Challenges in manufacturing optical tissue phantoms: an industrial perspective

Optical tissue phantoms can serve many needs encountered in the translational path between fundamental research and clinical acceptance. Each of these needs call for a different set of requirements on the phantom design. Earlier stage research will require the phantom to reproduce adequately the measurement challenges of the intended application. Phantoms used during the final verification and validation phase of a medical device seeking FDA clearance will focus more on stability, repeatability and traceability. Developing and producing phantoms meeting these quality requirements is a challenging task. Unlike MRI or CT, optical technologies will not reach clinical practice as versatile multipurpose imaging platforms but as a collection of application specific instruments. This variety in the instrumentation translates into very diverse requirements for phantoms and is somehow a barrier to the standardization of diffuse optical spectroscopy. One common point of all diffuse optical spectroscopy instrumentation is the need for calibration which can be served by simple homogeneous reference material. A general consensus on the metrology of the optical properties of such reference material is required before it can become generally accepted by the community.