A cross-sectional X-ray shows what's called a "sunken chest." The bright circle near the bottom is the spine; the gray blob on the right is the heart. Living LLC/Getty Images hide caption

itoggle caption Living LLC/Getty Images

Most living kidney donors return to their daily lives in a matter of weeks, but for some, unforeseen physical and financial complications arise. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Budding scientists, engineers and doctors lined up to try surgical robots from Intuitive Surgical at a science festival in Washington, D.C., over the weekend. Scott Hensley/NPR hide caption

itoggle caption Scott Hensley/NPR

Young-min Kwon of Massachusetts General Hospital holds the metal-alloy ball of Susy Mansfield's faulty artificial hip joint. The yellowish tissue on top is dead muscle caused by a reaction to the metal debris produced by the defective hip implant. Richard Knox/NPR hide caption

itoggle caption Richard Knox/NPR