Quality of density deformations in patient anatomy during synthetic CT guided online adaptive radiation therapy for pelvic cancer

CBCT-based sCT adaptation effectively aligns external contours but does not accurately handle gaseous volumes, which may vary in great extent. Minimizing the time between CBCT acquisition and treatment is crucial to maintain alignment accuracy. Advanced imaging solutions enabling direct dose calculation without involving sCT generation could further enhance dose reconstruction but may not resolve the time-sensitive nature of gaseous volume changes.