A compact 200 W level diode-side-pumped microsecond (µs) pulse linearly polarized rod Nd:YAG laser oscillator was demonstrated with nearly diffraction-limited beam quality. The oscillator was based on a thermally near-unstable cavity design with two concave lenses in the cavity to enlarge the volume of the fundamental mode, leading to improvement of the laser efficiency and beam quality. Consequently, a record-high average power of 222 W was obtained at a repetition rate of 400 Hz with a 180 µs pulse width, corresponding to an optical-to-optical (o-o) conversion efficiency of 37%. The average beam quality factor was measured to be =1.32, resulting in a brightness value as high as of 11.25/⋅. To the best of our knowledge, this represented the highest average power, the highest o-o efficiency, and the highest brightness for a µs pulse 1064 nm rod Nd:YAG laser oscillator.
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http://dx.doi.org/10.1364/AO.458761 | DOI Listing |
J Imaging
December 2024
Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
In recent years, synthetic Computed Tomography (CT) images generated from Magnetic Resonance (MR) or Cone Beam Computed Tomography (CBCT) acquisitions have been shown to be comparable to real CT images in terms of dose computation for radiotherapy simulation. However, until now, there has been no independent strategy to assess the quality of each synthetic image in the absence of ground truth. In this work, we propose a Deep Learning (DL)-based framework to predict the accuracy of synthetic CT in terms of Mean Absolute Error (MAE) without the need for a ground truth (GT).
View Article and Find Full Text PDFCardiovasc Intervent Radiol
December 2024
Interventional Radiology Department, Radiology Institute, University of Sao Paulo Medical School, São Paulo, Brazil.
Purpose: To investigate the feasibility and initial results of superior (SRA) and middle (MRA) rectal artery embolization for patients with symptomatic hemorrhoidal disease.
Materials And Methods: Prospective, single-center cohort that included ten consecutive patients (Goligher classification was II in 70% and III in 30%.) who underwent SRA and MRA embolization using a combination of microspheres and metallic coils, who completed a follow-up period of 12 months.
J Radiat Res
December 2024
Section of Radiation Safety and Quality Assurance, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577, Japan.
We assessed the effect of beam size on plan robustness for intensity-modulated proton therapy (IMPT) of head and neck cancer (HNC) and compared the plan quality including robustness with that of intensity-modulated radiation therapy (IMRT). IMPT plans were generated for six HNC patients using six beam sizes (air-sigma 3-17 mm at isocenter for a 70-230 MeV) and two optimization methods for planning target volume-based non-robust optimization (NRO) and clinical target volume (CTV)-based robust optimization (RO). Worst-case dosimetric parameters and plan robustness for CTV and organs-at-risk (OARs) were assessed under different scenarios, assuming a ± 1-5 mm setup error and a ± 3% range error.
View Article and Find Full Text PDFJ Craniomaxillofac Surg
December 2024
Glasgow University Dental Hospital & School, Glasgow, UK. Electronic address:
This study was carried out to compare the stability of Le Fort I maxillary advancement between the surgery-first approach (SFA) and the orthodontics-first approach (OFA), and to evaluate the impact of the quality of postoperative occlusion on maxillary stability. In total, 26 patients (13 SFA and 13 OFA) were included in this study. Cone beam computed tomography (CBCT) scans taken at T0 (1 week before surgery), T1 (1 week after surgery), and T2 (6 months after surgery) were used for the assessment of maxillary stability.
View Article and Find Full Text PDFJ Appl Clin Med Phys
December 2024
Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands.
Background: For the development and validation of dynamic treatment modalities and processes on the MR-linac, independent measurements should be performed that validate dose delivery and linac behavior at a high temporal resolution. To achieve this, a detector with both high temporal and spatial resolution is necessary.
Purpose: This study investigates the suitability of a Delta4 Phantom+ MR (Delta4) detector array for time-resolved dosimetry in the 1.
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