금 나노 입자의 형태적 특성에 따른 T_1, T_2 이완 시간의 변화 측정 = Measurements of T_(1-) and T_(2-)relaxation Time Changes According to the Morphological Characteristics of Gold Nanoparticles (GNPs)

다국어 초록 (Multilingual Abstract)

Purpose : The aim of this study is to measure the typical MR variables such as T_(1-) and T_(2-)relaxation times according to morphological characteristics of gold nanoparticles as a preliminary study to perform theragnosis using local heating by gold nanoparticles.
Materials and Methods : Two types of gold nanoparticles were used. Spheres were synthesized by various methods and stirring speed. Rods were synthesized by adding various concentrations of sphere nanoparticles.
Gold nanoparticles were mixed with 2% agarose gel at 1:1 ratio and then signals were acquired using a 1.5T MRI. For the measurements of T_(1-) and T_(2-)relaxation times, TR and TE were varied, respectively.
The results were acquired through T_1 and T_2 curves based on the intensities of MR image using self-developed software. And Statistical analysis was performed.
Results : T_1 times were measured 1.86 sec and 2.08 sec for sphere and rod, respectively. On the other hands, T_2 times were measured 57 ms and 35.45 ms for sphere and rod.
Conclusion : The changes of the MR variables according to the morphological characteristics of the gold nanoparticles were confirmed. Optimal MR imaging conditions can be obtained by choosing proper TR and TE according to the type of nanoparticles.

국문 초록 (Abstract)

목적 : 본 연구에서는 금 나노 입자를 통한 국소 가열과 MR 온도 영상 기법을 결합한Theragnosis 개념에 대한 기초연구로 금 나노 입자의 특성 및 제조 조건에 따른 MR 변수의 변화를 연구하였다.
대상 및 방법 : 실험실에서 제조된 구형과 막대형 금 나노 입자를 사용하였다. 구형 입자는 합성방법과 교반속도(stirring speed: rpm)를 변수로 설정하였고, 막대형 입자는 첨가된 구형 입자의 양을 변수로 하여 조건을 다양화하였다. 금 나노 입자를 2% 아가로즈 젤에 1:1로 혼합하여 임상용 1.5T MRI 시스템에서 신호를 획득하였고, T_1과 T_2 이완시간의 측정을 위해 TR과TE를 조절하였다. 획득한 영상의 화소별 신호 강도를 이용하여 제작한 소프트웨어로 T_1과 T_2이완곡선을 추정하였고, 통계 분석으로 유의성을 검증하였다.
결과 : 구형 입자의 평균 T_1 값은 1.86 ± 0.04초, 막대형은 평균 2.08 ± 0.04초로 막대형이더 길게 측정되었고, 반면 평균 T_2 값은 구형과 막대형 각각 57 ± 2.4 ms와 35.45 ± 0.1ms로 구형 나노 입자에서 더 길게 측정되었다.
결론 : 금 나노 입자의 형태적 특성 및 제조 조건에 따른 MR 영상 변수 T_1과 T_2 이완시간의 변화를 확인하였다. 금 나노 입자를 이용한 MR 영상 연구의 수행 시 금 나노 입자의 형태와 제조조건에 따른 적절한 TR과 TE로 최적화된 영상을 얻을 수 있을 것으로 기대된다.

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