symptom observation, and weight measurement were performed for 2 weeks, followed by observation of autopsy findings. There were no deaths, and no statistically significant weight change was observed. Mild hair loss, fissures, and crusting were observed by general symptom observation, but it was not a toxic change related to the Thyrokitty injection (I-131). Gastric atrophy and a decrease in the size of the spleen were observed by the autopsy. As a results of single subcutaneous administration of the Thyrokitty Injection (I-131) to rats at a maximum dose of 18.0 mCi/kg, a decrease in the size of the spleen and gastric atrophy were observed as the dose of the Thyrokitty Injection (I-131) increased, which may be related to the test substance. No abnormal findings related to the Thyrokitty injection (I-131) were observed. Therefore, the approximate lethal dose of the Thyrokitty injection (I-131) was 18.0 mCi/kg or more. In addition, as reported for the treatment of feline hyperthyroidism with radioiodine (131I), side effects of the Thyrokitty injection (I-131) are expected to be extremely rare. Temporary dysphagia and fever may occur, but it will recover naturally. It should be administered with caution in cats with diseases such as urinary system, cardiovascular system, gastrointestinal system and endocrine system, especially with kidney disease. And it should not be used in cats who are pregnant, lactating, or likely. It is expected that the Thyrokitty injection (I-131) can be used for clinical treatment in Korea as a veterinary drug.

Radioiodine (131I) has been used for the treatment of feline hyperthyroidism since the 1990s in the USA and Europe, and it is recommended as the most effective treatment for feline hyperthyroidism because it has a high therapeutic effect, small side effects, and does not require anesthesia. In this study, the pharmacological properties of the Thyrokitty injection (I-131), which is being developed as a treatment for feline hyperthyroidism, using radioiodine (131I) as an active ingredient, was tested. The %cell uptake of the Thyrokitty injection (I-131) in FRTL- 5 thyroid cells was 0.410 ± 0.016%, which was about 18 times higher compared to Clone 9 hepatocytes, and it was decreased by 30.7% due to the competitive reaction with iodine (sodium iodide). In addition, the %cell growth of the FRTL-5 thyroid cells was reduced by 25.0% by treatment with the Thyrokitty injection (I-131). As a result of the tissue distribution test, the Thyrokitty injection (I-131) was distributed at the highest concentration at 0.083 hours (5 minutes) after subcutaneous administration to animals in most organs except the stomach, small intestine, large intestine, muscle and thyroid gland, and it was excreted mainly through the kidneys. The stomach and thyroid gland showed a typical distribution pattern observed when radioiodine (131I) was administered. In addition, about 78.45% of the total amount of excretion was excreted within 48 hours, of which more than 85% was excreted in urine. In conclusion, the Thyrokitty injection (I-131) has the same mechanism of action, potency, absorption, distribution, metabolism and excretion characteristics as radioiodine (131I) reported in connection with the treatment of feline hyperthyroidism. In the future, using the results of this study, it is expected that the Thyrokitty (I-131) could be safely used in the clinical treatment of feline hyperthyroidism.

This transport cask for radioactive materials will be used in the Gijang reactor. It will transport the Ir-192 10,000 Ci or I-131 80 Ci. In this case, the safety evaluation, such as protection of leakage of radioactive material, and radiation shield should be carried out before it is used in the research reactor. The safety regulation requires various tests, such as water spray, free drop, penetration, and water immersion. But this paper considers only the regulations related with thermal-stress and drop impact under the normal conditions because it will be used only in the research reactor building. In this paper, coupled numerical analysis was performed using finite element simulation to investigate the effect of position of tungsten and lead to enhance the safety of transport cask. As a result of simulation, it was verified that the Tungsten-Lead structure is the most durable among the cases considered in the study with a viewpoint of thermal-stress and drop impact.

