[ RadSafe ] " Short life of an isotope "
edmond0033 at comcast.net
Sat Jul 4 09:43:25 CDT 2009
I have visited this business. They are very professional and handle the
radioactive material with care. What they do is very important, but the
'greens', etc don't care. They just have an agenda and regardless of the
cost and suffering others may have to endure they don't care. It's like
here in the USA, proposed the Cap and Theft (sorry Trade) Act will be a big
boomdoggle (money spent for little gain). They want us to replace all our
incandesent bulbs with new type that contains Hg (mercury). Disposal is a
problem and breakage is another one. The Government wants to shutdown the
coal plants that make ~50% of our power and Nuclear plants that supply ~ 25%
(I may be high on this one). Where are we supposed to get our electricity?
They could care less unless it's inconvient for 'them'. I'm getting tired
of the 'promises' that the government easily breaks. Health care will soon
be problem. Anyone over 60 should now make arrangmemts for their demise, as
the health care will be only for certain segments (who can't or won't pay)
of the population. The president promised 'change', well we will get it,
but not what was sold to the people.
edmond0033 at comcast.net
----- Original Message -----
From: "Jaro" <jaro-10kbq at sympatico.ca>
To: "multiple cdn" <cdn-nucl-l at mailman.mcmaster.ca>; "RADSAFE"
<radsafe at radlab.nl>
Sent: Saturday, July 04, 2009 10:16 AM
Subject: [ RadSafe ] " Short life of an isotope "
> Interesting reading....
> Short life of an isotope
> A "For Rent" sign stands in front of a nondescript building in Dorval's
> industrial park, giving no hint of the life-saving work going on inside.
> By Aaron Derfel, The Gazette, July 4, 2009
> The building's windows are tinted and the front door is locked. Yet behind
> the walls, Geiger counters are crackling as technicians prepare doses of
> radioactive medical isotopes to help doctors diagnose cancer and heart
> The radiopharmacy runs seven days a week, 24 hours a day, supplying most
> Montreal's hospitals, but its owners want to keep the location a secret.
> "We don't want any publicity," said Cyrille Villeneuve, vice-president
> (international) of Lantheus Medical Imaging. "You know, there are
> and we have radioactive materials." A single dose of medical isotopes is
> more radioactive than a chest X-ray. But the technicians at the Dorval
> radiopharmacy handle generators buzzing with isotopes that are hundreds of
> times more radioactive than what is in injected into a patient's arm.
> Still, "it's not something to be scared of - working with radiation," said
> Sacha Des Serres, a technician with a meticulous manner and an easy smile.
> "We're well protected," she added, showing off a dosemeter ring, which
> measures her potential radiation exposure. "We stand behind lead shields
> everybody works well together." Unlike the corner pharmacy, the Lantheus
> facility does not stock drugs with long-term expiry dates. Medical
> which course through the body as tracers to diagnose disease and to treat
> some forms of cancer, cannot be stockpiled. You can't see these isotopes
> with your own eyes, smell them or taste them because they're nothing more
> than a small collection of radioactive atoms.
> Their sole purpose is to emit gamma rays from internal organs for scanning
> by medical-imaging cameras.
> As if they weren't elusive enough, the most common isotope employed in
> nuclear medicine - technetium-99m - has a half-life of only six hours.
> Derived from the Greek word "technikos," meaning "artificial,"
> technetium-99m doesn't even exist in nature. It's forged partly in a
> reactor, and after six hours, half of a dose disappears, and after another
> six hours, half of what remains vanishes as well, and so on.
> Therefore, time is of the essence when dealing with medical isotopes, and
> that's why a radiopharmacy operates 24 hours a day. But since the end of
> May, when Ontario's aging Chalk River nuclear reactor shut down because of
> leak, isotopes have been in short supply across North America.
> Quebec hospitals have put off at least 12,000 diagnostic tests and have
> delayed the treatment of some patients with thyroid cancers. The Dorval
> radiopharmacy has resorted to ordering isotopes that are manufactured by
> nuclear reactors in Europe and South Africa.
