BacKground: This study aimed to investigate improvements in ⁶⁸ga-faPi PeT/cT image quality due to using total variation regularized expectation maximization (TVr-eM) and ordered subset expectation maximization (oS-eM) reconstruction. MeThodS: data from a total of 24 patients were retrospectively analyzed in this study. Positron emission tomography (PeT) images were reconstructed using oS-eM and TVr-eM for 2 and 3 minutes-per-bed (min/bed) acquisition. The SuV_mean of a region-of-interest on the liver, image noise, signal-to-noise ratios (Snr), the SuV_max of the lesions and the tumour-to-background ratios (TBr) were measured and compared between the 2 methods. Subjective image qualities were evaluated by two experienced radiologists using a 5-point score scale (5-excellent, 1-poor). reSulTS: in total, 132 lesions were analyzed. The image noise in TVr-eM reconstruction groups was lower than in the oS-eM groups (all P<0.05). The Snr, SuV_max of lesions and the TBr were higher for the TVr-eM reconstruction groups compared to oS-eM groups (all P<0.05). also, the SuV_max of the lesions in the TVr-eM groups increased by at least 12% compared to oS-eM 3 min/bed group. The SuV_max for small (<10 mm) and large lesions (>10 mm) in the TVR-EM 2 min/bed group were significantly larger compared to the OS-EM 3 min/bed groups (all P<0.05). The highest image quality score resulted from the TVr-eM 3 min/bed group with a penalization factor of 0.25 (3.92±0.19). concluSionS: TVr-eM reduces image noise and improved the Snr, SuV_max and TBr of the lesions. it also enables fast acquisition without compromising image quality compared to standard oS-eM. (Cite this article as: liu h, liu l, Xu S, lu Z, Mok gS, Wang y, et al. Total variation regularized expectation maximization reconstruction improves ⁶⁸ga-faPi-04 PeT/cT image quality as compared to ordered subset expectation maximization reconstruction. Q J nucl Med Mol imaging 2023;67:280-6. DOI: 10.23736/S1824-4785.22.03409-4) © 2023 EDIZIONI MINERVA MEDICA.