In vivo 19F spin relaxation in index finger bones.

19F free induction decay (FID) signals have been observed from the index fingers of four male and two female adult volunteers using a 27-MHz pulsed nuclear magnetic resonance spectrometer equipped with a split ring resonator probe. The value of the in vivo spin-lattice relaxation time T1 of the fluoride ions naturally accumulated in bone mineral has been determined to be 2.0 +/- 0.3 s. The shape of the observed FID signals in the inhomogeneous external magnetic field indicates that the F distribution is not uniform along the length of the finger. The fluoride ion content of the index finger (within a 65-mm length from its distal end) was measured with a sensitivity of +/- 0.5 mg F within a 30-min observation time.

In vivo analysis of bone fluoride content via NMR.

In vivo free induction decay signals have been detected from the fluoride ion (F) content of human finger bones by a 27 MHz pulsed single-coil nuclear magnetic resonance (NMR) spectrometer. The intensity of these dipolar-broadened NMR signals can be used to estimate the F content of the middle phalanx of the index finger. This NMR procedure is the first non-invasive method capable of monitoring bone F contents. The preliminary results we report were obtained from patients known by previous biopsies to have relatively high bone F concentrations in their pelvis. This new monitoring technique does not yet have adequate sensitivity or accuracy for routine clinical use. As a research technique, it has applications to the diagnosis of fluorosis (both industrial and endemic) as well as renal osteodystrophy, and to the establishment of optimal NaF does for the treatment of osteoporosis.