The use of radiation has enabled spectacular advances in different fields of knowledge, from space technology, aeronautics to telecommunications (with practically universal use of mobile telephony), as well as in the field of health. The application of radiation in both diagnosis and therapy has revolutionised the health sciences, from physiotherapy to medicine, and has meant a spectacular advance in the treatment guidelines for different ailments, ranging from the use of electromagnetic fields in physiotherapy to today's highly complex equipment for both radiotherapy and medical imaging for diagnosis.