title: Dose calculation algorithm accuracy for small fields in non-homogeneous media: The lung SBRT case.
abstract: This review addresses the theme of dose calculation accuracy in the case of the stereotactic treatment of lung lesions. Based on the classical categories of type "a", "b" and "c" algorithms (according to their degree of complexity in the management of charged particle transport), a summary of findings from literature is reported. Two main critical areas have been identified: the use of small fields and the presence of low density medium. Concerning the latter point, the algorithm accuracy is intrinsic of the algorithm core, and, notwithstanding the materials discretization and their chemical composition knowledge, type "c" are, at the most, able to reproduce the actual physical dose distribution in heterogeneous media. For what concerns the small field management, the final accuracy could be strongly related to the beam configuration appropriateness in the TPS (as well for MC this relates to the proper linac head description). As a very crude summary, type "a" should be considered as unsuitable for this kind of treatment calculations (with differences of the order of 20-30%), while type "b" and "c" could keep their accuracy approximatively within 10 and 5%, respectively.
authors.affiliation: Humanitas Research Hospital and Cancer Center, Radiotherapy and Radiosurgery Dept, via Manzoni 56, 20089 Milan-Rozzano, Italy. Electronic address: antonella.fogliata@humanitas.it.
authors.forename: Antonella
authors.initials: A
authors.lastname: Fogliata
authors.affiliation: Humanitas Research Hospital and Cancer Center, Radiotherapy and Radiosurgery Dept, via Manzoni 56, 20089 Milan-Rozzano, Italy; Humanitas University, Biomedical Science Faculty, via Manzoni 118, 20089 Milan-Rozzano, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Cozzi
mesh_terms: D000465:Algorithms; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy*; D011829:Radiation Dosage; D016634:Radiosurgery; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*
keywords: Inhomogeneity; Low density; Lung SBRT; Small fields