title: Three-dimensional treatment planning of astrocytomas: a dosimetric study of cerebral irradiation.
abstract: To demonstrate that 3-dimensional planning is both practical and applicable to the treatment of high-grade astrocytomas, 50 patients over a 2-year period have received cerebral irradiation delivered in focussed, non-axial techniques employing from 2 to 5 beams. Astrocytomas have been planned using rapid, practical incorporation of CT data to define appropriate tumor volumes. Tumor + 3.0 cm and tumor + 1.5 cm volumes have been treated to conventional doses of 4500 cGy and 5940 cGy, respectively, using beam orientations that maximally spared normal remaining parenchyma. Analyses of 3-dimensionally calculated plans have been performed using integral dose-volume histograms (DVH) to help select treatment techniques. Using identical CT-based volumetric data as input for generation of Beam's Eye View (BEV) designed blocks, DVH curves demonstrate dosimetric advantages of non-axial techniques over conventional parallel-opposed orientations. Assessment of the non-axial techniques in selected cases indicates that uniform target volume coverage could be maintained with a typical reduction of 30% in the total amount of brain tissue treated to high dose (95% isodose line).
authors.affiliation: Dept. of Radiation Oncology, University of Michigan Medical Center, Ann Arbor 48109-0010.
authors.forename: A F
authors.initials: AF
authors.lastname: Thornton
authors.forename: T J
authors.initials: TJ
authors.lastname: Hegarty
authors.forename: R K
authors.initials: RK
authors.lastname: Ten Haken
authors.forename: B R
authors.initials: BR
authors.lastname: Yanke
authors.forename: M L
authors.initials: ML
authors.lastname: LaVigne
authors.forename: B A
authors.initials: BA
authors.lastname: Fraass
authors.forename: D L
authors.initials: DL
authors.lastname: McShan
authors.forename: H S
authors.initials: HS
authors.lastname: Greenberg
mesh_terms: D001254:Astrocytoma / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D014057:Tomography, X-Ray Computed