background: the compositions of ferrous sulphate, agarose and xylenol orange dye (fax) and ferrous sulphate, gelatin and xylenol orange dye (fgx) in solution of distilled water and sulphuric acid are two tissue-equivalent gel dosimeters. ionizing radiation causes oxidation of fe2+ ion to fe3+ ions which diffuse through the gel matrix and blur the image of absorbed dose over a period of hours af...