Risk of Cancer Posed by CT Scans Should be Weighed Against Benefits in Diagnosing Diseases

The study findings are reported in the British Medical Journal today and involved researchers at eight other centres in Australia, Oxford University, and the International Agency for Research on Cancer in Lyon, France.

Professor Mathews said: "CT scans were very useful in providing detailed three dimensional pictures to diagnose or exclude disease in internal organs and in most cases, the benefits of having a scan clearly outweigh the risk of a later cancer. Nevertheless, our new findings will remind doctors to order CT scans only when there is a definite medical reason, and to insist that CT scans use the lowest possible X-ray dose'. he said.

"As an individual patient, your risk of cancer from a CT scan is very low. Nevertheless, it is clear from our study that if we reduce the number of scans performed in a large population, and continue to reduce the doses from individual scans, there will be a small but corresponding reduction in the number of cancers in later years."

It is well known that large doses of radiation can damage DNA and increase the risk of a later cancer. However, the radiation doses from CT scans are very small, and there has been uncertainty about whether such small doses would cause cancer, and whether any small increase in risk could be measured reliably.

This study answered questions by linking de-identified Medicare records of CT exposures for the entire population of young Australians, aged 0-19 years between 1985 and 2005, to cancers diagnosed up to the end of 2007.

The risk of cancer increased with the number of CT scans, and the proportional increase in risk was greater for those exposed at younger ages. Nevertheless, as CT usage increased with age, the majority of cancers in this study followed exposures in the teenage years. Although this study did not directly assess the effects of CT exposures after the age of 19, the results suggest that cancer risk will increase following CT scans in adult life.

With improvements in CT technology, the average radiation dose per scan is expected to fall, although CT scan numbers have continued to increase in many countries.

Source-Eurekalert

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Scientists Make New Discovery in Fight Against Deadly Meningococcal Disease

"Until now we have not known how it attaches to the human host. It has been a long-standing mystery how it attaches to the airway to colonise "People can be carriers of the bug and not get any symptoms, while some people progress to invasive disease.

To understand why, we need to know the detail of how the bacterium colonises the airway. Now that the pathway has been identified we can study this process to understand how invasive disease occurs. This is especially important considering the rapidly progressing and serious outcomes of meningococcal disease."If you understand how the bug first attaches and how it first signals its attachment then we may identify new risk factors or treatment procedures," Professor Jennings said.

The findings were published Friday in the highly regard PLOS Pathogens journal as featured research "Dual Pili Post-translational Modifications Synergize to Mediate Meningococcal Adherence to Platelet Activating Factor Receptor on Human Airway Cells." The paper states: There is no fully protective vaccine against this pathogen in current use and the key processes that dictate the transition from harmless carriage of the bacterium in the airway (the case for the vast majority of colonised hosts) to invasive disease are largely undefined.

A key missing link in this organism's interaction with the human host is the identity of the receptor that is the first point of contact for the organism within the airway.Professor Jennings said the receptor is used by a range of airway pathogens and the bacterium mimics a human structure to attach to this receptor."It's not actually protein that attaches to the receptor but decorations on the protein that are known as post-translational modifications. One of these is a sugar structure, which of course is of great interest to our work here at Glycomics," he said.The Institute of Glycomics is a world leader in the study of glycans and carbohydrates (sugars) and how they behave in terms of disease prevention and cure.

Source-Eurekalert

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