| Medulloblastoma
is the most common malignant pediatric brain tumor. It develops
in the part of the brain that controls balance and coordination.
It is also a fast-growing cancer that often spreads to the central
nervous system. By using Proton Beam radiation in these cases
allows the special radiation to be targeted to the tumor while
minimizes radiation to healthy tissue and other critical structures
in the brain and spine. As with all other proton therapy treatments
the goal is to minimize the dose to adjacent normal structures
minimizing treatment related complications. Pediatric patients
may benefit the most from such treatments because of the potential
harm to growing organs and bones from receiving conventional
radiation therapy alone.
See Enlarged
Image
Proton radiation ensures that no dose reaches the anterior
pelvic and thoracic structures when treating the entire spinal
column. The dose to the whole brain and spinal column is very
uniform preventing regions of unwanted high doses. The base
of skull is irradiated to a higher dose while avoiding the
cochlea (blue outline) as much as possible.
Radiation Therapy with Standard X-Rays and Protons
for Medulloblastoma
For certain tumors of the brain, radiation is given
to the back of the brain (posterior fossa). With standard
radiation there is incidental dose given to healthy brain
tissue surrounding the tumor. An example of this is the cochlea,
the organ in the middle ear that is responsible for bringing
sound into the ear through the nerves. Injury to the cochlea
can have the potential long-term effect of hearing loss. One
benefit of proton therapy is the ability to shape the radiation
so that less dose is delivered to the cochlea. Clinical studies
are under way to determine the long term affects in children.
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