Reduction of Breast Surface Dose, Cancer and Mortality Risks Using Lead Apron during the Head Scanning a Computed Tomography Technique.

Introduction: The present study aimed to assess the reduction of breast surface dose, breast radiationinduced cancer incidence, and mortality risks when the lead apron shielding was positioned on the chest regions during head computed tomography (CT). Material and Methods: In this study, routine head CT scans were performed on 28 female patients with a mean body mass index (BMI) of 25.2 ± 2.8 kg/m². The common lead aprons (0.5 mm thicknesses) were folded and positioned in the chest regions. The breast surface doses were measured using six thermoluminescent dosimeters (TLD-100), three TLDs were located above the apron and three ones positioned under the apron. Breast radiation-induced cancer incidence and mortality risks were estimated using the Biological Effects of Ionizing Radiation (BEIR-VII) model. Finally, the measured doses and cancer/mortality risks were compared using Paired sample T-Test in SPSS software. Results: The breast surface doses under and over the apron were obtained at 0.18±0.06 and 0.49±0.13 mGy, respectively, (P-value<0.05). Although all cancer/mortality risks for both groups (over and under the apron) were very low, using the lead apron could decrease (significantly) breast cancer incidence risk ([1.24±0.32]×10-3 % over the apron vs. [0.46±0.15] ×10-3 % under the apron) and mortality risk ([0.30±0.08]×10-3 % over the apron vs. [0.11±0.04] ×10-3 % under the apron) about 63% in all patients. Conclusion: The use of common lead aprons in the chest regions for patients undergoing head CT scans could significantly reduce the breast surface doses and radiation-induced cancer/mortality risks.