title: "Donut's shape" radiosurgical treatment planning for large cystic metastatic brain tumors.
abstract: BACKGROUND
  Radiosurgical management of large cystic metastatic brain tumors represents a significant challenge. Nevertheless, modified dose planning has shown beneficial results in such cases.
  
  
  RESULTS
  "Donut's shape" radiosurgical treatment planning is based on the chain-like application of multiple, small-sized isocenters for selective coverage of the contrast-enhancing tumor capsule and minimal irradiation of the central cystic area. Such an approach was used for the management of large cystic intracranial metastases, which were not accompanied by a significant mass effect and did not require immediate volume reduction. Treatment was done using Leksell Gamma Knife model C with automatic positioning system. The majority of treated lesions showed significant shrinkage after radiosurgery and no major complications were met.
  
  
  CONCLUSIONS
  Large cystic metastatic brain tumors may be successfully treated with gamma knife radiosurgery alone using the proposed "donut's shape" dose planning with coverage of the contrast-enhancing tumor capsule by multiple small-sized isocenters.
authors.affiliation: Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University, Tokyo, Japan. GKRmoto@aol.com
authors.forename: M
authors.initials: M
authors.lastname: Hayashi
authors.forename: M
authors.initials: M
authors.lastname: Chernov
authors.forename: N
authors.initials: N
authors.lastname: Tamura
authors.forename: M
authors.initials: M
authors.lastname: Tamura
authors.forename: M
authors.initials: M
authors.lastname: Izawa
authors.forename: Y
authors.initials: Y
authors.lastname: Muragaki
authors.forename: H
authors.initials: H
authors.lastname: Iseki
authors.forename: Y
authors.initials: Y
authors.lastname: Okada
mesh_terms: D000230:Adenocarcinoma / Q000556:secondary* / Q000601:surgery*; D000368:Aged; D001932:Brain Neoplasms / Q000556:secondary* / Q000601:surgery*; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000295:instrumentation / Q000379:methods*; D016634:Radiosurgery / Q000295:instrumentation / Q000379:methods*; D016896:Treatment Outcome