An optical modeling process for facial regions and other body surfaces has been developed. The body part in question is digitized using optical 3-D metrology to obtain a comprehensive dataset. The data is then prepared for further use by smoothing the point clusters. The radiophysically significant position of the radioactive material, e.g., seeds, aluminum tubes, etc., can be accurately determined using CAD modeling. Subsequently, a rapid prototyping process (fused deposition modeling [FDM]) is used to implement the CAD model directly in order to create a radiation applicator that can be used in practice. Biologically compatible polycarbonate can be used for this purpose.