Comparison of technetium 99m-phytate and technetium 99m-sulphur colloid in primary bone tumours

Eleven patients with proven primary bone tumour (five Ewing sarcomas, six osteosarcomas) and two cases of metastatic bone involvement (primary other than bone) were investigated with^99mTc-phytate and^99mTc-sulphur colloid to compare the behaviour of the two radiopharmaceuticals at the tumour site. After intravenous administration of the respective radiopharmaceutical, imaging of the tumour site and its contralateral part was carried out at 15 min and 1 h intervals. The data were stored in our computer. Bone scanning was also carried out in all patients.^99mTc-phytate uptake was observed at the tumour site in ten cases. The^99mTc-sulphur colloid study revealed sparse or no significant uptake in eight cases. In two patients, with osteosarcoma^99mTc-sulphur colloid investigation showed uptake at the primary tumour site. However, the distribution pattern is different from that of^99mTc-phytate. No significant uptake of either 99mTc-phytate or^99mTc-sulphur colloid was observed in the two patients with metastatic skeletal disease. It may be concluded that the unusual accumulation of^99mTc-phytate at the tumour site is not due to any generalized reticuloendothelial phenomenon and that the radiopharmaceutical itself is responsible for this.