The silicon photomultiplier (SIPM) is an emerging detector technology that enables both high sensitivity and high dynamic range detection of visible and near-infrared light at a fraction of the cost of conventional vacuum tube photomultiplier tubes (PMTs). A low-cost detection circuit is presented and the performance of a commercial SIPM is evaluated for high-speed laser scanning microscopy applications. For moderate-to-high-speed fluorescent imaging applications, the measurements and imaging results indicate that the SIPM exceeds the sensitivity of GaAsP PMTs, while providing higher dynamic range and better saturation behavior. For low speed or applications requiring large detector areas, the GaAsP PMT retains a sensitivity advantage due to large area and lower dark counts. The calculations presented show that, above a critical detection bandwidth, the SIPM sensitivity exceeds that of a GaAsP PMT.