Beam Spot Size Research Articles

A horizontal multi-purpose microbeam system

A horizontal multi-purpose microbeam system with a single electrostatic quadruplet focusing lens has been developed at the Columbia University Radiological Research Accelerator Facility (RARAF). It is coupled with the RARAF 5.5 MV Singleton accelerator (High Voltage Engineering Europa, the Netherlands) and provides micrometer-size beam for single cell irradiation experiments. It is also used as the primary beam for a neutron microbeam and microPIXE (particle induced x-ray emission) experiment because of its high particle fluence. The optimization of this microbeam has been investigated with ray tracing simulations and the beam spot size has been verified by different measurements.

Theoretical analysis of angular distribution of scattering in nozzle components using a response-function method for proton spot-scanning therapy

In spot-scanning proton therapy, highly precise beam control is required in the treatment nozzle such that the proton beam does not spread out during transportation by restraining the divergence of the beam angle and spot size, simultaneously. In order to evaluate the beam-broadening behaviour induced by passing through the various nozzle components, we have developed a new method to calculate the angular divergence profile of a proton beam in the nozzle. The angular divergence of the proton beam for each nozzle component is calculated by the Monte Carlo simulation code, Geant4, assuming that the initial beam has no divergence. The angular divergence profiles generated in the various nozzle components are then fitted by the analytic function formula with triple Gaussian distributions. The fitted profiles can be treated like analytic response functions and the angular divergence profile in the nozzle can be easily and systematically calculated by using a convolution theorem. The beam-broadening behaviour during transportation in the nozzle is carefully evaluated. The beam profiles are well-characterized by the proposed angular divergence analysis, i.e. triple Gaussian profile analysis. The primary Gaussian part of the beam profile is mainly generated by air and dose monitors with plate electrode components. The secondary and tertiary Gaussian parts are so-called wide-angle scattering and generated mainly by spot-position and profile monitors with metal window and wire components. The scattering of the nozzle component can be analysed using the proposed response function method for the angular distribution. Multiple convolved angular scattering can be determined from the response function of the individual nozzle components. The angular distribution from small to large angle regions can then be quantitatively evaluated by the proposed method. The method is quite simple and generalized, and is a straightforward way to understand the nozzle and component characteristics related to the beam-broadening behaviour.

High energy femtosecond laser peening of 2024 aluminum alloy

A femtosecond laser with a pulse energy of up to 100 mJ is used to investigate the feasibility of laser peening of a 2024 aluminum alloy that is widely used in aerospace industry. Laser beam directly irradiates the as-received aluminum sample surface in air without any protective coating for laser absorption and transparent overlay for plasma confinement. The effects of pulse energy, pulse duration and beam spot size on peening performance are studied. Optical microscope and SEM are used to examine the surface morphology of laser peened samples. Vickers hardness test is used to determine the microhardness on the surface. Residual stresses on the surface and at selected depths are measured using x-ray diffraction method. It is found that femtosecond laser can impart compressive residual stresses to a depth of more than 100 µm for this material, but the surface stress condition is not altered significantly.

Production and Laser Characteristics of Fe2+:ZnSxSe1−x Polycrystals

A method is developed for producing active laser elements (spectrum range 4 to 5 μm) based on polycrystalline solid solutions ZnSxSex-1 doped with iron ions. Bilateral diffusion doping of the elements by Fe2+ ions is performed during hot isostatic pressing. Spectral and energy characteristics of the laser are investigated with the Fe2+:ZnS0.1Se0.9 active element kept at room temperature. It is found that the absorption band of the Fe2+:ZnS0.1Se0.9 crystal is blueshifted with respect to the Fe2+:ZnSe absorption band, while the lasing spectra of the Fe2+:ZnSe and Fe2+:ZnS0.1Se0.9 lasers and their energy parameters are almost identical. The lasing energy of 580 mJ is obtained at the slope efficiency with respect to the absorbed energy of 46%. Further increase in the lasing energy is limited by development of transversal parasitic oscillation at a large size of the pump beam spot.

레이저 폴리싱에서 레이저 빔의 다양한 경로조건에 따른 표면거칠기 분석 연구

In laser polishing, a laser beam is used to melt the surface of a work piece to improve surface quality. An optimum combination of process controlling parameters and state of laser beam output is the key strength of laser polishing. Laser beam output power, feed rate, path interval, and spot size are critical parameters in the laser polishing process effect on the thermal state of surface quality. In this study, experimental tests demonstrate that it is an optimum value of the proper processes condition in the pulse laser and CW laser system. The proposed dominant controlling parameters, method for examining morphology; several experimental conditions; and details from performance improvement of surface roughness are presented.

