Abstract: A micro-fluidic device has a micro-fluidic circuit layer and a charged-particle detection layer disposed proximate the micro-fluidic circuit layer. The micro-fluidic device is constructed to provide a two-dimensional image of charged-particle emissions from a sample within the micro-fluidic circuit layer while in operation. A method of quantification of radioactivity in a biological sample includes directing a fluid containing the biological material into a microfluidic device, detecting charged particles emitted from the biological material with a two-dimensional imaging sensor, and forming a two-dimensional image over time corresponding to radioactivity of the biological sample.