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Purpose Patient‐Specific Quality Assurance (PSQA) measurement analysis depends on generating metrics representative of calculation and measurement agreement. Considering the heightened capability of discrete spot scanning protons to modulate individual dose voxels, a dose plane comparison approach that maintained all of the capabilities of the well‐established γ test, but that also provided a more intuitive error parameterization, was desired. Methods Analysis was performed for 300 dose planes compared by searching all calculated points within a fixed radius around each measured pixel to determine the dose deviation. Dose plane agreement is reported as the dose difference minimum (DDM) within an empirically established search radius: ΔDmin(r). This per‐pixel metric is aggregated into a histogram binned by dose deviation. Search‐radius criteria were based on a weighted‐beamlet 3σ spatial deviation from imaging isocenter. Equipment setup error was mitigated during analysis using tracked image registration, ensuring beamlet deviations to be the dominant source of spatial error. The percentage of comparison points with

This paper presents a study on the synthesis of a position-phase optimized reconfigurable linear array antenna with uniform amplitude distributions. The objective is to produce a pencil/flat-top beam pair. In this position-phase method, a pencil beam is duly generated with zero degree phases and phases are varied between −180° and 180° to produce a flat-top beam keeping position of the elements and amplitude excitations common to both pencil and flat-top beams. The amplitude distribution of the elements is kept uniform. The phases as well as position of the elements are optimized by Teaching Learning Based Optimization (TLBO), modified Quantum Particle Swarm Optimization (QPSO) and Symbiotic Organisms Search (SOS) algorithms to produce the beam pair. The simulations are done for two Sets of elements and a null placement is included in one of the Sets. The results obtained using these algorithms are duly compared with each other and it is found that SOS algorithm performed in par with TLBO algorithm in the generation of the radiation pattern parameters and better over TLBO and QPSO in statistical values.

The objective of this study is to determine X-ray dose distribution and the correlation between central, peripheral and weighted-centre peripheral doses for various phantom sizes and tube voltages in computed tomography (CT). We used phantoms developed in-house, with various water-equivalent diameters (Dw) from 8.5 up to 42.1 cm. The phantoms have one hole in the centre and four holes at the periphery. By using these five holes, it is possible to measure the size-specific central dose (Ds,c), peripheral dose (Ds,p), and weighted dose (Ds,w).The phantoms are scanned using a CT scanner (Siemens Somatom Definition AS), with the tube voltage varied from 80 up to 140 kVps. The doses are measured using a pencil ionization chamber (Ray safe X2 CT Sensor) in every hole for all phantoms. The relationships between Ds,c, Ds,p, and Ds,w, and the water-equivalent diameter are established. The size-conversion factors are calculated. Comparisons between Ds,c, Ds,p, and Ds,ware also established. We observe that the dose is relatively homogeneous over the phantom for water-equivalent diameters of 12-14 cm. For water-equivalent diameters less than 12 cm, the dose in the centre is higher than at the periphery, whereas for water-equivalent diameters greater than 14 cm, the dose at the centre is lower than that at the periphery. We also find that the distribution of the doses is influenced by the tube voltage. These dose distributions may be useful for calculating organ doses for specific patients using their CT images in future clinical practice.

Purpose Most clinical computed tomography (CT) protocols use helical scanning; however, the traditional method for CTDIvol measurement replaces the helical protocol with an axial scan, which is not easily accomplished on many scanners and may lead to unmatched collimation settings and bowtie filters. This study assesses whether CTDIvol can be accurately measured with a helical scan and determines the impact of pitch, collimation width, and excess scan length. Methods CTDIvol was measured for 95 helical protocols on 31 CT scanners from all major manufacturers. CTDIvol was measured axially, then again helically, with the scan range set to the active area of the pencil chamber seen on the localizer image. CTDIvol measurements using each method were compared to each other and to the scanner-displayed CTDIvol . To test the impact of scan length, the study was repeated on four scanners, with the scan range set to the phantom borders seen on the localizer. Results It was not possible to match the collimation width between the axial and helical modes for 12 of the 95 protocols tested. For helical and axial protocols with matched collimation, the difference between the two methods averaged below 1 mGy with a correlation of R2 = 0.99. The difference between the methods was not statistically significant (P = 0.81). The traditional method produced four measurements that differed from the displayed CTDIvol by >20%; no helical measurements did. The accuracy of the helical CTDIvol was independent of protocol pitch (R2 = 0.0) or collimation (R2 = 0.0). Extending the scan range to the phantom borders increased the measured CTDIvol by 2.1%-9.7%. Conclusion There was excellent agreement between the two measurement methods and to the displayed CTDIvol , without protocol or vendor dependence. The helical CTDIvol measurement can be accomplished more easily than the axial method on many scanners and is reasonable to use for QC purposes.

Highlights • Heterogeneous lung tissue causes degradation of pristine proton pencil beams. • A degradation model was implemented into a treatment planning system. • For large tumor volumes, degradation was negligible. • The mean lung dose was not negatively affected in any of the investigated cases. • Small tumor volumes surrounded by lung tissue might get a local target underdose., Background and purpose Proton therapy may be promising for treating non-small-cell lung cancer due to lower doses to the lung and heart, as compared to photon therapy. A reported challenge is degradation, i.e., a smoothing of the depth-dose distribution due to heterogeneous lung tissue. For pencil beams, this causes a distal falloff widening and a peak-to-plateau ratio decrease, not considered in clinical treatment planning systems. Materials and methods We present a degradation model implemented into an analytical dose calculation, fully integrated into a treatment planning workflow. Degradation effects were investigated on target dose, distal dose falloffs, and mean lung dose for ten patient cases with varying anatomical characteristics. Results For patients with pronounced range straggling (in our study large tumors, or lesions close to the mediastinum), degradation effects were restricted to a maximum decrease in target coverage (D95 of the planning target volume) of 1.4%. The median broadening of the distal 80–20% dose falloffs was 0.5 mm at the maximum. For small target volumes deep inside lung tissue, however, the target underdose increased considerably by up to 26%. The mean lung dose was not negatively affected by degradation in any of the investigated cases. Conclusion For most cases, dose degradation due to heterogeneous lung tissue did not yield critical organ at risk overdosing or overall target underdosing. However, for small and deep-seated tumors which can only be reached by penetrating lung tissue, we have seen substantial local underdose, which deserves further investigation, also considering other prevalent sources of uncertainty.

