A sensor module and method for determining and imaging fluorescence lifetime based on the time-of-flight values are disclosed. The sensor module comprises an opaque housing (OH) having a first chamber (CH1) and a second chamber (CH2) which are separated by a non-transparent barrier (LB). Further, it comprises an optical emitter (OE) arranged in the first chamber (CH1) and configured to emit light through a first aperture (AP1). Pulsed excitation light of a specified wavelength is directed to optically excite a fluorescent probe (FP) positioned in the optical path of the excitation light. The module also comprises a detector (MD) arranged in the second chamber (CH2) and configured to detect through a second aperture (AP2) photons originating from the fluorescent probe (FP). The module further comprises: a measurement block (MB) configured to determine a temporal difference between an arrival time of one of the received photons with respect to the emission pulses； a histogram block (HIST) configured to accumulate the difference values in a histogram； a processing circuit (PRC) configured to compute time-of-flight values based on an evaluation of the histogram and then to compute a fluorescence lifetime from the time-of-flight values and generate an output signal (OS) being indicative of the fluorescence lifetime of the fluorescent probe； and a control unit (CU) configured to initiate pulsed emission of the optical emitter (OE).
