Ahmed, Khaled SayedEl-Metwally, Shereen M.2019-12-192019-12-192015Cited References in Web of Science Core Collection: 110302-9743https://link.springer.com/chapter/10.1007/978-3-319-16480-9_11Accession Number: WOS:000410784400011Many designs of radiation therapy rooms miss the correct shielding requirements due to improperly selected equipment or incorrectly chosen design. These designs may have been established based on the most common devices in the market at design time or based on previous work or experiences. Furthermore, the device upgrading from low energy to high energy or from cobalt tele-therapy gamma-ray units to linear accelerator may result in an imperfect shielding. Through implementation, problems may be faced to keep the required safety levels, furthermore, to satisfy the needed protection. In this paper, we illustrate through selected case studies, some of the problems faced and how it could be overcome in order to reach the required protection levels. This study includes seven bunkers at different places whose designs prevented to establish a linear accelerator due to room areas, room surrounding spaces or type of existing shielding: wall or layers thickness and material. Three rooms were predesigned for a cobalt tele-therapy system with an overall wall thickness of 70 cm; two rooms were inadequately designed with irregular walls of 1 m thickness, and the other two rooms were designed for low energy devices and are to be upgraded to high energy, in-addition to different inadequate conditions surrounding these bunkers. Combined solutions were used to overcome the faced problems. The presented solutions incorporate using other shielding materials than concrete as lead, borated polyethylene, gamma-600 together with changing and/or controlling the obliquity factor (changing the incident angle of radiation). The existing shielding may be also be modified by adding an internal/external layer of lead. Moreover, the position of the device inside the room was re-allocated with a certain angle to the incident rays in order to reduce leakage radiation. The resulting design solutions were validated via the atomic energy commission at those countries.enUniversity of Acceptable level; shielding; radiation protection; adequate spaceArticle