• Journal of Radiation Protection and Research
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• v.28 no.2
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• pp.117-125
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• 2003

It was reported that radiopharamaceuticals induced radiation adaptive response (RAR) in patients undergoing nuclear medicine imaging studies. Individual variations of RAR were not studied well. The purpose of this study was to evaluate individual variation of RAR in patients undergoing nuclear medicine imaging studies. Peripheral lymphocytes were collected from 23 patients undergoing $^{99m}Tc-diethylenetriamine$ pentaacetic acid $(^{99m}Tc-DTPA)$ renal scintigraphy, 18 patients undergoing $^{99m}Tc-methylene$ diphosphonate $(^{99m}Tc-MDP)$ bone scintigraphy and 21 patients undergoing $^{99m}Tc-tetrofosmin\;(^{99m}Tc-TF)$ scintigraphy were collected before and 4 hours after injection of radiopharmaceuticals. The lymphocytes were exposed to challenge dose of 2 Gy gamma rays using a cell irradiator. Numbers of ring-form (R) and dicentric (D) chromosomes were counted under the light microscope. and used to calculate the frequency of chromosomal aberration [Ydr=(D+R)/total number of counted lymphocytes]. Adaptation index (k) was defined 3s ratio of Ydr in conditioned lymphocytes over Ydr in unconditioned lymphocytes. Coefficients of variance of k in $^{99m}Tc-DTPA,\;^{99m}Tc-MDP\;and\;^{99m}Tc-TF$ were 35%, 34% and 21%, respectively k was not dependent upon age, sex, and underlying diseases. There was a wide variation of RAR induced by radiopharmaceuticals among patients undergoing nuclear medicine procedures. It remains to be determined for causes of such variation.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.269-274
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• 1996

월성원자력발전소 2호기와 같은 CANDU 6형 원자로의 반응도제어기구 설치대에는 여러 반응도제어기구가 삽입되기때문에 원자로심으로부터의 방사선흐름현상으로 인한 방사선피폭이 예상될 수 있는 위치이다. 좁고 긴 반응도제어기구 도관에서의 방사선 흐름으로 인한 반응도제어기구 설치대에서의 방사선량을 예측하기 위해 몬테 칼로 MCNP 코드를 1차원 각분할법 코드인 ANISN과 연계하여 사용하였다. 월성원자력2호기의 상단차폐해석을 위한 ANISN 계산, 도관의 방사선흐름을 평가하기 위한 MCNP 계산, 그리고 반응도제어기구 설치대에서의 방사선량율 평가를 위한 MCNP 계산등 3단계 계산 기법의 적응이 시도되었다.

• The Korean Journal of Nuclear Medicine
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• v.34 no.3
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• pp.252-259
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• 2000

Purpose: The purpose of this study was to compare the radiation adaptive response (RAR) in peripheral lymphocytes (PL) of patients induced by Tc-99m MDP and Tc-99m DTPA scintigraphies. Materials and Methods: Lymphocytes from 45 patients (25 males, 20 females, mean age $44{\pm}18$ years) were collected before and after scintigraphies using 740 MBq Tc-99m MDP (n=22) or Tc-99m DTPA (n=23). Lymphocytes from 20 controls (12 males, 8 females, mean age $43{\pm}7$ years) were also collected. They were exposed to challenge dose of 2 Gy ${\gamma}-rays$ using a Cs-137 cell irradiator Number of ring-form (R) and dicentric (D) chromosomes was counted under the light microscope. From them a representative score, Ydr, was calculated as Ydr=(D+R)/cells. Adaptation index (AI) was defined as difference of Ydr between unconditioned and conditioned lymphocytes. Ydr was also measured after an administration of cycloheximide (CHM), a protein synthesis inhibitor, before challenge dose. Results: RAR was induced in both groups of patients. CHM abolished the adaptive response in both groups. AI of Tc-99m MDP group was significantly higher than that of Tc-99m BTPA group. Conclusion: Tc-99m MDP induced RAR was more prominent than those induced by Tc-99m DTPA.

• Radiation Oncology Journal
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• v.12 no.1
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• pp.1-8
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• 1994

When cells are exposed to low doses of a mutagenic or clastogenic agents. they often become less sensitive to the effects of a higher dose administered subsequently. Such adaptive responses were first described in Escherichia coli and mammalian cells to low doses of an alkylating agent. Since most of the studies have been carried out with human lymphocytes, it is urgently necessary to study this effect in different cellular systems. Its relation with inherent cellular radiosensitivity and underlying mechanism also remain to be answered. In this study, adaptive response by 1 cGy of gamma rays was investigated in three human lymphoblastoid cell lines which were derived from ataxia telangiectasia homozygote, ataxia telangiectasia heterozygote, and normal individual. Experiments were carried out by delivering 1 cGy followed by 50 cGy of gamma radiation and chromatid breaks were scored as an endpoint. The results indicate that prior exposure to 1 cGy of gamma rays reduces the number of chromatid breaks induced by subsequent higher dose (50 cGy), The expression of this adaptive response was similar among three cell lines despite of their different radiosensitivity. When 3-aminobenzamide, an inhibitor of poly (ADP-ribose) polymerase, was added after 50 cGy, adaptive responses were abolished in all the tested cell lines. Therefore it is suggested that the adaptive response can be observed in human lymphoblastoid cell lines, which was first documented through this study. The expression of adaptive response was similar among the cell lines regardless of their radiosensitivity. The elimination of the adaptive response by 3-aminobenzamide is consistent with the proposal that this adaptive response is the result of the induction of a certain chromosomal repair mechanism.

