Assessment of Iterative Closest Point Registration Accuracy for Different Phantom Surfaces Captured by an Optical 3D Sensor in Radiotherapy

An optical 3D sensor provides an additional tool for verification of correct patient settlement on a Tomotherapy treatment machine. The patient’s position in the actual treatment is compared with the intended position defined in treatment planning. A commercially available optical 3D sensor measures parts of the body surface and estimates the deviation from the desired position without markers. The registration precision of the in-built algorithm and of selected ICP (iterative closest point) algorithms is investigated on surface data of specially designed phantoms captured by the optical 3D sensor for predefined shifts of the treatment table. A rigid body transform is compared with the actual displacement to check registration reliability for predefined limits. The curvature type of investigated phantom bodies has a strong influence on registration result which is more critical for surfaces of low curvature. We investigated the registration accuracy of the optical 3D sensor for the chosen phantoms and compared the results with selected unconstrained ICP algorithms. Safe registration within the clinical limits is only possible for uniquely shaped surface regions, but error metrics based on surface normals improve translational registration. Large registration errors clearly hint at setup deviations, whereas small values do not guarantee correct positioning.

Download Full-text

ITVT-07. Robotic alignment module Cirq for navigated brainstem tumor biopsies

Neuro-Oncology ◽

10.1093/neuonc/noab196.919 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi229-vi229

Author(s):

Kirsten van Baarsen ◽

Peter Woerdeman ◽

Mariam Slot ◽

Eelco Hoving

Keyword(s):

Brain Stem ◽

3D Ct ◽

Registration Accuracy ◽

Brainstem Tumor ◽

Intended Target ◽

Registration Errors ◽

Surgical Devices ◽

Brain Stem Tumors ◽

Tumor Biopsies ◽

Euclidian Distances

Abstract BACKGROUND With the incorporation of the robotic alignment module Cirq (Brainlab, Germany) into our neurosurgical armamentarium, we aimed to know our baseline accuracy in stererotactic biopsies. We therefore retrospectively reviewed our data on biopsy accuracy for brain(stem) tumors using the non-robotic alignment instrument Varioguide (Brainlab, Germany). Because of unexpectedly large deviations from the intended target, we sought to improve our registration accuracy when we introduced Cirq. Intraoperative 3D CT with bone fiducials was added to the pre-operative 3D T1 MRI with skin fiducials. This made it possible to compare surgical devices as well as registration methods. AIMS To share our experience with the new robotic alignment module Cirq for navigated brain(stem) tumor biopsies and to evaluate its target accuracy with bone fiducial registration, as compared to the previously used Varioguide with skin fiducial registration. METHODS All patients (0–18 years old) that underwent a brain(stem) biopsy in our institution were included. Over 2018–2020, data were collected retrospectively (cohort Varioguide with 3D T1 MRI registration with skin fiducials). From 2021, data were collected prospectively (cohort Cirq with both 3D T1 MRI registration with skin fiducials and intraoperative CT registration with bone fiducials). For both cohorts, Euclidian distances were calculated between the intended target and the obtained target. For the prospective cohort, registration errors were calculated for bone versus skin fiducials. PRELIMINARY REUSLTS The deviation from the intended target was much smaller in the Cirq cohort versus the Varioguide cohort. Within the Cirq cohort, registration errors were submillimetric for bone fiducial registration as compared to several millimeters for skin fiducial registration. CONCLUSION: The Cirq robotic arm is convenient, safe and highly accurate, especially when combined with intraoperative 3D CT bone fiducial registration. Skin fiducial registration does not offer the level of precision that is mandatory in brainstem tumor biopsies.

Download Full-text

Experimental and Preliminary Clinical Study of Real-Time Registration in Liver Tumors During Respiratory Motion Based on a Multimodality Image Navigation System

Technology in Cancer Research & Treatment ◽

10.1177/1533033819857767 ◽

2019 ◽

Vol 18 ◽

pp. 153303381985776

Author(s):

Chao Ren ◽

Shi-rong Liu ◽

Wen-bo Wu ◽

Xiao-ling Yu ◽

Zhi-gang Cheng ◽

...

