Introduction
HMD
Within the last few years, virtual reality and augmented reality (AR) have been increasingly used in the fields of entertainment and gaming. More recently, they have also been implemented in the field of medicine, particularly for training [For example, superimposing a computed tomography (CT) image over anatomical structures enables the operator to visualize deeper structures that would otherwise not be visible on just the surface. This, in combination with planned navigation, has been used to guide injections or biopsies [In this study, we assessed AR US, which has the following capabilities: Images seen through a HMD can by using a voice command either be set steady, to follow the eyes, or be positioned at a certain location, for example below an ultrasound (US) probe. Furthermore, use of tracking objectives by implementing a quick response (QR) code at the US probe can enable the image to follow the tracked US probe. The US image can thus be displayed directly below the US probe in the exact real time anatomical position (in situ image). In a previous phantom study, the performance of inexperienced operators was found to be superior when they used an AR in situ technique [