• The Journal of Korean Society for Radiation Therapy
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• v.9 no.1
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• pp.1-7
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• 1997

다량의 방사선에 피폭되는 경우 인체에 해로운 영향을 미치는 것은 틀림이 없으나 미량의 방사선인 경우에는 다량의 방사선인 경우와 다른 효과를 나타내며 심지어 정반대의 영향을 나타내기도 한다고 볼 수 있으며 여러 역학조사에서 이러한 사실이 증명되고 있다. 1991년의 국제방사선방어기구(ICRP) 보고서 및 1994년의 UNSCEAR 보고서는 미량의 방사선에 대한 적응반응을 인정하고 있다. 일부 학자들은 소량의 방사선에 지속적으로 피폭(연간 1 rem)됨으로써 암사망률을 감소시킬 수 있다고 주장하면서 현재의 개념을 수정하여 피폭한계 및 법적 제한 등을 변경하여 환경방사능을 증가시킴으로써 향후 인류의 생활의 질을 향상시켜야 한다고 주장하고 있다.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.05a
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• pp.395-395
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• 2004

• Journal of Radiation Protection and Research
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• v.20 no.2
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• pp.97-102
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• 1995

Adaptive response induced by low dose ${\gamma}-ray$ irradiation in human peripheral lymphocytes was examimed. Human lymphocytes were exposured to low dose of ${\gamma}-ray$ (priming dose, 0.01Gy) followed by high dose (challenging dose, 1.5Gy) after various time intervals (4, 7, 20 hours). Frequencies of micronuclei were enumerated in both primed and unprimed groups. Maximum reduction in frequency of micronuclei was observed when challenging dose irradiation was followed by priming dose after 4hr incubation period. When challenging doses were irradiated 7 or 20hr after priming dose, frequencies of micronuclei were reduced slighty. However, these reduction were not statistically significant. In this study, human peripheral lymphocytes were irradiated at Go phase and they showed adaptive response induced by low dose radiation. Since micronucleus assay is relatively simpler and faster than other methods, it may be a good tool for evaluating radiation-induced adaptive responses.

• Radioisotope journal
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• v.15 no.3
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• pp.78-92
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• 2000

낮은 선량의 방사선피폭으로 인한 건강 위해의 여부에 대하여 과학적 현황을 고찰하였다. 선량과 영향 사이에 문턱 없는 선형비례 모델(LN-T모델)에 대해 역학적, 수학적, 방사선생물학적 측면의 긍정적 논리와 호메시스, 적응반응, 통계적 관점의 비판적 논거를 대비하여 평가하였다. 방사선 피폭이력자에게 발현한 확률적 영향 특히 백혈병을 포함한 암에 대해 그 질환의 방사선 인과성 판단에 대한 애로와 접근 방향을 논의하였다. 객관적인 평가 지표의 하나로 기인확률(PC)을 적용하되 근로자에 대한 제도적 배려 등 고려할 사항을 논의하였다.

• 대한핵의학회:학술대회논문집
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• 1997.05a
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• pp.166-166
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• 1997

• The Korean Journal of Nuclear Medicine
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• v.35 no.5
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• pp.313-323
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• 2001

Purpose: The purpose of this study was to search activated genes that could be related to radiation adaptive response (RAR) induced by low-level radiation from $^{99m}Tc$ in human cell lines. Methods: We used gene discovery array (GDA) and representational difference analysis (RDA) methods. $^{99m}Tc$-pertechnetate was added to $2{\times}106/mL$ NC-37 cells (human lymphoblastic cells) to make concentrations ranging from 148 MBq/mL to 148 Bq/mL by serial 10 fold dilutions. After 44 hours, 2 Gy gamma irradiation was given to them using a Cs-137 cell irradiator. Results: As compared to the control (Con) group to which no $^{99m}Tc$ was added, those cells to which 148 and 14.8 KBq of $^{99m}Tc$ were added showed significantly lower damage to chromosomes, which was evaluated by metaphase analysis. Cells with 148 KBq $^{99m}Tc$ (T148 group) showed most significant protection. Activated genes in the T148 group as compared to Con group were evaluated by GDA and GDA methods. GDA revealed genes of casein kinase 2 (CK2) beta chain, immunoglobulins (lg), human leukocyte antigen (HLA)-B, and two novel genes. Twenty RAR related clones were selected by RDA method. The size of those genes was from 234 to 603 base pairs. Conclusions: RAR was induced by low dose irradiation from $^{99m}Tc$ in NC-37 cell lines. Genes related to the response included CK2, lg, HLA-B in human lymphoblastic cell lines.