Minim Invasive Neurosurg 2011; 54(05/06): 286-289
DOI: 10.1055/s-0031-1297987
Technical Note
© Georg Thieme Verlag KG Stuttgart · New York

“Donut’s Shape” Radiosurgical Treatment Planning for Large Cystic Metastatic Brain Tumors

M. Hayashi1, 2, M. Chernov1, 2, N. Tamura1, M. Tamura2, M. Izawa1, Y. Muragaki1, 2, H. Iseki1, 2, Y. Okada1
  • 1Department of Neurosurgery, Neurological Institute, Tokyo Women’s Medical University, Tokyo, Japan
  • 2Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women’s Medical University, Tokyo, Japan
Further Information

Publication History

Publication Date:
25 January 2012 (online)



Radiosurgical management of large cystic metastatic brain tumors represents a significant challenge. Nevertheless, modified dose planning has shown beneficial results in such cases.

Method and 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.


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.