Dune Medical, which markets a tool that spots residual breast cancer cells following a lumpectomy, has raised $12.3 million. The funds will drive the development of the company’s technology for other types of cancer.

Breast cancer patients may undergo a mastectomy—removal of the whole breast—or a lumpectomy, which only removes the part of the breast containing the tumor. The goal of a lumpectomy is to get rid of the tumor, as well as some of the breast tissue around it. But sometimes, cancerous cells are left behind, which can necessitate a second procedure.

Dune Medical’s MarginProbe uses radiofrequency spectroscopy to identify cancerous tissue in real time. RF spectroscopy spots cancerous tissue by measuring the reflection of electromagnetic fields from the patient’s tissue. Healthy tissue and cancerous tissue have different electrical properties.

MarginProbe is used during a lumpectomy procedure. If it turns up residual cancer cells, the surgeon may then remove more tissue while the patient is still under anesthesia.

Dune Medical is looking to apply its RF spectroscopy platform to other cancer types, including prostate, colon, lung and pancreatic cancers. The company scored a European Commission Horizon 2020 grant last summer to develop a “smart biopsy system” based on its RF spectroscopy tech.