Objective To investigate optimization strategies for low-dose CT acquisition parameters in positron emission tomography/computed tomography (PET/CT) and to evaluate the impact of a body weight-based tube current adjustment protocol on radiation dose, CT image quality, and the stability of PET quantitative measurements. Methods A total of 130 patients who underwent 18F-fluorodeoxyglucose (18F-FDG) PET/CT at the First Affiliated Hospital of Henan University of Science and Technology between June 2024 and June 2025 were retrospectively enrolled. According to the low-dose CT protocol used, patients were assigned to either a control group, scanned with the conventional low-dose protocol, or an observation group, scanned with a body weight-stratified tube current optimization protocol. CT radiation dose metrics, including volume CT dose index (CTDIvol), dose-length product (DLP), and effective dose (ED), were compared between the two groups. CT image quality, including image noise and signal-to-noise ratio (SNR), were compared between the two groups. Simultaneously PET quantitative stability, including the mean standardized uptake value (SUVmean) of the liver and mediastinal blood pool, were compared between the two groups. Results CTDIvol, DLP, and ED were all significantly lower in the observation group than in the control group (all P＜0.05). Image noise was significantly higher and SNR was significantly lower in the observation group (both P＜0.05). However, no significant difference was observed between the two groups in the acceptability of fused-image interpretation (P＞0.05). The liver SUVmean and mediastinal blood pool SUVmean did not differ significantly between groups (both P＞0.05), and the relative deviations in SUVmean remained within an acceptable range. Conclusion A body weight-based tube current optimization protocol can effectively reduce the radiation dose from the CT component of PET/CT while maintaining PET quantitative stability and acceptable fused-image interpretability, indicating good potential for clinical application.