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Purpose Surface-guided radiotherapy is useful for the pre-positioning and monitoring of radiotherapy. The purpose of this study was to investigate the impact of surface guidance on the repeatability of patient localization and to estimate the specific point at which high positional errors occur. Materials and methods Ten patients without the VOXELAN system (non-VXLN group) and 10 patients with the VOXELAN as the pre-positioning procedure (VXLN group) were included in this analysis. Twelve regions of interest (ROI) were defined in all the patients to verify any misalignment during radiotherapy. Thirteen ROIs were defined on the isocenter. Results Compared with the non-VXLN group, the translational positional errors of the VXLN group were the same for all the ROIs. The mean translational positional errors of the VXLN group in the longitudinal direction were approximately 0.1 mm, and the standard deviation was the largest among the three directions in all the ROIs. The magnitude of the standard deviation in the non-VXLN group varied independently of the ROI and direction. The standard deviations of the VXLN group in the longitudinal direction were large in all the ROIs, while the standard deviations in the vertical and lateral directions were small. Conclusion Pre-positioning with a surface guidance system reduced the body twist and rotation, which could not be corrected by image-guided radiotherapy alone. Since the VOXELAN can detect positioning errors quickly and without additional radiation exposure to the patient, it can be used as a tool for pre-positioning in radiotherapy.

OBJECTIVE To evaluate the acceptance of orthodontists, laypeople and the patient when progressive mandibular advancements are performed in class II subjects with mandibular retrognathism. SETTING AND SAMPLE 3D images were obtained by an optical surface scanning of fifteen individuals (12 males and three females, mean age of 23 years and 8 months) with mandibular retrognathism in three mandibular positions: maximum intercuspation (MIC) and progressive mandibular advancement of 2 and 4 mm. METHODS The images (n = 45) were evaluated through a scale by two groups of panellist, 20 orthodontists, 20 laypeople and by the patients themselves (n = 15). The participants evaluated and rated each video and give scores between 0 and 10, according to their perception of facial harmony. MANOVA for repeated measures was used for intra- and intergroup differences and to evaluate the patients' self-perception. RESULTS Laypeople reported better face acceptance than orthodontists in MIC and progressive mandibular advancement of 2 and 4 mm (P

This experimental study provides a further understanding of the post-burning nature of sharp force trauma. The main objective is to analyse the distortion that fire may inflict on the length, width, roughness, and floor shape morphology of toolmarks induced by four different implements. To this end, four fresh juvenile pig long bones were cut with a bread knife, a serrated knife, a butcher machete, and a saw. A total of 120 toolmarks were induced and the bone samples were thus burnt in a chamber furnace. The lesions were analysed with a 3D optical surface roughness metre before and after the burning process. Afterwards, descriptive statistics and correlation tests (Student's t-test and analysis of variance) were performed. The results show that fire exposure can distort the signatures of sharp force trauma, but they remain recognisable and identifiable. The length decreased in size and the roughness increased in a consistent manner. The width did not vary for the saw, serrated knife, or machete toolmarks, while the bread knife lesions slightly shrunk. The floor shape morphology varied after burning, and this change became more noticeable for the three knives. It was also observed that the metrics of the serrated knife and machete cut marks showed no significant variations. Our results demonstrate that there is a variation in the toolmark characteristics after burning. This distortion is dependent on multiple factors that influence their dimensional and morphological changes, and the preservation of class features is directly reliant upon the weapon employed, the trauma caused, and the burning process conditions.

A computational tool is developed to measure the local deformations in optical surfaces from the interference patterns obtained by the Chalmers test principle and from the analysis of a reflective optical surface using a commercial Fizeau interferometer of the ZYGO. The tests were made on a concave spherical mirror with a radius of curvature of 60 cm and a diameter of 13 cm. To obtain the measurements of local deformations, a computational tool proposed for the localization of dark fringes is used by evaluating the maximum and minimum of the image obtained in the interference patterns. The results obtained show that the computational tool allows locating fringes within an interference pattern, allowing faster inter-fringe measurements and assigning an error on the surface in terms of wavelength.

