title: A frameless method for stereotactic radiotherapy.
abstract: A frameless method for stereotactic multiple arc radiotherapy (SMART) is described. Three short gold wires are implanted in the scalp approximately 100 mm apart. These are localized in a computed tomographic or angiographic study along with the target. Subsequently the gold markers are localized on beam films and the target position calculated using a computer program ISOLOC. This program provides the couch movements required to move the target to the isocentre and a micropositioner attached to the couch is used to make the adjustment. Beam films are repeated until the movements required are less than 1 mm in any direction. It is shown that the simple procedures of implanting the markers subcutaneously do not provide a stable reference system in about 25% of patients and the markers are now screwed into the cranium. The precision of the method is evaluated by phantom studies and measurements taken during several hundred treatments.
authors.affiliation: Northwest Medical Physics Center, Lynnwood, WA 98036-7306.
authors.forename: D
authors.initials: D
authors.lastname: Jones
authors.forename: D A
authors.initials: DA
authors.lastname: Christopherson
authors.forename: J T
authors.initials: JT
authors.lastname: Washington
authors.forename: M D
authors.initials: MD
authors.lastname: Hafermann
authors.forename: J W
authors.initials: JW
authors.lastname: Rieke
authors.forename: J J
authors.initials: JJ
authors.lastname: Travaglini
authors.forename: S S
authors.initials: SS
authors.lastname: Vermeulen
mesh_terms: D001927:Brain Diseases / Q000532:radiotherapy; D005069:Evaluation Studies as Topic; D006046:Gold; D006801:Humans; D008961:Models, Structural; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D011881:Radiotherapy, Computer-Assisted / Q000379:methods*; D013238:Stereotaxic Techniques
chemical_list: D006046:Gold