Open AccessEvaluation of dose distributions in gamma chamber using glass plate detector
Author(s) -
Pradeep Narayan,
S.G. Vaijapurkar,
P. K. Bhatnagar
Publication year - 2008
Publication title -
journal of medical physics/journal of medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.292
H-Index - 24
eISSN - 1998-3913
pISSN - 0971-6203
DOI - 10.4103/0971-6203.41277
Subject(s) - materials science , irradiation , optics , densitometry , linearity , dose profile , optical density , gamma ray , absorbed dose , nuclear medicine , radiation , analytical chemistry (journal) , physics , chemistry , imaging phantom , nuclear physics , medicine , chromatography , quantum mechanics
A commercial glass plate of thickness 1.75 mm has been utilized for evaluation of dose distributions inside the irradiation volume of gamma chamber using optical densitometry technique. The glass plate showed linear response in the dose range 0.10 Kilo Gray (kGy) to 10 kGy of cobalt-60 gamma radiation with optical sensitivity 0.04 Optical Density (OD) /kGy. The change in the optical density at each identified spatial dose matrix on the glass plate in relation to the position in the irradiation volume has been presented as dose distributions inside the gamma chamber. The optical density changes have been graphically plotted in the form of surface diagram of color washes for different percentage dose rate levels as isodose distributions in gamma chamber. The variation in dose distribution inside the gamma chamber unit, GC 900, BRIT India make, using this technique has been observed within +/- 15%. This technique can be used for routine quality assurances and dose distribution validation of any gamma chamber during commissioning and source replacement. The application of commercial glass plate for dose mapping in gamma chambers has been found very promising due to its wider dose linearity, quick measurement, and lesser expertise requirement in application of the technique.