Salwa Mahmoud Haidar, Presenter: Nothing to Disclose

Ellen Charkot, Abstract Co-Author: Nothing to Disclose

Constance Krajewski, Abstract Co-Author: Nothing to Disclose

Rahim Moineddin, Abstract Co-Author: Nothing to Disclose

Paul Sheppard Babyn MD, Abstract Co-Author: Nothing to Disclose

Using computerized radiography (CR) we investigated whether skin radiation dose could be reduced by the addition of a copper filter to the X-Ray beam without compromise to image quality.

Using two identical portable x-ray machines, a copper filter (0.1mm) was installed in the collimator port at the x-ray source of one of the two machines. The two units were tested before filter installation to ensure identical radiation output. After filter installation, each unit was checked for radiation output using an ionization chamber. Radiographic density was documented as well using a step wedge. A series of exposures were performed with and without copper filtration for 20 cadavers undergoing routine skeletal survey prior to autopsy. TLD disks were placed in the beam for 4 exposures i.e. head, chest, abdomen and lower limb and skin dose was measured for each exposure. Blind evaluation of image quality and resolution was performed by 3 pediatric radiologists.

Our results show that copper filter was successful in reducing the radiation dose by 15-20% (p<0.05). In addition, the readers agreed in 68% that the images performed using copper filter are equal or better to those without copper. The interobserver variability using intraclass correlation method was 89%. Overall, none of the images were evaluated as poor or non-diagnostic studies.

Use of a copper filter is efficient in reducing the radiation dose by 15-20% without significant image quality degradation. This simple technique can be easily applied and appears effective and considering the accumulative radiation dose in the life span, this reduction is believed to be significant especially in pediatric population.

Haidar, S, Charkot, E, Krajewski, C, Moineddin, R, Babyn, P, Use of a Copper Filter to Reduce Skin Dose in Computerized Radiography for Pediatric Imaging.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4416138.html