HMRI radiation oncology researchers are aiming to negate the need for CT scans when calculating prostate cancer treatment dosages

Radiation oncology researchers at Calvary Mater Newcastle are aiming to negate the need for CT scans when calculating prostate cancer treatment dosages.

Using magnetic resonance imaging (MRI) data only, ‘synthetic’ CT scans are now being generated in the Australian-first study led by Professor Peter Greer from the University of Newcastle and the Hunter Medical Research Institute’s Cancer Research Program.

It helps clinicians to refine the treatment protocol to accurately deliver a high dose of radiation to the prostate and as little as possible to surrounding tissues.

Patients traditionally undergo two scanning sessions, with MRI enabling visualisation of soft tissue in the prostate while the CT provides electron density information for dose calculations.

“This is a burden, both to patients as well as the health system, so we looked into addressing the issue by replacing the CT scan with an MRI-only workflow,” Professor Greer explains.

“As well as being cheaper and better for the patient it may also reduce systematic errors in treatment planning introduced by image registration uncertainties.

Professor Greer and his team have collated an ‘atlas’ of MRI and CT scans from 40 prostate cancer patients. New MRI scans are then rigorously matched with those in the library, allowing the corresponding CT scan to be ‘virtually’ assigned.

The first MRI-only prostate patient has just received their first radiation therapy treatment. The study will eventually involve 25 patients across sites at the Calvary Mater and Liverpool Hospital.

“In the future, we’re hoping to completely eliminate the need for CT scans for these patients,” Professor Greer said. “And with the increase of accuracy, we’re hoping to reduce the amount of normal tissues that we are treating, and so reduce the side effects, or possibly be able to give more of a dose to the tumour itself.”

The same method may eventually be used to create treatment plans for other cancers, particularly brain, head and neck, and pelvic and abdominal cancers.