A game changer for global healthcare with potential to reduce radiation from x-rays
An international study led by a Monash physicist could pave the way for radically reducing medical radiation dose from x-rays and CT scans.
Senior Research Fellow Dr Marcus Kitchen from the Monash School of Physics and Astronomy is investigating novel phase contrast x-ray imaging techniques for studying the physiology of organs in various developmental and disease states.
He was the lead author in a study published recently in Scientific Reports, which uses phase contrast X-ray imaging to significantly reduce radiation dose for medical imaging.
“X-ray radiography and computed tomography (CT) are two of the most common imaging modalities in diagnostic medicine,” said Dr Kitchen.
“Soft tissues have similar X-ray absorption properties resulting in poor contrast obscured by noise, Dr Kitchen explains.
Photon (Poisson) noise can be reduced by increasing radiation dose, but dose must be minimised for patient safety and for high throughput applications.
New techniques have been developed to enhance image contrast by an order of magnitude or more using phase shifts (i.e. refraction) of X-rays.
“Our study demonstrated that dose reduction lowers the requirements for brightness of micro-focus X-ray sources that can be used for medical phase-contrast X-ray imaging, thus potentially opening the way for the introduction of this method into routine clinical practice,” said Dr Kitchen.
“These findings will hopefully have a large impact on the future of X-ray imaging with major benefits expected for global healthcare.”
The research team imaged the thorax of a newborn rabbit to show the impact of phase retrieval on improving the image SNR (signal-to-noise ratio) while maintaining sufficiently high spatial resolution to resolve individual alveoli (the smallest lung airspaces).
They then looked at the gain in SNR to determine how far the exposure time, hence radiation dose, could be reduced using phase retrieval.
“The ability to improve CT image quality, or to reduce radiation exposure by factors in the hundreds to thousands, would have a dramatic impact on clinical diagnostics,” said Dr Kitchen.
“Using less radiation will enable higher throughput imaging with fewer motion artefacts and be safer for human imaging or for longitudinal preclinical studies,” he said.
Kitchen, M. J., et al. (2017). “CT dose reduction factors in the thousands using X-ray phase contrast.” Scientific Reports 7(1): 15953.