Proton boron capture therapy offers a promising enhancement to conventional proton therapy by leveraging the 11B(p,a)3a nuclear reaction for localized dose amplification. This study systematically investigates the Bragg curve characteristics of proton beams using the Geant4 Monte Carlo toolkit, with a particular focus on the dosimetric impact of ??B. The introduction of a pure ??B target induced a consistent forward shift in the Bragg peak position, attributed to increased stopping power and nuclear reactions. Furthermore, Proton boron capture therapy demonstrated enhanced local energy deposition along the central axis due to the generation of high linear energy transfer alpha particles, with minimal lateral broadening. To facilitate precise treatment planning, Bragg curve data for 800 distinct proton energies (0-80 MeV) in water were generated. Various machine learning algorithms were subsequently employed to develop predictive models for the Bragg peak position. Comparative analysis identified gaussian process regression as the optimal model, achieving an R? of 0.999997 and a root mean squared error of approximately 0.0273 mm for predicting Bragg peak positions in water. Crucially, this research pioneers a novel pathway for proton boron capture therapy treatment planning by combining high-accuracy machine learning-based prediction of the initial Bragg peak (in water) with a characterized correction for the ??B-induced forward shift, enabling more precise determination of the actual treatment depth. This work provides critical dosimetric characterization, quantifies key ??B-induced phenomena, and offers a validated predictive framework, thereby establishing a theoretical foundation and technical support for dose optimization in this emerging therapeutic modality.
Values for diagnostic reference levels are proposed for intraoral dental radiography in the Republic of Serbia. Proposed numbers for diagnostic reference levels were based on measurements on 119 intraoral units in clinical settings for an adult posterior bitewing X-ray. Values of 3.17 mGy, 3.11 mGy, and 1.58 mGy incident air kerma were found for image receptors film E class, charge-coupled device, and photostimulable phosphor plate, respectively. Similarly, 89.6 mGycm2, 88 mGycm2, and 44.6 mGycm2 air kerma-area products were found for the same detectors. All values are greater than those published in several other similar studies. This is especially true for charge-coupled device image receptors since this technology enables lower patient doses as reported before. This calls for urgent action to optimize intraoral dental imaging, so we present the radiographic techniques used and equipment description to help guide optimization actions.
Aleksandar Kovacevic, Nenad Munic, Nenko Brkljac
et al.
This paper presents an interlaboratory comparison of radiated emission measurements in the frequency range of 30-1000 MHz. A tubular dipole was specifically designed and employed as a reference emitting source. The most important for a tubular dipole is stability in the testing process. The stability is not the performance of the sample, but the emission signal of the sample is stable. In addition, two ways of determining the reference value of the electromagnetic field strength are considered. The first reference value is obtained by using robust analysis. It is a robust average value that is calculated by averaging the measurement results provided by the participating testing laboratories. The other reference value is obtained through the simulation-experimental results of the tubular dipole in the semi-anechoic chamber or full anechoic chamber, for horizontal and vertical polarizations and 3 m distance measurement, respectively. In addition, this value is assigned by the coordinator. Measurement results are compared using the robust z-scores and -scores, respectively.
In fluoroscopy guided interventional procedures, a ceiling suspended screen is used to protect personnel for scattered X-ray radiation arising from patient treatment. The correct positioning of the screen is crucial for proper occupational radiation protection. The proposed solution in this paper provides reliable and efficient protection from scattered radiation, based on an X-ray device and the protective screen merging into one system via an appropriate interface. After the initial manual positioning, automatic repositioning of the screen is executed, by curving the screen laterally, clockwise or counterclockwise, and then with the upper or lower edge forward. All potential clinical situations were analyzed, considering the need for screen position correction: the semi-automatic solution is designed and realized to follow medical procedure in order to maintain an efficient level of staff radiation protection. Furthermore, the assessment of the occupational radiation dose, provided for screen position optimization, will be included into the radiation dose structural report. With application of the universal interface, the presented solution can be applied not only to newly manufactured ones, but to existing C-arm X-ray devices as well.
From a homeland security point of view, it is important to detect the transportation of radioactive materials or potential radioactive contamination. The most commonly used devices are radiation portal monitors with plastic scintillation detectors. A signal from such detectors is processed by an amplitude analyser which can separate pulses into several mutually independent energy windows (representing energy intervals of gamma radiation). Therefore, the most appropriate method of evaluation is by the use of algorithms for multidimensional processing. This article describes a novel generalised approach designed with respect to the properties of radiation portal monitors. It includes a description of formulas and a whole algorithm as well as the procedure for determining the appropriate critical and detection limits. The predicted probability distribution for the proposed method of calculation was verified by simulations and experimental measurements. The algorithm was also compared with a commonly used gross counting algorithm.
KLF Collaboration, Moskov Amaryan, Mikhail Bashkanov
et al.
