Transmission images of highly scattering objects can be produced by recording and discriminating between the times of flight of transmitted photons. High spatial resolution requires a detector with high temporal resolution, and a streak camera has proven to be particularly effective. However, since the aperture of a streak camera is necessarily a narrow slit, the camera must consecutively sample different regions of the object in order to generate a two-dimensional image. A method is described that involves sampling a series of lines across an object. The benefits and limitations of this method are discussed, and the results of an experiment are presented that illustrate the inherent spatial resolution. Our conclusion is that the line scan method is more efficient than a point scan method in terms of light collection and probably need not result in a substantial decrease in spatial resolution.