Multiscale optical surface (MOS) that contains non-rotational symmetry micro-features and large sag height macro-features is promising in optics, due to their special optical advantages. Diamond turning with the slow tool servo (STS) or fast tool servo (FTS) is widely used for fabricating optical surfaces. However, due to the limited dynamic performance of STS and the small stroke of FTS, applying STS or FTS alone cannot efficiently fabricate MOS. Therefore, in this paper, a hybrid tool servo (HTS) diamond turning technique was presented to efficiently produce MOS. By integrating characters of the high dynamic performance of FTS and long stroke of STS, the new technique fulfills the strict requirements of manufacturing MOS. Methods for generating tool path in CAD software and separating the tool path into STS path and FTS path based on its spectral features were proposed. Besides, tool path evaluations were conducted to predict the profile errors with considering the dynamic performance of STS and FTS, based on the suitable machining parameters selected. A machining experiment of a typical MOS was carried out using the proposed technique. Results showed that the MOS was efficiently fabricated with no tool interference mark on the fabricated surface and a maximum profile error of about 2.8 μm.

Purpose To evaluate the accuracy of surface‐guided radiotherapy (SGRT) in cranial patient setup by direct comparison between optical surface imaging (OSI) and cone‐beam computed tomography (CBCT), before applying SGRT‐only setup for conventional radiotherapy of brain and nasopharynx cancer. Methods and Materials Using CBCT as reference, SGRT setup accuracy was examined based on 269 patients (415 treatments) treated with frameless cranial stereotactic radiosurgery (SRS) during 2018‐2019. Patients were immobilized in customized head molds and open‐face masks and monitored using OSI during treatment. The facial skin area in planning CT was used as OSI region of interest (ROI) for automatic surface alignment and the skull was used as the landmark for automatic CBCT/CT registration. A 6 degrees of freedom (6DOF) couch was used. Immediately after CBCT setup, an OSI verification image was captured, recording the SGRT setup differences. These differences were analyzed in 6DOFs and as a function of isocenter positions away from the anterior surface to assess OSI‐ROI bias. The SGRT in‐room setup time was estimated and compared with CBCT and orthogonal 2D kilovoltage (2DkV) setups. Results The SGRT setup difference (magnitude) is found to be 1.0 ± 2.5 mm and 0.1˚±1.4˚ on average among 415 treatments and within 5 mm/3˚ with greater than 95% confidence level (P 5.0mm and 9 (2.2%) are >3.0˚. The setup differences show minor correlations (|r| < 0.45) between translational and rotational DOFs and a minor increasing trend (

To analyse and compare the surface topography and roughness of three different types of diffractive multifocal IOLs.Using scanning electron microscope (SEM, Inspect F, 5.0 KV, maximum magnification up to 20,000) and atomic force microscope (AFM, Park Systems, XE-100, non-contact, area profile comparison, 10 × 10 µm, 40 × 40 µm), the surface quality of the following diffractive IOLs was studied: the AcrySof IQ PanOptix (Alcon, USA), the AT LARA 829MP (Carl Zeiss Meditec, Germany), and Tecnis Symfony (JohnsonJohnson Vision, USA). The measurements were made over three representative areas (central non-diffractive optic, central diffractive optic, and diffractive step) of each IOL. Roughness profile in terms of mean arithmetic roughness (RIn SEM examination, all IOLs showed a smooth optical surface without any irregularities at low magnification. At higher magnification, Tecnis Symfony showed unique highly regular, concentric, and lineate structures in the diffractive optic area which could not be seen in the other studied diffractive IOLs. The differences in the measured RVarious different topographical traits were observed in three diffractive multifocal IOLs. The RDie Qualität und die morphologischen Eigenschaften der Oberfläche einer Intraokularlinse (IOL) können die Sehqualität beeinflussen. In dieser Studie wurden die Oberflächentopografie sowie die Rauheit von 3 verschiedenen diffraktiven multifokalen OLs analysiert und verglichen.Mittels Rasterelektronenmikroskopie (REM, Inspect F, 5,0 kV, maximale Vergrößerung bis zu 20 000) und Rasterkraftmikroskopie (auf Englisch: atomic force microscope [AFM], Park Systems, XE-100, Nichtkontaktmodus, Vergleich des Oberflächenprofils, 10 × 10 µm, 40 × 40 µm) wurde die Oberflächenbeschaffenheit der folgenden diffraktiven IOLs untersucht: AcrySof IQ PanOptix (Alcon, USA), AT LARA 829MP (Carl Zeiss Meditec, Deutschland) und Tecnis Symfony (JohnsonJohnson Vision, USA). Die Messungen erfolgten bei jeder IOL in folgenden 3 repräsentativen Bereichen: zentraler nicht diffraktiver Bereich, zentraler diffraktiver Bereich und diffraktive Stufen. Die Rauheit in Bezug auf den Mittenrauwert (RBei der REM-Untersuchung mit geringer Vergrößerung zeigten alle IOLs eine glatte optische Oberfläche ohne Unregelmäßigkeiten. Bei höherer Vergrößerung zeigte die Tecnis Symfony einzigartige regelmäßige, konzentrische und lineare Strukturen im diffraktiven Optikbereich, die in anderen untersuchten diffraktiven IOLs nicht zu sehen waren. Die Unterschiede der gemessenen RIn 3 diffraktiven multifokalen IOLs wurden verschiedene topografische Merkmale beobachtet. Der R

