The how and why of a $10 optical coherence tomography system

Abstract

Optical Coherence Tomography (OCT) is the fastest growing medical imaging modality with more than $1Bln worth of scans ordered and over $400M worth of equipment shipped in 2010, just nine years after its commercialization. It is at various stages of acceptance and approvals for eye care, coronary care and skin cancer care and is spreading rapidly to other medical specialties. Indeed, it is the leading success of translation of biophotonics science into clinical practice. Significant effort is being made to provide sufficient evidence for efficacy across a broad range of applications, but more needs to be done to radically reduce the cost of OCT so that it can spread to underserved markets and address new, fast growing opportunities in mobile health monitoring. Currently, a clinical OCT system ranges in price from ~$50k to ~$150k, typically is housed on a bedside trolley, runs off AC power, and requires skilled, extensively trained technicians to operate. The cost, size, and skill level required keep this wonderful technology beyond the reach of mainstream primary care, much less individual consumers seeking to monitor their health on a routine basis outside of typical clinical settings and major urban medical centers. Beyond the first world market, there are 6.5 billion people with similar eye and skin cancer care needs which cannot be met by the current generation of large, expensive, complex, and delicate OCT systems. This paper will describe a means to manufacture a low cost, compact, simple, and robust OCT system, using parts and a configuration similar to a CD-ROM or DVD pickup unit (see figure 1). Essentially, this system—multiple reference OCT (MR-OCT)—is based on the use of a partial mirror in the reference arm of a time domain OCT system to provide multiple references, and hence A-scans, at several depths simultaneously (see figure 2). We have already shown that a system based on this configuration can achieve an SNR of greater than 90 dB, which is sufficient for many medical imaging and biometry applications.