title: Treatment volume shaping with selective beam blocking using the Leksell gamma unit.
abstract: The Leksell gamma unit at the University of Pittsburgh uses 201 highly focused 60Co beams arranged in a hemispherical array. Selective beam blocking can be used to modify the treatment volume into ellipsoid shapes oriented in different directions to match better the shape of the target volume. Dose distributions for different blocking patterns were calculated using specially developed computerized 3-D treatment planning software. The changes in dose distribution with different blocking patterns predicted by computer were verified by film densitometry. Techniques for using selective beam blocking to match more closely the treatment volume to the intended target volume have the potential of reducing the likelihood of complications for radiosurgery with the Leksell gamma unit and need to be further developed.
authors.affiliation: University of Pittsburgh School of Medicine, Joint Radiation Oncology Center, PA.
authors.forename: J C
authors.initials: JC
authors.lastname: Flickinger
authors.forename: A
authors.initials: A
authors.lastname: Maitz
authors.forename: A
authors.initials: A
authors.lastname: Kalend
authors.forename: L D
authors.initials: LD
authors.lastname: Lunsford
authors.forename: A
authors.initials: A
authors.lastname: Wu
mesh_terms: D001932:Brain Neoplasms / Q000532:radiotherapy*; D003037:Cobalt Radioisotopes / Q000627:therapeutic use*; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted; D011882:Radiotherapy, High-Energy / Q000295:instrumentation / Q000379:methods; D013238:Stereotaxic Techniques
chemical_list: D003037:Cobalt Radioisotopes