In order to evaluate the degree of accuracy of measurement of total body bone mineral content (TBBMC) by dual photon absorptiometry (DPA), the TBBMC in four healthy male volunteers were measured serially for 3 to 12 months. In three to six determinations of TBBMC in various stage of radiation source (153-Gd), the coefficients of variation in four subjects were 1.59, 0.74, 1.25 and 1.27%. Thus, the mean CV was 1.22 +/- 0.35% (mean +/- SD). This indicates that the measurement of TBBMC using DPA is an accurate tool for long-term follow up of bone mineral content and up to 1.6% change of TBBMC might be considered to be a significant change in TBBMC. No apparent drift of TBBMC associated with source decay was noticed in the present study. Subsequently, fifteen females with osteoporosis were studied to evaluate the efficacy of certain therapeutic modes. The patients were divided into two groups. Group 1 (n = 10) given 10 to 40 U of elcatonin (eel calcitonin derivative) intramuscularly every week for 3 to 6 months. Group 2 (n = 5) were treated with 0.5 mu/day of oral 1-alpha-OHD3 for 3 to 6 months. The TBBMC of these fifteen patients were followed by DPA (Lunar DP-4). Seven patients out of ten treated with elcatonin (70%) showed significant (up to 1.6% change in TBBMC compared with baseline) increase in TBBMC after 3 to 6 months treatment. The mean percentage change in TBBMC in group 1 was 101.9 +/- 2.7% (mean +/- SD) when the initial TBBMC was taken as 100%.(ABSTRACT TRUNCATED AT 250 WORDS)