Stereotactic radiosurgery. XVII: Recurrent intrasellar craniopharyngioma.

Stereotactic radiosurgery for craniopharyngioma is usually a high risk procedure due to the intimate relationship of the tumour to the optic chiasm and conservative dosing has been advocated to reduce complication rates. In 2002, in a publication from Karolinska Hospital, Sweden, 13 out of 21 patients received only a marginal dose of 6 Gy (not considered a radical dose) and 11 out of 13 tumours progressed. This recent report must argue against single dose stereotactic radiosurgery as the primary radiation therapy modality in most cases.

Acute symptoms after gamma knife radiosurgery.

Object: The purpose of this study was to examine the widely held assumption that early-onset symptoms after gamma knife radiosurgery (GKS) are uncommon. The study was designed to include all types of morbidity and not just those that lead to neurological dysfunction. It was hoped that the results of the study could lead to a more rational follow-up protocol.

Can magnetic resonance imaging alone accurately define the arteriovenous nidus for gamma knife radiosurgery?

Object: Current radiosurgical treatment of arteriovenous malformations (AVMs) relies on planning protocols that integrate data from both magnetic resonance (MR) imaging and stereotactic angiography studies. Angiography, however, is invasive and associated with a small but well-defined risk of neurological and systemic complications. Magnetic resonance imaging, on the other hand, is noninvasive with multiplanar capability, demonstrates good anatomical detail, and has been shown to be superior to angiography in the delineation of selected AVMs.

Stereotactic radiosurgery XIV: The role of the haemosiderin 'ring' in the development of adverse reactions following radiosurgery for intracranial cavernous malformations: a sustainable hypothesis.

There are strong data supporting the clinical efficacy of ionizing radiation therapy in the treatment of extracranial cavernous angiomas; no unusual complications occur. There is no a priori reason to anticipate a high rate of complications following radiosurgery for brain cavernous angiomas and yet equivalent dose prescriptions (site, size and target volume) to those used for AVM are associated with a considerably higher complication rate. The observed sub-acute reactions sometimes recover with steroid therapy.

Is distortion correction necessary for digital subtraction angiography in the Gamma Knife treatment of intra-cranial arteriovenous malformations?

Objective: The published literature maintains that distortion correction of digital subtraction angiography is essential for accurate definition of the arteriovenous malformation (AVM) nidus when performing Gamma Knife radiosurgery. However, as Gamma Knife treatments usually involve small volume targets, which are purposely positioned as close to the centre of the frame as possible, we postulated that the angiographic target images should be minimally distorted. Thus, the use of uncorrected images would not significantly compromise the accuracy of the treatment.