The limitation on the detector efficiency due to the required spatial resolution of a fast-neutron imaging system is known as the detector problem. Here, this problem is described and a proposal for a novel fast-neutron imaging system is given to overcome this problem. The novelty is to replace the standard flat mirror in an imaging system by a parabolic mirror with its focal point at the fast-neutron source position. The spatial resolution will only be limited by the intrinsic resolution of the scintillator of the order of 0.06mm. The intrinsic fast-neutron detection efficiency can be increased to about 20–30% without loss of spatial resolution.