Shallow Penetration Research Articles

High-speed simultaneous multiscale photoacoustic microscopy

.Photoacoustic microscopy (PAM) is a fast-growing biomedical imaging technique that provides high-resolution in vivo imaging beyond the optical diffusion limit. Depending on the scalable lateral resolution and achievable penetration depth, PAM can be classified into optical resolution PAM (OR-PAM) and acoustic resolution PAM (AR-PAM). The use of a microelectromechanical systems (MEMS) scanner has improved OR-PAM imaging speed significantly and is highly beneficial in the development of miniaturized handheld devices. The shallow penetration depth of OR-PAM limits the use of such devices for a wide range of clinical applications. We report the use of a high-speed MEMS scanner for both OR-PAM and AR-PAM. A high-speed, wide-area scanning integrated OR-AR-PAM system combining MEMS scanner and raster mechanical movement was developed. A lateral resolution of and penetration depth in vivo was achieved using OR-PAM at 586 nm, whereas a lateral resolution of and penetration depth of in vivo was achieved using AR-PAM at 532 nm.

The Surface Cracking Resistance of Al2O3‐Modified SiCf/SiC‐B4C Composites after Cyclic Oxidation in Wet Environment

Aluminum oxide is introduced into SiCf/(SiC + B4C) composites to improve the surface cracking resistance after oxidizing at 1100 °C in O2/H2O (40/60) atmosphere. Research on morphology observation of oxidized composites reveals that Al2O3 can lead to the formation of a dense and smooth oxidation layer, resulting in a relatively shallow oxygen penetration depth. In‐depth studies on acoustic emission reveal that composites with Al2O3 can improve the surface cracking resistance after oxidizing at 1100 °C in O2/H2O (40/60) atmosphere since the retention rates of σmin (first acoustic emission [AE] stress) and σonset (AE onset stress) are significantly increased compared with virgin composites. Moreover, a small number of cumulative events and steep slope of strength–time curves at the initial stage further confirm the improvement of surface cracking resistance after oxidation.

Overcoming tissue scattering in wide-field two-photon imaging by extended detection and computational reconstruction.

Compared to point-scanning multiphoton microscopy, line-scanning temporal focusing microscopy (LTFM) is competitive in high imaging speed while maintaining tight axial confinement. However, considering its wide-field detection mode, LTFM suffers from shallow penetration depth as a result of the crosstalk induced by tissue scattering. In contrast to the spatial filtering based on confocal slit detection, here we propose the extended detection LTFM (ED-LTFM), the first wide-field two-photon imaging technique to extract signals from scattered photons and thus effectively extend the imaging depth. By recording a succession of line-shape excited signals in 2D and reconstructing signals under Hessian regularization, we can push the depth limitation of wide-field imaging in scattering tissues. We validate the concept with numerical simulations, and demonstrate the performance of enhanced imaging depth in in vivo imaging of mouse brains.

Nanotransducers for Near-Infrared Photoregulation in Biomedicine.

Photoregulation, which utilizes light to remotely control biological events, provides a precise way to decipher biology and innovate in medicine; however, its potential is limited by the shallow tissue penetration and/or phototoxicity of ultraviolet (UV)/visible light that are required to match the optical responses of endogenous photosensitive substances. Thereby, biologically friendly near-infrared (NIR) light with improved tissue penetration is desired for photoregulation. Since there are a few endogenous biomolecules absorbing or emitting light in the NIR region, the development of molecular transducers is essential to convert NIR light into the cues for regulation of biological events. In this regard, optical nanomaterials able to convert NIR light into UV/visible light, heat, or free radicals are suitable for this task. Here, the recent developments of optical nanotransducers for NIR-light-mediated photoregulation in medicine are summarized. The emerging applications, including photoregulation of neural activity, gene expression, and visual systems, as well as photochemical tissue bonding, are highlighted, along with the design principles of nanotransducers. Moreover, the current challenges and perspectives in this field are discussed.

