When surgeons dig around inside of you trying to cut out a tumour, they're actually going off of pre-op info to find the tumour. An electroscalpel, combined with a mass spectrometer, will let them map cancerous cells in real time.
The thing about electroscalpels is that they put off gaseous ions, which, besides being something you shouldn't breath in, it so happens are perfect for being analysed via mass spectrometry — a method of identifying molecules based on their mass and change. A spectrometer pulls in the fumes from the electroscalpel, and analysis of the chemical sample happens almost instantly, allowing surgeons to, in near real time, "draw a map and say this part is healthy liver, that is connective tissue, this is adipose tissue, that is cancer" according to Zoltán Takáts, a Justus-Liebig University professor who came up with the idea.
Like any other technology-driven medical advance when it comes to cancer, it's not cheap to implement: The electrosurgery setup alone is $US8000, while the mass spectrometry setup is $US120,000. I wonder how much the first medical tricorder is gonna cost. [Technology Review]