8 years of hard work pay off | Chris O'Brien Lifehouse
 In Lifehouse News

Johnny Estuardo Morales began working at RPA in 2006 and joined the team here at Lifehouse upon opening in 2014. He is now a senior physicist and part of the team that looks after maintaining the stereotactic radiosurgery service in radiation oncology.

In short? He has the huge job of making sure the equipment we use in radiation oncology is in the best condition for us to deliver radiation as accurately and safely as possible.

On top of his full-time role at Lifehouse, Johnny has spent the last eight years working on his PhD in Medical Physics and Radiotherapy – and he has just completed it!

Entitled Advances in Very Small X-Ray Field Dosimetry for Circular Cones used in Stereotactic Radiosurgery, Johnny completed his thesis to have a direct impact on patient care.

In radiotherapy, linear accelerators (pictured below) are used to deliver a dose of radiation through X-ray fields aimed to kill the patient’s cancer cells. When a cancer spreads to the brain, the cancer lesions usually develop in very small volumes. Johnny’s research focused on the doses of radiation needed to treat these lesions and how that is implemented.

When a patient is receiving treatment for a tumour inside their head, the radiation has to pass through the skin. Unfortunately, this radiation can burn the skin, causing harsh side effects.

Because of this, radiation is delivered through small circular cones of X-ray fields – this minimises the effect felt by the patient. Johnny’s work was looking at these circular cones and the doses of radiation they are able to deliver to these small lesions in the brain.

This was not an easy feat however. Usually dosage of radiation is measured in field sizes of roughly three centimetres. This size already has a well-established process of measurement. However, the field sizes that Johnny was dealing with were as small as four millimetres.  When Johnny began his work, there was limited knowledge and no protocol in place for fields less than three centimetres.

“Because the volumes are very small, the radiation fields are very small as well. It’s very difficult to accurately measure the levels that are given to the patient,” Johnny says.

Johnny implemented a new methodology that involved extrapolating different field sizes down to the smallest size and obtaining the correct value for the dose delivered. He also tested a new type of detector called the OSLD, which basically reduced the size from five millimetres down to one millimetre.

The measurements in Johnny’s research allow doctors to calculate the correct value for the dose that the patient is receiving. With the use of computer calculations, Johnny was able to predict the dose and confirm that through measurement.

This involved mathematical calculations using super computers, with up to 600 computers used simultaneously to do some of the measurements. The Queensland University of Technology had a supercluster that was capable of producing that computing power.

Johnny says the completion of this research would not have been possible without the assistance of his supervisor from QUT, Dr Jamie Trapp, and co supervisor, Dr Scott Crowe. His colleagues here at Lifehouse, Dr Robin Hill and Dr Martin Butson, also provided a tremendous amount of support as they read and provided continued feedback throughout the process.

“Without those four people: James, Scott, Robin and Martin, this would not have been possible; simple.”

Johnny’s ultimate goal for his research is to improve the already highly advanced treatments and services provided to patients.

“We always need to improve techniques and outcomes for patients. We need to explore new frontiers and invent new things. We should never be complacent with what we have.”

“It’s an achievement for me, but also for Lifehouse,” he says.

Johnny plans to continue undertaking research projects like this in the future and to continue publishing papers. He is already in the process of working on two or three papers, some on mathematical models for the new linear accelerators.

“There’s always room for improvement,” he says. “That’s the good thing about doing a PhD, it pushes you to keep the momentum.”


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