The study included 95 patients having metastatic bone lesions, subjected to serial quantitative skeletal scintigraphy before and after treatment every 3 months for 6 months. To study the fate of metastatic bone lesions the effect of different treatment modalities, an objective index was used. This index was introduced in 1985 by Israel et al. (1), and was designated TF. A significant drop in TF ratio was observed 6 months following therapy in the groups who received combined localized radiotherapy together with systemic therapy and those who received half body irradiation. In contrast, a marked increase in TF ratio was observed in the patients who did not receive any specific treatment. The response of metastatic skeletal lesions was nearly similar whatever the site of involvement whether in the spine, flat or long bones except for an initial response in the long bones with drop of TF ratio after localized radiotherapy. 1 fig., 3 tabs.