UWA Medical Physics Blog

Science journalists explore medical physics

In September 2013 we welcomed Eugene Tan and Jefferson Allan, year 10 and 11 students from Shenton College, who visited the School of Physics for a week of work experience. Taking on the role of science journalists, Eugene and Jefferson interviewed staff and students in the School’s outreach program and medical physics research. Enjoy their article.

work experience students

Science journalists: Eugene and Jefferson

 

Physics has played a major role in the invention of many key medical technologies, such as X-rays, ultrasound, MRI and PET scanners, and radioactive tagging. Medicine would undoubtedly not be at its current level of sophistication without the work of physicists. Recent discoveries seem set to continue the trend, with advances in the field of nanotechnology and biomagnetics offering new pathways into medical physics and biophysics. In particular, nanotechnology and biomagnetics are beginning to offer the possibility of new techniques for diagnosing illnesses and administering drugs.

The Biomagnetics Group, led by Prof. Tim St Pierre, including Dr Stephan Karl has successfully created a method for separating malarial cells using magnetic fields. A piece of apparatus for explaining the physical principles involved was designed by the group and used by Asst/Prof. Anita Adhitya for the purpose of medical physics demonstrations. The apparatus now spends most of its time in the pool of demonstrations in the School of Physics, where it is used in the outreach program. As Anita says, “I’m excited that we can create these demonstrations because it gives everyone insight into what goes on behind the scenes. We can’t practically take 100 people into the lab, but we can show them a demonstration which really makes what we do seem more tangible.” This forms part of an effort by Anita to raise awareness about medical physics as a field of study and as a career opportunity for physics graduates.

Senior Teaching Technician Joe Coletti, who is actively involved in the School of Physics outreach programs, explained that, “In this demonstration white polystyrene balls represent healthy cells, and red ones represent malarial cells. The latter have small magnets inside them. By dropping the balls through a tube with a large magnet on the outside, the ‘healthy cells’ pass straight through, while ‘malarial cells’ became stuck to the walls of the tube.”

This demonstration closely matches the process developed for separating malarial cells. The concept is fairly simple – when the malaria parasite digests red blood cells, it produces crystals of iron within the cells as a waste product. These crystals are paramagnetic, which distinguishes them from healthy red blood cells, which are non-magnetic. Paramagnetic materials only exhibit magnetic properties in the presence of an external magnetic field.

Under the influence of a strong magnet, the blood sample is passed through a filter consisting of thousands of tiny steel spheres. Both the malarial cells and the steel particles are paramagnetic and, when under the influence of the external magnetic field, attract each other. The healthy cells are not affected and simply pass through. When the full sample has been filtered, it is removed from the magnetic field. The malarial cells lose their magnetism and are no longer attracted to the steel particles. They can then simply be washed out.

A syringe-shaped filter was developed to aid in the execution of this process. The syringe has a compartment for the blood to be tested, and a small cylinder of paramagnetic material through which the blood exits. There is also a permanent magnet that houses the syringes during filtration. The technology for this testing is not new, but as Stephan says, the significance of the research is in producing an efficient and affordable system to utilize these ideas.

This method of detection opens the possibility for more affordable diagnosis of asymptomatic carriers of malaria. The current lack of diagnostic equipment for third world countries (approximately 80% of the world’s population), in addition to the frequency of malarial infections in these areas, means this technology could be transformative. Magnetic filtration can give the third world access to malaria diagnoses for as little as 35 cents.

Diagnostics is not the only medical area that benefits from the research into nanotechnology and magnetism. Another team of UWA researchers including honours student Naviin Hardy, supervised by Dr Swaminathan Iyer (BioNano group) and Prof. Livia Hool (Cardiovascular Electrophysiology Laboratory), along with the assistance of Dr Helena Viola and Biomagnetics group members Research Asst/Prof. Robert Woodward and Research Assoc/Prof. Michael House, is exploring and testing the effectiveness of using nano-sized particles as a means for transporting and administering drugs to patients. This is being studied in particular in relation to ischemic reperfusion injuries, a kind of damage to the heart that is caused by the sudden return of blood supply following heart attack.

During cardiac arrest, the heart experiences a lack of oxygen. The use of surgical stents to reopen the chambers of the heart has the unfortunate side effect of a sudden rush of oxygenated blood to the tissue. This exposes the heart to the danger of damage from free radicals, which are charged particles that are found naturally within the body but also cause damage to cells. Oxygen, despite being essential to animal life, is a free radical and causes oxidative stress, which is a kind of cellular damage. This leaves the organ in a worse condition than before the attack despite the treatment. Administering certain drugs, namely antioxidants and a kind of reparative protein, may limit this damage.

The main concept of the research is the use of nano-sized polymers to act as a container for these drugs. This acts as a means of transporting the drug to a particular area, allowing it to be targeted at certain parts of the body. This may allow for the drugs to be administered at lower doses, have fewer side effects, and work faster. Magnetism may play an important role in this research. The researchers may one day embed magnetic nanoparticles within the polymer case to allow them to be monitored with the use of MRI (magnetic resonance imaging). They are also trialing the use of a fluorescent die as a similar means of tracking the particles.

Currently, this process is being tested in guinea pig hearts. While it is still in its early stages, the team hopes that this technique could lead to a more efficient way to treat not only ischemic reperfusion injuries, but also a variety of other ailments.

Medical physics will continue to be important to the lives of people and their everyday health. However, there is a shortage of researchers in the field of medical physics. Fostered by the outreach program, medical physics research at UWA has the promise to deliver many innovations in years to come.

– Eugene Tan & Jefferson Allan, Year 10 and 11 students, Shenton College

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