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Researchers have warned doctors to ensure that CT scans carried out on children are clinically justified, after agovernment-funded study found that exposure to ionising radiationduring such scans could triple the risk of under-15s developing brain cancer or leukaemia later in life. Two or three scans would be sufficient to heighten the risk to suchlevels for brain cancer, while five to 10 would similarly lift therisk of leukaemia, according to a study funded by the Department of Health and the US National Cancer Institute . Brain tumours and leukaemia, while the most common childhoodcancers, are still relatively rare. While the risk of developingthem after scans remains low in absolute terms, and CT scanningcould be vital in saving young people's lives, the figures reportedin Lancet Online will encourage doctors to seek alternativediagnostic procedures to computed tomography scans where possible.These include ultrasound and magnetic resonance imaging. Children are more sensitive to radiation than older people. Theresearch, involving experts from the UK, US, the Netherlands, SouthKorea and Canada, is the first to provide direct evidence of a linkbetween exposure to radiation from CT scans in childhood and cancerrisk, and to quantify that risk. The study looked at data covering nearly 180,000 patients under 22who had not already been diagnosed with brain tumours or leukaemiaand who had had CT scans between 1985 and 2002 at seven in 10 UKhospitals; estimated doses of radiation energy absorbed through thebrain and bone marrow (which varies by age and body part scanned);and data linked to cancer incidence and mortality across the UKbetween 1985 and 2002. From this they calculated "excess incidence"of leukaemia and brain tumours. The researchers found the relative risk of leukaemia increased0.036 times for every milligray (mGy) of radiation exposure. Forbrain turmors, the increased risk per milligray was 0.023. One mGyis the amount of radiation energy absorbed by 1kg of human tissueor other material. For children under 10 receiving head scans,about one extra case of leukaemia and one extra brain tumour per10,000 patients would be expected after the procedure. CT scans were introduced in the 1970s and their use in the UK, forexamining patients for a range of conditions including tumours,bone disorders and internal injuries, rose by 68% between 1998 and2008. In 2007, an estimated 72m scans were carried out in the US. Lead researcher Mark Pearce, from the University of Newcastle,said: "The immediate benefits of CT outweigh the potentiallong-term risks in many settings and because of CT's diagnosticaccuracy and speed of scanning, notably removing the need foranaesthesia and sedation in young patients, it will, and should,remain in practice for the foreseeable future." But, said Pearce, "further refinements to allow reduction in CTdoses should be a priority, not only for the radiology community,but also for manufacturers. Alternative diagnostic procedures thatdo not involve ionising radiation exposure, such as ultrasound andMRI, might be appropriate in some clinical settings. "Of utmost importance is that where CT is used, it is only usedwhere fully justified from a clinical perspective." In a comment accompanying the research, Andrew Einstein, fromColumbia University medical centre in New York, said it confirmedthat CT scans "almost certainly produce a small cancer risk", butwith their use rising, "we must redouble our efforts to justify andoptimise every CT scan". The DoH said: "Clinicians should make decisions on a case-by-casebasis, making sure scans are given only when the benefits outweighthe risks. "The UK uses lower levels of radiation in CT scans than othercountries. We also have clear regulations to ensure a CT scan isonly carried out when clinically justified. These regulations arebased on expert knowledge of anatomy and medical radiation physicsto ensure that scans are not given unnecessarily.". We are high quality suppliers, our products such as China Automatic Carton Machine , Carton machines Manufacturer for oversee buyer. To know more, please visits Carton Machinery.
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