AR is a variant of virtual reality (VR), adding, deleting, emphasizing, or attenuating information in the surrounding reality at the time in question, literally expanding the real world seen by humans [14, 15]. While VR replaces reality with an artificially constructed reality, AR modifies part of reality [14, 15]. Information has been presented for all human sense organs and somatosensory sensations, including sight, hearing, and touch, as a way to extend the reality of computers. VR emphasizes the reality of virtual objects presented to people, while AR also emphasizes the association with context, including real-world position and objects. Therefore, a simple presentation method may be used to extend reality, and head-mounted displays and other such means are used to present the visual information [20, 21]. In the medical field, VR is applied as a way to present information for surgical support and diagnostic imaging [16–21, 23].
The main uses of OST-HMD are expected to be as sub-monitors for inspection/measurement equipment and work performed while checking images sent from drones. It can be used in scenarios in which the operator can check the hand area and any information needed within the field of vision with very little head movement, the work can proceed smoothly and efficiency be improved . The BT-35E/30E can output device video information to the monitor without delay by setting up a wired connection to existing systems. Therefore, even in the medical field, in which safety is essential, there are a number of reports on the application of BT-300 and BT-35E to medical technology by connecting to medical devices [19, 20, 23].
Using this procedure, the Moverio BT-35E is used as an OST-HMD device and CNB is implemented under direct vision via the gap at the bottom of the display with ultrasound images on the OST-HMD display worn on the head. Conventional ultrasound-guided CNB is problematic because it restricts the examination doctor’s posture and movements due to the need to perform the procedure while maintaining their posture toward fixed ultrasound equipment. However, with this procedure, even if the head is moved for OST-HMD, the procedure is secured on a safe monitor with the projected image, and CNB can be executed smoothly without posture restrictions. Therefore, the procedure can be performed without the use of restricted postures, even in a limited biopsy space such as an examination room, and even a training surgeon can practice the appropriate procedures without stress.
In this procedure, the BT-35E was used as the OST-HMD, but there are other devices available (ODG R-7/8/9 Glasses System [Osterhout Design Group Inc, San Francisco, CA, USA]; Microsoft HoloLens /2 [Microsoft Corp, Redmond, WA, USA]). Compared to these devices, BT-35E is inexpensive and compact. The light weight of this device can be a significant advantage when this procedure is performed with the OST-HMD worn on the head. In addition, because of its compact size, it is possible to use the gap at the bottom, enabling monitoring support and use of direct vision techniques at the same time. Although it is possible to see the monitor image without using a flip shade, it is also possible to attach a flip shade to project the ultrasound image more clearly and work under direct vision through the gap at the bottom of the display, thereby adopting a hybrid system using these techniques in tandem.