Purpose The aim of the study is evaluate whether CT dose indicators CTDIvol/ DLP, used for DRLs establishment and procedure optimization, are at the sufficient quality to achieve goal which is comparison of the radiological practices among different centers. Methods Accuracy of the CTDIvol and DLP values reported by scanners has been evaluated. Accuracy and uncertainty of the ionization chambers has been evaluated in scope of possibility of performing calibration of the CT scanner according to international definition of the calibration process given by BIPM or ISO IEC 17025 standard, which is the comparison of values delivered by a device with those of known accuracy. Results It has been found that manufacturers specification for CT dose indicators reported by scanners vary between ± 20% up to ± 40%. Uncertainty of the ionization chambers available on the market is ± 5% and include repeatability as well as all relevant characteristics like energy dependence. That means QC of CT scanner and measurement checks of CTDIvol/ DLP reported by scanners vs values measured by ionization chambers can be treated as calibration process leading to establishment of calibration correction factors for CTDivol/ DLP with uncertainty around 5–7%. Conclusions The deviation in the provided data for establishing DRLs are high even for same clinical indication and similar equipment available, as the difference in local population and different local requirements for image quality contribute to different Data sent to DoseDataBases used for establishing DRLs. Therefore it is important to minimize contributed uncertainty as far as possible. Use of correction factors for Dose Values instead of reporting manufacturers specification limits and showing direct data taken from CT scanner, seems to be helpful in this process. Comparison of data sent without necessary correction factors might lead to huge mistakes in final evaluation and furthermore to wrong optimization decision on the local level, especially if the scanner with ± 40% accuracy specification is used in clinic, and high values of correction factors are found. During process of building National/ Regional Databases and DRLs values establishment it is important to distinguish between accuracy and uncertainty of the CT dose indicators.