Possibility of thyroidism diagnosis by laser induced breakdown spectroscopy of human fingernail
Seyed Hassan Tavassoli
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Introduction: A modern technique for elemental analysis of biological samples is laser induced breakdown spectroscopy (LIBS). This technique is based on emission of excited atoms, ions, and molecules in plasma produced by focusing a high power laser pulses on sample surface. Because of several advantages of LIBS including little or no sample preparation; minimally invasive; fast analysis time and very easy to use, in this study, this method was used for investigating the mineral content of fingernails. As the trace element of nail can be changed by several pathological, physiological, and environmental factors, we analyze the human fingernails to evaluate the possibility of thyroidism diagnosis. Method: A Q-switched Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) laser operating at wavelength of 1064 nm, pulse energy of 50 mJ/pulse, repetition rate of 10 Hz and pulse duration of 6 ns was used in this analysis. Measurements were done on 28 fingernails belonging to 5 hypothyroid, 2 hyperthyroid and 21 normal subjects. For classification of samples into different groups based on thyroid status, a discriminant function analysis (DFA) was used to discriminate among normal and thyroidism groups. Results: The elements detected in fingernails with the present system were: Al, C, Ca, Fe, H, K, Mg, N, Na, O, Si, Sr, Ti as well as CN molecule. Classification in two groups of normal and patient subjects and also in three groups of normal, hyperthyroid and hypothyroid subjects shows that 100% of original grouped cases were correctly classified. So, efficient discrimination among these groups is demonstrated. Conclusion: It is shown that laser-induced breakdown spectroscopy (LIBS) could be a possible technique for the analysis of nail and therefore identification of health problems.