| abstract |
In patients with carcinomas tumor cells are shed into the blood, enumeration and characterization of these cells offers the opportunity to obtain a “real time” biopsy of the tumor and may improve the management of the disease. The frequency of circulating tumor cells is rare (<1 cell/ml) and technology is needed that has sufficient sensitivity and specificity to enumerate and characterize these cells. The present system was developed to provide an immunophenotype, fluorescence wave forms as well as images of immunomagnetically enriched cells. Blood volumes ranging from 7.5-30 ml are immunomagnetically enriched for epithelial cells. The sample volume is reduced to 320 μl and inserted into an analysis chamber. Upon introduction of the chamber in a magnetic field, the immunomagnetically tagged cells rise out of the sample and align between nickel lines (period 30 μm, space 15 μm) that are present on the viewing surface of the chamber. A multi laser system is used to detect the fluorescence emitted by DAPI, Phycoerythrin and Allophycocyan labeled and magnetically aligned cells. Compact disk optics are used to maintain alignment and focus of the laser beams onto nickel lines while moving the chamber. The chamber is scanned with a speed of 10 mm/sec and the entire chamber is analyzed in approximately 5 minutes. The fluorescent signals obtained from the events provide an immunophenotype similar to that of a flow cytometer. The fluorescence waveforms improve the characterization of the events and add to the classification as background, cellular debris and cells. Since the cell locations are preserved, objects that immunophenotypically classify as epithelial cells can be revisited for further analysis. Bright field and fluorescent images of the selected objects are captured to confirm that the identified objects are tumor cells. |