Introduction We investigated the correlation between optical surface imaging using a three‐dimensional (3D) scanner and magnetic resonance imaging (MRI) for suggesting feasibility in the clinical process of tracking volume changes in head and neck patients during radiation treatment. Methods Ten patients were divided into two groups depending on the location of their tumor (i.e., right or left side). With weekly imaging data, the change in volume based on MRI was evaluated during the treatment course. Four volumes of interest (VOIs) were calculated on the 3D surface image of the facial and cervical areas using an optical 3D scanner, and the correlation between volumetric parameters were analyzed. Results The target volume changed significantly overall for both groups. The changes parotid volume reduced by up to 3.8% and 28.0% for groups A (right side) and B (left side), respectively. In Group A, VOI 1 on the facial area and VOI 3 on the cervical area decreased gradually during the treatment course by up to 3.3% and 10.7%, respectively. In Group B, only VOI 4 decreased gradually during the treatment course and reduced by up to 9.2%. In group A, the change in target volume correlated strongly with right‐side parotid, VOI 1, and VOI 3, respectively. The parotid also showed strong correlations with VOIs (P 0.05). In group B (left side), the change in target volume correlated strongly with each volumetric parameter, including weight loss. For individual patient, PTV showed more correlation with VOIs on the cervical area than VOIs on the facial area. Conclusions An optical 3D scanner can be applied to track changes in volume without radiation exposure during treatment and the optical surface image correlated with MRI.

This paper presents the measurement of the laser Threshold damage of an optical surface at different roughness coefficients. The study procedure is achieved through the manufacturing of two types of parallel-sided borosilicate plate (Glass Bk7, and SF13). The Laser used is ND: YAG pulsed laser and the longitudinal mode TEM00 laser pulses with pulse width τ =30ns and wave length λ=1.064μm, the laser beam is focused using F=30 mm lens. The concentrated laser beam is guided by a converging lens towards the optical surface of the parallel surface plate. Finally, we obtained a graph of roughness coefficient is drawn in relation the optical Threshold Damage of the optical surface, Before and after processing the optical surface. We were able to raise the threshold by about 15% after conducting thermal treatment of the optical surface

Endoluminal surgery for the treatment of colorectal neoplasia is typically carried out using electrocautery tools which imply limited precision and the risk of harm through collateral thermal damage to the adjacent healthy tissue. As a potential alternative, we present the successful colonic epithelial laser ablation by means of picosecond laser pulses. Laser ablation studies performed in ex-vivo colon tissue result in cavities with comparable thickness to early stage colorectal cancers. The corresponding histology sections exhibit only minimal collateral damage to the surrounding tissue and the depth of the ablation can be controlled precisely by means of the pulse energy. High-speed imaging has been used for the first time to visualize picosecond laser ablation of cancerous tissue in a clinically relevant model. This information was correlated with histopathology and optical surface profilometry revealing the dynamic nature of the laser tissue interaction and the need for temporal or spatial separation of pulses for optimum efficacy with regards to tissue removal. Overall, the application of picosecond laser pulses to ablate endoluminal bowel lesions demonstrates significantly improved precision and reduced thermal damage to the adjacent tissue in comparison to conventional procedures and hence will enable more precise surgical treatment of cancers.

The work is devoted to the development of the technology for the formation of the required microrelief of the optical surfaces of glass-ceramic substrates. The solution of the problem using a controlled local deposition of silicon dioxide on the polished surface by laser pyrolysis of tetraethoxysilane vapor in the presence of ozone is shown. The characteristics of the experimental samples, their comparison with the data of mathematical modeling of the results of technological processes are presented. The possibility of using the developed technology for the production of substrates of optical parts with a defined wedge-shaped value is shown.

