Cobalt bomb
kills cancer cells
Radioactive cobalt emits gamma radiation,
which could eliminate cancer tumours in the brain.Bond villain Goldfinger threatens
to destroy the USA’s gold
reserves (to add value to his own
gold) by using a radioactive cobalt bomb.
In reality, doctors use cobalt radiation to
treat cancer by means of the gamma knife
method developed by Swedish doctor Lars
Leksell in 1968. Natural cobalt is a metalthat normally has 27 protons and 32
neutrons in its atomic nucleus. The
cobalt-60 isotope includes an extra
neutron, so it is unstable and decays into
nickel metal. When cobalt becomes nickel,
gamma radiation is emitted during the
conversion, and this can be used to kill
cancer cells by destroying their DNA.Cobalt turns into nickel
1 A gamma knife is equipped with 201 units of cobalt-60, an isotope of
cobalt metal. The isotope is unstable, and
so it decays into nickel-60 metal. In the
process, two gamma rays are emitted.Radiation hits tumour
2 Doctors MRI-scan the patient’s head to find the tumour. Subsequently, they
place the head in a frame, so the radiation
will influence only the tumour. The cobalt
is encapsulated in a shell that allows
radiation to escape only via narrow cracks.Radiation destroys DNA
3 Gamma radiation is ionising – meaning it includes sufficient
energy to steal electrons from
molecules. The radiation ionises cancer
cells’ DNA, so the cells cannot reproduce,
and the tumour dies.VILLAIN
In Goldfinger (^) ( (^1964) ),
the villain of the
same name collected gold.
He (^) wanted (^) to destroy the
USA's gold reserves (^) in
order to add markedly to
the (^) value of (^) his own (^) gold.
A gamma knife
aims cobalt
radiation at
cancer cells
in the brain.
Gamma ray
Gamma radiation
Cobalt Shield
Helmet radiationGamma
Destroyed DNA
60 Co
60 Ni
ASTIER-CHRU LILLE/SPL
ALL
AST
R (^) P
UICT
RE
LIB
RAR
Y/U
NIT
ED
RTA
IST
/RS
ITZ
AU
SCA
NP
IX
KEN
(^) IKE
DA
MA
DSE
N (^) &
(^) SH
UTT
ERS
TOC
K
30 | SCIENCE ILLUSTRATED