CT: reducing risks to children
REDUCING RADIATION risks to children from computed tomography (CT) scans continues to engage the attention of medical specialists. At the latest annual meeting of the Radiological Society of North America (RSNA-2006) in Chicago, researchers led by Dr David Larson from the University of Colorado Health Sciences Center in Denver showed that they could easily educate parents about radiation risks with the aid of a brochure.
Parents' role
Parents may contribute to the demand for CT. The researchers hope that they can achieve a reduction in this demand by informing parents of the risks associated with CT. Eric Barnes, the staff writer, AuntMinnie.com reported that the on-going initiative appeared to have been successful in educating the parents (December 28, 2006).
After reading the brochure, parents became slightly less willing to have their child undergo CT, if their doctor felt that either CT or observation should be equally effective, but their willingness to have their child undergo a CT scan recommended by their doctor did not change significantly.
No indiscriminate use
CT is a unique tool to diagnose disease, trauma or abnormality and to plan, guide and monitor treatment. However, we must not use it indiscriminately ( The Hindu, May 23, 2002).
Researchers supported by the Atomic Energy Regulatory Board analysed over 5000 CT examinations and showed that paediatric CT scans are substantial at12.8 per cent of the total tests.
"Every unnecessary and unjustifiable test is one test too many" (Cardiac Ultrasound, May 5, 2005), Dr Eugenio Picano from the Institute of Clinical Physiology, Pisa, Italy asserted. This is true for all such tests particularly those of children. When used appropriately, the benefits of CT far exceed the potential risk.
Dr Thomas L.Slovis, Department of Paediatric Imaging, Children's Hospital, Michigan, who wrote a telling editorial in the April 2002 issue of Paediatric Radiology revealed that 25-35 per cent of paediatric examinations might not be necessary.
Excess cancer risk
The editorial noted that the individuals who were exposed to radiation dose comparable with the dose involved in helical CT have suffered excess cancer incidence.
Though the risk is small, it becomes a public health issue when one multiplies a large number of CT scans in children with the small risk. Children are 10 times more sensitive to radiation than adults; girls are more sensitive than boys.
The technologists must use weight related parameters for CT in children. "Manufacturers need to be more user-friendly and must provide the tools to prevent excess doses", the editorial argued.
Dose reduction
In conventional X-ray procedures, overexposure to patients produces a darker image in the film. The physician may realize it. Over exposure to the patient in a CT scan will not be obvious, as the excess dose will not compromise the image's quality (USFDA, 2001).
Physicians must use CT equipment optimally balanced between image quality and radiation dose. Reducing the tube current can reduce patient dose.
Increasing the table increment (axial scanning) or pitch (helical scanning) also helps to reduce dose. Wherever possible, physicians should recommend procedures with less or no ionising radiation.
Data collected by the Atomic Energy Regulatory Board from 120 CT scan units indicate that 30 of them do not have paediatric protocol. But they claimed that they adjust the parameters manually while x-raying children.
Parents may ask the radiologist or the technologist performing the test whether they are using the correct technique factors while scanning their children. If the technologist cannot adjust the parameters in the equipment, the parents can ask the physicians to refer the case to a centre where such facility exists.
The wake up call
Eight articles on radiation doses in CT scans in the American Journal of Roentgenology (AJR, 2001) provided the wake-up call. "The availability and intellectual acceptance of information does not always translate into appropriate action.
"This is particularly true regarding computed tomographic radiation dose to children," Dr Slovis asserted. "Our reward for this effort will be to ensure safer use of our technology and better care of our most valuable asset — our children!"
K.S. PARTHASARATHY
Former Secretary, AERBksparth@yahoo.co.uk
Printer friendly
page
Send this article to Friends by
E-Mail
Sci Tech
