Background: As compared to the flattened photon beam, removing the flattening filter (FF) from the head of a gantry decreases the average energy of the photon beam and increases the dose rate, leading to an impact on the quality of treatment plans.
Objective: This study aimed to compare the quality of intensity-modulated radiation therapy (IMRT) treatment plans for esophageal cancer with and without a flattened filter photon beam.
Material And Methods: In this analytical study, 12 patients, who had already been treated with a 6X FF photon beam, were treated based on new IMRT methods using a 6X the flattening filter-free (FFF) photon beam. Both 6X FF IMRT and 6X FFF IMRT plans used identical beam parameters and planning objectives. All plans were evaluated with planning indices and doses for organs at risk (OARs).
Results: Insignificant dose variation was for HI, CI, D, and V between FF and FFF photon beam IMRT plans. FF-based IMRT plan delivered a 15.51 % and 11.27% higher mean dose to both lungs and heart than the FFF plan, respectively. The integral dose (ID) for the heart and lungs was 11.21% and 15.51%, respectively, less in the IMRT plan with an FFF photon beam.
Conclusion: In contrast to the FF photon beam, a filtered photon beam-oriented IMRT plan provides significant OAR sparing without losing the quality of the treatment plan. High monitor units (MUs), low ID, and Beam on Time (BOT) are major highlights of the IMRT plan with FFF beam.
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http://dx.doi.org/10.31661/jbpe.v0i0.2108-1381 | DOI Listing |
Nano Lett
January 2025
Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States.
Metasurfaces supporting narrowband resonances are of significant interest in photonics for molecular sensing, quantum light source engineering, and nonlinear photonics. However, many device architectures rely on large refractive index dielectric materials and lengthy fabrication processes. In this work, we demonstrate quasi-bound states in the continuum (quasi-BICs) using a polymer metasurface exhibiting experimental quality factors of 305 at visible wavelengths.
View Article and Find Full Text PDFUltramicroscopy
January 2025
Nanopatterning-Nanoanalysis-Photonic Materials Group, Department of Physics, Paderborn University, Warburgerstr. 100, Paderborn, 33098, Germany. Electronic address:
Electron energy-loss spectroscopy (EELS) performed in a scanning transmission electron microscope (STEM) is susceptible to noise, just like every other measurement. EELS measurements are also affected by signal blurring, related to the energy distribution of the electron beam and the detector point spread function (PSF). Moreover, the signal blurring caused by the detector introduces correlation effects, which smooth the noise.
View Article and Find Full Text PDFDentomaxillofac Radiol
January 2025
Associate Professor, Division of Oral Diagnostic Sciences, School of Dentistry, Oregon Health & Science University, Portland, OR, USA.
Objectives: To compare a novel photon-counting sensor, two CBCT protocols and two CMOS sensors on the detection of gaps between a gutta-percha cone and root canal walls.
Methods: Twenty-five mandibular incisors were prepared to 45/.04 (size/taper) at working length.
Light Sci Appl
January 2025
Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Cité and CNRS, Paris, 75013, France.
Vortex beams are currently drawing a great deal of interest, from fundamental research to several promising applications. While their generation in bulky optical devices limits their use in integrated complex systems, metasurfaces have recently proven successful in creating optical vortices, especially in the linear regime. In the nonlinear domain, of strategic importance for the future of classical and quantum information, to date orbital angular momentum has only been created in qualitative ways, without discussing discrepancies between design and experimental results.
View Article and Find Full Text PDFBiomed Opt Express
January 2025
School of Optometry, Indiana University, Bloomington, IN, USA.
To measure the influence of ganglion cell layer (GCL) thickness on the changes in size and red blood cell (RBC) flow in small retinal vessels evoked by full-field flicker. We used a dual-beam adaptive optics scanning laser ophthalmoscope to image 11 healthy young controls in two retinal areas with significantly different GCL thicknesses. All capillaries and arterioles of the superficial vascular plexus were responsive to the flicker stimulation.
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