Radiation dose optimization in thoracic imaging

Abstract

Guidelines for reduction of CT radiation dose were introduced in 1997 and are now more than 12 years old. The process initiated by the European Regulatory authorities to reduce the excess of radiation from CT has however not produced the expected results. Reference diagnostic levels (DRL) from surveys are still twice as high as needed in most European countries and were not significantly reduced as compared to the initial European ones. Many factors may at least explain partially the lack of dose reduction. One of them is the complexity of the dose optimization process while maintaining image quality at a diagnostically acceptable level. Chest is an anatomical region where radiation dose could be substantially reduced because of high natural contrasts between structures, such as air in the lungs and fat in the mediastinum. In this article, the concept of CT radiation dose optimization and the factors that contribute to maintain global excess in radiation dose are reviewed and a brief summary of results from research in the field of chest CT radiation dose is given.

Dose Reduction in Cardiothoracic CT: Review of Currently Available Methods

“…At chest CT and pulmonary CT angiography performed at a fixed tube current-time product, a dose range between 40 and 90 mAs is usually sufficient (Figs 6-8). As a rule of thumb, for chest CT and pulmonary CT angiography, 1 mAs/ kg can be used on the vast majority of scanners (28). This method has been used for scanners not equipped with AEC.…”

Multidetector computed tomography of chest trauma: indications, technique and interpretation

“…The kilovolt value can be reduced to 80–100, and the mAs value can be decreased to 30–80 (Fig. 5) [20]. If cardiac and thoracic aorta (especially a. ascendens) trauma is suspected, we can use ECG synchronisation to eliminate motion artifacts [21].…”