Heartbeat July 2020

The Krypton Factor – a 40 year
success story
IMAGING
Nuclear medicine, otherwise known
by the friendlier moniker 'medical
physics' at our Trust has recently
celebrated its 40 year anniversary
leading the National Krypton
Generator Service.
What was once a local research project
by Dr K Chackett at our Trust back in the
late 1970s led to a collaboration project
with Birmingham University supplying
the country krypton gas generators,
generators for lung ventilation imaging;
a vital part of the V/Q study for
pulmonary embolus (PE) diagnosis.
Sharing his thoughts Head of Nuclear
Medicine Dr Bill Thomson, said: “My
predecessor, Dr K Chackett, founded
the service and with his knowledge of
the Cyclotron Unit in the Department
of Physics at Birmingham University this
quickly led to a collaboration to produce
the radioactive Rubidium81, which could
be sent to hospitals in the area to be
used in their studies. The Rubidium is
trapped in a small column within a lead
shield and sent to hospitals to be used
the same day.
“The radioactive decay of the
Rubidiumb81 produces a constant
supply of Krypton gas which only has
a 13 second half-life. An airflow pump
sweeps the gas out when needed, is
breathed in by the patient and a gamma
camera gives an immediate picture of
the lungs gas flow. Along with that, a
standard Tc99m radiopharmaceutical
is injected and can image the lung
blood flow. Any lung segments without
perfusion (on the Tc99m images) but
which do have ventilation (on the
Krypton image) can indicate PE.
“At first, our service operated three days
a week, but it soon rapidly expanded as
the demand for imaging for PE grew.
Using our generators, about 15- 20
patients could be scheduled for imaging
in a day, not feasible with the other
agents.
“There were some very nervous times
though. By the late 1990s we were
managing to supply as far as Exeter and
Liverpool, the only other supplier in the
UK was the MRC research cyclotron at
the Hammersmith Hospital, supplying
generators mainly to the London area.”
The generators once faced a potentially
devastating blow that was luckily
From left – Matt Elms, Bill Thomson, Jilly Croasdale, Emma Harrop, Alanah Hefferman (Mark Tudor is
absent, shielding).
avoided. Bill explained: “In 2000, the
university announced they were closing down
their cyclotron. Devastating news! I had to
develop a business plan for a laboratory to be
fitted out on our City site, and arrange for the
Rubidium81 solution to be supplied from the
MRC cyclotron unit in Hammersmith. This was
a complete change in operation, and we had
to rely on our transport service to pick up two
daily batches of radioactive Rubidium81 from
Hammersmith for us to continue operating.
“A further blow came in 2004 when suddenly
Hammersmith Hospital shut down their
service and we quickly had to come up with a
new plan. Luckily, the physics department at
the university had just acquired a second-hand
cyclotron for research work. This cyclotron
was the same model as the MRC system, but
much newer! Serendipity again played a huge
part in keeping the service alive.
“It was also clear that with the expansion
in production we now needed to have the
krypton laboratory beside the cyclotron unit
to cut out the road transfer of very ‘hot’
Rubidiumb81 stock solution. Taking on all
of the Hammersmith production doubled
our production overnight! We also had to
establish new transport routes for the delivery
Official opening of the krypton lab on City site
by Dr Chackett (8th from Left) in 2001 (and Bill
Thomson second left)
of the generators to the whole London area
as well as our local hospitals.
“Finally in 2005, we moved production
back to the university, we finished
production at the City site lab on Friday
morning, while the MRC did their last
production run at the Hammersmith
Hospital. We had to leave time for our
rig activity to decay, so on Saturday and
Sunday, we dismantled and rebuilt the rig at
the university lab (there were LOTS of heavy
lead ‘bricks’ involved! Think LEGO, but with
10kg bricks, all to fit back together in their
place). After testing the rig on Sunday, the
university produced their first run for real,
and we started sending out generators
with no interruption in supply to ours or
the London customers! I still find that
remarkable, and a testimony to the staff
who made the whole new service work
seamlessly.
“In recent years, Computerised Tomography
(CT) scanners have been developed to
provide a diagnosis for pulmonary embolus.
With this ability to run 24/7, this seemed
like the latest death knell for our service.
However, it soon became clear that certain
patients could not have these scans, and
also our lung study gave much lower breast
dose – important in young women, and PE
has a higher incidence during pregnancy.
“I’m sure there will likely be other hurdles
in future. But for now, we are still operating
the only national Krypton81m generator
facility in the UK, providing generators
five days a week to nuclear medicine
departments across England and Wales.
With about 95,000 generators supplied in
the 40 years, and probably more than half a
million patients having their V/Q scan using
our Kr81m, it’s been quite a success from
our simple beginnings 40 years ago.”
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