Did you know that astronauts lose bone strength in zero gravity? That means extended or repeated space missions could put their skeletal health in jeopardy, increasing their risk of experiencing a life-altering fracture. (Studies in this population have already contributed to a greater understanding of osteoporosis, and how to treat bone mass loss both on Earth and in space.)
To minimize the chance of such an occurrence, obviously it’s important to evaluate astronauts’ bone strength as accurately as possible both before they blast off, and after they return home. Yet DEXA (dual x-ray absorptiometry), the type of imaging that’s currently used to gauge bone density provides just a partial picture. It can estimate only one aspect of bone integrity — mineral content — but can’t peer below the surface to see whether the underlying supporting structure is sturdily constructed, or shoddily built.
However, technology pioneered here in Canada by Dr. Angela Cheung, a renowned senior scientist at the Krembil Research Institute in Toronto, and her colleagues, offers additional information that helps fill that gap. She, along with other experts, collaborated to create a new, more finely-tuned set of guidelines for assessing astronauts’ bone strength, which incorporates this technique, known as HR pQCT or high-resolution peripheral qualitative computed tomography. Now used primarily in research, this type of scan uses specialized equipment that can, among other things, measure the inner, honeycomb-like bone.
You can read a bit about Dr. Cheung’s work in this piece that I wrote for Krembil Arthritis Magazine 2019 (distributed by the Globe & Mail.) I only wish I had been allotted far more space — this project represents a small fraction of the fascinating research she’s done.