Photo- and Sono-Dynamic Therapy: A Review of Mechanisms and Considerations for Pharmacological Agents Used in Therapy Incorporating Light and Sound

As irreplaceable energy sources of minimally invasive treatment, light and sound have, separately, laid solid foundations in their clinic applications. Constrained by the relatively shallow penetration depth of light, photodynamic therapy (PDT) typically involves involves superficial targets such as shallow seated skin conditions, head and neck cancers, eye disorders, early-stage cancer of esophagus, etc. For ultrasound-driven sonodynamic therapy (SDT), however, to various organs is facilitated by the superior... transmission and focusing ability of ultrasound in biological tissues, enabling multiple therapeutic applications including treating glioma, breast cancer, hematologic tumor and opening blood-brain-barrier (BBB). Considering the emergence of theranostics and precision therapy, these two classic energy sources and corresponding sensitizers are worth reevaluating. In this review, three typical therapies using light and sound as a trigger, PDT, SDT, and combined PDT and SDT are introduced. The therapeutic dynamics and current designs of pharmacological sensitizers involved in these therapies are presented. By introducing both the history of the field and the most up-to-date design strategies, this review provides a systemic summary on the development of PDT and SDT and fosters inspiration for researchers working on 'multi-modal' therapies involving light and sound.

Resistivity model of hallow subsurface to find the path of geothermal manifestation in Bora Village of Sigi Regency of Central Sulawesi

Bora geothermal is one of the manifestations that appear at the meeting of two fault zones namely Palu-Koro Fault and Palolo Fault. This geothermal is classified as non-volcanic. Existing tectonic activity, presumably leading to the formation of a depressive zone that triggers a rock intrusion process that conducts heat conductively. To find out the sub-surface structure, we apply the electrical resistivity tomography (ERT) method. The data collection technique we use is 2-D imaging with Wenner configuration, where the number of electrodes is 21 pieces at 6 m intervals. Shallow depths Penetration targeted about 20 m below ground surface (m.bgs. The resistivity values obtained are in the range < 0.15 Ohm.m to > 56.6 Ohm.m which indicates the subsurface layer is strongly influenced by the fluid. However, the interesting thing here is that the hot water pool formed on the surface of about 6 m dimension is passed through the path of ERT measurement around the electrode number 11 and 12, illustrated in the resistivty section to ± 10 m.bgs depth and turning toward the electrode number 4 up to 7 as the lowest anomaly source at depth > 15 m.bgs. This configuration of low resistivity anomaly is what we interpret as a shallow ground pathway with local high temperatures as the source of the emergence of Bora geothermal manifestations.

Near-Infrared-Responsive Photoelectrochemical Aptasensing Platform Based on Plasmonic Nanoparticle-Decorated Two-Dimensional Photonic Crystals

The photoelectrochemical (PEC) analysis is an emerging and fast developing biosensing technique. However, the in vivo PEC biosensing in deep tissue is seriously hampered because of the shallow penetration depth of ultraviolet and visible light. Expanding the optical absorption wavelength of photoelectrodes from the visible light region into the near-infrared (NIR) light region is highly desirable because of its deep tissue penetrability and minimal invasiveness for organisms, but the exploration of the facile strategy to implement efficient NIR absorption with good biocompatibility is still challenging. Herein, a NIR PEC aptasensor is proposed by coupling plasmonic nanoparticles (NPs) into periodic two-dimensional nanocavity (NC) photonic crystals as photoelectrodes, where the Au NPs are sputtered on a periodic two-dimensional TiO2 NC photonic crystal substrate to significantly enhance the NIR PEC response and successfully achieve sensitive PEC detection of Hg2+ under irradiation of NIR light in blood. We believe that the proposed NIR-responsive Au/TiO2 NC-based PEC aptasensor will open a new in vivo biosensing model for a series of important biomolecules and pave up an avenue for the practical applications of PEC biosensing in deep tissue or even in organs and brain of the living body.

Sediment classification in a Brazilian reservoir: Pros and cons of parametric low frequencies

Sediment is the main factor that limits the reservoir lifetime. Therefore, sediment classification is an essential tool for planning and operating reservoir management measures. There has been important development in the hydroacoustic classification of lakebed, especially with linear systems. The main restrictions while using linear hydroacoustic systems for lakebed classification are the shallow penetration in high-frequency applications or the low vertical and horizontal resolution when using low frequencies. With the new developments in the area of echo sounders, parametric systems can achieve high penetration while preserving the high vertical and lateral resolution. To investigate the performance of parametric systems, a new lakebed classification approach was implemented by using a SES2000 Compact. The area studied was the Passauna reservoir in Parana State, Brazil. We used the first echo division method for processing the acoustic data combined with sediment core and grab sampling. The two physical parameters investigated, were the share of the finest fraction (&lt;63 µm) and wet bulk density (WBD). The results showed a high correlation between the primary frequency of 100 kHz (166 µs pulse length) and the physical parameters. Additionally, a significant correlation was observed with the acoustic parameters at 10 kHz frequency. The best correlating acoustic parameter was Attack/Decay (E1´/E1). The gas presence was found to be an important factor determining the penetration depth of the parametric system and the performance of the classification. The advantages of parametric systems, such small directivity and layering effect, represent the major restrictions in sediment classification applications.

