Beyond the Biopsy: A Tiny Monitor for Cancer

DOCTORS doing a needle biopsy to analyze tissue for cancer may one day add a second step to the procedure: depositing a tiny device at the site to report on growth of a tumor — and even the effects of chemotherapy.

Researchers at the Massachusetts Institute of Technology have created prototypes for cancer monitors the size of a grain of rice, small enough to fit easily into the bore of a biopsy needle. Tiny coated particles inside the devices can bind with molecules linked to cancer at the site, creating minuscule clumps that can be detected by a non-invasive scan like an M.R.I., said Michael J. Cima, a professor of materials science and engineering at M.I.T. and leader of the team that created the devices.