The Hyperion-II radio-frequency oxygen ion source on the UCLA ims1290 ion microprobe: Beam characterization and applications in geochemistry and cosmochemistry

A radio-frequency plasma ion source, the Hyperion-II, has been commissioned on a CAMECA ims1290, a high resolution/high transmission secondary ion mass spectrometer at UCLA. Performance characteristics (e.g., beam density, spot size, etc.) of the primary oxygen beam are documented and application to isotopic analyses requiring high lateral resolution with high secondary ion transmission are described. The Hyperion source delivers on average 10 times and 6 times the current density delivered by the CAMECA duoplasmatron for 16O− and 16O2− beams, respectively. This significantly enhanced current density allows for reduction of the analytical spot size by at least a factor of three while maintaining the beam intensity, making it possible to perform isotopic measurements at smaller scales without sacrificing analytical precision. In addition, the smaller Hyperion beam spot size also reduces the crossover size and spherical aberrations in the secondary ion optics, thereby improving secondary ion transmission at mass resolving power of 3000–12,000 by 25–80% compared to that achieved with a duoplasmatron.

Microstructural and tribological behavior of in situ synthesized Ti/Co coatings on Ti-6Al-4V alloy using laser surface cladding technique

The enhancement of the tribological properties of titanium (Ti-6Al-4V) has been the subject of wide range research over the years. The constraints associated with Ti-6Al-4V in severe tribological conditions due of its low hardness and poor wear properties can be enhanced by appropriate enhancement of the microstructure via surface modification technique without altering the bulk material. In this work, Cp-Ti and Co powders were deposited at different admixed percentages by laser cladding on Ti-6Al-4V substrates with respect to laser processing parameters. The laser optimized parameters used are laser power 900 W, powder feed rate 1.0 g/min, beam spot size 3 mm, and gas flow rate 1.2 L/min while scan speed were varied at 0.6and 1.2m/min. The microstructural evolution as well as wear morphology of the coatings were studied using scanning electron microscope equipped with energy dispersed spectrometry (SEM/EDS) while the phase identification were observed using X-ray diffractometer (XRD). Microhardness values of the coatings were obtained while wear test was conducted using a reciprocating set up. The coatings exhibited a good metallurgical bonding between the coatings and the substrate. Results revealed that laser clad sample with high scan speed was more effective in improving the hardness and wear resistance of Ti-Co/Ti6Al4Vcompared to low scan speed. The coatings possess an average hardness value of 730 HV0.1, a value that is about two times greater than that of the substrate. The enhanced wear resistance with high laser scan speed has been attributed to the presence of flower-like structures and formation of fractions of CoTi2, CoTi, AlTi2, AlCo5, AlCo2Ti, and Al2Ti inter-metallic phases dispersed within the coating matrix. In addition, analysis of worn surfaces and wear mechanism indicated improved resistance to tribological actions.

Evolution of a circularly polarized laser beam in an obliquely magnetized plasma channel

AbstractThe evolution of the spot size and amplitude of a circularly polarized laser beam propagating in a plasma channel embedded in an obliquely applied magnetic field has been investigated. The wave equation describing the evolution of the radiation field is set up and a variational technique is used to obtain the equations governing the evolution of the spot size and amplitude. Numerical methods are used to analyze the evolution of the laser beam spot size and amplitude. It is seen that the amplitudes of the two transverse components of the electric field of the laser beam evolve differently, since they are driven by unequal current densities. This leads to the conversion of a circularly polarized laser beam into an elliptically polarized beam, under appropriate conditions.

A Feasibility Study: Can the Dose to Recurrent Sacral Chordoma be Safely Escalated to 84.6Gy (RBE) Using Pencil-Beam-Scanning Proton Therapy and Volumetric-Modulated Arc Therapy?

