AGE-RELATED CHANGE OF TECHNETIUM-99M-HMDP DISTRIBUTION IN THE SKELETON

To understand age-related changes of whole-body and regional skeletal metabolism, it is important to investigate the mechanisms of age-relat ed bone loss and to develop suitable treatments for it. Bone biopsies show metabolism of the particular site examined while biochemical mark ers for bone metabolism reflect total skeletal metabolism. Bone scinti graphy is a convenient and simple way to analyze whole-body and region al skeletal metabolism. We attempted to study and understand age-relat ed changes in bone metabolism by quantifying the bone scan and correla ting it with biochemical bone metabolic markers. Methods: The whole-bo dy skeletal uptake (WBSU) and whole-body skeletal tracer distribution pattern were studied in men and women by bone scintigraphy using Tc-99 m-hydroxy-methane-diphosphonate (HMDP). Bone scans were performed usin g a standard protocol and quantified by setting regions of interest (R OIs) on selected regions. WBSU and the skeletal distribution pattern w ere compared with simultaneously obtained serum biochemical markers. R esults: WBSU showed an increase with age in both sexes, but in women, uptake in the head and legs increased more relatively than in the thor acic region, while in men no such tendency was observed. Increase of W BSU and relative increase of uptakes in the head demonstrated a weak c orrelation with the serum levels of alkaline phosphatase and type 1 co llagen metabolites. Conclusion: These results show an age-related incr ease of skeletal turnover and sex-dependent regional skeletal metaboli sm. The age-related changes seen in bone scintigrams might be a sign o f progressive bone loss, reflecting changes in local bone metabolism.