A method, apparatus and a computer readable medium containing executable instructions for monitoring a system pressure within a mammal, human or animal, via a tracer/contrast agent, in space in time for determining non-invasively actual interstitial fluid pressure and/or concentration of the tracer/contrast agent. Further, an imaging method, an apparatus and a product for non-invasive mapping of actual interstitial fluid pressure and/or a tracer/contrast agent concentration for assessing drug delivery and resistance to therapy of a tumor or organ within a mammal, to suppress or reduce pressure in a tumor or organ and to control the delivery of drugs to a tumor or organ.