PH-activated heat shock protein inhibition and radical generation enhanced NIR luminescence imaging-guided photothermal tumour ablation

Photothermal therapy had great potential in being a new approach of tumour ablation due to their high selectivity and low side effect. However, the shallow penetration depth of near-infrared (NIR) irradiation resulted in the limited curative effect. Herein, a novel nanomedicine was developed based on the indocyanine green-loaded vanadium oxide nanocomposites (VO2-ICG) for pH-activated NIR luminescence imaging-guided enhanced photothermal tumour ablation. In acidic tumour microenvironment, the VO2 NPs were decomposed and released VO2+, which could not only inhibit the function of 60 kDa heat shock protein (HSP60), but also generate hydroxyl radical (OH) by catalysing intratumoral H2O2. Furthermore, the ICG was also released in the decomposition process of VO2 NPs, allowing the pH-activated NIR luminescence imaging and photothermal therapy. The inhibition of HSP60 down-regulated the heat tolerance of cells and the generation of OH up-regulated the intracellular oxidative stress, which enhanced the photothermal therapeutic efficiency. Our work demonstrated a promised method to enhance photothermal therapeutic effect, highlighting the importance of HSP inhibition and OH generation in promoting cell apoptosis under mild hyperthermia.

Flash Surface Treatment of CH3NH3PbI3 Films Using 248 nm KrF Excimer Laser Enhances the Performance of Perovskite Solar Cells

For perovskite solar cells (PSCs), the surface traps of perovskite films have great influence on the charge carrier behavior at the interface of perovskite and charge transport layers. In this investigation, a 248 nm KrF excimer laser with high photon energy and shallow penetration depth is introduced to perform surface modification on the CH3NH3PbI3 film through irradiation for reducing its surface trap density for the first time. A whole excimer laser surface modification (ELSM) process can be completed in few seconds, and the actual interaction time of the excimer laser and perovskite film is only several hundred nanoseconds. After ELSM, the trap density of the CH3NH3PbI3 film decreases from 1.61 × 1016 cm−3 to 5.81 × 1015 cm−3, and the nonradiative recombination is suppressed effectively. As a result, the open‐circuit voltage and the power conversion efficiency (PCE) of CH3NH3PbI3‐based PSCs increase from 1082 ± 27 to 1117 ± 16 mV and from 16.69% ± 0.77% to 18.50% ± 0.65%, respectively, and the PCE of the champion device reaches 19.38%. In addition, the measured larger charge recombination resistance, slower open‐circuit photovoltage decay, and longer charge recombination lifetime confirm the effective suppression effect of ELSM on the charge carrier recombination in PSCs.

Geophysical characterization of the Daskop granophyre dyke and surrounding host rocks, Vredefort impact structure, South Africa

AbstractGranophyre dykes in the central part of the Vredefort impact structure are believed to be the remnants of the impact melt sheet, which intruded downwards along the fractures in the crater floor. Little is known about their original penetration depth, dip, structural relationships with the host rocks, and their general geophysical characteristics. This information is critical to understand the emplacement history of the granophyre dykes, as it relates to the formation and modification of large impact structures. We conducted magnetic and resistivity surveys across the Daskop granophyre dyke (DGD), one of the impact melt dykes in the structure's core. The magnetic survey revealed that the DGD gives a strong magnetic response at positions where the dyke outcrop exceeds the surface topography, but a very weak response where the outcrop is nearly at the same elevation as the surrounding topography. The magnetic anomaly is thus predominantly due to the outcrop protruding above ground level, suggesting a limited volume of dyke material in the subsurface and a small penetration depth. The resistivity survey performed on two profiles, set perpendicularly across the DGD, indicated a shallow penetration depth (&lt;3 m), consistent with the magnetic interpretation. Thus, our geophysical study demonstrates that the DGD is currently at the very bottom of its original emplacement. This may either be an erosional coincidence, or it may be controlled by a fundamental process of impact cratering. Further studies are warranted to determine if other granophyre dykes at Vredefort are similarly at their lowermost terminations.

A Noninvasive Accurate Measurement of Blood Glucose Levels with Raman Spectroscopy of Blood in Microvessels.