Chordomas locally recurrent after surgery are difficult to control. Increasing the total radiation dose has the potential of increasing local control. We investigated the feasibility of dose escalation (84.6Gy RBE, 1.8Gy RBE/fraction) to the gross-tumor-volume (GTV) for recurrent chordomas while respecting dose constraints to organs-at-risk (OARs) using different pencil beam scanning (PBS) beam spot sizes and beam angles as well as VMAT planning. Several patients with recurrent sacral chordomas were selected retrospectively. These patients were originally treated at our institution with pre-operative RT with 50.4Gy RBE, followed by surgery and post-operative boost of 21.6Gy RBE. In this study, GTV is contoured on the recurrent CT image. Treatment plans were generated to provide dose escalation (84.6Gy RBE) to the recurrent GTV with a 3 mm margin. PBS plans were generated using intensity-modulated proton therapy (IMPT) with two sets of beams: one with posterior-anterior (PA) only, and the other with a left- and a right-posterior-oblique beam (LP and RP). Two different spot sizes were evaluated: 8 mm to 15 mm sigma versus 2.3 mm to 4.4 mm sigma in air at isocenter with energies from 220 MeV to 90 MeV. VMAT plans used four partial arcs. OAR dose constraints are listed in the Table and used as optimization objectives and constraints for IMPT and VMAT. The use of posterior-oblique beams reduced the maximum and mean dose to small bowel and bladder compared to a single PA beam. PBS (spot size of 2.3 mm to 4.4 mm) provided the best mean and maximum dose to OARs and improved GTV coverage. Neither PBS with PA beam using spot size of 8 mm to 15 mm, nor the VMAT, plans met the maximum dose constraints for bladder, small bowel and skin. Intergluteal-fold dose was lower with two posterior-oblique beams. VMAT plans had similar maximum and mean dose to some OARs compared to spot size of 8 mm to 15 mm. High dose radiation (84.6Gy RBE) can be delivered to GTV while respecting dose constraints to OARs with PBS using spot size of 2.3 mm to 4.4 mm. PBS generally provides lower mean OARs dose compared to VMAT. Institutions with larger spot size should compare PBS and VMAT plans with different PBS beam angles for certain OARs. Institutions with smaller spot size, two posterior-oblique beams may be favorable compared to a single PA beam.Abstract 3762Maximum dose (Gy RBE)OAR dose constraintsPBS-PA 8 mm-15 mmPBS-PA 2.3 mm-4.4 mmPBS-LP-RP 8 mm-15 mmPBS-LP-RP 2.3 mm-4.4 mmVMATGTV84.987.687.687.587.589.0Sigmoid77.467.066.866.866.465.7Bladder60.066.752.928.635.665.3Small Bowel57.66457.157.955.265.8Rectum77.476.170.977.768.772.7Cauda77.424.10.529.31.23.9Skin rim6674.174.065.262.389.1Mean dose (Gy RBE)PBS-PA 8 mm-15 mmPBS-PA 2.3 mm-4.4 mmPBS-LP-RP 8 mm-15 mmPBS-LP-RP 2.3 mm-4.4 mmVMATGTV85.78685.786.285.7Sigmoid21.015.619.29.821.6Bladder5.04.60.30.319.8Small Bowel2.53.61.20.89.5Rectum29.112.331.214.430.4Cauda2.80.04.70.11.9Skin rim4.57.55.83.44.4 Open table in a new tab

Scanning Beam Spot Preservation for Head and Neck Proton Therapy: Machine, Universal, or 3D-Printed Patient-Related Range Shifter?

