Radiation dose for pediatric scoliosis patients undergoing whole spine radiography: Effect of the radiographic length in an auto-stitching digital radiography system.

ABSTRACT

OBJECTIVE: This study investigated the influence of spatial overlap and radiographic length (RL) on the effective dose (ED) and organ dose for pediatric patients undergoing whole spine radiography using an auto-stitching digital radiography (DR) system. METHODS: First, the system parameters were tested on a 10-year-old pediatric anthropomorphic phantom with a Shimadzu DR system, and the effects of the spatial overlap and RL on radiation doses were validated. The ED and organ dose were calculated on the basis of a Monte Carlo simulation program. Subsequently, 82 patients with adolescent idiopathic scoliosis were recruited. The spatial overlap and RL for each patient were modified to further investigate the dose reduction feasibility. RESULTS: RL and ED were appropriately correlated on the basis of patients' height. For a patient measuring 158 cm, the Shimadzu DR system was equipped with a 17-inch detector with a cut-off RL of 75 cm. The phantom simulations indicated that ED was reduced to a minimum value of 0.188 ± 0.001 mSv with a high RL for RL < 75 cm. The minimum value increased to 0.300 ± 0.002 mSv for an RL of 75 cm and dropped to 0.222 ± 0.001 mSv for the maximum RL. By employing optimized RLs for patients, EDs were significantly reduced (p < 0.05). Moreover, ED reductions were higher when longer RLs were employed. CONCLUSION: A decrease in the spatial overlap and number of radiographic acquisitions by adjusting RLs when possible could reduce ED and almost all organ doses. This study emphasized the effects of RL on the radiation dose and provided useful guidance for modifying the RL for patients to reduce the whole spine radiography dose using a modern auto-stitching DR system.