Abstract: Objective To investigate the feasibility of low-dose computed tomography (CT) purification for adult interstitial lung disease (ILD). Methods Sixty patients with ILD admitted to our hospital between August 2024 and February 2025 were randomly assigned to Groups A and B, with 30 patients in each group. Group A was examined using high-resolution CT. Group B was scanned using a low-dose energy-spectrum purification technique with a Sn tube voltage of 100 kV. Groups A and B adopted an advanced modeling iterative reconstruction algorithm (level 3). The radiation dose, subjective image score (overall chest evaluation and intrapulmonary lesion evaluation), and objective evaluation indices were compared between the two groups. Statistical analyses were performed using IBM SPSS Statistics for Windows, version 26.0. Results The effective radiation dose in Group B was lower than that in Group A, and the subjective score of the mediastinal window of the chest image in Group B was significantly lower than that in Group A (P < 0.05). The objective evaluation of the images in Group A was significantly higher than that in Group B (P < 0.05). No statistically significant differences were observed in the subjective scores for the overall lung window of the chest images and the evaluation of pulmonary lesions within the lung window between the two groups (P > 0.05). Conclusion The Sn l00 kV protocol for low-dose energy-spectrum purification technology in the CT review of adult ILD satisfies the requirements of imaging diagnosis for intrapulmonary lesions and can effectively reduce the radiation dose in patients.