Evaluation of the geometric and dosimetric accuracies of deformable image registration of targets and critical organs in prostate CBCT-guided adaptive radiotherapy.

Purpose: Kilovoltage cone beam computed tomography (kVCBCT)-guided adaptive radiation therapy (ART) uses daily deformed CT (dCT), which is generated automatically through deformable registration methods. These registration methods may perform poorly in reproducing volumes of the target organ, rectum, and bladder during treatment. We analyzed the registration errors between the daily kVCBCTs and corresponding dCTs for these organs using the default optical flow algorithm and two registration procedures.

Dosimetric comparison between microSelectron iridium-192 and flexi cobalt-60 sources in high-dose-rate brachytherapy using Geant4 Monte Carlo code.

Purpose: Manufacturing of miniaturized high activity iridium-192 (Ir) sources have been made a market preference in modern brachytherapy. Smaller dimensions of the sources are flexible for smaller diameter of the applicators, and it is also suitable for interstitial implants. Presently, cobalt-60 (Co) sources have been commercialized as an alternative to Ir sources for high-dose-rate (HDR) brachytherapy, since Co source have an advantage of longer half-life comparing with Ir source.