“Augmented Reality” in Conventional Simulation by Projection of 3-D Structures into 2-D Images

Abstract

The presented method provides an easy way to determine entity-specific safety margins related to patient setup errors upon registration of bony anatomy (prostate 0.9 cm for 90% of cases, breast 1.3 cm). The important role of planar X-ray imaging was clearly demonstrated. The innovation can also be applied to adaptive image-guided radiotherapy (IGRT) protocols.

A strategy for the use of image-guided radiotherapy (IGRT) on linear accelerators and its impact on treatment margins for prostate cancer patients

“…The mean shifts give the remaining systematic setup error for the case of conventional simulation alone. Since the average shifts are zero or close to zero in all directions, no systematic errors in our treatment planning and simulation process could be detected [3]. Table 1 shows how the systematic error and its SD vary with the number of CBCTs involved.…”

“…Moreover, all patients received conventional simulation prior to radiation therapy resulting in the already low systematic errors. In a prior study with 158 patients, the average shifts observed at the simulation stage amounted 0.07 cm in L-R, 0.01 cm in C-C and -0.06 cm in A-P with SD of 0.36 cm, 0.24 cm and 0.43 cm, respectively [3]. In case of virtual simulation without "compensating" IGRT, larger treatment margins would have been necessary, namely 1.23 cm in the L-R, 1.21 cm in the C-C and 1.74 cm in the A-P direction.…”

What technical barriers exist for real‐time fluoroscopic and video image overlay in robotic surgery?

“…Augmented reality by projection of 3D structures into 2D images has also been attempted (16). However, a major drawback of such techniques is that the surgeon still does not have a real-time feedback from the imaging modalities.…”

kV Cone-Beam CT-Based IGRT

“…Prostate rotation compensation adapting gantry/collimator angle or MLC configuration [21] has been suggested. Robotic couches can perform rotational corrections, but the range of rotational motion is too small for prostate, where rotations up to 15° are observed, inducing substantial secondary patient displacements [33].…”