In robotic radiosurgery, the compensation of motion of internal organs is vital. This is currently done in two phases: an external surrogate signal (usually active optical markers placed on the patient's chest) is recorded and subsequently correlated to an internal motion signal obtained using stereoscopic X-ray imaging. This internal signal is sampled very infrequently to minimise the patient's exposure to radiation. We have investigated the correlation of the external signal to the motion of the liver in a porcine study using epsilon-support vector regression. IR LEDs were placed on the swines' chest. Gold fiducials were placed in the swines' livers and were recorded using a two-plane X-ray system. The results show that a very good correlation model can be built using epsilon-SVR, in this test clearly outperforming traditional polynomial models by at least 45 and as much as 74%. Using multiple markers simultaneously can increase the new model's accuracy.
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http://dx.doi.org/10.1007/978-3-642-04271-3_44 | DOI Listing |
Comput Biol Med
January 2025
University of Lübeck, Ratzeburger Allee 160, Lübeck, 23562, Schleswig-Holstein, Germany. Electronic address:
Ultrasound imaging can provide 3D images of soft tissue structures in real-time without harmful radiation. Due to its high level of availability and low-cost characteristics, it is becoming more and more interesting for therapy guidance purposes like in radiotherapy. However, for usage in radiotherapy a robust and real-time image analysis method is required to be able to track the target during the treatment session.
View Article and Find Full Text PDFQuant Imaging Med Surg
January 2025
Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
Background: Magnetic resonance (MR) diffusion-derived 'vessel density' (DDVD) is calculated according to: DDVD = Sb0/ROI - S/ROI, where S and S refer to the tissue signal when -value is 0 or 2 s/mm. S and ROI can also be approximated by other low -values diffusion-weighted imaging (DWI). This study investigates the influence of the second motion probing gradient -value and T2 on DDVD calculations of the liver, spleen, and liver simple cyst.
View Article and Find Full Text PDFCurr Med Imaging
January 2025
Department of Radiology, Jingzhou Hospital Affiliated to Yangtze University, Jingzhou 434000, Hubei, China.
There exists a close relationship between liver fibrosis and Hepatocellular Carcinoma (HCC). Prolonged progression of liver fibrosis may ultimately lead to cirrhosis, thereby increasing the risk of developing HCC. Current research is exploring non-invasive methods for assessing liver fibrosis.
View Article and Find Full Text PDFMagn Reson Med
January 2025
Advanced Research Promotion Center, Health Sciences University of Hokkaido, Ishikari, Japan.
Purpose: Redox homeostasis plays a key role in regulating the overall health and development of organisms. This study aimed to develop a compact and mobile continuous-wave (CW) electron paramagnetic resonance (EPR) imager to facilitate stable, highly sensitive fast three-dimensional (3D) whole-body imaging of nitroxide-infused mice.
Methods: A multiturn loop gap resonator with a diameter of 30 mm and length of 35 mm was designed for whole-body EPR imaging.
Clin Oncol (R Coll Radiol)
December 2024
Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark; Department of Oncology, Copenhagen University Hospital - Herlev and Gentofte, Herlev, Denmark.
Aims: Determining appropriate PTV margins for SBRT of liver metastases is a non-trivial task, especially with motion management included. The widely used analytical van Herk margin recipe (van Herk et al., 2000) could break down due to (i) a low number of fractions, (ii) non-Gaussian errors, or (iii) non-homogenous dose distributions.
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