CT or MRI for Image-based Brachytherapy in Cervical Cancer

Abstract

Magnetic resonance imaging remains the gold standard for tumour delineation, but computed tomography with clinical information can give comparable results, which need to be studied further. Computed tomography-based contouring can be used comfortably for delineation of organs at risk.

A prospective observational study with dose volume parameters predicting rectosigmoidoscopic findings and late rectosigmoid bleeding in patients with uterine cervical cancer treated by definitive radiotherapy

“…Given that CT-based brachytherapy is more assessable technique [25-28] globally than the MRI-based one because of the problems of logistics and resources, our result may be meaningful in clinical practice and should be verified by further studies in broader societies using 3D image-based brachytherapy, especially in the institutes where fractionated regimen is used on outpatient basis.…”

The usefulness of fleet rectal enemas on high-dose-rate intracavitary cervical cancer brachytherapy. A prospective trial

“…Many institutions cannot carry this out in clinical routines, therefore other strategies have been developed, such as the use of CT/MR images on alternate applications [30] or the use of MRI acquired outside a radiotherapy protocol [31]. We do not believe that the use of MRI would modify rectum doses, because recently published results failed to demonstrate rectal and bladder dose differences related to the segmentation with CT or MRI [32,33]. Future work needs to address the effect of rectal volume in a large population of patients treated with brachytherapy for locally advanced cervical cancer, and evaluate how it effects total dose accumulation.…”

MRI-Guided High–Dose-Rate Intracavitary Brachytherapy for Treatment of Cervical Cancer: The University of Pittsburgh Experience

“…At our institution, we use either MRI or hybrid CT/MRI to assess treatment response, to more accurately delineate HRCTV, and to account for critical organs (19). Compared to CT, MRI has been shown to have improved detection of parametrial extension, and regarding brachytherapy contouring, CT often overestimates uterine width and underestimates residual disease (11)(12)(13)30). Smaller uterine width contours can allow for further constriction of the isodose lines, providing a better ability to reach higher doses and spare surrounding critical organs, leading to low rates of toxicity.…”

“…MRI allows for better soft tissue delineation and, specific to cervical cancer, improved detection of parametrial extension and less interobserver variability than computed tomography (CT) imaging (11). Integration of MRI with brachytherapy planning has shown enhanced target volume visualization, given that CT often underestimates residual disease and overestimates uterine width (12,13). Several single-institution series have demonstrated the efficacy of MRI-guided brachytherapy, although most studies have been limited by smaller sample sizes (14)(15)(16)(17)(18)(19).…”