Lustermans Didier, Abdulrahim Roua, Taasti Vicki Trier, Szkitsak Juliane, Švėgždaitė Evita, Clarkin Sarina, Reniers Brigitte, Verhaegen Frank, Paiva Fonseca Gabriel
Department of Radiation Oncology (Maastro), GROW Research Institute for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, The Netherlands.
Research Group NuTeC, Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium.
Phys Imaging Radiat Oncol. 2024 Oct 20;32:100656. doi: 10.1016/j.phro.2024.100656. eCollection 2024 Oct.
In radiotherapy, the image quality of four-dimensional computed tomography (4DCT) is often degraded by artifacts resulting from breathing irregularities. Quality assurance mostly employ simplistic phantoms, not fully representing complexities and dynamics in patients. 3D-printing allows for design of highly customized phantoms. This study aims to validate the proof-of-concept of a realistic dynamic thorax phantom and its 4DCT application.
Using 3D-printing, a realistic thorax phantom was produced with tissue-equivalent materials for soft tissue, bone, and compressible lungs, including bronchi and tumors. Lung compression was facilitated by motors simulating customized breathing curves with an added platform for application of monitoring systems. The phantom contained three tumors which were assessed in terms of tumor motion amplitude. Three 4DCT sequences and repeated static images for different lung compression levels were acquired to evaluate the reproducibility. Moreover, more complex patient-specific breathing patterns with irregularities were simulated.
The phantom showed a reproducibility of ±0.2 mm and ±0.4 mm in all directions for static 3DCT images and 4DCT images, respectively. Furthermore, the tumor close to the diaphragm showed higher amplitudes in the inferior/superior direction (13.9 mm) than lesions higher in the lungs (8.1 mm) as observed in patients. The more complex breathing patterns demonstrated commonly seen 4DCT artifacts.
This study developed a dynamic 3D-printed thorax phantom, which simulated customized breathing patterns. The phantom represented a realistic anatomy and 4DCT scanning of it could create realistic artifacts, making it beneficial for 4DCT quality assurance or protocol optimization.
在放射治疗中，四维计算机断层扫描（4DCT）的图像质量常常因呼吸不规则产生的伪影而下降。质量保证大多采用简单的模体，不能充分体现患者的复杂性和动态变化。3D打印技术可实现高度定制化模体的设计。本研究旨在验证一种逼真的动态胸部模体及其4DCT应用的概念验证。
利用3D打印技术，制作了一个逼真的胸部模体，其采用了软组织、骨骼和可压缩肺组织等效材料，包括支气管和肿瘤。通过电机模拟定制的呼吸曲线并添加监测系统应用平台来实现肺组织的压缩。该模体包含三个肿瘤，对其肿瘤运动幅度进行了评估。采集了三个4DCT序列以及不同肺压缩水平下的重复静态图像，以评估其可重复性。此外，还模拟了更复杂的具有不规则性的患者特异性呼吸模式。
对于静态3DCT图像和4DCT图像，模体在各个方向上的可重复性分别为±0.2毫米和±0.4毫米。此外，如在患者中观察到的那样，靠近膈肌的肿瘤在上下方向上的幅度（13.9毫米）高于肺上部的病变（8.1毫米）。更复杂的呼吸模式显示出常见的4DCT伪影。
本研究开发了一种动态3D打印胸部模体，可模拟定制的呼吸模式。该模体呈现了逼真的解剖结构，对其进行4DCT扫描可产生逼真的伪影，这有利于4DCT质量保证或方案优化。
