Leonardi M, Celestini M, Micale C, Surace A, Pietrogrande V
Ital J Orthop Traumatol. 1978 Apr;4(1):41-6.
The authors studied a technique based on the use of a radiographic negative in antero-posterior projection of the third lumbar vertebra, from which the index of osteoporosis was obtained quantitatively by spectrophotometric examination. This index is about 0.50 in normal cases and approaches unity in cases of osteoporosis.