be used as necessary and desired in one embodiment polyethersulfone filters may be used to filter liquids for example filter f 1 may be filter type 65770 manufactured by filtertek and f 5 may be filter type slgp 033rb manufactured by milipore other filters for filtering liquids may be used as necessary and desired as noted above valves v 1 v 2 v 3 v 4 v 5 and v 6 direct the flow of gasses and fluids within system 100 in one embodiment v 1 v 2 v 3 v 4 and v 5 are pinch valves that pinch tubing in order to disrupt fluid or gas flow an example of a suitable pinch valve is model s104 08 z030a 24vdc manufactured by sirai in one embodiment v 6 may be a medical valve an example of a suitable medical valve is type 562416 manufactured by elcam valve v 6 may be a three position valve providing two directions of flow and an u201c off u201d position as noted above controller 180 controls the operation of valves v 1 v 2 v 3 v 4 v 5 and v 6 ionization chamber 130 and scale 140 in one embodiment controller 180 may be a microprocessor driven controller for example a plc such as b amp r series 2003 manufactured by b amp r industrieelektronik austria may be used in another embodiment at least some of valves v 1 v 2 v 3 v 4 v 5 and v 6 may be manually controlled referring to fig2 a method for measurement of radioactivity concentration and total radioactivity of a radiopharmaceutical.