> By plane and by truck, the isotopes arrive at the Dorval facility each day
> in boxes marked with the stark tri-blade radiation symbol. Inside those
> boxes sit 300-pound, lead-encased isotope generators, or cows, as the
> technicians prefer to call them. To the untrained eye, a generator could
> mistaken for a milk bucket.
> In the unseen core of each generator is a pencil-sized column of alumina
> powder. It's the alumina that absorbs the isotopes - in this case,
> molybdenum-99. Moly-99 is what is actually created in the nuclear reactor.
> It has a half-life of 66 hours, making the isotope ideal at this stage for
> transport in trans-Atlantic flights to radiopharmacies.
> As Moly-99 decays inside the generator, it gives birth to a daughter -
> daughter is the word nuclear physicists use - named technetium-99m, or
> Tc-99m for short. The generator is good for a week before it runs out of
> most of its isotopes.
> So what Des Serres and her colleagues do is "milk" the "moly cow" for
> technetium. Actually, the process is quite delicate: It involves infusing
> saline solution into the column in the generator and rinsing Tc-99m from
> alumina. The isotope, in a clear liquid, is milked out of the top of the
> generator into a vacuum-pressurized vial.
> Since Moly-99 is not soluble, it stays behind in the generator,
> decaying into technetium.
> Usually, a technetium generator is milked once or twice a day. But given
> that the Chalk River reactor is down and had met more than 30 per cent of
> the world's isotope needs, radiopharmacy technicians are now milking their
> moly cows up to four times daily. This poses a problem, because the
> technicians must also squeeze in the time to prepare doses in syringes.
> What's more, quality-control technicians have to double-check the
> for impurities right after it's milked from the moly cow as well as the
> doses before they are shipped to hospitals.
> "It's more trouble," said Richard Dubois, manager of the Dorval
> "We're doing the best we can but we're limited by the amount of raw
> we get. As a result, we have to work much harder just to produce the same
> number of doses."
> Standing behind a lead shield, Des Serres started to fill an isotope
> prescription for a patient who was only known to her as a bar code on a
> label. She peered through a thick lead glass window as she stuck the
> of a syringe into the top of a vial in a lead container, slowly drawing
> the technetium. The Geiger counters clicked in the background; if they
> suddenly screeched, that would have signaled a major radiation leak.
> Depending on the purpose of the dose - whether to study heart function or
> determine whether a cancer has spread to the bone - the technetium is
> "tagged" to a chemical compound. The syringes are then encapsulated in
> colour-coded lead tubes, and placed inside virtually indestructible lead
> suitcase. Drivers waiting outside transport the suitcases in unmarked vans
> to hospitals. To make sure the patient receives enough of a dose, Des
> will boost the amount of initial radiation in the syringe to take into
> account transport time and technetium's short half-life.
> "If we can free up the hospitals by making these doses, that's a good
> thing," she said.
> Ironically, the one hospital in Montreal that doesn't receive doses from a
> radiopharmacy is not suffering from a lack of isotopes. In fact, Jean
> Hospital is sending some of its excess isotopes to other local hospitals.
> Years ago, Jean Talon signed a contract with a U.S. supplier for weekly
> shipments of technetium generators. Each weekday at the community hospital
> in Villeray, a technician milks the generator and readies the doses.
> "Since we do everything at our hospital, there is no loss of isotopes,"
> explained André Arsenault, Jean Talon's chief of nuclear medicine. "When
> isotopes are prepared at a radiopharmacy at 5 a.m., by the time they
> at our hospital, half the doses are gone because of their short
> This is not to suggest that the isotope shortage could be resolved if
> hospital was furnished with its own generators. The crisis came about in
> first place because of Chalk River's breakdown, not because of any
> in the distribution network. And Jean Talon, unlike some of the big
> hospitals, doesn't have a huge volume of patients.
