The first couple of chapters of this graduate thesis describe the basic terms that one must familiarize with when working in the field of ionising radiation. The thesis names, describes and explains the types of ionising radiation, its sources as well as radiation’s interactions with the matter. What comes next is a detailed description of the effect the ionising radiation has on humans, but also the means of protection, focusing mainly on the use of shields. For the experimental portion of the thesis, the measurements that prove the efficiency of lead, copper and polymethyl methacrylate (more commonly known as acrylic glass or plexiglass) materials as protectors against the gamma radiation are conducted. Therefore, the methods of the measurements are explained and measuring instruments, the sources of radiation, as well as used shields are described. Moreover, the results of the measurements that detail the dependency of the ambient dose rate equivalent of the distance square and the thickness of the protective shield are all specified. The measurements were all done during September of 2020 in the Radiation Protection Unit with the Institute for Medical Research and Occupational Health in Zagreb. This graduate thesis focuses entirely and only on ionising radiation, which is why solely the term “radiation” was used in the continuation of the paper because of simplification.