SITE-SPECIFIC ASSESSMENT OF KILOVOLTAGE IMAGING FOR PATIENT POSITIONING ACCURACY COMPARED WITH CONE-BEAM COMPUTED TOMOGRAPHY IN IMAGE-GUIDED RADIOTHERAPY AT A NIGERIAN TERTIARY HOSPITAL
DOI:
https://doi.org/10.33003/fjs-2026-1008-4922Keywords:
Setup accuracy, Treatment verification, kV imaging, Couch shiftAbstract
Cone-beam computed tomography (CBCT) is widely used in image-guided radiotherapy (IGRT) because it provides volumetric verification of patient setup, but routine use may be difficult to sustain in resource-constrained settings. Planar kilovoltage (kV) imaging is faster and simpler, although its positioning accuracy may vary across treatment sites. The research aimed to assess the impact of kV imaging on patient positioning accuracy across different treatment sites compared with CBCT. This prospective within-patient method-comparison study included 39 patient-courses treated at the University of Nigeria Teaching Hospital, comprising breast (n = 9), head and neck (n = 10), spine (n = 10), and pelvis (n = 10).Paired CBCT and orthogonal kV images were acquired on Fractions 1 and 6.Translational couch shifts in the vertical, longitudinal, and lateral directions were analysed using paired t-tests, Bland-Altman analysis, and clinical agreement rates within ±0.3 cm.Interobserver reliability of kV matching was assessed using intraclass correlation coefficient. Mean three-dimensional differences between kV and CBCT were not significant for breast (0.07 cm; p = 0.158), head and neck (0.04 cm; p = 0.584), and spine (0.095 cm; p= 0.099), but were significant for pelvis (-0.38 cm; p = 0.002).Agreement within ±0.3 cm was highest in spine (100%), followed by head and neck (80-100%) and breast (66.7–88.9%), while pelvis showed the lowest agreement (50-70%). kV interobserver reliability was good to excellent (ICC = 0.724-0.945). kV imaging can provide clinically acceptable positioning accuracy in relatively rigid treatment sites, especially spine and head and neck, but pelvic cases still require CBCT support.References
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Copyright (c) 2026 Abdullahi Shuaibu, Charles Ugwoke Eze, Anakwue Angel-Mary, Mohammed Yusuf Mohammed, Abdurrahman Umaru, Everistus Obinna Abonyi, Inwang Edet Usoro
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