Dose to the Metaphyseal Growth Complexes in Children Undergoing99mTc-EHDP Bone Scans

Abstract

The spatial and temporal distribution of radionuclides in children may differ from that accepted for adults. Following injection of a bone-seeking agent (99mTc-EHDP [Sn-1-hydroxyethane-1-1-diphosphonate]), radioactivity in the metaphyseal growth complexes of the distal femur and proximal tibia was quantitated in a series of children 4-16 yr of age, using a gamma camera/computer system. The dose to the growth plate ranged from 0.8-4.7 rads when adjusted to an administered activity of 200 .mu.Ci/kg, compared to approximately 0.6 rad to the adult skeleton for a corresponding study. [These children were being evaluated for bone metastases.