Purpose: Quantify dose enhancement fractions (DEF) caused by backscattered electrons of gold nanoparticles with different size and shape using thermoluminescent dosimeters (TLD). Methods: Gold nanorods (AuNP‐rod) of 45nm and spherical gold nanoparticles (AuNP) of 5nm average diameter were used in this study. Fourteen Lithium Fluoride TLDs (LiF‐100) groups were pre‐calibrated in the 200kV x‐ray beam studied. Different mass‐fractions of gold (0%, 0.1%, 0.2%, 0.3%, 0.5%, 0.7% and 0.8%) were casted only in one surface of each tablet. An acrylic plate with a small recess properly designed to fit tablets of a same group each time; 10cm of acrylic were also positioned down the TLDs to guarantee backscattering conditions. 2Gy were delivered to all groups. The AuNPs films were down positioned related to the beam incidence during the experiments aiming to measure backscattered electrons of AuNPs. TLDs were positioned in two depths: surface and build‐up. DEF was calculated as the ratio between dose measured with TLD tablets with and without AuNP. Results: Experimental DEF varies between 1 and 1.26 to both AuNP‐rods and AuNPs when positioned on the surface. At the build‐up depth the experimental DEFs found were 1, 1.02, 1.04, 1.09, 1.12, 1.16 and 1.17 respectively to concentrations 0%, 0.1%, 0.2%, 0.3%, 0.5%, 0.7% and 0.8% of AuNP‐rods; To the same gold concentrations of spherical nanoparticles the DEFs found were 1, 1.02, 1.02, 1.03, 1.04, 1.08 and 1.11. A linear behavior between gold concentration casted and DEFs measured was observed to both depths of irradiation. Conclusions: Differences of 6% in fractions of dose enhancements can be found when 45nm AuNP‐rods and 5nm spherical AuNPs are considered. The angular distribution of scattered electrons in AuNP combined to nanoparticle size and shape implies in its self attenuation inside the nanoparticles and thereof the fractions of dose enhancements around the particles.