title: Intensity-modulated radiosurgery with rapidarc for multiple brain metastases and comparison with static approach.
abstract: Rotational RapidArc (RA) and static intensity-modulated radiosurgery (IMRS) have been used for brain radiosurgery. This study compares the 2 techniques from beam delivery parameters and dosimetry aspects for multiple brain metastases. Twelve patients with 2-12 brain lesions treated with IMRS were replanned using RA. For each patient, an optimal 2-arc RA plan from several trials was chosen for comparison with IMRS. Homogeneity, conformity, and gradient indexes have been calculated. The mean dose to normal brain and maximal dose to other critical organs were evaluated. It was found that monitor unit (MU) reduction by RA is more pronounced for cases with larger number of brain lesions. The MU-ratio of RA and IMRS is reduced from 104% to 39% when lesions increase from 2 to 12. The dose homogeneities are comparable in both techniques and the conformity and gradient indexes and critical organ doses are higher in RA. Treatment time is greatly reduced by RA in intracranial radiosurgery, because RA uses fewer MUs, fewer beams, and fewer couch angles.
authors.affiliation: Department of Radiation Oncology, Moores Cancer Center, University of California, San Diego, La Jolla, CA, USA. jwang@ucsd.edu
authors.forename: Jia-Zhu
authors.initials: JZ
authors.lastname: Wang
authors.forename: Todd
authors.initials: T
authors.lastname: Pawlicki
authors.forename: Roger
authors.initials: R
authors.lastname: Rice
authors.forename: Arno J
authors.initials: AJ
authors.lastname: Mundt
authors.forename: Ajay
authors.initials: A
authors.lastname: Sandhu
authors.forename: Joshua
authors.initials: J
authors.lastname: Lawson
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Murphy
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000473:pathology / Q000556:secondary* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D016896:Treatment Outcome