Use of optically stimulated luminescence (OSL) in the detection of irradiated spices.

In this study, the validity of using the optically stimulated luminescence (OSL) technique as a scanning method for the detection of irradiated foodstuffs was investigated. Gamma-irradiated thyme, mint and clove samples were stimulated with a continuous wave blue light (CW-OSL) and their OSL signal sensitivity and stability properties were measured. While no OSL signal was observed for all non-irradiated spices, a significant increase in the intensity of OSL signals was noted for all samples after irradiation with 5 kGy, 10 kGy and 20 kGy. It was also observed that the measured OSL signals were well above the background level even after one year of irradiation. It is therefore concluded that irradiated thyme, mint and clove samples can clearly be identified using the CW-OSL technique without any pre-treatment even one year after irradiation. This result indicates that, where spices contain sufficient silicate minerals, the CW-OSL technique could be used as a method for detecting irradiation.

ESR and TL investigations on gamma irradiated linden (Tilia vulgaris).

Electron spin resonance (ESR) and thermoluminescence (TL) signals induced by gamma irradiation in linden (Tilia vulgaris) were studied for detection and dosimetric purposes. Before irradiation, linden leaf samples exhibit one singlet ESR signal centred at g = 2.0088. Besides this central signal, in spectra of irradiated linden samples, two weak satellite signals situated about 3 mT left (g = 2.0267) and right (g = 1.9883) were observed. Dose-response curves for the left satellite signal and the central single signal were constructed, and it was found that both of these curves can be described best by the combination of two exponential saturation functions. Variable temperature and fading studies at room temperature showed that the radiation-induced radicals in linden leaf samples are very sensitive to temperature. The stabilities of the left satellite (g = 2.0267) and the central single (g = 2.0088) signal at room temperature over a storage period of 126 days turned out to be best described by a sum of two first-order decay functions. The kinetic features of the left satellite signal were studied over the temperature range of 313-373 K. The results indicate that the isothermal decay curves of the left satellite ESR signal also proved to be best fitted by the combination of two first-order decay functions. Fading and annealing studies suggested the existence of two different radiation-induced free radical species. At the same time, Arrhenius plots evidenced two different kinetic regimes with two different activation energies. TL investigation of polyminerals from the linden samples allowed to discriminate clearly between irradiated and unirradiated samples even 75 days after irradiation.

Radiation dose in balloon dacryocystoplasty: a study using Rando phantoms and thermoluminescent dosimetry.

PURPOSE: The radiation dose to the lens of the eye, skin, thyroid and brain of patients who underwent diagnostic and interventional radiological procedures of the lacrimal drainage system have been measured with thermoluminescent dosimeters (TLD-100 and TLD-700) by using an adult male and female Rando phantom. All dose values for one second of fluoroscopic exposure and one frame of digital subtraction dacryocystography (DS-DCG) exposure have been obtained individually in the pastero-anterior (PA) and lateral (LAT) projections. MATERIALS AND METHODS: An adult male and female Rando phantom was used instead of the patients. The procedures were performed by using an Advantx AFM C-arm unit coupled with a DX Hiline digital image acquisition and processing system. The 6-inch mode of a triplefield image intensifier (II) was used, with a circular collimation of the same or a slightly smaller size. Two different lithium floride (LiF) thermoluminescent chips were used for absorbed dose measurements: TLD700, approximately 4.5 mm in diameter and 0.9 mm in thickness; TLD100, 3.7 mm square and 0.9 mm in thickness. RESULTS: The average values of absorbed doses (lens of the eye, skin, thyroid and brain) measured separately with TLD100 and TLD700 dosimeters after irradiation of the male and female Rando phantom are presented for LAT and PA projections. CONCLUSION: This study suggests that useful information for dose determination can be obtained by use of the radiation dose to the lens of the eye, thyroid and brain received during radiological procedure of the LDS for one frame of DS-DCG and one second of fluoroscopy.