A system and method for adjusting the light output of an optoacoustic imaging system is presented. An optoacoustic imaging system includes a light source such as a laser, the light source having a light output control, a probe for delivering light to a volume, the probe being associated with one or more sensors, a light path operatively connected to the first light source, the light path providing light from the first light source to the probe. Generally, the light output of an optoacoustic imaging system may be harmful to the eye, and may be subject to maximum safe fluence levels incident upon the volume of interest in a clinical setting. Accordingly, the light output control may be set to an initial, relatively low value. After the light source is pulsed, the light output may be measured at or near the probe at the distal end of the light path. The measured light output can used to determine whether, and how much, to change the setting of the light output control. The system and method may also be used for closed loop control of the light output to keep fluence levels within a desired range. The rate of change of the light output control can be varied based upon the difference between the measured fluence and the desired fluence or range.
