Radiation dose and image quality comparison during spine surgery with two different, intraoperative 3D imaging navigation systems

Abstract

Careful protocol selection is required during intraoperative three‐dimensional (3D) imaging for spine surgery to manage patient radiation dose and achieve clinical image quality. Radiation dose and image quality of a Medtronic O‐arm commonly used during spine surgery, and a Philips hybrid operating room equipped with XperCT C‐arm 3D cone‐beam CT (hCBCT) are compared. The mobile O‐arm (mCBCT) offers three different radiation dose settings (low, standard, and high), for four different patient sizes (small, medium, large, and extra large). The patient's radiation dose rate is constant during the entire 3D scan. In contrast, C‐CBCT spine imaging uses three different field of views (27, 37, and 48 cm) using automatic exposure control (AEC) that modulates the patient's radiation dose rate during the 3D scan based on changing patient thickness. hCBCT uses additional x‐ray beam filtration. Small, medium, and large trunk phantoms designed to mimic spine and soft tissue were imaged to assess radiation dose and image quality of the two systems. The estimated measured “patient” dose for the small, medium, and large phantoms imaged by the mCBCT considering all the dose settings ranged from 9.4–27.6 mGy, 8.9–33.3 mGy, and 13.8–40.6 mGy, respectively. The “patient” dose values for the same phantoms imaged with hCBCT were 2.8–4.6 mGy, 5.7–10.0 mGy, and 11.0–15.2 mGy. The CNR for the small, medium, and large phantoms was 2.9 to 3.7, 2.0 to 3.0, and 2.5 to 2.6 times higher with the hCBCT system, respectively. Hounsfield unit accuracy, noise, and uniformity of hCBCT exceeded the performance of the mCBCT; spatial resolution was comparable. Added x‐ray beam filtration and AEC capability achieved clinical image quality for intraoperative spine surgery at reduced radiation dose to the patient in comparison to a reference O‐arm system without these capabilities.

Feasibility and accuracy of a robotic guidance system for navigated spine surgery in a hybrid operating room: a cadaver study

“…In this study, no lead aprons were used as all use of radiation was done with all staff outside of the OR. Meanwhile, the patient radiation exposure from the CBCT with the ARSN system is lower than the radiation dose from comparable intraoperative 3-dimensional image systems 22,47 .…”

Intraoperative cone beam computed tomography is as reliable as conventional computed tomography for identification of pedicle screw breach in thoracolumbar spine surgery

“…All three protocols had a fixed tube kilovoltage of 120 kV, and a tube current time product ranging from 50 to 325 mAs, modulated by an automatic dose rate control to achieve a similar image quality independent of the patient size. Beam spectral filtration of 0.4 mm copper (Cu) and 1 mm aluminum (Al) was used for all protocols, in addition to 3.5 mm Al inherent x-ray tube filtration yielding 2.4 to 3.1% noise levels based on the ACR 464 CT phantom [ 27 , 28 ]. For image acquisition, the C-arm rotated 180° in 8–10 s, and in an additional 15 s, a 3D reconstructed volume with 0.5 mm voxel size was displayed at 1 mm thickness in axial and sagittal views with a contrast resolution of 3 to 5 HU [ 28 , 29 ].…”

“…Beam spectral filtration of 0.4 mm copper (Cu) and 1 mm aluminum (Al) was used for all protocols, in addition to 3.5 mm Al inherent x-ray tube filtration yielding 2.4 to 3.1% noise levels based on the ACR 464 CT phantom [ 27 , 28 ]. For image acquisition, the C-arm rotated 180° in 8–10 s, and in an additional 15 s, a 3D reconstructed volume with 0.5 mm voxel size was displayed at 1 mm thickness in axial and sagittal views with a contrast resolution of 3 to 5 HU [ 28 , 29 ]. This procedure was performed under temporary apnea in clinical cases [ 22 ].…”

Intraoperative cone beam CT in hybrid operating room set-up as an alternative to postoperative CT for pedicle screw breach detection

“…Consequently, the dimension of the imaged region of interest (ROI) corresponds to a 25x25 cm in the axial plane by 19.5 cm in the cranial-caudal direction 12 (Fig. 2).…”