Radiosurgery
A radiological stereotactic technique developed for cutting or destroying tissue by high doses of radiation in place of surgical incisions. It was originally developed for neurosurgery on structures in the brain and its use gradually spread to radiation surgery on extracranial structures as well. The usual rigid needles or probes of stereotactic surgery are replaced with beams of ionizing radiation directed toward a target so as to achieve local tissue destruction.
Intracranial Arteriovenous Malformations
Congenital vascular anomalies in the brain characterized by direct communication between an artery and a vein without passing through the CAPILLARIES. The locations and size of the shunts determine the symptoms including HEADACHES; SEIZURES; STROKE; INTRACRANIAL HEMORRHAGES; mass effect; and vascular steal effect.
Neuroma, Acoustic
A benign SCHWANNOMA of the eighth cranial nerve (VESTIBULOCOCHLEAR NERVE), mostly arising from the vestibular branch (VESTIBULAR NERVE) during the fifth or sixth decade of life. Clinical manifestations include HEARING LOSS; HEADACHE; VERTIGO; TINNITUS; and FACIAL PAIN. Bilateral acoustic neuromas are associated with NEUROFIBROMATOSIS 2. (From Adams et al., Principles of Neurology, 6th ed, p673)
Brain Neoplasms
Neoplasms of the intracranial components of the central nervous system, including the cerebral hemispheres, basal ganglia, hypothalamus, thalamus, brain stem, and cerebellum. Brain neoplasms are subdivided into primary (originating from brain tissue) and secondary (i.e., metastatic) forms. Primary neoplasms are subdivided into benign and malignant forms. In general, brain tumors may also be classified by age of onset, histologic type, or presenting location in the brain.
Particle Accelerators
Stereotaxic Techniques
Skull Base Neoplasms
Meningioma
A relatively common neoplasm of the CENTRAL NERVOUS SYSTEM that arises from arachnoidal cells. The majority are well differentiated vascular tumors which grow slowly and have a low potential to be invasive, although malignant subtypes occur. Meningiomas have a predilection to arise from the parasagittal region, cerebral convexity, sphenoidal ridge, olfactory groove, and SPINAL CANAL. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2056-7)
Trigeminal Neuralgia
A syndrome characterized by recurrent episodes of excruciating pain lasting several seconds or longer in the sensory distribution of the TRIGEMINAL NERVE. Pain may be initiated by stimulation of trigger points on the face, lips, or gums or by movement of facial muscles or chewing. Associated conditions include MULTIPLE SCLEROSIS, vascular anomalies, ANEURYSMS, and neoplasms. (Adams et al., Principles of Neurology, 6th ed, p187)
Spinal Neoplasms
Cranial Irradiation
Neurocytoma
A benign brain tumor composed of neural elements which most often arise from the SEPTUM PELLUCIDUM and the walls of the lateral ventricles. Immunohistochemistry and electron microscopy evaluations may reveal expression of neuron specific enolase and synaptophysin and cells containing microtubuli, neurosecretory granules, and presynaptic vesicles. (From Acta Med Port 1994 Feb;7(2):113-9)
Meningeal Neoplasms
Glomus Jugulare Tumor
A paraganglioma involving the glomus jugulare, a microscopic collection of chemoreceptor tissue in the adventitia of the bulb of the jugular vein. It may cause paralysis of the vocal cords, attacks of dizziness, blackouts, and nystagmus. It is not resectable but radiation therapy is effective. It regresses slowly, but permanent control is regularly achieved. (From Dorland, 27th ed; Stedman, 25th ed; DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, pp1603-4)
Treatment Outcome
Neurosurgery
Radiation Dosage
The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).
Arteriovenous Malformations
Abnormal formation of blood vessels that shunt arterial blood directly into veins without passing through the CAPILLARIES. They usually are crooked, dilated, and with thick vessel walls. A common type is the congenital arteriovenous fistula. The lack of blood flow and oxygen in the capillaries can lead to tissue damage in the affected areas.
Radiotherapy Planning, Computer-Assisted
Credentialing
Trigeminal Nerve Diseases
Diseases of the trigeminal nerve or its nuclei, which are located in the pons and medulla. The nerve is composed of three divisions: ophthalmic, maxillary, and mandibular, which provide sensory innervation to structures of the face, sinuses, and portions of the cranial vault. The mandibular nerve also innervates muscles of mastication. Clinical features include loss of facial and intra-oral sensation and weakness of jaw closure. Common conditions affecting the nerve include brain stem ischemia, INFRATENTORIAL NEOPLASMS, and TRIGEMINAL NEURALGIA.
