Applying Dose Reduction to CT Colonography

There is increasing awareness of the radiation dose delivered to patients using computed tomography (CT). It is important to properly manage the radiation dose when performing CT colonography (CTC) for colorectal cancer screening since the test may be repeated several times over the lifetime of the individual. There must be a balance of the overall benefit of screening CTC versus any theoretical risk of radiation. Technically there must also be a balance of radiation dose with image quality. Efforts continue to lower the radiation dose as much as possible while maintaining diagnostic accuracy for CTC in conjunction with overall national efforts by professional organizations, providers of medical imaging services, and equipment manufacturers. This article reviews the strategies that may be used to reduce the radiation dose for CTC including practical methods, modifications of specific CT parameters, and the use of new iterative reconstruction techniques.