A method and system for physiological gating for radiation therapy is disclosed. In order to add a new list entry to the list, the root pointer included in the root pointer register is copied into a next pointer field of the added list entry. The atomizing nozzle assembly includes: a spray applicator enclosure having a fluid entry zone, a flow shape profiler region, a transducer, and a cavitation enhancer module, wherein the cavitation enhancer module includes a residence modulation zone and the residence modulation zone includes a backward facing step region. The diffracted light beams are superposed and the resultant light beam is returned to the beam splitter. Further, the integrator is able to integrate both positive and negative input signals regardless of their magnitude.