We have calculated the absorbed dose in tissue-equivalent medium(polyethylene) from radioactive filter paper with beta dose point kernels

and then elicited the dose-density curve with autoradiography. There is a linear relationship between density and absorbed dose within the range of 0-68.84mGy. So the absorbed dose from the radiaoactive filter paper in non tissue-equivalent medium could be calculated inversely: the absorbed dose rate from 1MBq/cm2 radiaoactive filter paper on the other side of glass bottom of the culture bottle is 21.9 cGy/h. The method is simple and can be used to inspect the radio-uniformity of radioactive filter paper at the same time.