Schematic diagram for OM instrument. (Credit: Edoardo Ferocino)

Optical mammography (OM), which uses harmless red or infrared light, has been developed for use in conjunction with x-rays for diagnosis or monitoring in cases demanding repeated imaging where high amounts of ionizing radiation should be avoided. Researchers have developed an instrument that increases the sensitivity of OM by as much as 1000-fold.

The newly developed instrument replaces two photomultiplier tubes (PMTs) of existing instruments with an eight-channel probe involving silicon photomultipliers (SiPMs) and a multichannel time-to-digital converter. These changes eliminate a time-wasting pre-scan step that was required to avoid damage to the PMTs. In addition to increased sensitivity, the new instrument is both more robust and costs less.

One major disadvantage to OM imaging is the poor spatial resolution that has been achieved to date. A possible advantage to OM, however, is that only gentle pressure need be applied to the breast tissue, in stark contrast to the standard technique for x-ray imaging. While poor spatial resolution of OM methods remains a challenge, the method does show promise for use in pre-surgical chemotherapy.