Establishing Local Diagnostic Reference Levels (LDRL) for Low-Dose Lung Cancer Screening Ct Using a Dose Management System: Impact of Gender and Body Weight.
Abstract
Purpose
To establish the local diagnostic reference levels (LDRL) for low-dose CT (LDCT) using an automated dose management system and to evaluate the relative impacts of gender and body weight on radiation dose.
Methods
A retrospective analysis was conducted on clinical LDCT data from 785 patients collected over a six-month period (April to September 2025). Dose metrics (including CTDIvol and DLP), gender, and body weight were extracted from the dose management system. Statistical analysis was performed to compare the 75th percentile (LDRL), mean, and median doses between male and female cohorts, with a specific focus on stratified analysis within the same weight intervals.
Results
The 75th percentile of CTDIvol for the entire cohort, males, and females was 2.32 mGy, 2.50 mGy, and 1.88 mGy, respectively. Within the 55–75 kg weight category, the 75th percentile of CTDIvol for males (2.28 mGy) remained notably higher than for females (2.00 mGy). A consistent trend was observed in DLP metrics, where male doses (85.12 mGy*cm) significantly exceeded female doses (72.41 mGy*cm) within the same weight interval. Similar patterns were also found in both mean and median values of CTDIvol and DLP. Interestingly, there were no significant differences in dose metrics between the entire cohort and the 55–75 kg sub-group. Overall, gender demonstrated a more significant impact on dose variance than body weight.
Conclusion
The study demonstrates that gender is a significant independent factor influencing LDCT dose, likely due to anatomical attenuation differences. Establishing gender-specific LDRLs may provide a more accurate benchmark for clinical quality assurance and facilitate personalized protocol optimization in lung cancer screening programs.