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Performing brain surgery without a scalpel - Hyunsoo Joshua No

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    Every year, tens of thousands of people
    world-wide have brain surgery
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    without a single incision:
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    there’s no scalpel, no operating table,
    and the patient loses no blood.
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    Instead, this procedure takes place in a
    shielded room
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    with a large machine that emits invisible
    beams of light
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    at a precise target inside the brain.
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    This treatment is called stereotactic
    radiosurgery,
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    and those light beams are
    beams of radiation:
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    their task is to destroy tumors by
    gradually scrubbing away malignant cells.
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    For patients, the process begins with
    a CT-scan,
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    a series of x-rays that produce a
    three-dimensional map of the head.
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    This reveals the precise location, size,
    and shape of the tumor within.
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    The CT-scans also help to calculate
    something called ‘Hounsfield Units’,
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    which show the densities
    of different tissues.
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    This offers information about how
    radiation
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    will propagate through the brain,
    to better optimize its effects.
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    Doctors might also use magnetic resonance
    imaging, or “MRI’s,”
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    that produce finer images of soft tissue,
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    to assist in better outlining a
    tumor’s shape and location.
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    Mapping its precise position and size is
    crucial
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    because of the high doses of radiation
    needed to treat tumors.
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    Radiosurgery depends on the use
    of multiple beams.
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    Individually, each delivers a low dose
    of radiation.
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    But, like several stage lights converging
    on the same point
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    to create a bright and inescapable
    spotlight, when combined,
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    the rays of radiation collectively
    produce enough power to destroy tumors.
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    In addition to enabling doctors to target
    tumors in the brain
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    while leaving the surrounding healthy
    tissue relatively unharmed,
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    the use of multiple beams also
    gives doctors flexibility.
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    They can optimize the best angles and
    routes through brain tissue
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    to reach the target and adjust the
    intensity within each beam as necessary.
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    This helps spare critical structures
    within the brain.
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    But what exactly does this ingenious
    approach do to the tumors in question?
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    When several beams of radiation intersect
    to strike a mass of cancerous cells,
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    their combined force essentially
    shears the cells’ DNA,
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    causing a breakdown
    in the cells’ structure.
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    Over time, this process cascades into
    destroying the whole tumor.
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    Indirectly, the rays also damage the area
    immediately surrounding the DNA,
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    creating unstable particles
    called free radicals.
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    This generates a hazardous
    microenvironment
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    that’s inhospitable to the tumor,
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    as well as some healthy cells
    in the immediate vicinity.
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    The risk of harming non-cancerous tissue
    is reduced
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    by keeping the radiation beam coverage
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    as close to the exact shape
    of the tumor as possible.
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    Once radiosurgery treatment has destroyed
    the tumor’s cells,
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    the body’s natural cleaning
    mechanism kicks in.
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    The immune system rapidly sweeps
    up the husks of dead cells
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    to flush them out of the body, while
    other cells transform into scar tissue.
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    Despite its innovations, radiosurgery
    isn’t always the primary choice
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    for all brain cancer treatments.
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    For starters, it’s typically reserved for
    smaller tumors.
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    Radiation also has a cumulative effect,
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    meaning that earlier doses can overlap
    with those delivered later on.
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    So patients with recurrent tumors
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    may have limitations with future
    radiosurgery treatments.
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    But these disadvantages weigh up
    against some much larger benefits.
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    For several types of brain tumors,
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    radiosurgery can be as successful as
    traditional brain surgery
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    at destroying cancerous cells.
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    In tumors called meningiomas,
    recurrence is found to be equal, or lower,
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    when the patient undergoes radiosurgery.
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    And compared to traditional surgery––
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    often a painful experience with
    a long recovery period––
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    radiosurgery is generally pain-free,
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    and often requires little
    to no recovery time.
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    Brain tumors aren’t the only target for
    this type of treatment:
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    its concepts have been put to use on
    tumors of the lungs, liver, and pancreas.
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    Meanwhile, doctors are experimenting
    with using it to treat conditions
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    such as Parkinson’s disease, epilepsy,
    and obsessive compulsive disorder.
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    The pain of a cancer diagnosis can be
    devastating,
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    but advancements in these non-invasive
    procedures
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    are paving a pathway
    for a more gentle cure.
Title:
Performing brain surgery without a scalpel - Hyunsoo Joshua No
Speaker:
Hyunsoo Joshua No
Description:

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Video Language:
English
Team:
closed TED
Project:
TED-Ed
Duration:
04:57

English subtitles

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