In-room exposure around the C-arm and operating table. The exposure values are in units of (mR) per unit scan dose (mGy) for a single CBCT scan, assuming a Pb apron as detailed in the text. Measurement points are marked with black circles, P1–P7 are typical staff positions in spine surgery (P1–P3: anesthesiologist, P4: surgeon, P5: nurse, P6–P7: surgical assistant). Per ALARA principles, staff either leaves the room or step behind a shield wall to receive near approximately zero radiation exposure.