[Preparation for transcutaneous irradiation].

Abstract

To give a precise dose of radiation in an anatomically defined volume a succession of clinical and technical procedures is necessary. Clinical evaluation of tumor extension contributes to the definition of the different target volumes. Then, medical imaging techniques adapted from X ray diagnostic machines (simulators) are generally used. Number, size, shape and orientation of the different beams are defined. More complex techniques with CT scan or MRI can be useful to localise directly the different target volumes and organs at risk. Dosimetric studies are performed with radiophysicists. Calculations can be simply made from measurements of deepness or external outlining. More complex calculations including CT or MRI slices can be performed when an optimization of the treatment planning is attempted. These different steps are rewritten on a technical sheet, mandatory for the quality control assurance of the whole treatment.