To investigate whether machine-related range shifter (MRS) should be replaced by universal proton range shifter (UPRS) or personalized 3D-printed patient specific range shifters (PSRS) to preserve the scanning beam spot size and dosimetric advantage of pencil beam scanning (PBS) proton therapy for head and neck and brain (HNB) patients. In PBS proton therapy, it is critical to maintain the smallest possible spot size to achieve the best organs at risk (OARs) sparing and dose conformality to targets for HNB patient. The spot properties are influenced by range shifter material, dimensions and air gap to patient. Currently MRS and UPRS or 3D-printed PSRS may be used in HNB proton therapy. Their ability to minimize the air gap from the range shifter to patient surface varies with MRS, UPRS and PSRS dimensions and location within the treatment geometry to avoid clearance issues. We analyzed the pros and cons of UPRS developed and routinely used in our clinic along with PSRS relative to MRS by means of in proton beam data measurements, analytical calculations (Differential Moliere formula and Eclipse TPS Analytical Algorithm) and Volumetric Imaging. The UPRS (consists of U-shape, thick couch top) can be consistently placed close to the patient (2-8 cm) and maintain the integrity of the proton spot size (within<0.5mm for a 2cm air gap) during HNB treatment, while the MRS often couldn’t be positioned close to the patient (air gap>15 cm), due to clearance issues. As a result, higher quality dose distributions were achieved (heterogeneity index D5/D95 ∼10% lower) by employing the in house developed UPRS which minimizes air gaps and preserves the spot size. A 3D-printed PSRS may create a virtually near zero air gap and fully preserve the integrity of the spot size. Improved dosimetric plan quality relative to MRS was observed in terms of OAR sparing and dose conformality to target when UPRS and 3D printed PSRS were used for HNB patients. However, for a non-removable UPRS (e.g. thick couch top), the quality of in- room volumetric imaging such as cone beam computed tomography (CBCT) was found to be degraded due to high Z elements (Si and Al). The developments in precise 3D printing allowed the use of homogeneous materials with low Z elements for PSRS, minimizing the impact on CBCT image quality, while it could be also designed as a personalized patient immobilization system. UPRS was found to enhance dosimetry plan quality, but it could complicate the clinical workflow and hinder the value of IGRT when it includes high Z-material components, while the low Z 3D printed homogeneous PSRS may further enhance the dose distribution, minimally impact CBCT image quality and simplify clinical processes when acts as a personalized patient immobilization system for HNB patients.

Characterization of Brazilian ammunitions and their respective gunshot residues with ion beam techniques

In this work we explore the potentialities of analytical techniques based on swift ion beams for the analysis of ammunitions and the respective gunshot residues (GSR). To that end, PIXE (Particle-Induced X-ray Emission), RBS (Rutherford Backscattering Spectrometry) and micro-PIXE were employed in order to provide elemental characterization of three different ammunitions, namely CHOG, EXPO +P+ and Clean Range (CR). Pristine cartridges were taken apart for the characterization of bullets, cases, primer and propellant. Subsequently, shooting sessions were carried out and relatively large GSRs (of the order of 50–150μm across) ejected in the forward direction were collected and analyzed. The PIXE experiments were carried out employing 2.0MeV protons with a beam spot size of 1mm2. For the micro-PIXE experiments, the samples were irradiated with 2.2MeV proton beams of 2×2μm2. Finally, 1.2MeV alpha particles were used for the RBS experiments. Quantitative analyzes were obtained for all constituents of the cartridges. The results show that elements like Pb, Ba and Sb are present in the primer of CHOG and EXPO +P+ ammunitions. Traces of Ba and Pb were found in the CR primers as well, while Sb is absent from these primers. The morphology of the GSRs reveals a spherical-like shape for GSRs from EXPO +P+ and Clean Range ammunitions. On the other hand, particles with an uneven shape were detected for the CHOG ammunition.

Time zero determination for FEL pump-probe studies based on ultrafast melting of bismuth.

A common challenge for pump-probe studies of structural dynamics at X-ray free-electron lasers (XFELs) is the determination of time zero (T0)—the time an optical pulse (e.g., an optical laser) arrives coincidently with the probe pulse (e.g., a XFEL pulse) at the sample position. In some cases, T0 might be extracted from the structural dynamics of the sample's observed response itself, but generally, an independent robust method is required or would be superior to the inferred determination of T0. In this paper, we present how the structural dynamics in ultrafast melting of bismuth can be exploited for a quickly performed, reliable and accurate determination of T0 with a precision below 20 fs and an overall experimental accuracy of 50 fs to 150 fs (estimated). Our approach is potentially useful and applicable for fixed-target XFEL experiments, such as serial femtosecond crystallography, utilizing an optical pump pulse in the ultraviolet to near infrared spectral range and a pixelated 2D photon detector for recording crystallographic diffraction patterns in transmission geometry. In comparison to many other suitable approaches, our method is fairly independent of the pumping wavelength (UV–IR) as well as of the X-ray energy and offers a favorable signal contrast. The technique is exploitable not only for the determination of temporal characteristics of the experiment at the interaction point but also for investigating important conditions affecting experimental control such as spatial overlap and beam spot sizes.

Beam diameter thresholds as applying light depolarization for effective submicron and micron root mean square roughness evaluation.