Cranial Nerves
Surgery, Computer-Assisted
Magnetic Resonance Imaging
Craniopharyngioma
A benign pituitary-region neoplasm that originates from Rathke's pouch. The two major histologic and clinical subtypes are adamantinous (or classical) craniopharyngioma and papillary craniopharyngioma. The adamantinous form presents in children and adolescents as an expanding cystic lesion in the pituitary region. The cystic cavity is filled with a black viscous substance and histologically the tumor is composed of adamantinomatous epithelium and areas of calcification and necrosis. Papillary craniopharyngiomas occur in adults, and histologically feature a squamous epithelium with papillations. (From Joynt, Clinical Neurology, 1998, Ch14, p50)
Neurilemmoma
A neoplasm that arises from SCHWANN CELLS of the cranial, peripheral, and autonomic nerves. Clinically, these tumors may present as a cranial neuropathy, abdominal or soft tissue mass, intracranial lesion, or with spinal cord compression. Histologically, these tumors are encapsulated, highly vascular, and composed of a homogenous pattern of biphasic fusiform-shaped cells that may have a palisaded appearance. (From DeVita Jr et al., Cancer: Principles and Practice of Oncology, 5th ed, pp964-5)
Retrospective Studies
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
Postoperative Complications
Cranial Nerve Neoplasms
Benign and malignant neoplasms that arise from one or more of the twelve cranial nerves.
Radiation Equipment and Supplies
Follow-Up Studies
Dose-Response Relationship, Radiation
Trigeminal Nerve
The 5th and largest cranial nerve. The trigeminal nerve is a mixed motor and sensory nerve. The larger sensory part forms the ophthalmic, mandibular, and maxillary nerves which carry afferents sensitive to external or internal stimuli from the skin, muscles, and joints of the face and mouth and from the teeth. Most of these fibers originate from cells of the TRIGEMINAL GANGLION and project to the TRIGEMINAL NUCLEUS of the brain stem. The smaller motor part arises from the brain stem trigeminal motor nucleus and innervates the muscles of mastication.
Hemangiopericytoma
A tumor composed of spindle cells with a rich vascular network, which apparently arises from pericytes, cells of smooth muscle origin that lie around small vessels. Benign and malignant hemangiopericytomas exist, and the rarity of these lesions has led to considerable confusion in distinguishing between benign and malignant variants. (From Dorland, 27th ed; DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1364)
Cerebral Angiography
Dose Fractionation
Administration of the total dose of radiation (RADIATION DOSAGE) in parts, at timed intervals.
Pituitary Neoplasms
Neoplasms which arise from or metastasize to the PITUITARY GLAND. The majority of pituitary neoplasms are adenomas, which are divided into non-secreting and secreting forms. Hormone producing forms are further classified by the type of hormone they secrete. Pituitary adenomas may also be characterized by their staining properties (see ADENOMA, BASOPHIL; ADENOMA, ACIDOPHIL; and ADENOMA, CHROMOPHOBE). Pituitary tumors may compress adjacent structures, including the HYPOTHALAMUS, several CRANIAL NERVES, and the OPTIC CHIASM. Chiasmal compression may result in bitemporal HEMIANOPSIA.
Combined Modality Therapy
Neoplasm Recurrence, Local
Polyvinyls
'Polyvinyls' is a term that refers to a group of polymers synthesized from vinyl chloride, including polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC), which are widely used in various medical applications such as manufacturing of medical devices, tubing, packaging materials, and pharmaceutical containers due to their chemical resistance, durability, and versatility.
Cavernous Sinus
Radiometry
Skull Base
Optic Nerve Neoplasms
Benign and malignant neoplasms that arise from the optic nerve or its sheath. OPTIC NERVE GLIOMA is the most common histologic type. Optic nerve neoplasms tend to cause unilateral visual loss and an afferent pupillary defect and may spread via neural pathways to the brain.
Radiotherapy, Image-Guided
Embolization, Therapeutic
A method of hemostasis utilizing various agents such as Gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and INTRACRANIAL ARTERIOVENOUS MALFORMATIONS, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage.
Denture, Partial
Radiation Injuries
Spinal Cord Neoplasms
Benign and malignant neoplasms which occur within the substance of the spinal cord (intramedullary neoplasms) or in the space between the dura and spinal cord (intradural extramedullary neoplasms). The majority of intramedullary spinal tumors are primary CNS neoplasms including ASTROCYTOMA; EPENDYMOMA; and LIPOMA. Intramedullary neoplasms are often associated with SYRINGOMYELIA. The most frequent histologic types of intradural-extramedullary tumors are MENINGIOMA and NEUROFIBROMA.
Hemangioma, Cavernous, Central Nervous System
A vascular anomaly composed of a collection of large, thin walled tortuous VEINS that can occur in any part of the central nervous system but lack intervening nervous tissue. Familial occurrence is common and has been associated with a number of genes mapped to 7q, 7p and 3q. Clinical features include SEIZURES; HEADACHE; STROKE; and progressive neurological deficit.
Cerebral Hemorrhage
Pituitary ACTH Hypersecretion
Pinealoma
Neoplasms which originate from pineal parenchymal cells that tend to enlarge the gland and be locally invasive. The two major forms are pineocytoma and the more malignant pineoblastoma. Pineocytomas have moderate cellularity and tend to form rosette patterns. Pineoblastomas are highly cellular tumors containing small, poorly differentiated cells. These tumors occasionally seed the neuroaxis or cause obstructive HYDROCEPHALUS or Parinaud's syndrome. GERMINOMA; CARCINOMA, EMBRYONAL; GLIOMA; and other neoplasms may arise in the pineal region with germinoma being the most common pineal region tumor. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, p2064; Adams et al., Principles of Neurology, 6th ed, p670)