Estimation of organ and effective doses of CBCT scans of radiotherapy using size-specific field of view (FOV): a Monte Carlo study.

The kV cone beam computed tomography (CBCT) is one of the most common imaging modalities used for image-guided radiation therapy (IGRT) procedures. Additional doses are delivered to patients, thus assessment and optimization of the imaging doses should be taken into consideration. This study aimed to investigate the influence of using fixed and patient-specific FOVs on the patient dose.

Estimation of size-specific dose estimate (SSDE) of CT scans using an effective diameter electron density.

Objective: An assessment of the effective diameter of a patient's body using electron densities of tissues inside the scan area (D) was proposed to overcome challenges associated with the estimation of water-equivalent diameter (D), which is used for size-specific dose estimate (SSDE). The aims of this study were to (1) investigate the D method in two different forms using a wide range of patient sizes and scanning protocols, and (2) compare between four methods used to estimate the patient size for SSDE.

Materials And Methods: Under IRB approval, a total of 350 patients of varying sizes have been collected retrospectively from the Hospital.