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

Abstract

Introduction: The present study aimed to assess the reduction of breast surface dose, breast radiation-induced 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.

Keywords

• computed tomography
• radiation protection
• head
• breast
• thermoluminescent dosimetry