Blog dedicated primarily to randomly selected news items; comments reflecting personal perceptions

Wednesday, December 21, 2016

Nuclear Medicine Testing

"We are saying that unless there is a very high level of brainstorming between the federal government, the provinces and the profession to tackle these issues, the risk is that Canadians will not get access to important tests for the diagnosis and treatment of their diseases."
Dr. Norman Laurin, past-president, Canadian Association of Nuclear Medicine

"For patients, it means hospitals have to make decisions in terms of which tests they can afford to provide to patients."
"The tests that they can afford are not necessarily the best tests."
Dr. Jean-Luc Urbain, former president, Canadian Association of Nuclear Medicine
Photograph of the NRU reactor building
Out of time: the NRU reactor at Chalk River
"A pioneer in nuclear medicine, NRU continues to make an important contribution to the world’s medical isotopes used in both the diagnosis and treatment of life-threatening diseases. Isotopes from NRU benefit thousands of people each day, millions of people internationally each year – an amazing contribution to world health."
"One of the NRU reactor's most important contributions to health is without a doubt the cobalt-60 it produces. Cobalt-60 accounts for 10 million cancer therapy treatments each year and was originally produced in the NRX reactor through which Canada launched the modern field of nuclear medicine. The first cancer treatments using cobalt-60 were delivered at hospitals in Ontario and Saskatchewan in 1951. Today, cobalt-60 from NRU treats cancer patients in countries around the world."
"Canada has made impressive contributions to world health care, and Canadian scientists continue to research nuclear medicine techniques and explore the vastly refined techniques of medical science."
Canadian Nuclear Laboratories website

"A report from the US National Academies of Sciences, Engineering and Medicine (NAS) warns that the US could be facing severe shortages of the vital medical isotope technetium-99m once the ageing NRU nuclear reactor in Chalk River, Canada, stops producing molybdenum-99 next month. Technetium-99m, which is derived from the molybdenum-99 isotope, is widely used for medical imaging."
"Released this week, the report was commissioned by the US Congress and warns that there is a greater than 50% chance that severe shortages of molybdenum-99 and technetium-99m will occur in the US after the NRU stops production in October. Both isotopes have very short half-lives and cannot be stockpiled. While global supplies of molybdenum-99 are produced at six other reactors worldwide, most of these facilities are also very old and some are prone to unscheduled shutdowns."
CTV National News: Isotope reactor to shut down

Canada has, until recently, been the world's foremost supplier of medical isotopes. The National Research Universal reactor at Chalk River (NRU) was built in 1957. As the sole source of molybdenum-99 in North America, the suspension of production at the NRU will strike the entire continent hard. Medical isotopes will have to be brought in from abroad, from other aging reactors elsewhere in the world. In view of the fact that medical isotopes are of vital importance in the diagnosis of dire medical conditions, both Canada and the U.S. are developing more modern, accelerator-based facilities for production, but they will not be in production mode until 2018.

Hospitals are being left in a vacuum of critically short supply of a vital diagnostic tool whose constituents have a short lifespan and cannot be stockpiled. Nuclear medicine doctors have become alarmed at the sky-high cost of medical isotopes which, they warn, may impact on patient access to the sophisticated medical tests for cancer, heart disease and other illnesses that plague humankind. The soaring cost of some nuclear medicine has increased up to one thousand percent, partially resulting from the shutdown of isotope production at the NRU reactor.

According to Dr. Norman Laurin, this rapidly rising price is "significant enough that hospital budgets will either have to be revised or they will have to decrease procedures". The problem here is obvious enough; hospital budgets in Canada are already tight, with finite financial resources available to dedicate additional costs to manage these massive rising prices in the compounds used for diagnostic medical scans. A greater use of CT scans for diagnostic tests may result, producing less accurate measurements which can also expose patients to 25 to 50 percent more radiation.

The current president of the Canadian Association of Nuclear Medicine, Dr. Andrew Ross, warns that the situation will inevitably result in longer waiting lists for tests when the results they produce are required in much shorter time-spans for medical specialists to be able to respond in a timely manner to their patients' medical needs to ensure that their life-threatening disease does not progress beyond the capacity of medical science to deal with.

Medical isotopes are radioactive substances which in small amounts are used in the diagnosis of health conditions impacting the heart, the circulatory system and visceral body organs. The present situation surprises no one in the medical community, since experts had long warned of the inevitability of shortages and allied price hikes back in 2008 at a time that outages at the aging NRU reactor occurred and it was recognized that the reactor had an increasingly limited lifespan. A critical short-term upgrade was conducted and the reactor put back to work producing isotopes.

AECL plant in Chalk River
A warning sign is posted at the AECL plant in Chalk River, Ont. on Dec. 19 2007. (Fred Chartrand / THE CANADIAN PRESS)

But the NRU reactor situation clearly "highlighted [the] fragility of the supply chain that delivers medical isotopes . . . to patients in Canada and globally", stated Natural Resources Canada. At that time the government then in power announced that isotope production at NRU would be brought to a halt in 2016 and the reactor de-commissioned. That time has come for the world's oldest experimental reactor responsible for up to half of the world's medical isotope production, accounting for 80 percent of nuclear diagnostic procedures.

Plans are for the nuclear reactor to be placed on 'hot standby' for one and a half years so that it could in theory be restarted in short order, after which it will be shuttered permanently. It is not only the loss of one of the major producers of these critical diagnostic tools, but that the price of pharmaceutical agents that work in combination with the isotopes have risen sharply in price, as well. Suppliers in South Africa, Australia and elsewhere remain in production, but demand and scarcity add up to increased costs and decreasing availability.

What are medical isotopes and how are they used?

A medical isotope is an unstable (i.e. radioactive) atom derived from a stable one.
Molecular imaging – the imaging of molecules, biochemical processes, and physiological activity within the human body – is rapidly becoming one of the most powerful tools for the diagnosis and staging of disease. The main tools for molecular imaging are single-photon emission computed tomography (SPECT) and positron emission tomography (PET) scans that tag specific biomolecules (biologically active molecules) with medical isotopes. When medical isotopes decay, they emit particles that can be detected and used to pinpoint their location. By chemically connecting a medical isotope to a biomolecule and injecting that compound into a human body, clinicians can “see” where the body is using the biomolecule.
For example, if an incoming patient is thought to have had a heart attack, a doctor might inject a patient with Tc-99m attached to a biomolecule called teboroxime (this combination is called a “radiotracer”). The patient might then perform a rest-and-stress treadmill test. The Tc-99m will go to the heart because the teboroxime molecule is designed to accumulate there. When the heart is imaged with a SPECT camera, the picture will tell the doctor if the heart muscle has been damaged.
PET and SPECT scans differ by the type of decay of the isotope and therefore use different “cameras” to image or “scan” the patient. SPECT is better established, is prevalent in every hospital, and is presently cheaper than PET. PET is an emerging technology that offers higher resolution scans and access to more sophisticated biological information.

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