Purpose: The purpose of this study is to evaluate the performance characteristic of volumetric image-guided dedicated-nozzle pencil beam-scanning proton therapy (PT) system. Materials and Methods: PT system was characterized for electromechanical, image quality, and registration accuracy. Proton beam of 70.2–226.2 MeV was characterized for short- and long-term reproducibility in integrated depth dose; spot profile characteristics at different air gap and gantry angle; positioning accuracy of single and pattern of spot; dose linearity, reproducibility and consistency. All measurements were carried out using various X-ray and proton-beam specific detectors following standard protocols. Results: All electro-mechanical, imaging, and safety parameters performed well within the specified tolerance limit. The image registration errors along three translation and three rotational axes were ≤0.5 mm and ≤0.2° for both point-based and intensity-based auto-registration. Distal range (R90) and distal dose fall-off (DDF) of 70.2–226.2 MeV proton beams were within 1 mm of calculated values based on the international commission on radiation units and measurements 49 and 0.0156× R90, respectively. The R90and DDF were reproducible within a standard deviation of 0.05 g/cm2 during the first 8 months. Dose were linear from 18.5 (0.011 MU/spot) to 8405 (5 MU/spot) MU, reproducible within 0.5% in 5 consecutive days and consistent within 0.8% for full rotation. The cGy/MU for 70.2–226.2MeV was consistent within 0.5%. In-air X(Y) spot-sigma at isocenter varies from 2.96 (3.00) mm to 6.68 (6.52) mm for 70.2–226.2 MeV. Maximum variation of spot-sigma with air-gap of ±20 cm was ±0.36 mm (5.28%) and ±0.82 mm (±12.5%) along X- and Y-direction and 3.56% for full rotation. Relative spot positions were accurate within ±0.6 mm. The planned and delivered spot pattern of known complex geometry agreed with (γ%≤1) for 1% @ 1 mm >98% for representative five-proton energies at four gantry angle. Conclusion: The PT-system performed well within the expected accuracy level and consistent over a period of 8 months. The methodology and data presented here may help upcoming modern PT center during their crucial phase of commissioning.

Background: The aim of this study was to determine the concentrations of lead (Pb) and cadmium (Cd) in lipstick and eye pencil cosmetics of different grades in the markets of Iran. Methods: This descriptive study was conducted in Ahvaz city in 2018. Sixty different samples of lipstick and eye pencil of three common brands were selected and analyzed using the Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES) and the results were compared with standard values recommended by the Food and Drug Administration (FDA). The analysis of lipsticks was based on producer country and colors and producer country only for eye pencil. Results: The mean concentrations of Pb and Cd were 41.86 and 53.42 µg/g, respectively. Concentrations of lead were higher than those of Cd in lipsticks, while for eye pencil, Cd showed higher concentrations. The overall results indicated that in all brands and colors of lipsticks, only 33% of the samples had Pb content less than the FDA limit, and among lipstick samples, 44% had Cd concentration less than the FDA limit of 3 μg/g, however, in 100% of the eye pencil samples, the concentration of Cd was higher than the recommended value of 3 μg/g. Conclusion: Given the health risks of exposure to heavy metals and in order to increase community awareness about the harmful effects of cosmetics, it is necessary to monitor the concentration of these toxic elements in these products and encourage the manufactures to meet the FDA standards.

For calibration of eddy current testing, artificial defects are commonly used by virtue of its simple production and ease control of geometric parameters. However, such defects are significantly different in terms of geometric aspects from real ones, even with a precise control of the manufacturing process. To ensure reliable calibration results, it is mandatory to establish a relationship between the signals from artificial (machined) and real defects. This work exposes a detailed study correlating eddy current signals from electrical discharge machine notch (EDM notch) and fatigue cracks. To perform the tests an absolute pencil probe was used. Although there is a significant difference between the signals of EDM notch and fatigue cracks, the results show that it is possible to use artificial defects to represent fatigue cracks reliably if a proper correction is implemented. Keywords: Eddy current testing, EDM notches, Fatigue cracks

We summarize recent results and ongoing activities in mathematical algorithms and computer science methods related to proton computed tomography (pCT) and intensity-modulated particle therapy (IMPT) treatment planning. Proton therapy necessitates a high level of delivery accuracy to exploit the selective targeting imparted by the Bragg peak. For this purpose, pCT utilizes the proton beam itself to create images. The technique works by sending a low-intensity beam of protons through the patient and measuring the position, direction, and energy loss of each exiting proton. The pCT technique allows reconstruction of the volumetric distribution of the relative stopping power (RSP) of the patient tissues for use in treatment planning and pre-treatment range verification. We have investigated new ways to make the reconstruction both efficient and accurate. Better accuracy of RSP also enables more robust inverse approaches to IMPT. For IMPT, we developed a framework for performing intensity-modulation of the proton pencil beams. We expect that these developments will lead to additional project work in the years to come, which requires a regular exchange between experts in the fields of mathematics, computer science, and medical physics. We have initiated such an exchange by organizing annual workshops on pCT and IMPT algorithm and technology developments. This report is, admittedly, tilted toward our interdisciplinary work and methods. We offer a comprehensive overview of results, problems, and challenges in pCT and IMPT with the aim of making other scientists wanting to tackle such issues and to strengthen their interdisciplinary collaboration by bringing together cutting-edge know-how from medicine, computer science, physics, and mathematics to bear on medical physics problems at hand., 13 pages. Accepted for publication in IEEE Transactions on Radiation and Plasma Medical Sciences. August 16, 2021

Significance High-frequency testing is urgently needed to help prevent the spread of COVID-19. Here, we introduce Low-cost Electrochemical Advanced Diagnostic (LEAD), a diagnostic test that detects SARS-CoV-2 within 6.5 min, costs $1.50 per unit, and uses easily assembled materials such as human angiotensin-converting enzyme 2, modified graphite leads, and a plastic vial. LEAD presents sensitivity comparable to the gold-standard methods (limit of detection for the viral spike protein = 229 fg⋅mL-1) and displays an excellent performance profile when tested using clinical saliva (100.0% sensitivity, 100.0% specificity, 100.0% accuracy) and nasopharyngeal/oropharyngeal (88.7% sensitivity, 86.0% specificity, 87.4% accuracy) samples. Finally, no cross-reactivity with other viruses was detected and the test displayed a viable shelf-life of 5 d when stored at 4 °C., COVID-19 has led to over 3.47 million deaths worldwide and continues to devastate primarily middle- and low-income countries. High-frequency testing has been proposed as a potential solution to prevent outbreaks. However, current tests are not sufficiently low-cost, rapid, or scalable to enable broad COVID-19 testing. Here, we describe LEAD (Low-cost Electrochemical Advanced Diagnostic), a diagnostic test that detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within 6.5 min and costs $1.50 per unit to produce using easily accessible and commercially available materials. LEAD is highly sensitive toward SARS-CoV-2 spike protein (limit of detection = 229 fg⋅mL−1) and displays an excellent performance profile using clinical saliva (100.0% sensitivity, 100.0% specificity, and 100.0% accuracy) and nasopharyngeal/oropharyngeal (88.7% sensitivity, 86.0% specificity, and 87.4% accuracy) samples. No cross-reactivity was detected with other coronavirus or influenza strains. Importantly, LEAD also successfully diagnosed the highly contagious SARS-CoV-2 B.1.1.7 UK variant. The device presents high reproducibility under all conditions tested and preserves its original sensitivity for 5 d when stored at 4 °C in phosphate-buffered saline. Our low-cost and do-it-yourself technology opens new avenues to facilitate high-frequency testing and access to much-needed diagnostic tests in resource-limited settings and low-income communities.

