Sick Justin T, Rancilio Nicholas J, Fulkerson Caroline V, Plantenga Jeannie M, Knapp Deborah W, Stantz Keith M
School of Health Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907, USA.
Department of Veterinary Clinical Sciences, Purdue University College of Veterinary Medicine, 625 Harrison Street, West Lafayette, IN 47907, USA.
Phys Imaging Radiat Oncol. 2019 Nov 15;12:10-16. doi: 10.1016/j.phro.2019.10.003. eCollection 2019 Oct.
Ultrasound (US) is a non-invasive, non-radiographic imaging technique with high spatial and temporal resolution that can be used for localizing soft-tissue structures and tumors in real-time during radiotherapy (RT) (inter- and intra-fraction). A comprehensive approach incorporating an in-house 3D-US system within RT is presented. This system is easier to adopt into existing treatment protocols than current US based systems, with the aim of providing millimeter intra-fraction alignment errors and sensitivity to track intra-fraction bladder movement.
An in-house integrated US manipulator and platform was designed to relate the computed tomographic (CT) scanner, 3D-US and linear accelerator coordinate systems. An agar-based phantom with measured speed of sound and densities consistent with tissues surrounding the bladder was rotated (0-45°) and translated (up to 55 mm) relative to the US and CT coordinate systems to validate this device. After acquiring and integrating CT and US images into the treatment planning system, US-to-US and US-to-CT images were co-registered to re-align the phantom relative to the linear accelerator.
Statistical errors from US-to-US registrations for various patient orientations ranged from 0.1 to 1.7 mm for x, y, and z translation components, and 0.0-1.1° for rotational components. Statistical errors from US-to-CT registrations were 0.3-1.2 mm for the x, y and z translational components and 0.1-2.5° for the rotational components.
An ultrasound-based platform was designed, constructed and tested on a CT/US tissue-equivalent phantom to track bladder displacement with a statistical uncertainty to correct and track inter- and intra-fractional displacements of the bladder during radiation treatments.
超声（US）是一种无创的非放射成像技术，具有高空间和时间分辨率，可用于在放射治疗（RT）期间（分次间和分次内）实时定位软组织结构和肿瘤。本文介绍了一种在RT中纳入内部3D-US系统的综合方法。该系统比现有的基于US的系统更容易应用于现有治疗方案，旨在提供毫米级的分次内对准误差，并对分次内膀胱运动进行跟踪。
设计了一个内部集成的US操纵器和平台，以关联计算机断层扫描（CT）扫描仪、3D-US和直线加速器坐标系。相对于US和CT坐标系，旋转（0-45°）并平移（最大55毫米）一个基于琼脂的体模，该体模的声速和密度与膀胱周围组织一致，以验证该设备。在将CT和US图像采集并集成到治疗计划系统后，对US-US和US-CT图像进行配准，以相对于直线加速器重新对准体模。
对于不同患者体位，US-US配准的统计误差在x、y和z平移分量上为0.1至1.7毫米，旋转分量为0.0-1.1°。US-CT配准的统计误差在x、y和z平移分量上为0.3-1.2毫米，旋转分量为0.1-2.5°。
设计、构建并在CT/US组织等效体模上测试了一个基于超声的平台，以跟踪膀胱位移，其统计不确定性可在放射治疗期间校正和跟踪膀胱的分次间和分次内位移。
