The Size Specific Dose Estimates (SSDE) tool is billed by researchers as a more accurate measure of radiation dose, by taking into account a child's age and size.
Researchers hope improved measuring will ultimately reduce the amount of radiation needed to produce quality diagnostic images, such as CT scans.
Monash Medical Centre's head of paediatric imaging, Professor Michael Ditchfield, and CT Medical Imaging Technologist Dana Jackson will present their findings at the Royal Australian and New Zealand College of Radiologists annual conference in Sydney.
Prof Ditchfield says the risks of radiation exposure are 10 times greater in young children than adults.
The researchers hope the tool will minimise a child's exposure to potentially cancer-causing radiation by better taking into account the patient's size and adjusting the dosage accordingly.
They say CT scans are an important diagnostic tool, but each scan must be justified to ensure the benefits outweigh the risks.
Prof Ditchfield says medical radiation of the general public has increased dramatically in the past two decades, largely due to increased CT scans.
The profession is utilising measures to limit exposure, including automated exposure control, use of breast and thyroid shields, and using alternative imaging technologies, such as ultrasound and MRI, he says.