The differential gamma scattering spectroscopy technique is a novel means of nondestructive testing using Compton scattering to determine local density perturbations in a test sample. A narrow collimated beam of gamma rays irradiates a test sample, and the scattered radiation field is detected in a transversely placed high-purity germanium detector. This detector provides excellent energy resolution so that a detailed energy spectrum can be obtained. This spectrum is then subtracted from a reference spectrum that was collected from a well-known, unflawed sample to obtain the differential spectrum. This differential spectrum contains information characterizing the flaw. Using the relationship between scattering angle and scattering energy that characterizes Compton scattering, the single-scattered spectrum can be used to determine the location of scattering and, consequently, the density distribution along the portion of the primary beam path that passes through the sample. An attractive feature of this technique that distinguishes it from other Compton scattering techniques is the ability to detect flaws both on and off the primary beam path. A series of experiments was conducted to assess the sensitivity of the detection system for different sizes and shapes of flaws located throughout the sample. The results of these experiments are analyzed.