Purpose: To evaluate geometric variations of patients receiving stereotactic body radiotherapy (SBRT) after radical prostatectomy and the dosimetric benefits of stereotactic MRI guided adaptive radiotherapy (SMART) to compensate for these variations.
Materials/methods: The CTV and OAR were contoured on 55 MRI setup scans of 11 patients treated with an MR-LINAC and enrolled in a phase II trial of post-prostatectomy SBRT. All patients followed institutional bladder and rectum preparation protocols and received five fractions of 6-6.8 Gy to the prostate bed. Interfractional changes in volume were calculated and shape deformation was quantified by the Dice similar coefficient (DSC). Changes in CTV-V95%, bladder and rectum maximum dose, V32.5Gy and V27.5Gy were predicted by recalculating the initial plan on daily MRI. SMART was retrospectively simulated if the predicted dose exceeded pre-set criteria.
Results: The CTV volume and shape remained stable with a median volumetric change of 3.0% (IQR -3.0% to 11.5%) and DSC of 0.83 (IQR 0.79 to 0.88). Relatively large volumetric changes in bladder (median -24.5%, IQR -34.6% to 14.5%) and rectum (median 5.4%, IQR - 9.7% to 20.7%) were observed while shape changes were moderate (median DSC of 0.79 and 0.73, respectively). The median CTV-V95% was 98.4% (IQR 94.9% to 99.6%) for the predicted doses. However, SMART would have been deemed beneficial for 78.2% of the 55 fractions based on target undercoverage (16.4%), exceeding OAR constraints (50.9%), or both (10.9%). Simulated SMART improved the dosimetry and met dosimetric criteria in all fractions. Moderate correlations were observed between the CTV-V95% and target DSC (R2 = 0.73) and bladder mean dose versus volumetric changes (R2 = 0.61).
Conclusions: Interfractional dosimetric variations resulting from anatomic deformation are commonly encountered with post-prostatectomy RT and can be mitigated with SMART.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8200117 | PMC |
| http://dx.doi.org/10.3390/cancers13112802 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Parametric Design and Mechanical Characterization of a Selective Laser Sintering Additively Manufactured Biomimetic Ribbed Dome Inspired by the Chorion of Lepidopteran Eggs.
Biomimetics (Basel)
December 2024
Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University, 57001 Thermi, Greece.
The current research aims to analyze the shape and structural features of the eggs of the lepidoptera species sp. (Lepidoptera, Nympalidae) and develop design solutions through the implementation of a novel strategy of biomimetic design. Scanning electron microscopy (SEM) analysis of the chorion reveals a medial zone that forms an arachnoid grid resembling a ribbed dome with convex longitudinal ribs and concave transverse ring members.
View Article and Find Full Text PDFCranial variation across spiny pocket mice (Heteromys, Liomys) in new phylogenetic and taxonomic perspectives.
Zoology (Jena)
January 2025
Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA.
Spiny pocket mice are usually divided into two genera, Heteromys and Liomys, and more recently the latter have been subsumed into the former, leaving subfamily Heteromyinae with one genus. However, this arrangement conveys false equivalency among heteromyines, and does not represent the great morphological, molecular, and ecological diversity in this subfamily. To address this, geometric morphometric methods were used to explore interspecific cranial variation in this subfamily, which were then evaluated in the context of recent phylogenetic and taxonomic findings.
View Article and Find Full Text PDFSIRE: Scale-invariant, rotation-equivariant estimation of artery orientations using graph neural networks.
Med Image Anal
January 2025
Department of Applied Mathematics, Technical Medical Centre, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
The orientation of a blood vessel as visualized in 3D medical images is an important descriptor of its geometry that can be used for centerline extraction and subsequent segmentation, labeling, and visualization. Blood vessels appear at multiple scales and levels of tortuosity, and determining the exact orientation of a vessel is a challenging problem. Recent works have used 3D convolutional neural networks (CNNs) for this purpose, but CNNs are sensitive to variations in vessel size and orientation.
View Article and Find Full Text PDFCharacterization and evaluation methods of fused deposition modeling and stereolithography additive manufacturing for clinical linear accelerator photon and electron radiotherapy applications.
Phys Med
January 2025
Centre for Medical Radiation Physics, University of Wollongong Australia, Wollongong, NSW 2522, Australia.
Purpose: To propose comprehensive characterization methods of additive manufacturing (AM) materials for MV photon and MeV electron radiotherapy.
Methodology: This study investigated 15 AM materials using CT machines. Geometrical accuracy, tissue-equivalence, uniformity, and fabrication parameters were considered.
Geometric description of a gliding grey-headed albatross () for computer-aided design.
Bioinspir Biomim
January 2025
Department of Mechanical and Aeronautical Engineering, University of Pretoria, 1 Lynnwood Road, Pretoria, 0002, SOUTH AFRICA.
Albatrosses are increasingly drawing attention from the scientific community due to their remarkable flight capabilities. Recent studies suggest that grey-headed albatrosses may be the fastest and most energy-efficient of the albatross species, yet no attempts have been made to replicate their wing design. A key factor in aircraft design is the airfoil, which remains uncharacterized for the grey-headed albatross.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!