Acoustic (vestibular) neuroma - Gamma Knife and Who can be treated?
This 18-ton machine with a 201 permanently installed source of cobalt-60, spherically located around the patient's head. These sources emit gamma radiation, which is similar to diagnostic X-rays (not laser, as patients sometimes assume), but with higher energy. These rays are precisely formed through two successive sets of tungsten channels (collimators). They all focus on one point. Here the radiation is very powerful. However, each individual ray passing through the skull is weak and will not cause any detectable biological effects. Gamma rays destroy molecules in tumor cells, so they can no longer multiply and eventually die.
Gamma knife has an accuracy of half a millimeter or even less (about 1/50 inch). Thus, a high dose of radiation can be delivered to targets with little harm to important sensitive structures just millimeters or even close to the surface. Stereotactic radiosurgery is performed by a team of physicians consisting of neurosurgeons, radiation oncologists, medical physicists and technical medical personnel. Neuroimaging specialists join the team when needed.
Who can be treated?
In general, all acoustic tumors with an intracranial diameter up to an approximate size of 3 cm (1 1/4 ") meet the requirements for gamma knife radiosurgery. Large tumors are sometimes successfully treated with this technique, but the risk that these larger tumors, even before any treatment started, affect the circulation of cerebrospinal fluid (CSF) and cause hydrocephalus (excessive accumulation of CSF). In this case, a shunt may be required to divert CSF, and a large tumor that is treated with a gamma knife may sometimes lead to hydrocephalus, which was absent earlier. Surgical removal of a large tumor often, although not always, eliminates the need for this shunt.
Patients with large acoustic neuromas - especially elderly patients - may still prefer the combination of radiosurgery with a gamma knife and bypass surgery, a considerably less complicated procedure than microsurgical removal.
In fact, there are several reasons why radiosurgery with a gamma knife should not be considered first of all instead of microsurgery for the vast majority of patients with acoustic neuroma, including young patients. brazzers порно