Highlights from the 2012 AAAS Annual Meeting
March 05, 2012— Ottawa, Ontario
From February 16-20, the American Association for the Advancement of Science (AAAS) held its 2012 annual meeting in Vancouver, attracting more than 7,000 scientists from around the world. The meeting featured close to 170 symposia, and included a strong Canadian presence from government, industry and academic labs. Researchers from the National Research Council and partners were out in force. Here are some highlights from symposia they participated in.
Medical isotope breakthrough
Researchers from the Vancouver-based TRIUMF facility announced they’ve found a way to produce an isotope that is badly needed for medical diagnostics, and help solve a global shortage. The radioactive isotope technetium-99m (Tc-99m) is used in medicine as a tracer that can help doctors see what’s happening inside a patient’s body using imaging devices that detect it.
Dr. Carl Ross of NRC demonstrates how a linear accelerator can be used to produce molybdenum-99 — the “parent isotope” of technetium-99m.
Until now, Tc-99m production depended on nuclear reactors, and only a handful in the world (including the Chalk River reactor in Ontario) could produce it. A severe worldwide shortage occurred when two aging reactors were closed down, leading to serious delays in diagnostic tests.
With help from NRC, TRIUMF physicists have developed a method whereby Tc-99m could be produced in a cyclotron instead of a nuclear reactor, according to Dr. Tim Meyer of TRIUMF. TRIUMF has the world’s largest cyclotron and is a type of particle accelerator.
A total of 30,000 diagnostic tests per week are performed in Canada using radioactive tracers, and from 30,000–40,000 are done per day in the U.S. Close to 90 percent of these tests use Tc-99m. The isotope is used for bone scans, identifying certain types of cancer, looking at heart function and blood flow, diagnosing certain types of dementia and more.
TRIUMF is Canada’s national laboratory for nuclear and particle physics research and related sciences. One of the world’s leading subatomic physics laboratories, TRIUMF is owned and operated as a joint venture by a consortium of universities, with support from the Government of Canada via a contribution through the National Research Council. The Government of British Columbia provides additional support for building infrastructure.
Many major hospitals already have small, bathroom-sized cyclotrons on site that produce other types of medical isotopes and can be adapted to make Tc-99m. Canada has 18 cyclotrons and seven more are being planned. This breakthrough is clearly a win-win, not just for Canada, but globally.
Measuring is a fundamental activity in science. Understanding mass, time, energy and other quantities depends on the use of specific units, and scientists trust that data gathered around the world are all based on the same primary standards.
“The International System of Units (SI), also known as the metric system, is the common basis for consistent measurement for all of science and technology,” says Dr. Alan Steele, Director of Metrology at NRC. The SI is the world's most widely used system of measurement, both for everyday commerce and for science. A better system is now possible, and NRC researchers are contributing to an international effort to use fundamental constants to update some of the base definitions.
“The driver for this initiative is that we are almost able to consolidate some stunning improvements in precision electrical measurement into the SI without ‘breaking’ the system and causing problems for mass measurement,” adds Dr. Steele.
At NRC, researchers are using a watt balance to measure Planck’s constant (which describes the relationship between the energy and the frequency of a photon) and redefine the kilogram. This initiative involves measuring a 500 g mass in terms of electromagnetic quantities such as voltage and resistance.
Another NRC team is helping measure Avogadro’s constant (defined as the number of elementary particles in a mole) by measuring the mass of a single atom of silicon. The NRC contribution capitalizes on its expertise in precise quantification of the isotopic composition of the sample material. Once there is agreement that the SI values of these fundamental constants of nature are known with sufficient rigour, it will be possible to “turn the SI inside out” and redefine the base units — particularly the kilogram and the Ampere — using that knowledge, says Dr. Steele.
Dr. Dave Inglis, also of NRC, believes it is possible to achieve these important goals by 2015, "marking the end of the era where human-made objects such as the platinum-iridium reference kilogram artefact, rather than nature itself, set the reference for our system of units," he says.
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