Characterization and registration of 3D ultrasound for use in permanent breast seed implant brachytherapy treatment planning

Abstract

Permanent breast seed implant (PBSI) brachytherapy is a novel technique for earlystage breast cancer. Computed tomography (CT) images are used for treatment planning and freehand 2D ultrasound for implant guidance. The multimodality imaging approach leads to discrepancies in target identification. To address this, a prototype 3D ultrasound (3DUS) system was recently developed for PBSI. In this study, we characterize the 3DUS system performance, establish QA baselines, and develop and test a method to register 3DUS images to CT images for PBSI planning. METHODS AND MATERIALS: 3DUS system performance was characterized by testing distance and volume measurement accuracy, and needle template alignment accuracy. 3DUS-CT registration was achieved through point-based registration using a 3D-printed model designed and constructed to provide visible landmarks on both images and tested on an in-house made gel breast phantom. RESULTS: The 3DUS system mean distance measurement accuracy was within 1% in axial, lateral, and elevational directions. A volumetric error of 3% was observed. The mean needle template alignment error was 1.0 AE 0.3 and 1.3 AE 0.5 mm. The mean 3DUS-CT registration error was within 3 mm when imaging at the breast centre or across all breast quadrants. CONCLUSIONS: This study provided baseline data to characterize the performance of a prototype 3DUS system for PBSI planning and developed and tested a method to obtain accurate 3DUS-CT image registration for PBSI planning. Future work will focus on system validation and characterization in a clinical context as well as the assessment of impact on treatment plans.

Stereotactic Ablative Brachytherapy: Recent Advances in Optimization of Radiobiological Cancer Therapy

“…To facilitate high dose optimization, consistency of the delivered treatment, and to broaden BT potential in cancer treatment, image guidance technologies are used during the design and delivery of HDR-BT and LDR-BT [ 50 ]. Ultrasound guidance is employed in BT during prostate and breast cancer treatments [ 51 , 52 ]. Computed tomography (CT) guidance is mainly used for seed implantation into cancers located at head and neck, thoracic, primary/metastatic liver/adrenal, recurrent/metastatic pelvic cavity, and spinal areas [ 29 , 33 , 43 ].…”

“…Accordingly, SABT curative effects are largely assessed using observed improvements in tumor control rate. Conclusively, multiple studies have confirmed that BT irradiation methods delivered advanced curative outcomes and did not result in severe/acute gastrointestinal adverse effects [ 51 , 55 , 58 ]. There are novel methods, including urethral D10% color map (dose-area evaluation method), that help to reduce BT-related toxicity [ 60 ].…”