RT Journal Article SR Electronic T1 Protons and more: state of the art in radiotherapy JF Clinical Medicine JO Clin Med FD Royal College of Physicians SP s61 OP s65 DO 10.7861/clinmedicine.14-6-s61 VO 14 IS Suppl 6 A1 Peter J Hoskin A1 Indrani S Bhattacharya YR 2014 UL http://www.rcpjournals.org/content/14/Suppl_6/s61.abstract AB The purpose of modern radiotherapy is to deliver a precise high dose of radiation which will result in reproductive death of the cells. Radiation should transverse within the tumour volume whilst minimising damage to surrounding normal tissue. Overall 40% of cancers which are cured will have received radiotherapy. Current state of the art treatment will incorporate cross-sectional imaging and multiple high energy X-ray beams in processes called intensity modulated radiotherapy and image guided radiotherapy. Brachytherapy enables very high radiation doses to be delivered by the direct passage of a radiation source through or within the tumour volume and similar results can be achieved using rotational stereotactic X-ray beam techniques. Protons have the characteristics of particle beams which deposit their energy in a finite fixed peak at depth in tissue with no dose beyond this point – the Bragg peak. This has advantages in certain sites such as the spine adjacent to the spinal cord and particularly in children when the overall volume of tissue receiving radiation can be minimised.