Raman spectra of human skin obtained by laser excitation have been used to non-invasively detect blood glucose. In previous reports, however, Raman spectra thus obtained were mainly derived from the epidermis and interstitial fluid as a result of the shallow penetration depth of lasers in skin. The physiological process by which glucose in microvessels penetrates into the interstitial fluid introduces a time delay, which inevitably introduces errors in transcutaneous measurements of blood glucose. We focused the laser directly on the microvessels in the superficial layer of the human nailfold, and acquired Raman spectra with multiple characteristic peaks of blood, which indicated that the spectra obtained predominantly originated from blood. Incorporating a multivariate approach combining principal component analysis (PCA) and back propagation artificial neural network (BP-ANN), we performed noninvasive blood glucose measurements on 12 randomly selected volunteers, respectively. The mean prediction performance of the 12 volunteers was obtained as an RMSEP of 0.45 mmol/L and R2 of 0.95. It was no time lag between the predicted blood glucose and the actual blood glucose in the oral glucose tolerance test (OGTT). We also applied the procedure to data from all 12 volunteers regarded as one set, and the total predicted performance was obtained with an RMSEP of 0.27 mmol/L and an R2 of 0.98, which is better than that of the individual model for each volunteer. This suggested that anatomical differences between volunteer fingernails do not reduce the prediction accuracy and 100% of the predicted glucose concentrations fall within Region A and B of the Clarke error grid, allowing acceptable predictions in a clinically relevant range. The Raman spectroscopy detection of blood glucose from microvessels is of great significance of non-invasive blood glucose detection of Raman spectroscopy. This innovative method may also facilitate non-invasive detection of other blood components.

First investigation on processing parameters for laser powder bed fusion of Ni-Mn-Ga magnetic shape memory alloy

The Ni-Mn-Ga alloy develops strains of several percents in an applied magnetic field. These materials have potential as high-speed actuators, valves, pumps, robots, and microgrippers. Laser powder bed fusion (L-PBF) of Ni-Mn-Ga was investigated in order to establish a preliminary processing window and to understand the effects of processing parameters on end-product composition. In the future, L-PBF could enable the production of functional near net shape Ni-Mn-Ga components on an industrial scale. A series of experiments were conducted for prealloyed Ni-Mn-Ga powder using an L-PBF setup developed in-house. Two different substrate materials, stainless steel 316L and Incoloy 825, were used in the experiments. The single track experiments show that tracks deposited on Incoloy substrates, in comparison to tracks deposited on stainless steel substrates, are wider and have shallower penetration into the substrate. In addition, the tracks deposited on the Incoloy substrates are more likely to exhibit irregular and balling morphologies. The results of the single track and hatching distance experiments were used to manufacture Ni-Mn-Ga cuboids on an Incoloy substrate. Analysis of the cuboid compositions revealed that L-PBF of Ni-Mn-Ga dilutes manganese and gallium. The relative amounts of vaporized manganese and gallium increased as the value of volumetric energy density was increased.

A low inflammatory, Langerhans cell-targeted microprojection patch to deliver ovalbumin to the epidermis of mouse skin

In a low inflammatory skin environment, Langerhans cells (LCs) – but not dermal dendritic cells (dDCs) – contribute to the pivotal process of tolerance induction. Thus LCs are a target for specific-tolerance therapies. LCs reside just below the stratum corneum, within the skin's viable epidermis. One way to precisely deliver immunotherapies to LCs while remaining minimally invasive is with a skin delivery device such as a microprojection arrays (MPA). Today's MPAs currently achieve rapid delivery (e.g. within minutes of application), but are focussed primarily at delivery of therapeutics to the dermis, deeper within the skin. Indeed, no MPA currently delivers specifically to the epidermal LCs of mouse skin. Without any convenient, pre-clinical device available, advancement of LC-targeted therapies has been limited. In this study, we designed and tested a novel MPA that delivers ovalbumin to the mouse epidermis (eMPA) while maintaining a low, local inflammatory response (as defined by low erythema after 24 h). In comparison to available dermal-targeted MPAs (dMPA), only eMPAs with larger projection tip surface areas achieved shallow epidermal penetration at a low application energy. The eMPA characterised here induced significantly less erythema after 24 h (p = 0.0004), less epidermal swelling after 72 h (p < 0.0001) and 52% less epidermal cell death than the dMPA. Despite these differences in skin inflammation, the eMPA and dMPA promoted similar levels of LC migration out of the skin. However, only the eMPA promoted LCs to migrate with a low MHC II expression and in the absence of dDC migration. Implementing this more mouse-appropriate and low-inflammatory eMPA device to deliver potential immunotherapeutics could improve the practicality and cell-specific targeting of such therapeutics in the pre-clinical stage. Leading to more opportunities for LC-targeted therapeutics such as for allergy immunotherapy and asthma.

