Acquisition Start Condition (0018,0073) is the method of starting acquisition data collection. The Defined Terms and definitions are:
DENS = preset count density (counts/sec) was reached
RDD = preset relative count density difference (change in counts/sec) was reached
MANU = acquisition was started manually
AUTO = start automatically, when ready
CARD_TRIG = preset number of cardiac triggers was reached
RESP_TRIG = preset number of respiratory triggers was reached.