Fig 1.
Multi-angle laser device (MLD) was installed on the C-arm machine.
(a) Schematic diagram: The green cross laser (①) is positioned at the top of the C-arm at 90°, and the red cross lasers (②③) are positioned at 45° and 135° on the C-arm. The green line lasers (④-⑦) are placed perpendicularly and positioned at the X-ray tube and image intensifier sides. (b) Photograph: The green circle corresponds to laser ①, the red circle corresponds to lasers ②③, and the blue circle corresponds to lasers ④-⑦.
Fig 2.
Positioning of the lumbar spine phantom for imaging.
(a) 3D-printed phantom with an inserted needle as the imaging target. (b) The phantom was placed inside an opaque box on a surgical table. (c) Standard prone position. (d) 45° coronally rotated position.
Fig 3.
Comparison of traditional versus multi-angle laser assisted imaging.
(a) Traditional AP imaging. (b) AP imaging with MLD guidance. (c) Traditional LAT imaging. (d) LAT imaging with MLD guidance. Note: MLD lasers helped align the X-ray beam perpendicular to the phantom’s long axis (dashed line) before imaging.
Fig 4.
Determination of the imaging endpoint.
(a) Center point identification. The intersection of diagonals indicates the image center. (b) Deviation measurement. Deviation percentage = Distance between the needle tip and center (s) / Image radius (r). Imaging ends when deviation <10%.
Table 1.
Comparison of baseline characteristics.
Fig 5.
Comparison of imaging parameters between groups.
(a) Time (min) (b) Shots (n) (c) Deviation (%). Note: * indicates p<0.05 between groups. AP—anteroposterior, Lat—lateral, N—normal position, CR—coronally rotated position.
Table 2.
Comparison of imaging performance between groups.
Fig 6.
Shot deviation plots by position and view.
AP, normal (b) Lateral, normal (c) AP, rotated (d) Lateral, rotated X-axis—shots; Y-axis—deviation. Note: Blue dots–Group A; Orange dots–Group B.
Fig 7.
Questionnaire scores between groups.
Note: * indicates p < 0.05, statistically significant.
Table 3.
Questionnaire ratings between groups.