We propose to create a secondary beam of neutral kaons in Hall D at Jefferson Lab to be used with the GlueX experimental setup for strange hadron spectroscopy. The superior CEBAF electron beam will enable a flux on the order of $1\times 10^4~K_L/sec$, which exceeds the flux of that previously attained at SLAC by three orders of magnitude. The use of a deuteron target will provide first measurements ever with neutral kaons on neutrons. The experiment will measure both differential cross sections and self-analyzed polarizations of the produced $Λ$, $Σ$, $Ξ$, and $Ω$ hyperons using the GlueX detector at the Jefferson Lab Hall D. The measurements will span CM $\cosθ$ from $-0.95$ to 0.95 in the range W = 1490 MeV to 2500 MeV. The new data will significantly constrain the partial wave analyses and reduce model-dependent uncertainties in the extraction of the properties and pole positions of the strange hyperon resonances, and establish the orbitally excited multiplets in the spectra of the $Ξ$ and $Ω$ hyperons. Comparison with the corresponding multiplets in the spectra of the charm and bottom hyperons will provide insight into he accuracy of QCD-based calculations over a large range of masses. The proposed facility will have a defining impact in the strange meson sector through measurements of the final state $Kπ$ system up to 2 GeV invariant mass. This will allow the determination of pole positions and widths of all relevant $K^\ast(Kπ)$ $S$-,$P$-,$D$-,$F$-, and $G$-wave resonances, settle the question of the existence or nonexistence of scalar meson $κ/K_0^\ast(700)$ and improve the constrains on their pole parameters. Subsequently improving our knowledge of the low-lying scalar nonet in general.
During the transportation of spent nuclear fuels, the potential release of the radioactive materials into the atmosphere in the case of an accident becomes a serious threat to public health and the environment. In China, a commercial reprocessing plant is planned to be commissioned around 2025 based on the China nuclear roadmap. After being cooled on site the spent nuclear fuels are transported to the reprocessing plant by train or truck. This requires the assessment of radiological consequences of such accidents during transportation, therefore dose calculations under hypothetical accident conditions have been presented in this paper. The total effective dose equivalent and ground deposition are calculated using the HotSpot health physics computer code with site-specific meteorological conditions. The results indicate that the total effective dose equivalent and ground deposition are both decreased with the increase of the downwind distance. The maximum of the total effective dose equivalent is about 1.4?101 Sv, which is larger than the regulation limit for the public. The TEDE counter plot shows that the inner regions marked with dose contours of 1.0?10?3 Sv are higher than the regulation limits for the public, however this needs no intervention but any unnecessary trip to this area should be avoided.
Transplant arteriosclerosis is the hallmark of chronic allograft dysfunction (CAD) affecting transplanted organs in the long term. These fibroproliferative lesions lead to neointimal thickening of arteries in all transplanted allografts. Luminal narrowing then leads to graft ischemia and organ demise. To date, there are no known tolerance induction strategies that prevent transplant arteriosclerosis. Therefore, we designed this study to test the hypothesis that human regulatory T cells (Treg cells) expanded ex vivo can prevent transplant arteriosclerosis. Here we show the comparative capacity of Treg cells, sorted via two separate strategies, to prevent transplant arteriosclerosis in a clinically relevant chimeric humanized mouse system. We found that the in vivo development of transplant arteriosclerosis in human arteries was prevented by treatment of ex vivo–expanded human Treg cells. Additionally, we show that Treg cells sorted on the basis of low expression of CD127 provide a more potent therapy to conventional Treg cells. Our results demonstrate that human Treg cells can inhibit transplant arteriosclerosis by impairing effector function and graft infiltration. We anticipate our findings to serve as a foundation for the clinical development of therapeutics targeting transplant arteriosclerosis in both allograft transplantation and other immune-mediated causes of vasculopathy.
Ex vivo lung perfusion (EVLP) provides the ability to evaluate donor lungs before transplantation. Yet, limited prospective clinical data exist with regard to its potential to recondition unacceptable donor lungs. This paper summarizes the results of a prospective study of lung transplantation using only initially unacceptable donor lungs, which were improved by EVLP for 2–4 h. From March 2010–June 2011, 13 lungs were evaluated ex vivo. Median donor PaO2 at FiO21.0/PEEP5 was 216 mmHg (range 133–271). Four lungs, all with trauma history, showed no improvement and were discarded. Nine lungs improved to a ΔPO2 higher than 350 mmHg. Median PvO2 at final assessment in these lungs was 466 mmHg (range 434–525). These lungs were transplanted with a median total ischemic time of 577 min (range 486–678). None of the patients developed primary graft dysfunction grades 2 or 3 within 72 h after transplantation. One patient with secondary pulmonary hypertension was left on a planned prolonged extracorporeal membrane oxygenation postoperatively. Median intubation time was 2 days. Thirty‐day mortality was 0%. During the observation period, 119 patients received standard lung transplantation with comparable perioperative outcome. EVLP has a significant potential to improve the quality of otherwise unacceptable donor lungs.