Interlacing gives thin beams solid beam power
Since the 1990s, researchers have been trying to replace the solid beams used in conventional
radiation treatment with parallel arrays of very thin — 25 to 90 μm —
planar x-ray beams. High doses of microbeam radiation therapy control malignant
tumors in animals with little damage to surrounding tissue; unfortunately, few facilities
are equipped with the synchrotrons that can generate thin beams at adequate intensity.
As published in PNAS on June 20, researchers
at Brookhaven National Laboratory in Upton, N.Y., at Stony Brook University in
New York, at the Istituto Neurologico Mediterraneo in Pozzilli, Italy, and at Georgetown
University in Washington have reported that they may be able to create the same
effect with significantly thicker microbeams by interlacing beams within the target.
Because the technology used to form thicker microbeams is more widely available,
treatments that employ them may be possible in hospitals of the future.
Initially, scientists exposed healthy
rats to high doses of radiation using microbeams up to 0.68 mm thick to demonstrate
that a thickness within the capability of specialized x-ray tubes has little effect
on healthy tissues.
In further studies, they found that
they could interlace two sets of parallel arrays of thick microbeams at 90°
so that the beams of one array would fill the spaces of the opposite array and produce
the equivalent of a solid beam in the target only.
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