[en] The present paper summarizes the findings of studies carried out since 2014 in the uranium- and thorium bearing regions of Poli and Lolodorf, respectively, located in northern and southern Cameroon. It also underlines future prospects for strengthening the radiological protection of members of the public exposed to environmental natural radiation in Cameroon. In situ gamma spectrometry and car-borne surveys were performed in the above regions to determine activity concentrations of natural radionuclides in soil and air kerma rates to assess the effective external dose received by members of the public. High natural radiation areas were located and selected for indoor radon, thoron and thoron progeny measurements. Raduet detectors and thoron progeny monitors were deployed in 300 dwellings to measure radon, thoron and thoron progeny indoors in order to assess the inhalation dose received by members of the public. External effective dose ranges of 0.15-0.63 mSv/year with the average value of 0.4 mSv/year in the uranium bearing region of Poli and 0.1-2.2 mSv/year with the average value of 0.33 mSv/year in the uranium- and thorium bearing region of Lolodorf. The inhalation dose due to radon and thoron ranges, respectively, between 0.87-2.7 mSv/year and 0.08-1.0 mSv/year with average values of 1.55 mSv/year and 0.4 mSv/year for Poli, and between 0.6-3.7 mSv/year and 0.03-3.0 mSv/year with the average values of 1.84 mSv/year and 0.67 mSv/year for Lolodorf. Contribution of thoron to the total inhalation dose ranges around 3-34%, with an average value of 20.3% in the uranium region of Poli and 1-79% with the average value of 27% in the uranium- and thorium-bearing region of Lolodorf. Thus, thoron cannot be neglected in dose assessment in order to avoid biased results in radio-epidemiological studies. (author)