We report on the development of a simple and cost-effective potentiometric sensor array that is based on manual “drawing” on the polymeric support with the pencils composed of graphite and different types of zeolites. The sensor array demonstrates distinct sensitivity towards a variety of inorganic ions in aqueous media. This multisensor system has been successfully applied to quantitative analysis of 100 real-life surface waters sampled in Mahananda and Hooghly rivers in the West Bengal state (India). Partial least squares regression has been utilized to relate responses of the sensors to the values of different water quality parameters. It has been found that the developed sensor array, or electronic tongue, is capable of quantifying total hardness, total alkalinity, and calcium content in the samples, with the mean relative errors below 18%.

Herein, two novel ion-selective electrodes are reported for simultaneous potentiometric determination of Fe3+ and Cu2+ ions. The liquid polymeric membrane components were optimized and the resulting pencil graphite electrodes gave Nernstian slopes of 20.7 mV/decade and 31.2 mV/decade with lower detection of limit of 1×10-6 mol L-1 and 2×10-6 mol L-1, and wide pH range of 1.5-3.5 and 2.0-4.7 for Fe3+ and Cu2+ ions, respectively. The electrodes exhibited very fast response time (

We demonstrate for the first time the concept of ion sensing pencil (ISP). The pencil’s lead carries chemical sensing functionality and is constructed by compression of graphite and zeolite, while the clutch is prepared by 3D printing. The ISP can be used to draw a chemical sensor by simple abrasion onto a hydrophobic surface. The ISP can be stored at home, used immediately off-the-shelf without any handling prior to measurements. It’s simple preparation, handling, and measuring protocols offer the possibility of integration into large scale sensor networks or to be offered to the general public for use at home using readout devices already present at many homes. We demonstrate the chemical functionality of ISP by producing 14 ISPs prepared by compression of graphite and one of 14 different zeolites individually in 60:40 wt%. These ISPs are then used to draw electrodes which were characterized in analogy to ion-selective electrodes. The ISP-drawn electrodes were utilized as a multi-sensor array for the determination of water quality in a model sample, which is a first reported case of using zeolite-based electrodes in multisystem arrays, followed by the demonstration of their potential to be used by non-trained personnel. The implementation ISPs in potentiometric detection holds promise for further development of inexpensive and accessible tools for obtaining chemical information in areas where utilization of chemical sensors is currently limited.

The response of Al2O3:C optically stimulated luminescence detectors (OSLDs) was investigated in a 250 MeV pencil proton beam. The OSLD response was mapped for a wide range of average dose rates up to 9000 Gy s−1, corresponding to a ∼150 kGy s−1 instantaneous dose rate in each pulse. Two setups for ultra-high dose rate (FLASH) experiments are presented, which enable OSLDs or biological samples to be irradiated in either water-filled vials or cylinders. The OSLDs were found to be dose rate independent for all dose rates, with an average deviation −1 when irradiated in the two setups. A third setup for irradiations in a 9000 Gy s−1 pencil beam is presented, where OSLDs are distributed in a 3 × 4 grid. Calculations of the signal averaging of the beam over the OSLDs were in agreement with the measured response at 9000 Gy s−1. Furthermore, a new method was presented to extract the beam spot size of narrow pencil beams, which is in agreement within a standard deviation with results derived from radiochromic films. The Al2O3:C OSLDs were found applicable to support radiobiological experiments in proton beams at ultra-high dose rates.

Multifunctional and low-cost electrode materials are desirable for the next-generation sensors and energy storage applications. This paper reports the use of pencil graphite as an electrode for dual applications that include the detection of free residual chlorine using electro-oxidation process and as an electrochemical energy storage cathode. The pencil graphite is transferred to cellulose paper by drawing ten times and applied for the detection of free residual chlorine, which shows a sensitivity of 27 μA mM-1 cm-2 with a limit of detection of 88.9 μM and linearity up to 7 mM. The sample matrix effect study for the commonly interfering ions such as NO3-, SO42-, CO32-, Cl-, HCO3- shows minimal impact on free residual chlorine detection. Pencil graphite then used after cyclic voltammogram treatment as a cathode in the aqueous Zn/Al-ion battery, showing an average discharge potential plateau of ~1.1 V, with a specific cathode capacity of ~54.1 mAh g-1 at a current of 55 mA g-1. It maintains ~95.8% of its initial efficiency after 100 cycles. Results obtained from the density functional theory calculation is consistent with the electro-oxidation process involved in the detection of free residual chlorine, as well as intercalation and de-intercalation behavior of Al3+ into the graphite layers of Zn/Al-ion battery. Therefore, pencil graphite due to its excellent electro-oxidation and conducting properties, can be successfully implemented as low cost, disposable and green material for both sensor and energy-storage applications.

