The last RadoNorm course for 2022 titled Cellular effects of high and low LET ionising radiation – introduction to radiation biology (CELET) took place in Stockholm University from 14^th to 25^th November. The course was attended by 11 PhD students from the EU (Italy, France, Germany, Belgium, Spain, Poland, Finland), 2 MSc students from Japan and 11 MSc students from the Stockholm University. Among other activities, radon measurements were carried out outside the Stockholm University building where 18 kBq of radon were measured in the ground. The educational program also included a whole day guided tour of Uppsala with special focus on the museum devoted to Carl Linnaeus and the Uppsala university (the oldest university in Sweden) library with the world-famous silver bible from the 7^th century. During the last day of the course, participants presented the results of exercises. Overall, the course and its content were evaluated very highly.