Image Fusion for Radiosurgery, Neurosurgery and Hypofractionated Radiotherapy.

Precise target detection is essential for radiosurgery, neurosurgery and hypofractionated radiotherapy because treatment results and complication rates are related to accuracy of the target definition. In skull base tumors and tumors around the optic pathways, exact anatomical evaluation of cranial nerves are important to avoid adverse effects on these structures close to lesions. Three-dimensional analyses of structures obtained with MR heavy T2-images and image fusion with CT thin-sliced sections are desirable to evaluate fine structures during radiosurgery and microsurgery.

Optimal hypofractionated conformal radiotherapy for large brain metastases in patients with high risk factors: a single-institutional prospective study.

Background: A single-institutional prospective study of optimal hypofractionated conformal radiotherapy for large brain metastases with high risk factors was performed based on the risk prediction of radiation-related complications.

Methods: Eighty-eight patients with large brain metastases ≥10 cm(3) in critical areas treated from January 2010 to February 2014 using the CyberKnife were evaluated. The optimal dose and number of fractions were determined based on the surrounding brain volume circumscribed with a single dose equivalent (SDE) of 14 Gy (V14) to be less than 7 cm(3) for individual lesions.

Five-fraction CyberKnife radiotherapy for large brain metastases in critical areas: impact on the surrounding brain volumes circumscribed with a single dose equivalent of 14 Gy (V14) to avoid radiation necrosis.

The efficacy and toxicity of five-fraction CyberKnife radiotherapy were evaluated in patients with large brain metastases in critical areas. A total of 85 metastases in 78 patients, including tumors >30 cm(3) (4 cm in diameter) were treated with five-fraction CyberKnife radiotherapy with a median marginal dose of 31 Gy at a median prescribed isodose of 58%. Changes in the neurological manifestations, local tumor control, and adverse effects were investigated after treatment.

Spinal epidural arteriovenous fistulas with unusual manifestation of sudden onset of severe neurological deficits: case report.

Spinal epidural arteriovenous fistulas with perimedullary venous drainage cause venous hypertension, and usually manifest as slowly progressive myelopathy. We treated two patients presenting with sudden onset of severe neurological deficits. Moreover, in Case 1, the venous drainage was exclusively epidural and no perimedullary venous drainage was present.

Three-fraction CyberKnife radiotherapy for brain metastases in critical areas: referring to the risk evaluating radiation necrosis and the surrounding brain volumes circumscribed with a single dose equivalence of 14 Gy (V14).

The efficacy and toxicity of three-fraction CyberKnife radiotherapy were evaluated in patients with brain metastases in critical areas. One hundred and fifty-nine metastases in 145 patients including tumors >10 cm(3) were treated with three-fraction CyberKnife radiotherapy with a median marginal dose of 27 Gy at a median prescribed isodose of 60%. Changes in the neurological manifestations, local tumor control and adverse effects were investigated after treatment.

Other skull-base tumors.

Therapeutic policy and radiosurgical results for nonvestibular schwannomas and chordomas are reported. Fourteen patients with nonvestibular schwannomas treated with marginal doses of 12-15 Gy were followed for 5-13 years. All patients except one were stable and did not require additional treatments.

Long-term results of Gamma Knife surgery for arteriovenous malformations: 10- to 15-year follow up in patients treated with lower doses.

Object: Several adverse effects such as brain edema, necrosis, arterial stenosis, hemorrhage after obliteration, and delayed cyst formation have been reported as early and late complications of Gamma Knife surgery (GKS) for arteriovenous malformations (AVMs). These adverse effects seem to be decreased in a lower-dose treatment regimen compared with the classic higher margin doses of 25 Gy because the radiation insult to the surrounding tissue is minimized. Long-term results of lower-dose GKS for AVMs are presented.

Low-dose radiosurgery for large vestibular schwannomas: long-term results of functional preservation.

Object: The author conducted a study to assess the long-term results obtained in patients who underwent GKS for large vestibular schwannomas (> 3 cm in diameter). Facial and cochlear nerve functions were evaluated.

Methods: Twenty consecutive large tumors in 18 patients (including two cases of neurofibromatosus Type 2 [NF2]) were followed for more than 6 years.

Hemorrhage risks and obliteration rates of arteriovenous malformations after gamma knife radiosurgery.

Object: The purpose of this study was to analyze the risk of hemorrhage and the obliteration rate after treatment of patients with arteriovenous malformations (AVMs).

Methods: Between 1991 and 1995, 115 patients were treated using gamma knife radiosurgery (GKS). Surgical planning was based on angiograms and three-dimensional images.