how we can build a better screening tool. >> reporter: dr. otto acknowledges that training cancer detecting dogs is time consuming and expensive at more than $30,000 a dog each year, and dogs can only identify a limited number of samples each day. but she sees her research eventually leading to a more efficient screening tool. >> the dogs themselves probably aren't going to do the final job. they're helping us design the tool that will then become the screening tool. something that is more automated, something that is inexpensive and can screen thousands of women, millions of women a year. >> reporter: that's where dr. charlie johnson comes in. he's a physicist at the university of pennsylvania using nanotechnology to develop what amounts to an electronic nose capable of smelling cancer. so one day his device might be programmed to measure the gases and compounds emitted from tumors that dr. otto's dogs are smelling. >> our idea is to create a little device that can actually smell the vapors in the air and use it to smell the vapors that are emitt