Hamadan University of Medical Sciences Avicenna Journal of Medical Biochemistry 2345-4113 7 2 2019 12 01 An Efficient Radiochemical Method for Extraction of 226Ra From the Soil Samples 57 60 10.34172/ajmb.2019.10 EN Amir Mehdizadeh https://orcid.org/0000-0003-1453-2051 Sedigheh Sina https://orcid.org/0000-0001-5890-9645 Reza Faghihi https://orcid.org/0000-0003-3238-6887 Mohammad Hosein Sadeghi https://orcid.org/0000-0001-5219-4247 Journal Article 10.34172/ajmb.2019.10 2019 12 05 2019 12 20 Background: Radium-226 is a radioactive element, with a very long half-life of 1600 years, producing radon gas. According to the United States Environmental Protection Agency, radon gas is the second most important factor causing lung cancer. Objectives: The purpose of this study was to separate 226Ra from the soil of high background radiation area by a radiochemical method for using in radon calibration chamber. Methods: 226Ra can be used in standard calibration chambers for calibration of radon detection systems. For this purpose, radiochemical method was used to extract radium from the soil with a high concentration of 226Ra. Four soil samples used in this study were selected from high background radiation areas of Ramsar, north of Iran. Equal amounts of samples were gathered from each region and ground. The specific activity of radium-226 was measured with HPGe detector. The highest specific activity of radium-226 (44.8 Bq/g) belonged to Talesh-Mahaleh. After radiochemical separation of 226Ra, the specific activity of extracted radium crystals was measured with the HPGe detector. Results: According to the results, the specific activity of 226Ra was found to be 94.97 Bq/g. Therefore, the specific activity of 226Ra was 2.12 times greater in the extracted crystals than in the original soil samples. Conclusion: The results indicate that using the radiochemical method proposed in this study, 226Ra can be extracted with an efficiency of 42%