<prompt> Which of these is not a basic principle of radiation protection ?JustificationCollimationLimitationOptimization  <response>: In addition to the three basic principles of radiation protection justification, limitation, and optimization, one can apply the following additional techniques to reduce the radiation burden to the patient:Collimation of the x-ray beam.Correct focus-to-skin distance.Lead apron with thyroid collar.More radiation-sensitive image receptors. 