• Radiation levels used for scans are generally low
  • Project team further reduces radiation dosage by up to 30% without compromise on image quality
  • Worked with over 1,000 patients over a 9-month period

While the amount of background radiation we are exposed to daily may be negligible, the effects of radiation on the human body are permanent and cumulative.

Other sources of manmade radiation, such as medical scans, can also add to this.

“People are getting scanned more often these days, whether it is because of injury, illness or regular check-ups,” said Dr Yu Wai-Yung, Senior Consultant, Department of Neuroradiology, National Neuroscience Institute (NNI).

There are two effects of radiation exposure:

Deterministic effects, such as skin burns, hair loss and cataracts, usually manifest at high radiation doses.  They occur above a certain threshold, and the severity of its effects increases with increased doses.

Stochastic effects, on the other hand, occur by chance.  These include cancer induction and genetic effects.  There is no threshold – they either occur or they don’t, but the risk is cumulative.

Even though the doses used in diagnostic radiology are generally low, Dr Yu Wai-Yung and her team embarked on a project to minimise it further by working with the Adaptive Iterative Dose Reduction 3D (AIDR 3D) software.

The software reduces noise and improves spatial resolution.  Scanning can be performed at lower current settings, but still resulting in optimised reconstructed images.

“We started by collecting data on radiation dose before and at the time of the installation of AIDR 3D for CT head, intracranial CT angiogram (CTA) and CT perfusion (CTP), the three most frequently performed scans,” she explained.

“We then systematically reduced the tube current, using multiple Plan-Do-Study-Act (PDSA) cycles. At each stage, initial scans were reviewed by all of the neuroradiologists in the department for image quality.” 

After working with more than 1,000 patients over a nine-month period, the team successfully reduced the effective radiation doses for CT head by 28.3 per cent, CTA scans by 11.6 per cent and CTP scans by 30 per cent without compromising diagnostic image quality.

Since the project ended in September 2012, the institute has been employing the new lower levels of radiation for its scans.

“Using the Accelerated model for Improvement (AMI) frame work developed by Langley et al and multiple PDSA cycles, this quality improvement was achievable even in a busy department,” said Dr Yu.

According to Dr Yu, the settings the team has arrived at can only be applied to the Aquillon ONE scanner for CT head, CTA and CT perfusion.  Other departments who do not use the same scanner can leverage on the same methodology to lower radiation dose.

“At the end of the day, it’s all about improving patient safety and the quality of their healthcare,” said Dr Yu.

“We are very happy that what we have done has contributed to both.”

The team who worked on the Quality Improvement project comprises Chan Wai Yee, Nurse Manager, Ho Thye Sin, Principal Radiographer, CT-in charge, and Dr Yu Wai-Yung, Senior Consultant from the Department of Neuroradiology at NNI. 

The project was first featured in the January 2014 issue of EPIC Heroes.