  Implementation of real-time, continuous, and three-dimensional imaging (4D
intervention guidance) would be a quantum leap for minimally-invasive medicine.
It allows guidance during interventions by assessing the spatial position of
instruments continuously in respect to their surroundings. Recent research
showed that it is feasible using X-ray and novel tomographic reconstruction
approaches. Radiation dose stays within reasonable limits. This article
provides abstractions and background information together with an outlook on
these prospects. There are explanations of how situational awareness during
interventions is generated today and how they will be in future. The
differences between fluoroscopically and CT-guided interventions are eluted to
within the context of these developments. The exploration of uncharted terrain
between these current methods is worth pursuing. Necessary image quality of 4D
intervention guidance varies relevantly from that of standard computed
tomography. Means to analyze the risk-benefit ratio of 4D intervention guidance
are provided and arguments for gantry-based setups vs C-arm based setups are
given. Due to the lack of moving organs, neuro-interventions might be the first
field in which 4D intervention guidance might become available, however,
registration and fusion algorithms might make it applicable in complex
whole-body interventions such as aortic valve replacement soon thereafter.
