Possibility of using olive oil as a novel dosimeter in radiological accidents: First experimental results

Abstract

In this work, olive oil is proposed for the first time as a novel dosimeter in radiological accidents since it is one of the most common abundant materials worldwide. Sixty samples of extra virgin olive oil were irradiated at doses ranging between 0.25 Gy and 25 kGy from two Co-60 gamma sources. The sixty irradiated samples as well as the un-irradiated control sample were then investigated by recording the near UV–Vis absorption spectra in the range of 390 nm–750 nm. Absorption spectrum of control sample was characterized by 7 peaks at 415, 455, 483, 536, 560, 612, and 671 nm. When compared to the control group, the radiation induces significant and obvious alterations in the absorption spectra of the irradiated samples, especially at doses greater than 1 kGy. In order to deduce a mathematical relationship between the irradiation dose and the changes occurring in the absorption spectrum, the absorption spectrum has been divided into seven regions of interest, namely (390–443 nm), (443–473 nm), (473–528 nm), (528–554 nm), (554–585 nm), (585–632 nm), and (632–725 nm). The maximum absorbance for each peak position, the integrated absorbance for the whole spectrum, as well as the integrated absorbance for each region of interest, was recorded at each dose and is then plotted. Graphs showed that the area under the first region of interest (390 nm–443 nm) could be used as a dosimetric region where the doses up to 1 kGy could be represented by a rising exponential function in terms of integrated absorbance, while doses from 1 kGy to 25 kGy could be represented by decreasing exponential function. Absorption spectra were recorded again for all samples at 1 week, 2 weeks, and 4 weeks after irradiation to investigate the fading effect. It has been found that the recorded absorption spectra are unchanged over 28 days after irradiation at all doses. This gives the oil an advantage of keeping all information about the stored dose over time and hence it can be retrieved later if required. Other advantages that could be drawn from this study include quick measurements and no need for sample preparation beforehand. Results of this study proved that olive oil is a promising, quick, and novel retrospective dosimeter that could be used in radiological accidents.