Looking for osteoporosis with scattered light

Steroids are commonly prescribed for the treatment of rheumatoid arthritis. Glucocorticoids reduce inflammation around the joints and ease pain. But like most treatments, steroids have side effects. Studies have shown that they raise the risk of developing osteoporosis.

One way to study this problem is to treat laboratory mice with steroids and with various interventions meant to counteract the side effect. A key challenge is how to assess a bone's structural integrity. The gold standard, removing the bone and measuring the amount of force needed to snap it in half, can only be performed by sacrificing the animal. Standard X-ray techniques can noninvasively determine bone mineral density, but this has proven to be a poor predictor of fracture risk in humans with steroid-induced osteoporosis.

The Rochester team is developing a new technique that promises to be non-invasive, based on a technique called Raman spectroscopy. By measuring how light scatters off the materials inside bone, they have been able to calculate the relative amounts of mineral and protein matrix of intact bones. They hope to find new and better indicators of bone strength in the chemical information that Raman spectroscopy provides about both the bone mineral and collagen matrix that make up bone.

"Our ultimate goal is to be able to measure the properties of a bone within an intact mouse limb," said Berger. "We hope to develop a better way to spot osteoporosis early in its onset."

The presentation, "Steroid Induced Osteoporosis Detected by Raman Spectroscopy," takes place on Oct. 25 at the Frontiers in Optics (FiO) 2010/Laser Science XXVI -- the 94th annual meeting of the Optical Society (OSA), which is being held together with the annual meeting of the American Physical Society (APS) Division of Laser Science at the Rochester Riverside Convention Center in Rochester, N.Y., from Oct. 24-28.