Canadian scientists have reported a non-invasive method to measure strontium levels in human teeth.

Eric Da Silva and co-workers at Ryerson University, Toronto, used a ¹²⁵I excitation source with EDXRF (energy dispersive X-ray fluorescence spectroscopy) to measure characteristic strontium X-rays, which can allow the amount of strontium within the tooth to be calculated.

Measuring strontium levels in the skeleton is desirable as strontium has been linked to bone disorders such as rickets in children and to increased cases of bone cancer in locations affected by nuclear fallout (duo to exposure to radioactive ⁹⁰Sr). Strontium compounds have also been shown to be therapeutic at low levels in the treatment of the bone disorder osteoporosis.

Da Silva said 'The subject would just have to smile in front of the excitation source for approximately 20 minutes and absolute strontium concentrations can potentially be extracted,' but he also warned 'for this to be used on humans, a proper study of the dosimetry would be required.'

Previously, measuring strontium was only possible on bones, which had to be removed from the body as the soft tissue covering them significantly weakened the X-ray signals. Teeth are also part of the skeleton, but are easily accessible and not covered by tissue.

The team also carried out a study of dental strontium concentrations in Toronto, an urban area of high ethnic diversity, and the values had a much larger range than those of isolated populations. This may be due to factors such as differences in diet or general bone health between ethnic groups.

Da Silva hopes 'this simple and non-destructive technique can be easily extended to the measurement of other elements in calcified tissues'.

Ian Gray