Computed Radiography and Dosimetry: Some Practical Tips for Dose Optimization Procedures

This article provides some practical tips for dose optimization in computed radiography (CR). The article will not provide a comprehensive list of all factors that could be changed to optimize patient dose in CR examination. This article will also provide specific manufacturer examples that can be transferred to other manufacturers' CR systems. Due to the relatively large dynamic range of CR, stringent measures have to be put in place to ensure that patients are not being overexposed to ionizing radiation. Manufacturers of CR systems use dose indicators such as S-values, exposure index, and log-mean values to provide an indication of the "dose" received at the imaging plate. Manufacturers also provide a histogram analysis of the image pixel values. This histogram can also be used to evaluate the dose. The dose received at the imaging plate also has an effect on image quality. Radiographic factors of kV, mAs, and source to image distance affect the dose index, the histogram, and hence the image quality. These relationships will be reviewed and practical tips for dose optimization will be discussed.