Sahiner Huseyin, Srivastava Anjali, McCollough Cynthia H, Liu Xin
Missouri University of Science and Technology, Rolla MO, USA.
Mayo Clinic, Rochester MN, USA.
Biomed Phys Eng Express. 2015 Dec;1(4). doi: 10.1088/2057-1976/1/4/045103. Epub 2015 Nov 23.
Mechanistic questions regarding kidney stone formation have led researchers to look for the presence of trace elements. Neutron activation analysis is able to identify elements at parts-per-million concentrations. Four different types of kidney stones were irradiated with thermal neutrons to produce radioisotopes. Gamma spectroscopy of samples at different counting times was used to reduce identification errors by correlating results with the half-life of identified elements. For more precise identification, Monte Carlo simulation was used to cross-check the identification process. The simulation showed promising results that could lead to fast and accurate identification of trace elements as the simulation code is improved. Sodium (Na), potassium (K), calcium (Ca), bromine (Br), samarium (Sm), zinc (Zn), cadmium (Cd), ytterbium (Yb), gold (Au), cobalt (Co), and manganese (Mn) were identified as being present in the stones, by both the experimentally measured gamma spectrum and the simulation. Among these, Ca, Br, and Zn were found to be of potential clinical relevance via a literature review. Concentrations of the elements were compared to those noted in the literature. For uric acid stones, a correlation with the literature was found for Zn and Ca. A negative correlation was found between Zn and Br for non-uric acid stones. More samples are needed to test for statistical significance.
关于肾结石形成的机制问题促使研究人员寻找微量元素的存在情况。中子活化分析能够识别百万分之一浓度的元素。对四种不同类型的肾结石进行热中子辐照以产生放射性同位素。通过将不同计数时间的样品的伽马能谱结果与已识别元素的半衰期相关联,来减少识别误差。为了进行更精确的识别,使用蒙特卡罗模拟对识别过程进行交叉核对。随着模拟代码的改进,该模拟显示出了有前景的结果,这可能会实现对微量元素的快速准确识别。通过实验测量的伽马能谱和模拟,均确定钠(Na)、钾(K)、钙(Ca)、溴(Br)、钐(Sm)、锌(Zn)、镉(Cd)、镱(Yb)、金(Au)、钴(Co)和锰(Mn)存在于结石中。其中,通过文献综述发现钙、溴和锌具有潜在的临床相关性。将这些元素的浓度与文献中记录的浓度进行了比较。对于尿酸结石,发现锌和钙与文献存在相关性。对于非尿酸结石,发现锌和溴之间存在负相关。需要更多样本进行统计学显著性检验。