According to a very popular belief - very widespread among non-scientific communities - the exploitation of narrow beams, a.k.a. ‘‘pencil beamforming’’, results in a prompt increase of exposure levels radiated by 5G Base Stations (BSs). To face such concern with a scientific approach, in this work we propose a novel localization-enhanced pencil beamforming technique, in which the traffic beams are tuned in accordance with the uncertainty localization levels of User Equipment (UE). Compared to currently deployed beamforming techniques, which generally employ beams of fixed width, we exploit the localization functionality made available by the 5G architecture to synthesize the direction and the width of each pencil beam towards each served UE. We then evaluate the effectiveness of pencil beamforming in terms of ElectroMagnetic Field (EMF) exposure and UE throughput levels over different realistic case- studies. Results, obtained from a publicly released open-source simulator, dispel the myth: the adoption of localization-enhanced pencil beamforming triggers a prompt reduction of exposure w.r.t. other alternative techniques, which include e.g., beams of fixed width and cellular coverage not exploiting beamforming. The EMF reduction is achieved not only for the UE that are served by the pencil beams, but also over the whole territory (including the locations in proximity to the 5G BS). In addition, large throughput levels - adequate for most of 5G services - can be guaranteed when each UE is individually served by one dedicated beam., Simulated data from CNIT without using data from other partners

The design of phased arrays able to generate arbitrary-shaped beams through a sub-arrayed architecture is addressed here. The synthesis problem is cast in the excitation matching framework, so as to yield clustered phased arrays providing optimal trade-offs between the complexity of the array architecture (i.e., the minimum number of control points at the sub-array level) and the matching of a reference pattern. A synthesis tool based on the $k$ -means algorithm is proposed for jointly optimizing the sub-array configuration and the complex sub-array coefficients. Selected numerical results, including pencil beams with sidelobe notches and asymmetric lobes as well as shaped main lobes, are reported and discussed to highlight the peculiarities of the proposed approach also in comparison with some extensions to complex excitations of state-of-the-art sub-array design methods.

Proton minibeam radiotherapy (pMBRT) is a spatial fractionation method using sub-millimeter beams at center-to-center (ctc) distances of a few millimeters to widen the therapeutic index by reduction of side effects in normal tissues. Interlaced minibeams from two opposing or four orthogonal directions are calculated to minimize side effects. In particular, heterogeneous dose distributions applied to the tumor are investigated to evaluate optimized sparing capabilities of normal tissues at the close tumor surrounding. A 5 cm thick tumor is considered at 10 cm depth within a 25 cm thick water phantom. Pencil and planar minibeams are interlaced from two (opposing) directions as well as planar beams from four directions. An initial beam size of σ0 = 0.2 mm (standard deviation) is assumed in all cases. Tissue sparing potential is evaluated by calculating mean clonogenic cell survival using a linear-quadratic model on the calculated dose distributions. Interlacing proton minibeams for homogeneous irradiation of the tumor has only minor benefits for the mean clonogenic cell survival compared to unidirectional minibeam irradiation modes. Enhanced mean cell survival, however, is obtained when a heterogeneous dose distribution within the tumor is permitted. The benefits hold true even for an elevated mean tumor dose, which is necessary to avoid cold spots within the tumor in concerns of a prescribed dose. The heterogeneous irradiation of the tumor allows for larger ctc distances. Thus, a high mean cell survival of up to 47% is maintained even close to the tumor edges for single fraction doses in the tumor of at least 10 Gy. Similar benefits would result for heavy ion minibeams with the advantage of smaller minibeams in deep tissue potentially offering even increased tissue sparing. The enhanced mean clonogenic cell survival through large ctc distances for interlaced pMBRT with heterogeneous tumor dose distribution results in optimum tissue sparing potential. The calculations show the largest enhancement of the mean cell survival in normal tissue for high-dose fractions. Thus, hypo-fractionation or even single dose fractions become possible for tumor irradiation. A widened therapeutic index at big cost reductions is offered by interlaced proton or heavy ion minibeam therapy.

Background: Wire-guided localization is the gold-standard for the detection of non-palpable breast lesions, although with acknowledged limitations. The aim of this study was to evaluate the combined use of LOCalizerr™ (Hologic, Santa Carla, CA, USA), and intraoperative ultrasound (IOUS) for localization and surgery of non-palpable breast cancer. Patients and Methods: Patients with non-palpable breast lesions underwent localization procedure with LOCalizer™ and IOUS. After the placement of the marker, eight measures were made to guide the excision. LOCalizerr™ Pencil and IOUS were performed to obtain the distance between the dissection plane and the margins of lesions. Results: The procedure was feasible in the five enrolled patients and associated with clear oncological margins in all cases. Moreover, a high satisfaction according to Likert scale for surgeons, radiologists and patients, performing limited and tailored resections, was reported. Conclusion: Combining LOCalizerr™ and IOUS is an effective method for locating non-palpable breast cancer, guarantying excellent oncological and cosmetic results.

The concept of spatial fractionation in radiotherapy was developed for better sparing of normal tissue in the entrance channel of radiation. Spatial fractionation utilizing proton minibeam radiotherapy (pMBRT) promises to be advantageous compared to X-ray minibeams due to higher dose conformity at the tumor. Preclinical in vivo experiments conducted with pMBRT in mouse ear models or in rat brains support the prospects, but the research about the radiobiological mechanisms and the search for adequate application parameters delivering the most beneficial minibeam therapy is still in its infancy. Concerning preclinical research, we consider glioma, non-small cell lung cancer and hepatocellular carcinoma as the most promising targets and propose investigating the effects on healthy tissue, especially neuronal cells and abdominal organs. The experimental setups for preclinical pMBRT used so far follow different technological approaches, and experience technical limitations when addressing the current questions in the field. We review the crucial physics parameters necessary for proton minibeam production and link them to the technological challenges to be solved for providing an optimal research environment. We consider focusing of pencil or planar minibeams in a scanning approach superior compared to collimation due to less beam halos, higher peak-to-valley dose ratios and higher achievable dose rates. A possible solution to serve such a focusing system with a high-quality proton beam at all relevant energies is identified to be a 3 GHz radio-frequency linear accelerator. We propose using a 16 MeV proton beam from an existing tandem accelerator injected into a linear post-accelerator, boosted up to 70 MeV, and finally delivered to an imaging and positioning end-station suitable for small animal irradiation. Ion-optical simulations show that this combination can generate focused proton minibeams with sizes down to 0.1 mm at 18 nA mean proton current - sufficient for all relevant preclinical experiments. This technology is expected to offer powerful and versatile tools for unleashing structured and advanced preclinical pMBRT studies at the limits and also has the potential to enable a next step into precision tumor therapy.

Programmable metasurfaces have shown great potential in the areas of low-complexity phase array systems in comparison with the conventional phased array antennas. In this document, a 1-bit transmissive programable metasurface with high efficiency is proposed for the cost-effective beam-steering phased array. The designed transmissive metasurface is made up of reconfigurable cells with perfect 1-bit phase tuning and less transmission losses. Through dynamically programming the 1-bit code distributions of the metasurface, real-time scanning pencil beams in desired directions can be created.

