China
Africa
Explore chapters and articles related to this topic
Image-Guided Radiation Therapy (IGRT) and Motion Management
Published in Eric Ford, Primer on Radiation Oncology Physics, 2020
In the earlier 2000s a technique was developed which allowed for dynamic visualization of motion using CT scans, called “4DCT.” This technique was first described by Ford et al. (2003). For the first 4DCT movie see the video.
Quantitative imaging using CT
Published in Ruijiang Li, Lei Xing, Sandy Napel, Daniel L. Rubin, Radiomics and Radiogenomics, 2019
Lin Lu, Lawrence H. Schwartz, Binsheng Zhao
4D-CT is a new CT technology that can capture the location and movement of patient’s lesion and organ over time. For instance, for a lung 4D-CT scanning, a number of 3D-CT images tagged with breathing signals are acquired, and each 3D-CT image corresponds to a particular breathing phase. By gathering all 3D-CT imaging, the constituted 4D-CT scanning set can cover the entire breathing cycle of the patient. Since 4D-CT is designed to alleviate the imaging distortion caused by organ motion, radiomic features extracted from 4D-CT are expected to be more reproducible than those extracted from 3D-CT.
Precision and Uncertainties for Moving Targets *
Published in Harald Paganetti, Proton Therapy Physics, 2018
Christoph Bert, Martijn Engelsman, Antje C. Knopf
For motion evaluation before treatment, 4DCT imaging is still standard. Recently, it has been shown that prospective 4DCT reconstruction is superior to retrospective reconstruction resulting in less artifacts. Dou et al. [105] have proposed a promising implementation that was recently applied clinically. To capture motion variations and drift effects, the 4D MR may play a bigger role in the future [54].
Novel 4DCT Method to Measure Regional Left Ventricular Endocardial Shortening Before and After Transcatheter Mitral Valve Implantation
Published in Structural Heart, 2021
Gabrielle M. Colvert, Ashish Manohar, Francisco J. Contijoch, James Yang, Jeremy Glynn, Philipp Blanke, Jonathon A. Leipsic, Elliot R. McVeigh
The primary limitation of this preliminary study is the small number of patients analyzed (17 total) which precludes correlation of these results with clinical outcomes. However, the results demonstrate that regional shortening from CT can measure both the baseline state of the endocardium, and changes in regional cardiac function with high spatial resolution and high precision without making a priori assumptions about LV geometry on a wide variety of scanners. The 4DCT exams for the 17 total patients analyzed were acquired on 4 different scanner platforms and were obtained retrospectively for this study. As shown in Table 1, if images of sufficient quality were obtained, the analysis could be performed. With recent advances in CT scanners, including wide-detector technology, dual source x-ray, and high pitch acquisition platforms, ED and ES phases can be acquired in a single heartbeat and at very low x-ray dose.5,13 Poor image quality from step artifacts can be avoided with single-beat CT technology.
Analysis of early respiratory-related mortality after radiation therapy of non-small-cell lung cancer: feasibility of automatic data extraction for dose–response studies
Published in Acta Oncologica, 2020
Louise Stervik, Niclas Pettersson, Jonas Scherman, Claus F. Behrens, Crister Ceberg, Silke Engelholm, Kerstin Gunnarsson, Andreas Hallqvist, Jan Nyman, Gitte F. Persson, Mette Pøhl, Isak Wahlstedt, Ivan R. Vogelius, Anna Bäck
The patients were immobilised with a vacuum pillow or prefabricated breast board, preferably with the arms above their head, and a computed tomography (CT) scan was performed in treatment position. From 2009 to 2010 onwards, a positron emission tomography (PET) scan was acquired for most patients. 4DCT was implemented at the four hospitals between 2009 and 2012. The gross tumour volume (GTV) was delineated from the CT image series and guided by the metabolic tumour volume if a PET scan was performed. A clinical target volume (CTV) was created by adding approximately 5–10 mm margin to the GTV and adjusted to avoid, e.g., bones or large vessels. The planning target volume (PTV) was created by adding a 4–15 mm margin to the CTV. The margin included adjustment to tumour motion according to the 4DCT image series when available. The total lung tissue, i.e., both lungs excluding the GTV, was automatically defined using CT numbers according to local clinical protocols.
Current radiotherapy techniques in NSCLC: challenges and potential solutions
Published in Expert Review of Anticancer Therapy, 2020
Niccolò Giaj-Levra, Paolo Borghetti, Alessio Bruni, Patrizia Ciammella, Francesco Cuccia, Alessandra Fozza, Davide Franceschini, Vieri Scotti, Stefano Vagge, Filippo Alongi
Advancements in RT are closely linked to the ability to target cancer through imaging and avoid the surrounding normal tissue structure, lowering the irradiated volume and allowing for dose escalation. Image-guided radiotherapy (IGRT) takes place at every step of the treatment in lung cancer, from treatment planning with fusion imaging, to daily in-room repositioning. Managing tumor and organ motion has been possible since the introduction of routine four-dimensional computed tomography (4DCT) use. The assessment of respiratory motion has been performed with ‘passive’ techniques based on reconstruction images from 4DCT planning, or ‘active’ techniques adapted to the patient’s breathing. Additionally metabolic imaging has a great importance in radiotherapy planning, dose delivering and adaptive approach, with the aim to increase the accuracy in target definition and sparing of healthy tissues. Magnetic resonance imaging (MRI) and functional imaging also play an important role in lung cancer radiation and open the way for adaptive RT.