To further study the microscopic mechanism and beam diameter effect during light depolarization (LDP), we developed a compact laser instrument (λ=632.8 nm) with an adjustable beam diameter of ≥18 μm (approximately 28λ). Six nickel plate samples with rms roughness, Rq, of 42 nm to 2.3 μm (i.e., 0.067-3.7λ) fabricated by the fine-honing method are examined. To analyze the beam diameter effect as applying LDP for submicron and micron Rq evaluation, the cross-sectional beam-spot size (BSS) is adjusted from 20 μm to 650 μm during off-specular inspections. The results of BSS ≤40 μm (i.e., 60λ) have a 10-nm-level Rq sensitivity, while those of BSS ≥140 μm (220λ) have about a 100 times weaker sensitivity. It means that BSS of 60λ and 220λ should have instructional significance as applying LDP for precision levels of 10 nm and 1 μm surface roughness analyses, respectively. In addition, since the instrument is simple, portable, stable, and low-cost, it has great potential for both LDP analyses and practical online roughness testing.

A new method for depth profiling reconstruction in confocal microscopy

Confocal microscopy is commonly used to reconstruct depth profiles of chemical species in multicomponent systems and to image nuclear and cellular details in human tissues via image intensity measurements of optical sections. However, the performance of this technique is reduced by inherent effects related to wave diffraction phenomena, refractive index mismatch and finite beam spot size. All these effects distort the optical wave and cause an image to be captured of a small volume around the desired illuminated focal point within the specimen rather than an image of the focal point itself. The size of this small volume increases with depth, thus causing a further loss of resolution and distortion of the profile. Recently, we proposed a theoretical model that accounts for the above wave distortion and allows for a correct reconstruction of the depth profiles for homogeneous samples. In this paper, this theoretical approach has been adapted for describing the profiles measured from non-homogeneous distributions of emitters inside the investigated samples. The intensity image is built by summing the intensities collected from each of the emitters planes belonging to the illuminated volume, weighed by the emitters concentration. The true distribution of the emitters concentration is recovered by a new approach that implements this theoretical model in a numerical algorithm based on the Maximum Entropy Method. Comparisons with experimental data and numerical simulations show that this new approach is able to recover the real unknown concentration distribution from experimental profiles with an accuracy better than 3%.

Proton beam characterization in the experimental room of the Trento Proton Therapy facility

As proton therapy is becoming an established treatment methodology for cancer patients, the number of proton centres is gradually growing worldwide. The economical effort for building these facilities is motivated by the clinical aspects, but might be also supported by the potential relevance for the research community. Experiments with high-energy protons are needed not only for medical physics applications, but represent also an essential part of activities dedicated to detector development, space research, radiation hardness tests, as well as of fundamental research in nuclear and particle physics.Here we present the characterization of the beam line installed in the experimental room of the Trento Proton Therapy Centre (Italy). Measurements of beam spot size and envelope, range verification and proton flux were performed in the energy range between 70 and 228 MeV. Methods for reducing the proton flux from typical treatments values of 106–109 particles/s down to 101–105 particles/s were also investigated. These data confirm that a proton beam produced in a clinical centre build by a commercial company can be exploited for a broad spectrum of experimental activities. The results presented here will be used as a reference for future experiments.

Experimental validation of the Achromatic Telescopic Squeezing (ATS) scheme at the LHC

The Achromatic Telescopic Squeezing scheme offers new techniques to deliver unprecedentedly small beam spot size at the interaction points of the ATLAS and CMS experiments of the LHC, while perfectly controlling the chromatic properties of the corresponding optics (linear and non-linear chromaticities, off-momentum beta-beating, spurious dispersion induced by the crossing bumps). The first series of beam tests with ATS optics were achieved during the LHC Run I (2011/2012) for a first validation of the basics of the scheme at small intensity. In 2016, a new generation of more performing ATS optics was developed and more extensively tested in the machine, still with probe beams for optics measurement and correction at β* = 10 cm, but also with a few nominal bunches to establish first collisions at nominal β* (40 cm) and beyond (33 cm), and to analysis the robustness of these optics in terms of collimation and machine protection. The paper will highlight the most relevant and conclusive results which were obtained during this second series of ATS tests.

Post-accelerated beams at ISOLDE**This article belongs to the Focus on Exotic Beams at ISOLDE: A Laboratory Portrait special issue.