International audience; A precise characterization of therapeutic proton pencil beams is essential for commissioning of any treatment planning system (TPS). The dose profile characterization includes measurement of the beam lateral dose profile in the beam core and far from the beam core, in the so called low-dose envelope, and requires a sophisticated detection system with a few orders of magnitude dynamic range. We propose to use a single-quantum sensitive Minipix Timepix detector, along with an in-house designed holder to perform measurements of the pencil beam dose profile in air and in water. We validated the manufacturer calibration of the Minipix Timepix detector in proton beams of various energies and compared the deposited energy spectra to Monte Carlo (MC) simulations. The precision of the lateral dose profile measurements has been systematically validated against Krakow proton facility commissioning data and dose profile simulations performed with MC codes Gate/Geant4 and Fred. We obtained an excellent agreement between Minipix Timepix measurements and simulations demonstrating the feasibility of the system for a simple characterization and validation of proton pencil beams. The proposed approach can be implemented at any proton therapy facility to acquire experimental data needed to commission and validate analytical and MC based TPS.

Nowadays, the irradiation methodology in proton therapy is switching from the use of passively scattered beams to active pencil beams due to the possibility of more conformal dose distributions. The dose rates of active pencil beams are much higher than those of passive beams. The purpose of this study was to investigate whether there is any difference in the biological effectiveness of these passive and active irradiation modes. The beam qualities of double scattering and pencil beam scanning were measured dosimetrically and simulated using the Monte Carlo code. Using the medulloblastoma cell line DAOY, we performed an in vitro comparison of the two modes in two positions along the dose&ndash, deposition curve plateau and inside the Bragg peak. We followed the clonogenic cell survival, apoptosis, micronuclei, and &gamma, H2AX assays as biological endpoints. The Monte Carlo simulations did not reveal any difference between the beam qualities of the two modes. Furthermore, we did not observe any statistically significant difference between the two modes in the in vitro comparison of any of the examined biological endpoints. Our results do not show any biologically relevant differences related to the different dose rates of passive and active proton beams.

We propose the design and test of a 2-D Fabry-Perot structure based on a multilayer slab arrangement fed by a circular array of simple sources. Such a class of planar leaky-wave antenna can be made by low-loss commercial laminates and it is bounded on top by a sub-wavelength partially-reflecting surface. The antenna is designed to suppress undesired radiation from the quasi-TEM mode while leaking power by the excitation of a fast TM1 leaky mode, which is a perturbed version of the guided-wave supported by the corresponding parallel-plate waveguide. An accurate dispersive analysis for the multilayer structure is developed and an original feeding system is designed and optimized to provide the needed wideband impedance matching. Thanks to translational invariance enabled by the homogenized nature of the partially reflecting screen, the antenna is used as a radiating element in the design of a leaky-wave-enhanced phased array, constituted by an arrangement of vertical probes to generate directive pencil beams steerable at a single frequency in azimuth and by changing frequency in elevation.

Graphite pencil stroked electrodes for paper-based Microfluidic devices are gaining immense attention due to their electrochemical properties, cost efficiency, and ease-of-use. However, their widespread use has been hindered by the challenges associated with their manual fabrication such as non-uniformity in graphite deposition, applied pressure, etc. This work presents the design and development of an automated graphite pencil stroking device for graphite electrode fabrication with high efficiency through a compact, inexpensive and automatic process, with reduced fabrication time and human intervention leading to more uniformity. The motion platform of Graphtec plotter was used to create multiple strokes with the help of the proposed device. Such inexpensive graphite electrodes (less than the US $1) have been observed to be porous in nature, acting as diffusion agents. The automated graphite electrodes were used to study the performance of microfluidic paper fuel cells (MPFCs) with formic acid, oxygen, and sulphuric acid acting as fuel, oxidising agent and electrolyte respectively. From this configuration, the maximum current density and power density were measured to be 1,305.5 µA cm−2 and 135.5 µW cm−2, respectively at 0.3 V stable OCP at 100 strokes. Overall, the study enumerates the development of an automated pencil stroke device for fabricating graphite electrodes, which can potentially be harnessed in numerous miniaturized paper based applications.

Photoacoustic (PA) imaging&ndash, a technique combining the ability of optical imaging to probe functional properties of the tissue and deep structural imaging ability of ultrasound&ndash, has gained significant popularity in the past two decades for its utility in several biomedical applications. More recently, light-emitting diodes (LED) are being explored as an alternative to bulky and expensive laser systems used in PA imaging for their portability and low-cost. Due to the large beam divergence of LEDs compared to traditional laser beams, it is imperative to quantify the angular dependence of LED-based illumination and optimize its performance for imaging superficial or deep-seated lesions. A custom-built modular 3-D printed hinge system and tissue-mimicking phantoms with various absorption and scattering properties were used in this study to quantify the angular dependence of LED-based illumination. We also experimentally calculated the source divergence of the pulsed-LED arrays to be 58&deg, &plusmn, 8&deg, Our results from point sources (pencil lead phantom) in non-scattering medium obey the cotangential relationship between the angle of irradiation and maximum PA intensity obtained at various imaging depths, as expected. Strong dependence on the angle of illumination at superficial depths (&minus, 5&deg, /mm at 10 mm) was observed that becomes weaker at intermediate depths (&minus, 2.5&deg, /mm at 20 mm) and negligible at deeper locations (&minus, 1.1&deg, /mm at 30 mm). The results from the tissue-mimicking phantom in scattering media indicate that angles between 30&ndash, 75&deg, could be used for imaging lesions at various depths (12 mm&ndash, 28 mm) where lower LED illumination angles (closer to being parallel to the imaging plane) are preferable for deep tissue imaging and superficial lesion imaging is possible with higher LED illumination angles (closer to being perpendicular to the imaging plane). Our results can serve as a priori knowledge for the future LED-based PA system designs employed for both preclinical and clinical applications.

We report on a new X-ray imaging method, which generalizes Bragg ptychography to 3D mapping of embedded crystalline volumes within thick specimens. The sample is probed by a pencil X-ray beam. The diffracted beam is magnified by an objective and passes through a slit in the image plane to be monitored by a 2D detector in the far-field of the image plane. The dimensions of the incoming beam and the slit opening define a confocal Bragg volume. Scanning the sample with respect to this probe volume, an iterative oversampling routine is used to reconstruct the shape and projected displacement field of extended internal volumes. This routine takes into account the pupil function and known aberrations of the lens. We demonstrate the method by a numerical study of a 3.5 µm grain comprising a wall of edge dislocations. With a probe volume of ∼0.12 µm3 and a compound refractive lens with a numerical aperture of 0.49×10−3 as the objective, the dislocations are fully resolved with a displacement sensitivity of ∼10 pm. The spatial resolution is 26×27×123 nm3 (rms), with the poor resolution along the optical axis being limited by the probe size. With a four times larger numerical aperture, the resolution becomes 16×8×123 nm3 (rms). The lens aberrations are found to be not critical.

