kVpswitching

KVp switching, often written as kVp switching, is a technique in X-ray imaging whereby the kilovolt peak (kVp) of the X-ray tube is rapidly alternated between two discrete values during an imaging session. The goal is to capture data at multiple energy spectra within a single examination, enabling enhanced tissue characterization, contrast optimization, or dose management.

In computed tomography and other dynamic imaging modalities, kVp switching is implemented by alternating the tube voltage between high and low values on a rapid timescale or across alternating projections. Some systems use a single tube with fast voltage control, while others employ dual-source or dual-tube configurations. The technique requires precise synchronization between voltage control, exposure timing, and detector readout to preserve spatial alignment and image quality. Calibration is necessary to account for spectral differences and detector response.

Applications of kVp switching include dual-energy CT and spectral imaging, where data from different kVp spectra are combined to perform material decomposition, iodine quantification, bone removal, or artifact reduction. In conventional radiography, switching can support dose optimization by exploiting spectral differences in various anatomical regions and improving contrast for specific tissues.

Advantages of kVp switching include access to spectral information without extensive hardware changes, potential improvements in lesion conspicuity, and opportunities for dose efficiency. Limitations involve increased image noise at lower kVp values, greater demand on hardware and reconstruction algorithms, and complexities in calibration and post-processing. Ongoing development in detector technology and reconstruction methods continues to broaden its clinical utility.