Keyword(s):

Clinical Study ◽

Real Time ◽

Respiratory Motion ◽

Liver Tumors ◽

The Body ◽

Respiratory Monitoring ◽

Control Group ◽

Registration Errors ◽

Significant Difference ◽

Monitoring Module

Purpose: To develop a fusion imaging system that combines ultrasound and computed tomography for real-time tumor tracking and to validate the accuracy of performing registration via this approach during a specific breathing phase. Materials and Methods: The initial part of the experimental study was performed using iodized oil injection in pig livers and was focused on determining the accuracy of registration. Eight points (A1-4 and B1-4) at different positions and with different target sizes were selected as target points. During respiratory motion, we used our self-designed system to perform the procedure either with (experimental group, E) or without (control group, C) the respiratory monitoring module. The registration errors were then compared between the 2 groups and within group E. The second part of this study was designed as a preliminary clinical study and was performed in 18 patients. Screening was performed to determine the combination of points on the body surface that provided the highest sensitivity to respiratory motion. Registration was performed either with (group E) or without (group C) the respiratory monitoring module. Registration errors were compared between the 2 groups. Results: In part 1 of this study, there were fewer registration errors at each point in group E than at the corresponding points in group C ( P < .01). In group E, there were more registration errors at points A1 and B1 than at the other points ( P < .05). There was no significant difference in registration errors among the remaining points. During part 2 of the study, there was a significant difference in the registration errors between the 2 groups ( P < .01). Conclusions: Real-time fusion registration is feasible and can be accurately performed during respiratory motions when using this system.

Download Full-text

The Effect of Oxytocin on Reparative Histogenesis in the Periodontium and Mucous Membrane of the Airways (Experimental Study)

Journal of Anatomy and Histopathology ◽

10.18499/2225-7357-2019-8-3-18-25 ◽

2019 ◽

Vol 8 (3) ◽

pp. 18-25

Author(s):

V. N. Beznosik ◽

R. V. Beznosik ◽

A. A. Stadnikov ◽

N. N. Shevlyuk

Keyword(s):

Mucous Membrane ◽

Traumatic Injury ◽

Large Cell ◽

The Body ◽

Male Rats ◽

Cell Nuclei ◽

Additional Tool ◽

Periodontal Tissues ◽

Trachea And Bronchi ◽

Sexually Mature

The aim of the study was to elucidate the role and significance of oxytocin in reparative histogenesis of tissues of various genesis using the example of periodontal tissues and extrapulmonary airways.Material and methods. Periodontitis and tracheobronchitis were simulated on sexually mature white outbred male rats. Periodontitis was simulated by traumatic injury to the periodontium, followed by the wound infection with Staphylococcus aureus. Introduction of oxytocin as an additional tool was used in the treatment of periodontitis. Experimental tracheobronchitis was simulated in rats by intratracheal infection with S. aureus (strains with and without antilactoferrin activity). Paraventricular large-cell nuclei of the hypothalamus were additionally destroyed in the simulated experimental tracheobronchitis (in order to reduce the production of endogenous oxytocin). The resulting material (the periodontium, alveolar processes, trachea and extrapulmonary bronchi) was examined using histological methods of investigation.Results. Analysis of histological sections demonstrated that when oxytocin was used in the complex therapy of experimental periodontitis, the proliferation and cyto-differentiation of fibroblasts, osteoblasts and cementoblasts was intensified, followed by their activation; this resulted in the optimization of reparative histogenesis in the structures of the periodontium and alveolar ridge. In animals with destruction of the paraventricular nuclei of the hypothalamus (against the background of an oxytocin deficiency in the body), a decrease in the reparative potential of the tracheal and bronchial mucosa was observed. Moreover, the severity of the inflammatory process in the mucous membrane of the trachea and bronchi with the introduction of staphylococci with antilactoferrin activity was significantly higher than that of animals that were administered staphylococci without antilactoferrin activity.Conclusion. The results obtained indicate the optimizing and correcting effect of the hypothalamic nonapeptide oxytocin on the reparative regeneration of the studied periodontal and the trachea and bronchi structures.