In order to monitor the crack growth of the wood material better and reduce failure risks, this paper studied the attenuation characteristics of acoustic emission signals in wood through pencil lead breaking (PLB) tests, in the aim of estimating the true amplitude value of the acoustic emission source signal. The tensile test of the double cantilever beam (DCB) specimens was used to simulate the crack tip growth within wood material, monitoring acoustic activity and location of crack tips within wood material using acoustic emission technology and digital image correlation (DIC). Results showed that the attenuation degree of acoustic emission signals increased exponentially as the propagation distance increased, and the relationship between relative amplitude attenuation rate and the propagation distance of the acoustic emission signal was established by the regression method, which provides the input parameters for the establishment of the crack instability prediction model in the next step. Based on a thermodynamic approach, a theoretical model for predicting crack instability was established, and the model was verified by DCB tests. The model uses acoustic emission parameters as the basis for judging whether the crack is instable. It provides theoretical support for the application of acoustic emission technology in wood health monitoring.

With the development of image processing technology, pencil drawing has been widely used in video games and mobile phone applications. However, the existing pencil drawing algorithms require a large amount of time to convert a real picture into a pencil drawing; hence, it is difficult to apply them to real-time systems. This paper proposes a parallel fast pencil drawing generation algorithm based on the graphics processing unit (GPU) to accelerate the real-time rendering process of sketch painting. The parallelism of the pencil drawing generation algorithm is identified via a theoretical analysis at first. Then, sub-algorithms of the sequential algorithm are designed in parallel using the compute unified device architecture (CUDA) programming model and executed via thread-level parallel techniques. Furthermore, an optimal cache pattern of data that reduce the access time of the most frequently used data is structured using shared memory and constant memory. Finally, task-level parallelism is achieved by the CUDA stream technology, which overlaps independent sub-tasks for further acceleration. On the CUDA platform, the experimental results demonstrate that the proposed parallel algorithm can achieve a significant increase in speedup. The proposed algorithm achieves a performance improvement of 448.59 times compared with the sequential algorithm, on 2560×1920-resolution images, and maintains a high degree of similarity with the real pencil paintings. Hence, the proposed algorithm is suitable for real-time pencil drawing rendering and has promising application prospects in non-photorealistic rendering.

International audience; The constant increase of computed tomography (CT) exams and their major contribution to the collective dose led to international concerns regarding patient dose in CT imaging. Efforts were made to manage radiation dose in CT, mostly with the use of the CT dose index (CTDI). However CTDI does not give access to organ dose information, while Monte Carlo (MC) simulation can provide it if detailed information of the patient anatomy and the source are available. In this work, the X-ray source and the geometry of the GE VCT Lightspeed 64 were modelled, based both on the manufacturer technical note and some experimental data. Simulated dose values were compared with measurements performed in homogeneous conditions with a pencil chamber and then in CIRS ATOM anthropomorphic phantom using both optically stimulated luminescence dosimeters (OSLD) for point doses and XR-QA Gafchromic® films for relative dose maps. Organ doses were ultimately estimated in the ICRP 110 numerical female phantom and compared to data reported in the literature. Comparison of measured and simulated values show that our tool can be used for a patient specific and organ dose oriented radiation protection tool in CT medical imaging.

Differential eddy current probes are commonly used to detect shallow surface cracks in conductive materials. In recent years, a growing number of research works on their numerical modelling was conducted since the development of analytical or semi-analytical models for such a sensor may be prone to intractable complications. In this paper finite element modelling (FEM) has been employed to simulate the interaction of a reflection differential split-D probe with surface electrical discharge machined (EDM) notches in 3-dimensional (3-D) half-space. In order to attain a better insight into the correct setup of the FEM parameters, a simple multi-turn cylindrical absolute coil has also been modelled. The outcome generated through the simulated scan of this absolute coil over a surface notch in aluminum is validated with existing experimental impedance data taken from the literature. Parameters contributing to reliable FEM simulation results, such as maximum mesh size, mesh distribution, the extent of the surrounding air domain and conductivity of the air are investigated for the 3-D modelling of both absolute and differential probes. This study shows that the simulation results on a commercial reflection differential split-D surface pencil probe closely estimate the experimental measurements of the probe’s impedance variations as it scans three EDM notches having different depths in aluminum. The simulation results, generated by Comsol Multiphysics FEM package (COMSOL I, COMSOL multiphysics reference manual, version 5.3, COMSOL AB, 2018, www.comsol.com), for the cases of absolute and differential probes are checked for their extent of validity.

Physical review accelerators and beams 23(3), 031601 (1-25) (2020). doi:10.1103/PhysRevAccelBeams.23.031601, Thomson scattering sources with their hard x-ray pencil beams represent a promising candidate to drivehigh-resolution X-ray Fluorescence Imaging (XFI). As XFI is a scanning imaging modality, it specificallyrequires pencil-beam geometries along with a high beam mobility. In combination with laser-wakefieldacceleration (LWFA) such sources could provide the compactness needed for a future transition intoclinical application. A sufficient flux within a small bandwidth could enable in-vivo high-sensitivity XFIfor early cancer diagnostics and pharmacokinetic imaging. We thus report on a specific all-laser drivensource design directed at increasing the photon number within the bandwidth and opening angle defined byXFI conditions. Typical parameters of driver lasers and electron bunches from LWFA are utilized andcontrolled within realistic parameter regions on the basis of appropriate beam optics. An active plasma lensis implemented for chromatic focal control of the bunch. Source performance limits are identified andcompared to existing x-ray sources with regard to their potential to be implemented in future clinical XFI., Published by American Physical Society, College Park, MD

In this chapter, a battery-less wireless sensor system is proposed, which is called the Power REduced MonolithIc Sensor System (PREMISS), based on monolithic sensors with functions of wireless power receiving, wireless sensing, and wireless data transfer functions. In the PREMISS system, a base-station transmits RF energy and information to sensor nodes via pencil beams and receives the information back from those sensor nodes. In this chapter, the system analysis of the PREMISS system is presented.

