A system for use in monitoring one or more parameters of a subject's body is described. The system comprising: an illumination unit configured for providing pulsed coherent illumination and directing said illumination onto an inspected region on said subject's body; a collection unit configured for collecting light returning from said inspection region and generate a plurality of data pieces associated with secondary speckle patterns in said light; an external field stimulation unit configured for selectively generating external field stimulation onto the subject's body; and a control unit. The control unit is configured and operable for operating said illumination unit said collection unit and said external field stimulation unit and for receiving said plurality of data pieces from said collection unit to thereby determine said one or more conditions of the subject's body.