Not only that, from what I understand, Metastatic cancer cells travel via blood. If this could grab those, that'd be awesome. So many cancer stories seem to involve killing the main site of the disease only to have it reoccur a few months or years later somewhere else, this time metastatic and basically incurable.
Start this treatment up right after diagnosis, and continue it through the normal cancer treatment. If this device could be used to detect metastatic cancer cells in the blood, even better (but maybe this is reaching - still, cool to consider).