Fluorescence imaging system for an operating theatre, comprising a device illuminating the operating theatre and emitting a white light, and a fluorescence imaging device. Said fluorescence imaging device comprises a light source emitting radiation for excitation of a fluorescent marker in a range of emission wavelengths of between 600 and 900 nm. The light emitted by the illuminating device is filtered by a low-pass filter, of which the cut-off wavelength is below the emission range of the fluorescent marker, but is nonetheless able to show an increase or fluctuations in the attenuation for wavelengths above the emission range of the fluorescent marker, the product of the attenuation of the filter of the detector and of the attenuation of the low-pass filter of the illuminating device leading to an attenuation by a factor of at least 106.
