Abstract: Objective: To investigate the efficacy of the combined application of bismuth shielding and organ dose-modulation (ODM) techniques in reducing doses to superficial radiosensitive organs and its effect on image quality during lung computed tomography (CT) scanning. Methods: Based on a clinical lung CT scanning protocol, four scanning groups are created on a chest phantom: Group 1, without bismuth shielding and ODM; Group 2, with ODM only; Group 3, with bismuth shielding only; and Group 4, with both bismuth shielding and ODM. Skin doses in the thyroid and breast regions are measured, and the volume CT dose index (CTDI_vol) is recorded. Coronal images measuring 5 mm thick are reformed, and the contrast noise ratio (CNR) and figure of merit are calculated. The image quality is evaluated subjectively. The subjective scores and CNR are analyzed for different ODM methods and to determine whether bismuth shielding two-factor ANOVA is required. Results: Compared with the case of Group 1, the CTDI_vol of Groups 2~4 decrease by 8.2%, −0.06%, and 8.8%, respectively; the thyroid doses decrease by 17.9%, 44.7%, and 47.3%, respectively; and the breast doses decrease by 12.43%, 31.8%, and 41.1%, respectively. Although the CNR of the images decreases slightly after bismuth shielding and ODM are performed, the differences are insignificant. Group 1 indicates the highest subjective score while Group 4 indicates the lowest, with no statistical difference between the groups. Conclusion: The combined application of bismuth shielding and ODM techniques can significantly reduce radiation doses during lung CT scanning while ensuring image quality.