The Algebraic Reconstruction Technique (ART) of Lambert-Beer's attenuation approximation for parallel rays transmission projection is a variant of the ART model that aims to solve image reconstruction problems in nuclear based computed tomography for non-destructive testing where or radiation is used as a ray source. In this model, the path length of the ray that hits a pixel at any projection view and the size of detector grid are explicitly included in computation. Then, the model is used to investigate the influence of the ray path length and the width of detector grid in producing image quality. The image quality is represented as space and pixel resolution, respectively. In this paper, we demonstrate that the model is able to show the contribution of the ray path length and detector grid in producing image quality. By considering ray path length and detector grid, the model produces smaller Root Mean Square error compared to conventional ART.