Abstract: Objective: To investigate the relationship between entrance surface dose (ESD) of gonads and physiological parameters such as sex, age, height, and weight in digital X-ray exposure of both lower limbs and to explore the feasibility of full-width long-plate imaging with single-dose radiation exposure. Methods: A total of 300 patients at a weight-bearing position of both lower limbs were prospectively enrolled in a hospital in Beijing, including 129 males and 171 females. The TLD detectors were set at the gonads on both sides of the patient during scanning. After exposure, the TLD detectors were measured with an RGD-3B thermoluminescence dosimeter, and the corresponding dose values were obtained and analyzed. Results: The average triple exposure dose (AP+bilateral view) in the full-length plate adult mode was (1281±202) µGy, which was approximately three times the single exposure dose (429±99) µGy. The triple exposure dose (AP+bilateral view) was significantly lower than the radiation dose recommended by international standards. Multiple linear regression analysis showed that only height and weight affected gonadal radiation dose. Under the scanning parameters of children, the ESD dose was (359±27) µGy and (627±155) µGy when the height was less or more than 160 cm, respectively, with a significant statistical difference. In adult mode, height and weight did not affect the ESD dose. Conclusions: This study showed that the exposure dose of gonads during full-length scanning of both lower limbs in a weight-bearing position with a single exposure was affected by height and weight. The dose received by the gonads was within the safe range, and a single exposure of the full-length plate radiation dose is feasible in clinical practice.