Background: The image quality of PET/CT is affected by various factors which include technical errors, Biological factors, and Physical factors. The errors due to physical factors can be reduced by using standardized image reconstruction parameters. The choice of reconstruction parameters is a trade‐off between resolution and noise and has a major impact on the performance of clinically important tasks such as lesion detection. Moreover, these image reconstruction parameters are highly specific to manufacturer and scanner type thus making generalizations difficult.Materials and Methods: PET/CT scan of Deluxe Jaszczak phantom filled with water having 74 MBq F‐ 18 FDG was acquired on Biograph mCT (Siemens Healthcare) PET/CT scanner. PET scan was acquired in one bed for 5 minutes. Transverse slices were reconstructed using OSEM reconstruction method by varying FWHM from 1mm to 8 mm and for each FWHM, Iterations (IT) varied from 1 to 10. The image quality of 240 mages was assessed by two nuclear medicine physicians based on 4 point scale.Results: At constant iteration, increase in FWHM resulted in smooth images, but gradual decrease in image quality seen because of edge blurring. At constant FWHM, increase in number of iteration improved the contrast in the image but at the cost of inclusion of noise.Conclusion: Optimized value of iteration and FWHM were found to be 4 and 2 mm respectively.