Evening star., 1951-12-24
Minute Picture Details
Possible With Tritium
Rodiooutogrophs Are Made
By Rodiution From the Object
By Thomas R. Henry

By Radiation From the Object
By Thomos R. Henry
Tritium, the rare form of hydrogen
which would be the material used in
any hydrogen bomb, is making pos
sible the most detailed photographs"
ever reported. .
It enables the taking Of pictures
which reveal details as minute as a
25.000th Of an inch in diameter Such
pictures-or radioautographs, as they
are called, since they result from radia-
ton coming from the object being pho
tographed itself rather than from any
reflected light-promise to prove Of
considerable value in medical diagnosis
by means Of radioactive materials as
well as in general biological studies.
Since the Inauguration of the hydro
gen bomb experimental program tri-
tium, perhaps the rarest of all mate
rials existing in nature. has been made
available by the Atomic Energy Com
mission in minute amounts at rela-
lively small cost.
Development Of the tritium photog.
raphy technique has just been re-
ported to the American Association for
the Advancement of Science here by
Drs. Patrick j. Fitzgerald, M. L. Edin-
OF, j. E. Knoll and E. B. Simmel Of
the Sloan-Kettering Institute and Me-
mortal Hospital, New York. The work
was supported in part by Atomic En-
ergy Commission grants
RadiateS Beta Particles.
Tritium is triple-weight hydrogen.
Each atom weighs three times as much
as an atom Of ordinary hydrogen, light
est, simplest and most abundant sub
stance in creation. It radiates beta
particles. or electrons, which produce
darkening on specially prepared pho
tographic plates now available It has
a half-life-the period during which
one-half Of any number of atoms pres
ent will have exploded-of about IL
years. This is the reason why there
is so little of it in nature. One-half
Of that present had disappeared II
hours after creation and the amount
has been growing less at the same
rate ever since.
Any radioactive substance will pro-
duce the same kind Of radioautographs
on the special plates Most Of them,
however, give much too diffuse a pic
ture for useful results.
In using radioactive materials as
tracers for diagnosis and for the study
OF physiological reactions it is neces-
sary to know precisely where they con-
centrate in the organism. This is
pretty well known for many of them,
but on gross scale.I 1t is known, for
example. that radioactive iodine or sub
stances containing it, will concentrate
in the thyroid, radioactive gallium in
the bones. etc.
More Data Necessary.
But much more detailed information
is necessary-even to the particular
part OF a particular cell which takes
up material. Some substances might
60 only to the nucleus, some only to
the cytoplasm surrounding the nucleus,
some only to the still mysterious smaller
bodies found in cells.
Such fine determinations have, for
the most part, been impossible to deter
mine. 1t was necessary to have some
radioactive substance which would pho
tograph an area, in which it happened
to have become concentrated, with
diameters Of not much more than one
mlcron. There are more than Is 900
microns in an inch. The peculiarities
OF tritium radiation are such, it was
reported. that precisely such photo
graphs can be taken. They then can
be magnified 500-fold or more for
study
All sorts of organic compounds can
be made containing tritium. Hydro
n hn -
carbohydrates which include all energy
producing foods. It forms part of prac-
tically every organic substance.
Progress in Labelling.
Some OF the major progress in physi-
ology in the past few years had been
made through the labelling of drugs.
medicines and the like with radioactive
carbon. This has been, at the best. a
difficult technique and in many cases
has proved impossible. Each success
In, this work has been announced az
a major step ahead
In great many cases, the experi-
menters report, it is much easier to
incorporate the exploding hydrogen in
organic molecules. It serves the same
purpose as the carbon in addition to the
far greater detail shown by its radio
autographs.
Use of the material with human be.
mgs. however, still may be some dis
tance ahead. It first will be necessary.
the experimenters report. to have con-
slderably more detailed information on
specific sites Of localization of various
materials. It also will be necessary to
determine the half life Of the explod-
ing hydrogen much more accurately.