Introduction: Penetrating lesions by pencil in the temporal lobe in children and adolescents are uncommon. We present the case of a teenager with penetrating injury by strange object in the temporal lobe. Case: Twelve years old male patient, with history of trauma while he was playing with his friends, presents alteration of the consciousness state, weakness in right hemibody and dysphasia. Urgent surgery is practiced employing an incision in “C” form with improvement of the consciousness state during post-operative. Discussion: Penetrating lesions in the skull and brain are classified as missiles and non-missiles depending of their impact velocity. The wood is a porous organic material that provide a natural deposit of microbian agents, making it potentially lethal. Pre-operative radiological evaluation allows check the trajectory of the penetrating object and secondary lesions present guiding de neurosurgical approach. The prognostic depends on penetration site, timely handling and complications associated. Conclusion: Penetrating lesions by pencil are uncommon, an appropriate imaging evaluation is fundamental to determine the neurosurgical approach that allows prevent and/or decrease secondary damage.

Background and aim: Today, electron accelerators are taken into consideration as photoneutron sources. Therefore, for maximum production of epithermal neutron flux, designing a photoneutron target is of significant importance. In this paper, the effect of thickness and geometric shape of a photoneutron target on neutron output were investigated. Methods: In this study, a pencil photon source with 13, 15, 18, 20 and 25 MeV energies and a diameter of 2 mm was investigated using Monte Carlo simulation method using MCNP code. To optimize the design of the photoneutron target, the tungsten target with various geometries and thicknesses was investigated. Results: The maximum neutron flux produced for all target geometries and thicknesses occurred at neutron energy peak of around 0.46 MeV. As the thickness increased to 2 cm, neutron flux increased and then a decreasing trend was observed. For various geometrical shapes, the determining factor in photoneutron output was the effective target thickness in the photon interaction path that increased by the increase in the area of interaction. Another factor was the angle of the photon's incidence with the target surface that resulted in a significant decrease in photoneutron output in cone-shaped targets Conclusion: Three factors including the total neutron flux, neutrons energy spectrum, and convergence of neutrons plays an important role in the selection of geometry and shape of the target that should be investigated considering beam shaping assembly (BSA) shape

Proton therapy is affected by range uncertainty, which is partly caused by an ambiguous conversion from x-ray attenuation to proton stopping power. CT calibration curves, or Hounsfield look-up tables (HLUTs), are institution-specific and may be a source of systematic errors in treatment planning. A range probing method to verify, optimize and validate HLUTs for proton treatment is proposed. An initial HLUT was determined according to the stoichiometric approach. For HLUT validation, three types of animal tissue phantoms were prepared: a pig's head, 'thorax' and femur. CT scans of the phantoms were taken and a structure, simulating a water slab, was added on the scan distal to the phantoms to mimic the detector used for integral depth-dose measurements. The CT scans were imported into the TPS to calculate individual pencil beams directed through the phantoms. The phantoms were positioned at the therapy system isocenter using x-ray imaging. Shoot-through pencil beams were delivered, and depth-dose profiles were measured using a multi-layer ionization chamber. Measured depth-dose curves were compared to the calculated curves and the range error per spot was determined. Based on the water equivalent path length (WEPL) of individual spot, a range error margin was defined. Ratios between measured error and theoretical margin were calculated per spot. The HLUT optimization was performed by identifying systematic shifts of the mean range error per phantom and minimizing the ratios between range errors and uncertainty margins. After optimization, the ratios of the actual range error and the uncertainty margin over the complete data set did not exceed 0.75 (1.5 SD), indicating that the actual errors are covered by the theoretical uncertainty recipe. The feasibility of using range probing to assess range errors was demonstrated. The theoretical uncertainty margins in the institution-specific setting potentially may be reduced by ∼25%.

We report the fabrication and characterization results of a simple and low-cost pH sensor fabricated using a graphite pencil to define a working electrode and silver paste to define a reference electrode on scotch tape. The sensor operation is based on potentiometric measurement and thereby insensitive to fabrication variations in shape of the electrode unlike amperometric and chemiresistive measurement techniques. The substrate of the disposable sensor is prepared by pasting scotch tape atop a piece of chart paper, and two types of sensors fabricated with 6B and 2B graphite pencils are tested with three solutions with different pH values. The sensor functions as a passive sensing tag without requiring any external power or stimulus, and the measured sensitivities of the pH sensors fabricated using 2B and 6B pencil carbon electrodes (PCEs) are $-4.54mV/pH$ and $-4.09mV/pH$ respectively.

Direct and online continuous monitoring of anaesthetic intake by the patient's blood stream improves practices in the critical procedure of anaesthesia. Several systems have been proposed to address this challenge. Electrochemical techniques are highly appealing because of speed and accuracy, while blood spot sampling and fluidic devices are discouraged in this application, due to the necessity of having constant and continuous monitoring. To overcome this limitation, we developed a sensor suitable for measuring anaesthetics directly in patient's vein. We present here, for the first time, a disposable and low-cost needle-shaped sensor based on a three-electrode electrochemical cell, made of pencil leads and platinum wire. The proposed sensor shows high linearity (99%) in measuring propofol directly in undiluted human serum at the temperature of 37 degrees C in its therapeutic range (30 - 240 mu M), with a limit of detection of 7.2 +/- 3.0 mu M.

Medical physics (2020). doi:10.1002/mp.14119, Published by Wiley, Hoboken, NJ

Acoustic Emission (AE) is used in various fields of engineering and recently has been gained increasing attention in crack detection of cyclically loaded engineering structures. The crack location strategies are rather complicated for realistic structures with complex geometry. In this paper, pencil leads breaking (PLB) experiments and finite element simulation of lamb wave propagation are conducted to give a rational interpretation on acoustic wave propagation within composite structures. Identification of the fundamental extensional mode (S0) and flexural mode (A0) is successfully carried out. The proposed FE models are proven to be a suitable alternative/complement to the experiments, in the monitoring of realistic structures.

Linear arrays forming pencil beams with slowly decaying sidelobes make a good trade-off among excitation dynamic range ratio, beam efficiency, directivity, sidelobe level, and beamwidth. Popular arrays with such sidelobe behavior are Taylor, Gauss, Gegenbauer, and second-kind Chebyshev. In this paper, we propose a closed-form method for the design of pencil-beam arrays with a prescribed sidelobe level. The method exploits the least-squares approximation of a raised cosine function in the azimuth domain, thus bringing the beampattern with slowly decaying sidelobes. For common numbers of excitation coefficients and sidelobe levels, the proposed arrays simultaneously exhibit the optimum beamwidth, dynamic range ratio, and directivity.