본 연구는 고용량 131I 치료 후 방사선원이 된 퇴원 환자로부터 나오는 방사선 피폭에 관해 외부 선량률 을 측정하고, 그에 따른 피폭선량을 예측하는 것이 목적이다. 200 mCi 이상 고용량 131I 치료를 받은 30명의 환자에서 구리링 3개를 이용하여 환자로부터 거리 및 방위각에 따른 선량평가를 시행하였다. 정확한 방사 선 계측을 위하여 GM 계측기를 이용하여 2명의 측정자가 방위각 8 포인트와 거리 변화를 주며 계측하였 다. 측정값을 기반으로 3가지 예측 시뮬레이션을 설정하여 불특정 다수 일반인에 대한 피폭선량을 계산하 였다. 1m 높이에서 방위각에 따른 외부 선량률이 가장 높은 부위는 0도이다. 거리에 따른 선량률은 거리별 방위각의 선량률 평균값을 사용하였다. 거리에 따른 외부 선량률의 최고치는 50, 100, 150 cm에서 각각 214 ± 16.5, 59 ± 9.1 μSv/h, 38 ± 5.8 μSv/h 이다. 고용량 131I 치료 환자가 대중교통을 이용해서 5시간 이동할 때 반경 50 cm 지점의 옆좌석에 안은 불특정 일반인이 받을 수 있는 피폭선량은 1.14 mSv이다. 소변 통 (urin bag)을 착용한 퇴원환자로부터 100 cm 거리에서 4일 동안 간병인이 받을 수 있는 최대 피폭선량은 6.5 mSv이다. 퇴원 환자 귀가로 인해 7일 동안 150 cm 거리에서 보호자가 받을 수 있는 최대 피폭선량은 1.08 mSv이다. 개발된 예측 모델링으로 불특정 131I 치료 환자의 주변 일반인에게 적용하였을 때 연간 선량 한도 를 단시간에 초과하는 수준이었다. 따라서 본 연구를 통해 현행 고용량 131I 치료 환자의 퇴원 후 주변의 일반인의 방호체계의 합리적인 가이드라인을 제시하는 데 도움을 줄 수 있을 것으로 사료된다.

고용량 131I 치료는 분화갑상선암으로 인한 갑상선전절제술을 받은 환자에게 보편적으로 시행되어 왔다. 고용량 131I 치료를 하는 경우 환자로부터 일반인이 받게 되는 피폭선량을 선량한도 이내로 제한하기 위해 환자를 일정 기간 동안 격리하여야 한다. 유효반감기는 환자로부터 가족들이 얼마나 피폭되는지 계산하거 나 격리기간을 결정하는데 중요한 값이다. 이에 본 연구에서는 NM670 SPECT/CT를 이용해 고용량 131I 치 료환자의 유효붕괴상수, 유효반감기, 격리기간을 도출하였다. 본 연구를 통해 고용량 131I 치료환자의 유효반감기를 도출하였고, 체내에 잔류 방사능량이 퇴원기준인 1. 2 GBq 에 도달하는 시간을 확인하였다. 또한 치료선량별 유효반감기를 비교하였을 때 유의한 차이가 없 었으나, 격리기간은 치료선량이 커질수록 격리기간이 길어지는 것을 확인할 수 있었다. 전처치 유형별 유 효반감기를 비교하였을 때 rhTSH 환자군과 THW 환자군의 유효반감기가 유의한 차이를 보이지 않았으나, 격리기간은 rhTSH 환자군이 THW 환자군 보다 짧게 나타났다. 이는 치료선량의 차이로 인해 격리기간이 짧아진 것으로 판단된다. 따라서 현행 의료보험체계(rhTSH 사용 시 3.7 GBq 이하에서 보험적용)가 유지된다면, 전처치 유형별로 구분하여 현행 격리기간(2박 3일)보다 더 이른 시간에 환자를 퇴원시킬 수 있을 것이다.

This research was performed by means of several different virgin granular activated carbons (GAC) made of each coal, coconut and wood, and the GACs were investigated for an adsorption performance of iodine-131 in a continuous adsorption column. Breakthrough behavior was investigated that the breakthrough points of the virgin two coals-, coconut- and wood-based GACs were observed as bed volume (BV) 7080, BV 5640, BV 5064 and BV 3192, respectively. The experimental results of adsorption capacity (X/M) for iodine-127 showed that two coal- based GACs were highest (208.6 and 139.1 μg/g), the coconut-based GAC was intermediate (86.5 μg/g) and the wood-based GAC was lowest (54.5 μg/g). The X/M of the coal-based GACs was 2∼4 times higher than the X/M of the coconut-based and wood-based GACs.

요오드는 원자력 시설에서 사고가 발생할 경우 방사선 피폭을 검토할 때 고려해야 할 중요한 핵종 중 하나이다. 그러므로 체르노빌 사고 시 대기 중에는 유기물 형태의 요오드가 비유기물 형태의 요오드보다 많이 관찰되었다. 본 연구에서는 시료의 양 및 측정시간에 변화를 주었으며, 또한 131I 액체선원을 사용하여 증류수에 희석한 시료 및 다시마를함께 섞은 시료를 이용하여 검출하한치를 측정․분석하였다. 방사능농도 하한치에 들어 인체에는 무해함을 확인 할 수있었다. 131I선원의 시간이 흐를수록 카운트가 줄어듦을 알 수 있었다. 반감기를 계산해본 결과 7~9사이의 결과를 얻었고, 131I를 혼합한 시료의 경우 최고 7일이 지난 후에는 초기 조건에서 반으로 감소한다는 것을 알 수 있었다.