Qualitative and quantitative evaluation of the role of CBCT in rectal cancer radiotherapy

Verifying patients’ position and internal anatomical changes are important steps in the radiotherapy of rectal cancer. Cone Beam Computed Tomography (CBCT) is an advanced imaging method that allows for the quantification of these modifications, ensuring the delivery of radiation dose to the tumor volume, while protecting surrounding organs at risk. The aim of this review is to discuss and analyze the benefits offered by this method of imaging on board the linear accelerator. In view of this, a systematic search of the scientific literature in the Medline/PubMed database was performed for publications over the last decade, with 20 articles found to be relevant for this study. To highlight the benefits of this imaging technique in rectal cancer, the frequency of CBCT use, identification of tumor volume and organs at risk on CBCT images, quantification of the movement of these organs and tumor volume, analysis of positioning errors as well as evaluation of dosimetric parameters were analyzed.