> But the pony-tailed Arsenault, who has a strong independent streak and
> to keep a close watch on things in his department, prefers to have a
> technetium generator on site.
> On a rainy June morning, Arsenault was reviewing the medical file of a
> patient, 73-year-old Aimé Brunelle, who was about to undergo an isotope
> diagnostic scan of his heart.
> Two days earlier, a gamma camera scanned Brunelle's heart while he was at
> rest. And now Brunelle had returned to undergo a second scan during a
> test. Since Brunelle weighs more than 350 pounds, Arsenault decided
> having him run on a treadmill.
> A nurse injected him instead with Persantin to boost his heart rate.
> Brunelle lay on a stretcher, and after only a couple of minutes, his
> breathing grew laboured.
> "How are you doing?" Arsenault asked.
> "I'm fine," Brunelle huffed. "Never been better."
> The nurse then injected him with Myoview, a cardiac imaging agent that is
> tagged with technetium. The agent zeroes in on the heart, with the
> tagging along for the ride.
> Once the technetium reaches the heart, it emits gamma rays. Unlike an
> which is beamed from a machine outside into the body, isotopes shoot rays
> from within organs like the heart.
> X-rays take detailed images of fractured bones. MRI and PET scans reveal
> tumours swelling inside organs. By comparison, medical isotopes are used
> analyze organ function and can even predict the onset of disease. And
> what makes them so indispensible to modern medicine.
> A half hour later, Brunelle lay on a bed as it slid under a huge,
> multi-million-dollar gamma camera. The machine took 20-second images of
> heart from different angles, a computer recreating a 3-D image of the
> Later that morning in his office, Arsenault called up the images of
> Brunelle's heart on his computer screen.
> "For a big man, he has a small heart," Arseneault said, studying the
> "before" and "after" pictures.
> He clicked on his mouse, calling up a 3-D computerized animation of
> Brunelle's heart beating. This time, the "before" and "after" images were
> much easier for the layman to understand, highlighting in orange and red
> heart pumping blood.
> "His heart's fine," Arsenault concluded. "There's not much difference
> between the two images."
> Brunelle, a jovial snow-removal operator with 50 years' experience, had
> already left the hospital. He would receive some good news later that
> day -
> thanks, in part, to a daughter named technetium-99m.
> - - -
>>From Reactor to Hospital
> Swords into ploughshares: some of the highly enriched uranium from
> decommissioned U.S. nuclear warheads is sent to Chalk River to make
> Chalk River's National Research Universal reactor was shut down for a
> three-month repair at the end of May, and is to be phased out by 2016. For
> the purposes of this graphic, Chalk River is used as an example.
> A uranium-aluminum alloy no bigger than a highlighter marker is fixed as a
> target in the nuclear reactor. It's bombarded with neutrons for five to
> seven days. Through fission, radioactive molybdenum-99 is created, along
> with other isotopes.
> The irradiated target is cooled for a half a day, and undergoes
> processing at Chalk River. In liquid form, it's transported in a shielded
> cask to a "hot cell" at the nearby MDS Nordion facility for final
> for up to 19 hours. Workers operating remote manipulators treat the target
> with chemicals to recover pure Moly-99.
> The Moly-99 is sent by plane to a plant in Billerica, close to Boston, to
> incorporated into lead-shielded isotope generators.
> The generators are shipped to radiopharmacies and some hospitals across
> Canada and the U.S. Technicians extract from the generators the daughter
> radioisotope of Moly-99, technetium-99m.
> Time is critical because of the short halflife of Moly-99: Less than 24
> hours elapse from the moment it's purified at MDS Nordium until a
> generator is made in Billerica.
> About 97 per cent of the highly enriched uranium that is used in making
> medical isotopes ends up as waste that must be stored. It has a half-life
> 700 million years.
> Sources: Reporter interviews, U.S. Nuclear Radiation and Studies Board,
> Lantheus Medical Imaging
> aderfel at thegazette.canwest.com
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