Summary
This journal article explores the feasibility of real-time ultrasound monitoring for abdominal stereotactic body radiation therapy (SBRT). The purpose of the study is to demonstrate the potential of using 4D ultrasound for monitoring the motion of a 3D target during abdominal SBRT, taking advantage of ultrasound’s benefits, such as soft tissue contrast, non-ionization, portability, and cost-effectiveness.
To achieve this, the researchers designed an ultrasound probe holding system, allowing clinicians to move and lock the ultrasound probe. In a phantom study, an abdominal ultrasound phantom was secured on a programmable respiratory motion stage to mimic 3D target motion. For comparison, the phantom’s motion was tracked by an infrared camera, considered as the ground truth. Three healthy volunteers underwent a similar setup for abdominal SBRT with active breath control (ABC). 4D ultrasound B-mode images were acquired for both the phantom and volunteers for real-time monitoring, with ten breath-hold cycles monitored for each experiment.
The results of the study indicate that the ultrasound system integrated well with the clinical SBRT setup. The volunteer study showed that the reproducibility of 10 breath-holds was less than 2 mm in all three directions for all three volunteers. In the phantom study, the motion tracking error between inspiration and expiration monitored by ultrasound was less than 0.5 mm in any direction, demonstrating sub-millimeter accuracy. This research confirms the clinical feasibility of real-time ultrasound monitoring for abdominal SBRT and suggests its potential for accurate 3D motion monitoring during treatment.
