sciencehabit writes "When surgeons can't determine the edges of a tumor, it's a problem. Cut too much, and they risk hurting the patient. Cut too little, and they may leave stray cancer cells behind. Now, researchers have developed a surgical knife that can sniff the smoke made as it cuts tissue, almost instantly detecting whether cells are cancerous or healthy. The 'intelligent knife,' or iKnife could distinguish normal and tumor tissues from different organs, such as breast, liver, and brain, and could even identify the origin of a tumor that was a metastasis, a secondary growth seeded by a primary tumor elsewhere in the body."