EPR dosimetric properties of cystine

Radiation dosimetry using EPR is one of the most accurate and reliable techniques for passively evaluating radiation doses and is characterized by its non-destructive readout. In this manuscript, cystine is proposed as a radiation dosimeter using EPR. Cystine, a sulfur-containing amino acid, was studied from the EPR spectroscopy point of view, where its unirradiated and 1kGy gamma-irradiated samples spectra were recorded and analyzed. Samples were exposed to radiation doses ranging from 10 Gy to 1000 Gy. A direct and uniform relationship was found between the intensity of the peak-to-peak amplitude of the radiation-induced EPR signals and the received radiation dose. On the other hand, tissue equivalency over a wide range of photon energies was investigated. Furthermore, the time dependence of the radiation-induced radicals has been traced over 35 days which revealed that the decay behavior of the cystine radical EPR spectrum is predictable and shows reasonable stability enabling its use as a transfer dosimeter.