title: [Optimization of dose distribution of radiation in cancers of the cavum: association of an expert-system and a mathematical algorithm].
abstract: Optimization of radiation therapy in nasopharyngeal carcinoma is particularly complex due to both the proximity of at risk organs and the high dose that has to be delivered. To obtain an optimal dose distribution, a knowledge-based optimization technique has been designed that associates an expert-system, named CAVCAV, with numeric optimization (gradient projection method). Based on clinical and physical criteria, CAVCAV determines the geometric characteristics of the radiation fields (beam direction, location and shape of the shielding blocks) for the three stages of radiation therapy of nasopharyngeal carcinomas. Stage 2-treatment fields proposed by CAVCAV, though not perfectly adapted to the patient, are mathematically (beam weights, beam directions, isocenter position) and geometrically (adaptation of fields and shape of blocks by virtual simulation) optimized.
authors.affiliation: Unité de radiophysique, centre Alexis Vautrin, Vandoeuvre-lès-Nancy.
authors.forename: I
authors.initials: I
authors.lastname: Buchheit
authors.forename: P
authors.initials: P
authors.lastname: Aletti
authors.forename: S
authors.initials: S
authors.lastname: Elles
authors.forename: L
authors.initials: L
authors.lastname: Malissard
authors.forename: P
authors.initials: P
authors.lastname: Bey
authors.forename: M P
authors.initials: MP
authors.lastname: Chouvet
mesh_terms: D000465:Algorithms; D004307:Dose-Response Relationship, Radiation; D005103:Expert Systems; D006801:Humans; D008433:Mathematics; D008961:Models, Structural; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted