A method for removing excess unbound ferrofluid and imaging immunomagnetically enriched circulating tumor cells is provided. A vessels having a preformed grooves in the viewing surface is optimally designed for cell alignment and imaging. After separating the unbound particles by centrifugation, an externally-applied force is applied to transport magnetically responsive particle-CTC complex toward the transparent collection wall. The grooved inner surface of the viewing face of the chamber provide uniform distribution of the particles for easy imaging. The invention is also useful in conducting quantitative analysis and sample preparation in conjunction with automated cell enumeration techniques as in quantitative analysis of CTC in disease.