Surface guided radiation therapy (SGRT) is increasingly being adopted for use in radiation treatment delivery for Head and Neck (H&N) cancer patients. This study investigated the improvement of patient setup accuracy and reduction of setup time for SGRT compared to a conventional setup. A total of 60 H&N cancer patients were retrospectively included. Patients were categorized into three groups: oral cavity, oropharynx and nasopharynx/sinonasal sites with 20 patients in each group. They were further separated into two (2) subgroups, depending on whether they were set up with the aid of SGRT. The Align‐RT™ system was used for SGRT in this work. Positioning was confirmed by daily kV‐kV imaging in conjunction with weekly CBCT scans. Translational and rotational couch shifts along with patient setup times were recorded. Imaging setup time, which was defined as the elapsed time from the acquisition of the first image set to the end of the last image set, was recorded. Average translational shifts were larger in the non‐SGRT group. Vertical shifts showed the most significant reduction in the SGRT group for both oropharynx and oral cavity groups. Pitch corrections were significantly higher in the SGRT group for oropharynx patients and higher pitch corrections were also observed in the SGRT groups of oral cavity and nasopharynx/sinonasal patients. The average setup time when SGRT guidance was employed was shorter for all three treatment sites although this did not reach statistical significance. The largest time reduction between the SGRT and non‐SGRT groups was seen in the nasopharynx/sinonasal group. This study suggests that the use of SGRT decreases the magnitude of translational couch shifts during patient setup. However, the rotational corrections needed were generally higher with SGRT group. When SGRT was employed, a definite reduction in patient setup time was observed for nasopharynx/sinonasal and hypopharynx cancer patients.

In orthognathic or dental surgery, cone-beam computed tomography (CBCT) and optical surface scanning are commonly used in procedures for accurate diagnosis and treatment planning. Because the CBCT and optical scan surface have different scan ranges and orientations, surface matching is required to use the both scan data simultaneously. In this study, we use a highly reliable scan surface, called confidence surface, for improving the matching accuracy. To do this, we propose a method to measure the noise possibility, that is, the uncertainty of each surface. This is accomplished by estimation methods of geometric variation with respect to different scan data. An iterative closest point-based fine matching is performed using only the confidences surfaces. The matching accuracy was shown by root-mean-square-error (RMSE) and color-coded visualization of the distance between the surfaces obtained from different scanning data. The average RMSE of matching result by the proposed method was 0.3298. This experimental results show that our proposed method improves the accuracy than the comparison methods, even with CBCT data that includes severe metal artifacts.

To evaluate the accuracy of a commercial optical surface tracking (OST) system and to demonstrate how it can be implemented to monitor patient positioning during non-coplanar single isocenter stereotactic treatments of brain metastases. A 3-camera OST system was used (Catalyst HD (TM), C-RAD) on a TruebeamSTx with a 6DoF couch. The setup accuracy and agreement between the OST system, and CBCT and kV-MV imaging at couch angles 0 degrees and 270 degrees, respectively, were examined. Film measurements at 3 depths in the Rando-Alderson phantom were performed using a single isocenter non-coplanar VMAT plan containing 4 brain lesions. Setup of the phantom was performed with CBCT at couch 0 degrees and subsequently monitored by OST at other couch angles. Setup data for 7 volunteers were collected to evaluate the accuracy and reproducibility of the OST system at couch angles 0 degrees, 45 degrees, 90 degrees, 315 degrees, and 270 degrees. These results were also correlated to the couch rotation offsets obtained by a Winston-Lutz (WL) test. The Rando-Alderson phantom, as well as volunteers, were fixated using open face masks (Orfit). For repeated tests with the Rando-Alderson phantom, deviations between rotational and translational isocenter corrections for CBCT and OST systems are always within 0.2 degrees (pitch, roll, yaw), and 0.1mm and 0.5mm (longitudinal, lateral, vertical) for couch positions 0 degrees and 270 degrees, respectively. Dose deviations between the film and TPS doses in the center of the 4 lesions were -1.2%, -0.1%, -0.0%, and -1.9%. Local gamma evaluation criteria of 2%/2 mm and 3%/1 mm yielded pass rates of 99.2%, 99.2%, 98.6%, 89.9% and 98.8%, 97.5%, 81.7%, 78.1% for the 4 lesions. Regarding the volunteers, the mean translational and rotational isocenter shift values were (0.24 +/- 0.09) mm and (0.15 +/- 0.07) degrees. Largest isocenter shifts were found for couch angles 45 & x2da; and 90 & x2da;, confirmed by WL couch rotation offsets. Patient monitoring during non-coplanar VMAT treatments of brain metastases is feasible with submillimeter accuracy.