The purpose of this work is to correlate Sr/Ca ratio with internal body temperature from teeth and bones. Results obtained in exploratory measurements using human, bovine and swine teeth indicated some relation between temperature and Sr/Ca ratio, but no other parameters, as feeding habits that certainly has some influence over Sr/Ca ratio, were controlled. In this work, to eliminate feeding effects, we decided to compare Sr/Ca ratio of bones from some individual. The first bones irradiated were from a crocodile (Caiman Yacare), which regulates the internal body temperature by the temperature of its surroundings. The pieces irradiated were from the crocodile's tail, vertebral column and leg. To quantify Sr and Ca a 2.4 MeV proton beam was used in PIXE beam line at LAMFI - USP. Emitted X-rays were collected using a Si(Li) detector (150eV @ 6.4 KeV). First results show that the bones closer to the heart have a lower Sr/Ca ratio.

Human, bovine and swine teeth were analyzed by Proton Induced X-ray Emission (PIXE). The aim of this work was to determine the concentration of trace elements in enamel and dentine of different animal species. PIXE analysis was carried out at the Laboratório de Análise de Materiais por Feixes Iônicos da USP (LAMFI) using a 2.4 MeV proton beam to probe the samples. Healthy teeth from São Paulo region were analyzed. Thirteen elements were measured and quantified in the samples: P, S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Ba. The measured ratio of Ca:P in dentine and enamel teeth is the same expected for hydroxyapatite: 2.13, for all three types. Trace element concentrations were found to be very similar between the three species, except for S, Cl, Fe, Cu and Sr. Ni and Cu concentrations were found to be close to 1 ppm, which is also close to the detection limits of the SP-PIXE system.