Stereotactic and Functional Neurosurgery

Stereotactic Radiosurgery with the X-Knife System

Introduction Linear acceleration (LINAC)-based stereotactic radiosurgery became feasible because of the pioneering efforts in the 1980s of Betti in South America [1], Colombo in Italy [2], Barcia-Saloria in Spain [3], and in the United States, Winston and Lutz at the Joint Center for Radiation Therapy in Boston [4] and Friedman at the University of Florida […]

Stereotactic Radiosurgery with the Linac Scalpel Part 1

Introduction Since Lars Leksell’s conception of stereotactic radiosurgery [1], the technology has proliferated, and this treatment technique is widely available through both the Gamma Knife and modified linear accelerators (linacs). One of the early linac radiosurgery groups was based at the University of Florida [2]. The system they developed, the Linac Scalpel, included state of […]

Stereotactic Radiosurgery with the Linac Scalpel Part 2

Differential Collimators Choosing the collimator diameter separately for each arc within an isocenter may be done in conjunction with, or as an alternative to, arc elimination to produce a variety of ellipsoidal dose distributions. The general idea is to select the collimator for each arc, such that the collimator diameter closely matches the "beam’s-eye-view" (BEV) […]

Stereotactic Radiosurgery with the Linac Scalpel Part 3

Clinical Multi-Isocenter Planning The general sequence of multiple isocenter treatment planning is illustrated on an irregular metastasis shown in Figure 9. The general shape of the target volume is assessed in all three dimensions. A standard five-arc set is then placed, and the isocenter location and collimator diameter are chosen to treat the largest possible […]

Stereotactic Radiosurgery with the BrainLab System

Introduction The BrainLab stereotactic irradiation software, BrainScan, includes modules for planning stereotactic irradiation (SRS) using dynamic noncoplanar arcs or fixed conformal beams when the linear accelerator is equipped with a beam-shaping tool, either a mini multileaf collimator (mMLC) or cylindrical cerrobend collimators. We have been using BrainScan version 5.0 for the last year. Our system […]

Stereotactic Radiosurgery and Intensity Modulation Radiotherapy Part 1

Introduction Stereotactic radiosurgery (SRS) is a well-accepted treatment for a large number of neurosurgical pathologies, including arteriovenous malformations, primary and metastatic brain tumors, several skull base tumors, and selected chronic pain syndromes [Alexander et al, 1993; De Salles et al, 1993; Friedman et al, 1993; Kondziolka et al, 1991; Lunsford et al, 1992; Mehta et […]

Stereotactic Radiosurgery and Intensity Modulation Radiotherapy Part 2

Intensity Modulation Delivery As with inverse planning, several techniques have been proposed with regard to radiation delivery of IMRT. The most common approach to IMRT delivery is through the use of multileaf collimators. This can be performed in either a static or dynamic fashion, as explained in Figure 4. The most simple to implement and […]

Stereotactic Radiosurgery with the Cyberknife

Introduction Stereotactic radiosurgery combines stereotactic localization with multiple cross-fired beams from a highly collimated radiation source. This noninvasive method has proven to be an effective alternative to conventional neu-rosurgery, cranial irradiation, and brachytherapy for selected small cranial tumors and arteriovenous malformations. Current stereotactic techniques rely on a rigid frame fixed to a patient’s skull for […]

Movement Disorders: Indications (Stereotactic and Functional Neurosurgery)

Introduction Neurosurgical interventions for movement disorders have increased in the last decade. Several disorders that are refractory to medical treatment are now being considered for surgery. Progress in understanding the underlying pathophysiology in these disorders and the anatomical and physiological relationships of basal ganglia components has helped identify potential targets for surgical interventions. In addition, […]

Technical Considerations in Movement Disorders Surgery (Stereotactic and Functional Neurosurgery) Part 1

Introduction The major subcortical structures targeted for deep brain stimulation (DBS) or lesioning for the treatment of movement disorders include the nucleus ventralis intermedius (Vim) of the thalamus, the globus pallidus internal segment (GPi), and the subthalamic nucleus (STN). The major technical goal during surgery for movement disorders is to maximize both precision and safety. […]

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