Comparison of impact of target delineation of computed tomography- and magnetic resonance imaging-guided brachytherapy on dose distribution in cervical cancer (original) (raw)

Journal of Contemporary Brachytherapy

Purpose: The dose distributions obtained from three imaging approaches for target delineation in cervical cancer using high-dose-rate (HDR) brachytherapy were investigated. Material and methods: Ten cervical cancer patients receiving four fractions of HDR brachytherapy were enrolled. Based on different imaging approaches, three brachytherapy plans were developed for each patient: with the high-risk clinical target volume (HRCTV) delineated on magnetic resonance (MRI) images for every fraction (approach A; MRIonly); on MRI for the first fraction and computed tomography (CT) images for the subsequent fractions (approach B; MRI 1st /CT); and on CT images for all fractions (approach C; CT-only). The volume, height, width at point A, width at maximum level, and dosimetric parameters (D 100 , D 98 , D 95 , and D 90 of the HRCTV; and D 0.1cc , D 1cc , and D 2cc of all organs at risk, or organ at risk-OAR: bladder, rectum, sigmoid colon, and bowel) provided by each approach were compared. Results: The mean HRCTV volume, width, and height obtained from approach C (CT-only) were overestimated compared to those from approaches A (MRI-only) and B (MRI 1st /CT). The doses to the HRCTV for approaches A and B were similar. However, the HRCTV doses for approach C were significantly lower than those for approaches A and B for all parameters (D 95-D 100). As to the OAR, the three approaches showed no differences. Conclusions: A combination of MRI and CT is a safe alternative approach for cervical cancer HDR brachytherapy. The technique provides comparable dosimetric outcomes to MRI-based planning, while being more cost-effective.