Exploring stable thermoluminescence signal in natural Barite (BaSO4) for retrospective dosimetry.

We explore the possible use of Barite (BaSO4) for radiation dosimetry and geochronology using thermoluminescence technique. Natural Barite with Mn as an impurity has a glow peak at 608K with a minimum detectable dose of 1.45±0.12mGy. This peak shows ~35% fading on 30 days of storage time and is photo-bleachable with excellent reproducibility on repeated read-out. The sensitivity changes with dose and evidence of athermal fading is also seen. We infer that the signal can be used for both retrospective dosimetry and geochronology of young deposits extending to 20ka.

Survey of patient dosimetry for head and neck cancer patients undergoing external radiotherapy treatment: a study from northeastern hospitals of India.

AIM: To study dosimetry of patients during the external radiotherapy of head and neck cancers from different hospitals of the northeastern region (NER) of India. MATERIALS AND METHODS: 35 confirmed cases of head and neck cancers reporting to three different hospitals in the NER of India who underwent radiation treatment were the materials for the study. Dosimetry was carried out at 8(eight) anatomical points to these patients, namely, target (entrance and exit points), forehead, chest, abdomen, gonad, arm, and leg respectively by thermoluminescence (TL) as well as optically stimulated luminescence (OSL) dosimeters. Unlike conventional appliances, we used common iodized salt as TL/OSL phosphor. RESULTS: Patient dosimetry was found to vary with an average of 1.17 +/- 0.39 Sv at forehead, 1.24 +/- 0.39 Sv at chest, 0.52 +/- 0.13 Sv at gonad to a minimum of 0.26 +/- 0.07 Sv at leg areas when exposed to a cumulative dose of 65 Sv at the target. CONCLUSION: Maximum dose received from a stray radiation is about 1.5 Sv at forehead/chest and dosimetry of patient among the three centers is not significantly different at the 5% level of probability.