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Background: Dosimetry in intraoperative electron radiotherapy (IOERT) poses distinct challenges, especially with inclined applicators deviating from international protocols. Ion recombination in ionization chambers, electron beam degradation due to scattering in cylindrical applicators, coupled with a lack of a well-defined beam quality surrogate, complicate output factor determination with ionization chambers. Synthetic diamond-based detectors, offer potential solutions; however, their suitability requires further exploration.
Purpose: This study addresses output factor determination for beveled applicators. Objectives include assessing the suitability of PTW microDiamond detectors and determining correction factors for ionization chamber measurements based on energy variations at the depth of maximum dose (z) for beveled applicators. Experimental data are compared against results obtained from Monte Carlo simulations.
Methods: We conducted measurements using both PTW microDiamond and IBA CC01 detectors. In addition to benchmarking bevel factors with penEasy, we employed Monte Carlo simulations to determine angular response correction factors for microDiamond detectors and to evaluate energy variations at z for beveled applicators.
Results: The findings indicate that angular response correction factors are unnecessary for microDiamond detectors with beveled applicators. However, variations in mean energy at z potentially impact absorbed dose calculations with ionization chambers, particularly with the most inclined applicators.
Conclusions: Based on our results, the study recommends using microDiamond detectors over cylindrical ionization chambers for output factor determination in IOERT with inclined applicators. Addressing energy variations at z is crucial to improve accuracy in ionization chamber measurements. These findings have implications for dosimetry protocols in IOERT, contributing to enhanced delivery in clinical practice.
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http://dx.doi.org/10.1016/j.ejmp.2024.104836 | DOI Listing |
Rev Sci Instrum
September 2025
Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
Rydberg atoms are widely employed in precision spectroscopy and quantum information science. To minimize atomic decoherence caused by the dc Stark effect, the electric field noise at the Rydberg atom location should be kept below ∼10 mV/cm. Here, we present a simple yet effective electronic circuit, referred to as a clamp switch, that allows one to realize such conditions.
View Article and Find Full Text PDFPhys Med Biol
September 2025
Radiation Oncology, The University of Texas Southwestern Medical Center, 2280 Inwood Road, Dallas, Texas, 75235, UNITED STATES.
Objective: This study aims to investigate the responses of prototype diamond detectors under pulsed ultra-high dose rates (UHDR) pencil-beam-scanning (PBS) protons from a compact proton synchrocyclotron (IBA Proteus®ONE) for small-field UHDR dosimetry.
Approach: flashDiamond detectors (fD) were cross-calibrated with their relative proton responses characterized at conventional dose rates (CONV). Then, absolute UHDR dosimetry was performed and small-field response assessed.
J Egypt Natl Canc Inst
September 2025
Department of Radiation Oncology, Rajiv Gandhi Cancer Institute and Research Center, New Delhi, New Delhi, India.
Aim: This study aimed to evaluate the multifaceted clinical utility of the RUBY phantom as a comprehensive quality assurance (QA) platform in high-precision radiotherapy, particularly for stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT). The objective was to validate its performance in patient positioning, imaging system accuracy, isocenter congruency, and treatment plan verification across various complex clinical scenarios.
Materials And Methods: A series of QA workflows were conducted using the RUBY phantom and its dedicated modular inserts.
Phys Eng Sci Med
August 2025
Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Freeman Hospital, Freeman Road, Newcastle upon Tyne, NE7 7DN, UK.
To determine the optimum value of head scatter correction factor ([Formula: see text]) used in Radcalc software. The head scatter factors for a selection of multi-leaf collimator fields were measured on a Varian TrueBeam Edge and TrueBeam linear accelerators using an ionisation chamber in a mini-phantom. Radcalc calculated the head scatter values for the same fields.
View Article and Find Full Text PDFSensors (Basel)
August 2025
Department of Radiation Oncology, Fu Jen Catholic University Hospital, New Taipei City 24352, Taiwan.
In view of the great need for quality assurance in radiotherapy, this paper proposes a stitching-based detector (SBD) technique and a set of intelligent algorithms that can reconstruct the information of projected particle beams. The reconstructed information includes the intensity, sigma value, and location of the maximum intensity of the beam under test. To verify the effectiveness of the proposed technique and algorithms, this research study adopts the pencil beam scanning (PBS) form of proton beam therapy (PBT) as an example.
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