Evening star. [volume] (Washington, D.C.) 1854-1972, 1940-10-22
Of Stars, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study
BIZ Thomas r. Henri.

Pioneer experiments with q new way
to destroy -bombardment with
slow neutrons which set of atomic
mines" inside them-have just been re-
ported to the National Academy of
Sciences here.
The tests described by Drs. Paul A.
zahl and Franklin S. Cooper of Me-
mortal Hospital, New York, and John r.
Dunning of Columbia University have
been confined to tumors in mice but
the results may open the way to radia-
ton treatment of cancers in parts OF
the body which cannot be reached from
the outside by any other means and
which are not favorable for surgery.
In the past there have been three
ways of cancer Observation-Disclosures,
radium and fast neutrons. They de-
stroyed cancer tissue when they hit it
also tissue surrounding it and any
through which they must pass in reach
ing it. This made it extremely difficult
to treat any internal cancer The effects
Of the bombardment itself on healthy
body cells might be even worse than
those of the cancer. At the best, it
was necessary to locate the neoplasm
precisely and aim at that single spot.
In the new treatment the whole animal
placed in an aluminium shell and sur
rounded with paraffin. is bombarded re-
CARELESS of the site Of the tumor The
process continues three or four hours at
time. When a properly balanced
procedure is used the subjects seem to
suffer no i'll effects
' First the neutrons, infinitesimally
minute projectiles of the subatomic
world, were produced by bombarding the
elements berylium with protons in the
Columbia University cyclotron. These
neutrons are shot out with tremendous
energies and at speeds approaching that
of light. They pass easily through living
tissue and cause all sorts OF recoil reac-
tons when they hit atoms of the body.
These are very destructive. Any animal
exposed very long to neutron lombard
ment of the whole body would be killed.
The new procedure is to pass them
through the paraffln shield before they
hit the mouse Parafin is not greatly
different from living tissue. The neutrons
are caught by the hydrogen atoms In
this paraffin and slowed to the point
Where they have almost no energy left.
They will still pass through tissue but
cause no damage. OF themselves they
are unable to injure cancer or any other
cells. So far as they themselves are
concerned one probably could stand for
many hours in stream of them without
ever knowing the difference.
But here the new alchemy deyeloped
within the past five years comes into
play-the transmutation of elements bv
neutron bombardment One of these
unchanged particles smashes into the
nucleus OF an atom and sets I'D an
explosion in which atomic fragments are
shot out and new kind of atom formed
This reaction differs for different ele-
ments. For some, fast neutrons are re-
| CURED but with others the best results
are obtained with neutrons moving with
scarcely any energy at all. The most
sensational case of this is uranium 235
which when hit with slow neutrons splits
in two with the release of the greatest
energy ever known to man.
Another case is that of boron. The boron
atom, hit by slow neutron, breaks down
into form Of the element lithium and
hellum with the release of approximately
100000 volts of energy This is ex-
tremely destructive, but only within a
few millionths of a centimeter OF the
atomic explosion
The new procedure is to plant boron
atoms by the millions in the cancer bv
means of injection. Only when the slow
neutrons passing through the paraffin hit
these are there any explosions and the
damage is confined to the immediate
neighborhood Hence only cancer cells
are destroyed. The results to date have
been excellent with mice in whose bodies
have been planted cancers which ordi-
narlly would cause death In a few weeks.
There remain great hurdles to be
overcome, the experimenters report.
First is that of getting the boron into
the cancer SO that it will diffuse through
the whole growth and remain there for
several hours. This can be done with
special type of boron salve when the
growth is near the outside of the body
but to get the element in high concentra-
ton into internal cancers is a far more
difficult problem
Second, the parafin slows down only
certain percentage of the neutrons.
The other pass through it and through
the body. If these can be kept at a low
ratio there are no bad effects. The
problem is to arrange the thickness of
the paraffin sheath and the time of
1rradiation so that the maximum dosage
OF slow neutrons is received without
enough of the fast ones to cause serious
damage. Lithium, it has been found,
undergoes much the same sort of ex-
plosions under slow neutron lombard
ment and some progress has been made
IN the use Of dyes to whose molecules
hthium atoms are attached and which
seem to show considerable affinity for
cancerous tissue.