ARRS: Image filters help cut down on noise, radiation dose

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Adaptive image filters can allow for a lower radiation dose associated with CT scans, without sacrificing the image clarity, according to a study presented at the American Roentgen Ray Society (ARRS 2010) annual meeting in San Diego on May 3.

The study's lead author Sarabjeet Singh, MD, of Massachusetts General Hospital (MGH) in Boston, explained that image filters are used to lower image noise when low radiation doses are used.

“As we lower the radiation dose, the CT images become “noisy” or speckled, which makes it difficult to view the organs or the body structures in the image,” said Singh.

Citing the importance of the research, Singh stated: “With the increasing use of CT, radiation dose concerns have been rising in the medical community, patients, as well as the media. Hence various efforts have been made to lower the radiation dose associated with CT scanning.”

The researchers recruited 12 patients at MGH for their study, who each had a CT scan at four different levels of radiation dose in the chest and abdomen and all low dose images were processed with adaptive filters.

Post processing with image filters improved subjective noise for both chest and abdominal CT, regardless of radiation dose and helped lower the CT radiation dose levels for chest by up to 40 mAs and for the abdominal CT, by up to 100 mAs, they reported.

"There are many ways to lower patient radiation dose associated with CT scans,” offered Singh. “However, the filters are one of the simpler ways of reducing radiation dose with CT. They only require a selection of preset settings that can be applied automatically to improve image quality and thus enable lowering of the radiation dose.”