Electrochemical properties of linezolid, an antibiotic drug, using unmodified renewable pencil graphite and carbon paste electrodes, were investigated from pH 2 to 10 in Britton-Robinson buffer solution. Experimental studies were examined by square-wave (SW) and cyclic voltammetry (CV). Firstly, parameters affecting the performance of both electrode, such as electrode activation, support electrolyte selection, pH effect, interval of potentials, scan rates and voltammetric method parameters were investigated in detail by using square wave voltammetry. Linezolid was not reversibly oxidized in supporting electrolytes solutions, yielding well-defined peaks in the oxidation potential interval. Using the pencil graphite electrode (PGE), a linearity range between peak current and concentration was obtained between 0.01 and 0.2 mu g mL(-1) (2.96x10(-8)-5.93x10(-7) M), other one, at carbon paste electrode (CPE), a linearity range between 0.1 and 7.5 mu g mL(-1) (2.96x10(-7)-2.22x10(-5) M) was obtained by SWV. The selectivity, sensitivity, precision, and other validation parameters of the developed voltammetric method was evaluated. Lastly, the concentration of linezolid was examined in pharmaceutical and biological samples with standard addition technique.

This article presents the demonstration of several compact millimetre wave sources driven both by a pencil or sheet electron beam from a pseudospark (PS) discharge. The millimetre wave sources include two pencil beam extended interaction oscillators (EIO) in W-band (75-110 GHz), two sheet beam EIOs in W- and G-bands, two pencil beam backward wave oscillators (BWO) in W- and G-bands, and one pencil beam Cherenkov maser in Ka-band. These devices can generate up to kilowatts of output power, which are very attractive for many important applications.

International audience; In this paper, we report the successful combination of macroscopic uniaxial tensile testing of bulk specimen combined with In situ dislocation-scale observations of the evolution of deformation microstructures during loading at several stress states. The dislocation-scale observations were performed by Accurate Electron Channeling Contrast Imaging in order to follow the defects evolution and their interactions with grain boundaries for several regions of interest during macroscopic loading. With this novel in situ procedure, the slip systems governing the deformation in polycrystalline bulk β-Ti21S are tracked during the macroscopic uniaxial tensile test. For instance, curved slip lines that are associated with “pencil glide” phenomenon and tangled dislocation networks are evidenced.

Paper-based sensors fabricated using the pencil-on-paper method are expected to find wide usage in many fields owing to their low cost and high reproducibility. Here, hydrogen (H2) detection was realized by applying palladium (Pd) nanoparticles (NPs) to electronic circuits printed on paper using a metal mask and a pencil. We confirmed that multilayered graphene was produced by the pencil, and then characterized Pd NPs were added to the pencil marks. To evaluate the gas-sensing ability of the sensor, its sensitivities and reaction rates in the presence and absence of H2 were measured. In addition, sensing tests performed over a wide range of H2 concentrations confirmed that the sensor had a detection limit as low as 1 ppm. Furthermore, the sensor reacted within approximately 50 s at all H2 concentrations tested. The recovery time of the sensor was 32 s at 1 ppm and 78 s at 1000 ppm. Sensing tests were also performed using Pd NPs of different sizes to elucidate the relationship between the sensing rate and catalyst size. The experimental results confirmed the possibility of fabricating paper-based gas sensors with a superior sensing capability and response rate.

The three-dimensional structure of GaN/(In,Ga)N core-shell nanowires with multi-faceted pencil-shaped apex is analyzed by electron tomography using high-angle annular dark-field mode in a scanning transmission electron microscope. Selective area growth on GaN-on-sapphire templates using a patterned mask is performed by molecular beam epitaxy to obtain ordered arrays of uniform nanowires. Our results of the tomographic reconstruction allow the detailed determination of the complex morphology of the inner (In,Ga)N multi-faceted shell structure and its deviation from the perfect hexagonal symmetry. The tomogram unambiguously identifies a dot-in-a-wire configuration at the nanowire apex including the exact shape and size, as well as the spatial distribution of its chemical composition. Electronic supplementary material The online version of this article (10.1186/s11671-019-3072-1) contains supplementary material, which is available to authorized users.

One planar 18 \times 18 cm2 reflectarray prototype, capable of generating adjacent pencil beams with the orthogonal circular polarizations (CPs) in the Ka-band (19.2-20.2 GHz), has been designed, manufactured, and measured as a proof-of-concept to demonstrate the possibility of beam separation in the dual-CP applications. The prototype exhibits main beams pointing at elevation angles of 16.7° and 21.3° for left-hand CP and right-hand CP, respectively. A 1.5 dB gain variation and 66% of efficiency are achieved in the frequency band 19.2-20.2 GHz for a design center frequency of 19.7 GHz. These results will be useful for the future work, involving the design of multispot dual-CP and dual-band planar reflectarrays. Ministerio de Economía y Competitividad TEC2016-75103-C2-1-R European Space Agency (ESA) 4000117113/16/NL/AF Junta de Andalucía P12-TIC-1435

Corneal stromal and/or penetrating ocular injuries from pencils and pencil lead are more common in childhood and may lead to intraocular infection or severe intraocular sterile inflammatory reaction. Herein we report 3 children with ocular trauma due to pencil lead injuries. The first case had corneal stromal injury caused by a pencil. In the second case, a pencil perforated the cornea and contacted the iris. In the third case, pencil lead perforated both the cornea and iris and reached the vitreous through the lens zonules. Intracameral triamcinolone (2 mg/0.05 mL) was injected after the pencil lead was removed from the eyeball. Topical anti-inflammatory and cycloplegic drops were prescribed. In conclusion, corneal and especially penetrating ocular injuries from pencil lead may have a good prognosis with the use of appropriate anti-inflammatory and prophylactic antibiotic treatment and follow-up.

Positron emission tomography (PET) is one of the most mature techniques for monitoring in ion beam therapy. PET allows to reconstruct the β + activity generated in the patient by the nuclear interaction of the ions. Taking advantage of the spatial correlation between positron emitters created along the ions path and the dose distribution, it is possible to perform a quality control of the treatment. Usually, to reconstruct the activity generated within the irradiated volume, standard 3D PET reconstruction techniques are implemented. In this work, we explore a new reconstruction method (Straight Forward Reconstruction) particularly useful for reconstructing activity distribution generated by mono-energetic pencil beams. The method was validated by measuring the produced activity distribution with the DoPET system. Irradiations performed with mono-energetic pencil beams on phantoms mimicking human tissues were used for this study. Both reconstruction methods reach an accuracy in the reconstruction of the activity distribution width of the order of 1.5 mm for 2 ⋅ 1 0 8 primaries.