Simulation of T-bar penetration in soft clay with adhesive contact

To model the deep penetration process of T-bar in soft clay, an adhesive contact algorithm was developed in conjunction with the Coupled Eulerian–Lagrangian approach with consideration of the effect of strain softening. Numerical results show the simulated penetration resistance agrees well with the previous centrifuge experimental data. The failure mechanisms of the clay around the T-bar can be divided into three stages, including shallow penetration stage with global failure mechanism, partially and fully back-flow stages with local failure mechanism. Fluctuations of the penetration resistance can be explained by the formation and evolution of shear bands around the T-bar. Newly formed shear bands would intersect the previously formed shear bands in the partially back-flow stage, which results in the formation of “ear-shaped” areas rotating anticlockwise around the T-bar. The evolution of shear bands would form a similar fabric structure in the fully back-flow stage.

Microstrip Line-Based Glucose Sensor for Noninvasive Continuous Monitoring Using the Main Field for Sensing and Multivariable Crosschecking

Microstrip line (MLIN)-based glucose sensors have been used for noninvasive glucose monitoring. However, the current MLIN-based solutions do not provide enough sensitivity. The reason for this is that they rely on the fringing field of an MLIN that leads to a shallow penetration depth and thus low sensitivity. In this paper, we propose a sensitive MLIN-based glucose sensor using the main field. The idea is illustrated using the following three steps. Step 1 is sensing the glucose level by using the main field, which uses the material under test (MUT) as the substrate of an MLIN terminated with a load; Step 2 is identifying the contribution of different parameters and different components of parameters to sensitivity, which leads to Step 3, in which different parameters and/or different components of parameters are crosschecked for sensing. Two frequency bands, 100 to 500 MHz and 1.4 to 1.9 GHz, were investigated. In Step 1, the main field configuration was compared with its fringing field counterpart. It is shown that the proposed MLIN configuration presents an average sensitivity of $1.8\times 10^{-3}$ dB/(mg/dL) in terms of the reflection coefficient that is more than 10 times higher than that of its counterpart. In Step 2, different components of the reflection coefficient and the input impedance of the proposed configuration were examined, and their diverse contributions to the sensitivity were shown, which allows crosschecking to improve sensing accuracy. This was successfully shown in Step 3, in which algorithms for crosschecking were proposed, and the sensing accuracy was examined. In terms of the optimal sensing frequency band, 1.4 to 1.9 GHz shows higher sensitivity than 100 to 500 MHz, where the molecules may interact the most with the waves. This implies that the interaction between a wave and the sensing structure with the MUT contributes more to sensitivity than the direct interaction between the wave and the MUT. The radiofrequency safety of the proposed configuration was examined by checking the specific absorption rate of the MUT with the proposed structure. This paper offers a new avenue for the development of an MLIN-based noninvasive glucose sensor for continuous monitoring with high sensitivity in the near future. It can be used both as a single sensor and in a multiple-sensor glucose monitoring system.

Near-Infrared-Light Activatable Nanoparticles for Deep-Tissue-Penetrating Wireless Optogenetics.

Optogenetics has been developed to control the activities and functions of cells with high spatiotemporal resolution, cell-type specificity, and flexibility. However, current optogenetic tools generally rely on visible light (e.g., blue or yellow) with shallow tissue penetration ability that does require invasive fiber-optic probes to deliver visible light into organs and animal tissues. This often results in a series of side effects, such as tissue damage and unwanted inflammation. Fortunately, the emerging wireless optogenetic tools that can respond to deep-tissue-penetrating near-infrared (NIR) light have attracted increasing attention due to their much-reduced damage to living organisms. There are mainly two types of NIR-activatable optogenetic tools: one uses lanthanide-doped upconversion nanoparticles to transduce NIR light to visible light to modulate classical opsin-expressing neurons; the other type couples with an NIR absorber to convert NIR light to heat to activate thermosensitive proteins. These NIR-activatable optogenetic tools enable low-invasive "remote control" activation and inhibition of cellular signaling pathways. This approach has great potential to help create more innovative therapies for diseases like cancer, diabetes, and neuronal disorders in the near future. Therefore, this review article summarizes the recent advances on design strategies and synthetic methods of NIR-activatable nanomaterials for wireless optogenetic applications.

