• New study by researchers in regional NSW, China and Jordan aims to refine and improve X-ray computed tomography (CT) to improve patient diagnosis and treatment
• Research to benefit many branches of modern medicine – radiotherapy, nuclear medicine and dentistry – as well as improve the engineering and manufacture of medical technology
• The research is at the centre of people’s health because modern medicine relies heavily on medical imaging, such as X-ray CT, for patient diagnosis and treatment

Senior Lecturer in medical physics in the Charles Sturt School of Dentistry and Health Sciences in Wagga Wagga Dr Xiaoming Zheng leads the complex research by team members based in regional NSW, China and Jordan.

“We believe our work is a significant step forward in science, engineering and medicine,” Dr Zheng said.

 “It is a significant discovery that will have immediate consequences in quantitative CT diagnosis, dose delivery in radiotherapy, quantitative nuclear medicine, and implant treatment planning in dentistry.

 “There is no doubt that our work has opened a new way of thinking for further applications in medical CT as well general X-ray imaging to benefit many branches of modern medicine, as well as improve medical equipment manufacture and engineering.”

 The research by Dr Zheng and his team, ‘Body size and tube voltage dependent corrections for Hounsfield Unit in medical X-ray computed tomography: theory and experiments’, was published in Springer Nature’s ‘Scientific Reports’ on Thursday 24 September.

“The main discoveries of this paper are the role of Rayleigh scattering in medical CT imaging and the scheme established for correcting CT number variations of patient sizes and tissue locations,” Dr Zheng said.

Their related research, ‘Rayleigh scattering in medical X-ray computed tomography’, is the focus of an intended Australian Research Council (ARC) funding application.

These studies are part of current research efforts make clinical X-ray CT a quantitative modality as it is critical for quantitative patient diagnosis, dose delivery in radiotherapy, radionuclide distributions in nuclear medicine, and volumes and surfaces determinations in dental surgery.

Dr Zheng emphasised the complexity of the research and its every-day applications in modern medicine.

“People’s health is dependent on a good medical system, and medicine relies heavily on medical imaging, such as X-ray CT, for patient diagnosis and treatment,” he said.

“Accurate CT numbers are critical for both patients’ quantitative diagnosis and dose delivery in radiotherapy treatment.

“As medicine is moving towards personalised medicine and precision medicine, quantitative CT imaging is a prerequisite for both.

“The established body size and tissue location dependent correction scheme can be immediately applied to radiotherapy, nuclear medicine and dentistry to improve diagnostic accuracies and better clinical outcomes,” he said.

As an example, Dr Zheng explained that radiotherapy relies on CT numbers to calculate radiation doses to be delivered to patients. CT numbers vary for the same type of tissue if patient size changes. In clinics, CT number to dose conversion is calibrated by using a specific body size. There are errors when this conversion is applied to other body sizes because CT numbers are body size dependent.

“Our correction scheme is precisely designed to correct for such body size effect on CT numbers,” he said. 

“As a further example of how our findings can be applied, the scientific community is currently struggling to understand why children receive more radiation doses than adults under the same CT imaging conditions.

“Our work provides an answer; that Rayleigh scattering reduces the doses to adults or large patients in CT imaging.

“This further supports the need for reducing radiation doses to children by selecting optimal scan parameters in clinical practice, given children are more sensitive to radiation and life-long effects,” he said.

Dr Zheng and his team gratefully acknowledge an Open Access Publishing grant from the Charles Sturt Research Office.

Read the full research paper on the Nature Research website.