Bone imagings have played important role in early detection of acute osteomyelitis. In acute osteomylitis, bone scan findings precede the appearance of bone change on radiograph. Also, recent studies have reported accuracies of bone scan in diagnosis of osteomyelitis ranging from 84% to 100%. But, in above datas, bone scan reading were only qualitative studies. So we have reviewed Technetium-99m labelled methylen dipho sphonate(^99mTc-MDP) scan on 21 patients who had been diagnosed acute osteomyelitis by clinical symptoms, blood culture, pus culture and operative findings from January, 1984 to September, 1985. The purpose of this study is to establish the quantitative study of bone scan using computed pixel counting method. The 21 cases were classified into group I and group II according to initial radiographic findihgs. The group I showed normal radiographic finding or soft tissue swelling without osseous change. The group II showed osseous change. The results obtained were as follows: 1. We obtained positive bone scans in the all cases which were confirmed acute osteomyelitis. 2. We experienced diagnosis of acute osteomyelitis by bone scan which was confirmed as early as 48 hours after onset of clinical symptom. 3, In group I, the average uptake ratio of ^99mTc-MDP was 3.22±0.82 ranging from 2.20 to 4.80. 4. In group II, the average uptake ratio of ^99mTc-MDT was 6.20±2.27 ranging from 4.00 to 9.40. (p <0.001).