One-Step Solvothermal Formation of Pt Nanoparticles Decorated Pt2+-Doped α-Fe2O3 Nanoplates with Enhanced Photocatalytic O2 Evolution

The photooxidation of water into O2 has been identified as the barrier of water-splitting, and light-driven water oxidation catalysts have been intensively explored to develop highly active water splitting materials. Despite the fascinating advantages for photocatalytic water oxidation, such as abundance in nature, inexpensiveness, low toxicity, thermo/photostability, and suitable electronic band structures, hematite α-Fe2O3 is a poor photocatalyst for water oxidation due to its short exciton lifetime and hole diffusion length, weak carrier mobility, and shallow sunlight penetration depth. In this work, we have synthesized Pt nanoparticles decorated Pt2+-doped α-Fe2O3 nanoplates (Pt/Pt-Fe2O3 NPs) by a one-step solvothermal route which exhibit the enhanced photoactivity and photostability for water oxidation. The introduction of the Pt into the α-Fe2O3 by the means of elemental doping and nanoparticle decoration accounts for the enhanced performance. The doping of Pt2+ into α-Fe2O3 improves the isolation e...

Discrete numerical simulations of torpedo anchor installation in granular soils

Torpedo anchors are a viable approach for mooring marine hydrokinetic (MHK) energy devices to the seafloor. These anchors can serve to maintain station and to provide the reaction force for an MHK device. The ability of the anchor to perform these duties is a strong function of its penetration depth during installation. This is a large-strain problem not amenable to typical continuum numerical approaches. In the current work, we propose that the discrete element method (DEM) is a more appropriate tool to investigate the shallow penetration of torpedo anchors in sands. The effects of anchor mass, impact velocity, and soil interparticle friction are considered in the DEM simulations. The relative maximum penetration depths for different penetration conditions are quantified and presented. Granular material response at the microscale during penetration are used to provide insight into system response. Energy dissipation in the assembly by both friction and collision at the particle scale are considered. Results show that anchor penetration increases approximately linearly with an increase in impact velocity or anchor weight. Penetration decreases with an increase in interparticle friction (i.e., soil strength). Observations of microscale behaviors and energy calculations are used to provide insight into overall system response.

9. Commissioning of the first synchrotron-based scanning proton beamline for ocular melanoma treatments

Purpose Around 10 centers worldwide treat ocular tumors with proton therapy, all with dedicated eyelines. Our synchrotron-based facility is equipped with general-purpose fixed beamlines; proton and carbon ion treatments are delivered with pencil beam scanning modality (range in water 3 ÷ 32 cm). Recently, our proton beamline was adapted to treat also ocular diseases. The main dosimetric properties of this new eyeline are described in this work. Methods A 3 cm water-equivalent range shifter (RS) was placed along the beamline to reach shallower penetration depths. In order to achieve steep lateral dose gradients, the position of the RS and patient-specific collimator were simulated using MonteCarlo (MC) FLUKA code. Lateral dose profiles were measured with gafchromic EBT3 films to evaluate lateral penumbra width and dose homogeneity. Several beam scanning patterns were tested. Depth-dose distributions (DDDs) were measured with the Peakfinder system. To obtain uniform dose distributions (Spread-Out Bragg Peaks, SOBPs), the weights of each DDD were optimized simulating different targets. Absorbed doses were then measured in water with an advanced Markus chamber. Neutron dose at the contralateral eye was also evaluated with passive bubble dosimeters. Results MC simulations and experimental results showed that maximizing the distance between RS and collimator reduces the lateral dose penumbra of the collimated beam and increases field transversal dose homogeneity. Therefore, RS and patient-specific collimator were placed at about 98 cm (behind beam monitors) and 6 cm from the isocenter, respectively. The lateral penumbra (distal fall-off) ranged between 1.0 and 1.8 mm (1.0 and 1.6 mm). The measured SOBP doses were in very good agreement with MC simulations, as shown in Fig. 1. The mean neutron dose at the contralateral eye was 68.8 ± 10.2 μSv/Gy. Conclusions Our eyeline satisfied the requirements to treat ocular tumors. The first ocular patient was treated in August 2016. Around 60 patients have been treated so far.