Spectra: An Open Source, Two Square Inch Biomedical Imager

Biomedical imaging systems such as CAT and MRI machines provide medical professionals with a wealth of information when it comes to diagnosing ailments. Both machines are large and incredibly expensive, which makes them unavailable for candidates in the portable medical device sector, or even the hacker and maker communities for that matter.

Neuroscientist and avid hacker Jean Rintoul, the creative mind behind the medical devices Kiddo and Brightly (along with a host of others), has done the impossible by designing Spectra — a small, portable EIT (Electrical Impedance Tomography) medical imager capable of running bio-impedance spectroscopy and tomography applications (scientific jargon for looking inside things).

The Spectra imager was designed using a tiny two-inch PCB outfitted with 32 electrodes arrayed around a circular tank (AKA phantom) and employs a non-ionizing AC to produce image reconstructions of any conductive material placed inside, organic or otherwise.

The device functions by passing an AC wave through the object inside the container, where the electrical impedance magnitude and phase are measured by the electrode array. The process is run several times over, which provides a tomographic reconstruction of the object between 80–80KHz.

All in all, Spectra is capable of producing time series impedance measurements, bio-impedance spectroscopy, along with electrical impedance tomography, using the open-source software, which packs three types of tomographic reconstructions — GREIT, Gauss-Newton Method, and Back Projection. Rintoul is currently gearing up for a Crowd Supply crowdfunding campaign for the Spectra, which is expected to hit soon.