Patent ID: 8599383

Claim:
A system for obtaining an image of a cell comprising: (a) microscope capable of measuring a feature of interest in a sample; (b) a detector operatively coupled to the microscope; (c) a sample assembly comprising an observation chamber adapted to contain the cell, wherein the observation chamber comprises at least one perfusion conduit adapted to circulate a cell media within the chamber; (d) a reference assembly comprising: a first optical window; a first housing element adapted to hold the first optical window; a second optical window; a second housing element adapted to hold the second optical window; and a plurality of spacer elements disposable between the first optical window and the second optical window and adapted to separate the first and second optical windows to a defined distance; and (e) a plurality of reflective microparticles capable of adhering to the cell, wherein the average diameter of the reflective microparticles is between 0.5 μm and 30 μm.