Objective: To assess the electron beam dose verification, and to investigate the dependability and stability of the Startrack two-dimensional array.
Methods: The is cross-secional study was conducted from January to April 2021 at the Baghdad Centre for Radiotherapy and Nuclear Medicine, Baghdad Medical City, Baghdad, Iraq. Quality assurance measurements were made using a StarTrack two-dimensional detector on an electron beam with an energy of 12MeV at 1.5cm depth for field sizes 6cm×6cm and 14cm×14cm. The detector was positioned 100cm from the source to the surface of the linear accelerator infinity. Testing was done using the International Electrotechnical Commissioning protocol.
Results: There was a significant difference between field sizes 6cmx6cm and 14cmx14cm (-4.97±0.83, -2.01±0.68, respectively) (p<0.05). The beam profile measurements of penumbra, flatness and symmetry were within limits ±2 cm, and ±2 cm, 2%, respectively. The percentage of output dose curve against distance showed instability in crossline for 6cm x 6cm and 14cm x 14cm field size.
Conclusions: The output dose was found to be above the tolerance level, and should be corrected before patient treatment for 12MeV energy electron beam therapy.
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http://dx.doi.org/10.47391/JPMA-BAGH-16-18 | DOI Listing |
Appl Radiat Isot
January 2025
Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui, 230031, China. Electronic address:
This study investigated the influence of tissue electron density on proton beam dose distribution using TOPAS Monte Carlo simulation. Heterogeneous tissue models composed of 14 materials were constructed to simulate the dose deposition process of a 169.23 MeV proton beam.
View Article and Find Full Text PDFInt J Radiat Oncol Biol Phys
January 2025
Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Purpose: Randomized trials have demonstrated similar local tumor control in patients treated with accelerated partial-breast irradiation (APBI) compared with whole-breast irradiation. However, the optimal APBI dose for maximizing tumor control and minimizing toxicity is uncertain.
Methods And Materials: We enrolled patients ≥18 years of age with grade 1 or 2 ductal carcinoma in situ or stage I invasive breast cancer and resection margins ≥2 mm between 2003 and 2011 to a sequential dose-escalation trial using 3-dimensional conformal external beam APBI giving twice daily 4 Gy fractions with total doses of 32 Gy, 36 Gy, and 40 Gy.
J Microsc
January 2025
Department of Mechanical, Materials and Aerospace Engineering, University of Liverpool, Liverpool, UK.
Electron backscatter diffraction (EBSD) has developed over the last few decades into a valuable crystallographic characterisation method for a wide range of sample types. Despite these advances, issues such as the complexity of sample preparation, relatively slow acquisition, and damage in beam-sensitive samples, still limit the quantity and quality of interpretable data that can be obtained. To mitigate these issues, here we propose a method based on the subsampling of probe positions and subsequent reconstruction of an incomplete data set.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Department of Industrial Engineering and Management, Shanghai Jiao Tong University, Shanghai 200240, China.
Taking the titanium alloy wing-body connection joint at the rear beam of a certain type of aircraft as the research object, this study analyzed the failure mechanism and verified the structural safety of the wing-body connection joint under actual flight loads. Firstly, this study verified the validity of the loading system and the measuring system in the test system through the pre-test, and the repeatability of the test was analyzed for error to ensure the accuracy of the experimental data. Then, the test piece was subjected to 400,000 random load tests of flight takeoffs and landings, 100,000 Class A load tests, and ground-air-ground load tests, and the test piece fractured under the ground-air-ground load tests.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Centrum Výzkumu Řež s.r.o., Hlavní 130, 250 68 Husinec-Řež, Czech Republic.
Fuel failure caused by fretting damage to cladding remains a relevant issue despite decades of research and development aimed at enhancing the physical parameters of fuel. This paper presents the results of experiments conducted at the Research Centre Řež on Zr-1%Nb alloy tube specimens covered with protective coatings made of chromium (Cr) and nitrogen (N) compounds. The experiments involved debris-fretting tests under dry conditions at room temperature as well as microscopic measurements of groove depths.
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