Sir.—An unfortunate misunderstanding has arisen regarding an article by Tyson et al.1 Tyson and colleagues reported work done to evaluate the suitability of using the Norland model 278 Bone Densitometer to measure the radii of neonates. The model 278 did not perform well in measuring these small bones. The misunderstanding is in confusing the model 278 with its successor, the model 278-A.
The Norland model 278 Bone Densitometer, which Tyson and co-Workers1 evaluated, was designed to measure adult radii and phalanges, ie, bones with bone mineral content (BMC) of 0.4 to 1.6 g/cm. To accommodate the needs of those studying and treating infants, and also those working with small laboratory animals, we at the Norland Corporation, Fort Atkinson, Wis, redesigned the densitometer's computation algorithms and software to extend its measurement range down to the 0.03-g/cm level. The instrument with this new software, first delivered in July 1982, was
NORD RH. Bone Mineral Measurements in Neonates. Am J Dis Child. 1984;138(4):410-411. doi:10.1001/archpedi.1984.02140420076025