This video is in continuation with the previous one, to explain about the internal dose calculations by MIRD method. Concepts of Cumulated activity, Effective half life and Residence time have been described and the formula of Absorbed dose, including "S" value has been discussed Please note the correction. at the time 5:07 time of the video, it has been mentioned "rectangle".. actually it is , pack of number of infinite set of trapezoids and not: "rectangles"