This paper presents an overview of the REX-ISOLDE post-accelerator and a detailed description of the high intensity and energy ISOLDE (HIE-ISOLDE) energy upgrade. The status of the HIE-ISOLDE post-accelerator and its performance, including time structure, beam spot size, beam purity, etc. is presented. The high-energy beam transfer line is also described in detail and an overview of present and future instrumentation and plans for further developments is given. Finally, the hardware and beam commissioning is presented.

A light-weight compact proton gantry design with a novel dose delivery system for broad-energetic laser-accelerated beams

Proton beams may provide superior dose-conformity in radiation therapy. However, the large sizes and costs limit the widespread use of proton therapy (PT). The recent progress in proton acceleration via high-power laser systems has made it a compelling alternative to conventional accelerators, as it could potentially reduce the overall size and cost of the PT facilities. However, the laser-accelerated beams exhibit different characteristics than conventionally accelerated beams, i.e. very intense proton bunches with large divergences and broad-energy spectra. For the application of laser-driven beams in PT, new solutions for beam transport, such as beam capture, integrated energy selection, beam shaping and delivery systems are required due to the specific beam parameters. The generation of these beams are limited by the low repetition rate of high-power lasers and this limitation would require alternative solutions for tumour irradiation which can efficiently utilize the available high proton fluence and broad-energy spectra per proton bunch to keep treatment times short. This demands new dose delivery system and irradiation field formation schemes. In this paper, we present a multi-functional light-weight and compact proton gantry design for laser-driven sources based on iron-less pulsed high-field magnets. This achromatic design includes improved beam capturing and energy selection systems, with a novel beam shaping and dose delivery system, so-called ELPIS. ELPIS system utilizes magnetic fields, instead of physical scatterers, for broadening the spot-size of broad-energetic beams while capable of simultaneously scanning them in lateral directions. To investigate the clinical feasibility of this gantry design, we conducted a treatment planning study with a 3D treatment planning system augmented for the pulsed beams with optimizable broad-energetic widths and selectable beam spot sizes. High quality treatment plans could be achieved with such unconventional beam parameters, deliverable via the presented gantry and ELPIS dose delivery system. The conventional PT gantries are huge and require large space for the gantry to rotate the beam around the patient, which could be reduced up to 4 times with the presented pulse powered gantry system. The further developments in the next generation petawatt laser systems and laser-targets are crucial to reach higher proton energies. However, if proton energies required for therapy applications are reached it could be possible in future to reduce the footprint of the PT facilities, without compromising on clinical standards.

Comparison of single-event upset generated by heavy ion and pulsed laser

Single-event upset (SEU) is investigated using heavy ion and pulsed laser. The measured SEU cross sections of D and DICE flip-flops are compared. Measurement results indicate pulsed laser is capable of inducing similar SEU to those induced by heavy ion. 3D-TCAD simulation is performed to investigate the factors to impact pulsed laser induced SEU. Simulation results show that the beam spot size significantly impacts SEU cross sections in both low and high laser energy while the variation of the equivalent LET only impacts SEU cross sections in the low laser energy.

Neuropeptide expression and morphometric differences in crushed alveolar inferior nerve of rats: Effects of photobiomodulation.

Inferior alveolar nerve (IAN) injuries may occur during various dental routine procedures, especially in the removal of impacted lower third molars, and nerve recovery in these cases is a great challenge in dentistry. Here, the IAN crush injury model was used to assess the efficacy of photobiomodulation (PBM) in the recovery of the IAN in rats following crushing injury (a partial lesion). Rats were divided into four experimental groups: without any procedure, IAN crush injury, and IAN crush injury with PBM and sham group with PBM. Treatment was started 2days after surgery, above the site of injury, and was performed every other day, totaling 10 sessions. Rats were irradiated with GaAs Laser (Gallium Arsenide, Laserpulse, Ibramed Brazil) emitting a wavelength of 904nm, an output power of 70mWpk, beam spot size at target ∼0.1cm2, a frequency of 9500Hz, a pulse time 60ns, and an energy density of 6J/cm2. Nerve recovery was investigated by measuring the morphometric data of the IAN using TEM and by the expression of laminin, neurofilaments (NFs), and myelin protein zero (MPZ) using Western blot analysis. We found that IAN-injured rats which received PBM had a significant improvement of IAN morphometry when compared to IAN-injured rats without PBM. In parallel, all MPZ, laminin, and NFs exhibited a decrease after PBM. The results of this study indicate that the correlation between the peripheral nerve ultrastructure and the associated protein expression shows the beneficial effects of PBM.