Barnes Micah J, Afshar Nader, Batty Taran, Fiala Tom, Cameron Matthew, Hausermann Daniel, Hardcastle Nicholas, Lerch Michael
Centre of Medical Radiation Physics, University of Wollongong, Wollongong, Australia.
ANSTO Australian Synchrotron, Clayton, Australia.
Med Phys. 2025 Jun;52(6):4694-4704. doi: 10.1002/mp.17750. Epub 2025 Mar 16.
In clinical radiotherapy, the patient remains static during treatment and only the source is dynamically manipulated. In synchrotron radiotherapy, the beam is fixed, and is horizontally wide and vertically small, requiring the patient to be moved through the beam to ensure full target coverage, while shaping the field to conform to the target. No clinical system exists that performs both dynamic motion of the patient and dynamic shaping of the beam.
We developed and tested a new dynamic treatment delivery system capable of delivering conformal fields with a robotic patient positioning system for use on the Imaging and Medical Beamline (IMBL) at the Australian Nuclear Science and Technology Organisation, Australian Synchrotron.
An industrial robotic manipulator was modified to enable dynamic radiotherapy treatments on IMBL. The robot, combined with a carbon-fiber treatment couch-top and a recently developed dynamic collimator, formed the basis of the new treatment delivery system. To synchronize the motions of the robot and collimator, a real-time, hardware-based event-handling system was utilized. To test the system, a ball bearing in a medical physics phantom was treated with circular fields ranging from 5 to 40 mm in diameter and at treatment speeds from 2 to 50 mm . The position of the ball bearing was compared to the center of the circular fields and the positional and temporal accuracy of the treatment delivery system was assessed, and appropriate treatment margins for the system were determined.
The vertical position of the ball bearing varied with treatment delivery speed ( ) while the horizontal position remained consistent ( ). The time-delay between the robot and the collimator remained consistent ( ) at treatment speeds above . Data at was right at the edge of both the robot capabilities and the analysis technique, and had larger variations in timing ( ). Horizontal margins of and vertical margins of up to were calculated for the treatment delivery system.
We have implemented the first robotic treatment delivery system for synchrotron radiotherapy treatments. The largest errors were observed in the direction of motion of the patient through the beam and with future improvements, can be reduced. The system was both accurate and repeatable and is ready to support future treatments on IMBL.
在临床放射治疗中，患者在治疗期间保持静止，仅对源进行动态操作。在同步加速器放射治疗中，射束是固定的，水平方向宽而垂直方向窄，这就要求患者在射束中移动以确保完全覆盖靶区，同时对射野进行塑形以贴合靶区。目前尚无临床系统能同时实现患者的动态移动和射束的动态塑形。
我们开发并测试了一种新的动态治疗输送系统，该系统能够通过机器人患者定位系统提供适形射野，用于澳大利亚核科学与技术组织澳大利亚同步加速器的成像和医疗束线（IMBL）。
对一台工业机器人操纵器进行了改装，使其能够在IMBL上进行动态放射治疗。该机器人与碳纤维治疗床面以及最近开发的动态准直器相结合，构成了新治疗输送系统的基础。为了使机器人和准直器的运动同步，采用了基于硬件的实时事件处理系统。为了测试该系统，在医学物理体模中的一个滚珠轴承上使用直径从5到40毫米的圆形射野进行治疗，治疗速度为2到50毫米 。将滚珠轴承的位置与圆形射野的中心进行比较，评估治疗输送系统的位置和时间精度，并确定该系统合适的治疗边界。
滚珠轴承的垂直位置随治疗输送速度（ ）变化，而水平位置保持一致（ ）。在治疗速度高于 时，机器人和准直器之间的时间延迟保持一致（ ）。 时的数据恰好在机器人能力和分析技术的边缘，时间变化较大（ ）。为治疗输送系统计算出水平边界为 ，垂直边界最大为 。
我们已经实现了首个用于同步加速器放射治疗的机器人治疗输送系统。在患者穿过射束的运动方向上观察到了最大误差，通过未来的改进可以减小这些误差。该系统既精确又可重复，随时准备支持IMBL上的未来治疗。