Download Full-text

A systematized approach to AVHRR image navigation

Annals of Glaciology ◽

10.3189/s0260305500013185 ◽

1993 ◽

Vol 17 ◽

pp. 414-420 ◽

Cited By ~ 1

Author(s):

D.G. Baldwin ◽

W.J. Emery

Keyword(s):

Software Package ◽

Systematic Approach ◽

Control Point ◽

Registration Accuracy ◽

Registration Errors ◽

Modular Software ◽

Image Navigation ◽

Current Systems ◽

Different Sources ◽

Very High

Accurate co-location and geo-registration of AVHRR (Advanced Very High Resolution Radiometer) is necessary for most applications involving these data. To obtain the necessary accuracy, most of the current systems available for AVHRR image rectification require corrections to errors arising from several different sources. This paper presents a software package which is able to correct registration errors from all sources using effective roll, pitch, and yaw values determined from ground control point offsets. These effective values are used to establish a baseline registration against which other models are compared. Spacecraft and sampling geometry are revisited in order to systemize and better define the procedure of AVHRR geo-registration. This systematic approach has resulted in a modular software package which has a registration accuracy of 1 satellite pixel, and is easily modified and improved.

Download Full-text

Student Response Systems in a Technology Enhanced Flipped Classroom: A Qualitative Investigation in Higher Education

International Journal of Learning Teaching and Educational Research ◽

10.26803/ijlter.20.9.6 ◽

2021 ◽

Vol 20 (9) ◽

pp. 86-101

Author(s):

Sebastian Åhman ◽

Jonny Nguyen ◽

Naghmeh Aghaee ◽

Kevin Fuchs

Keyword(s):

Graduate Students ◽

Classroom Environment ◽

Flipped Classroom ◽

The Body ◽

Student Response ◽

Student Response Systems ◽

Southern Sweden ◽

Classroom Discussions ◽

Additional Tool ◽

Response Systems

Disruptive technology and a generation with an increased interest in using that technology to aid their learning has caused a need to change the current educational landscape. Student Response Systems are a contemporary means to integrate digital technology in the modern classroom. The purpose of this qualitative study is to examine the perspectives that impact students' engagement when using Student Response Systems in a technology enhanced classroom environment. The study was guided by qualitative methods of inquiry through non-participant observations, examination of the course material, and semi-structured interviews. The in-depth interviews (n = 14) were conducted with graduate students who participated in the technology enhanced flipped classroom (TEFC) during their STEM degree studies in southern Sweden. The collected data were analyzed through the means of content analysis. The results of the study show that Student Response Systems are an effective and innovative method to increase students’ engagement in the classroom and embrace a modern learning environment. The participants expressed a positive impact on their willingness to participate in classroom discussions and share their respective views. A drawback that was mentioned is the dissatisfaction to invest more time in preparation ahead of the discussion, compared to lecture-based learning. The Student Response Systems increased the graduate students’ esteem to comfortably engage in classroom discussions and offers educators an additional tool to enhance their current pedagogical methods. The study contributes to the body of knowledge by closing an identified research gap that lacks perceptions from graduate students in a STEM program in southern Sweden. There are a few limitations that the reader should consider. The collected data pertains to graduate-level studies in a STEM degree program. Further, ample data were collected through multiple sources; however, the reflections are limited to 14 interview participants and are, therefore, not generalizable to other populations than those examined in the context.

Download Full-text

Accuracy of rigid registration between amyloid / tau PET and MRI based on normalized mutual information

10.21203/rs.2.23496/v1 ◽

2020 ◽

Author(s):

Yuma Iwao ◽

Go Akamatsu ◽

Kei Wagatsuma ◽

Muneyuki Sakata ◽

Kenji Ishii ◽

...

Keyword(s):

Mutual Information ◽

Statistical Parametric Mapping ◽

Ground Truth ◽

Amyloid Pet ◽

Registration Accuracy ◽

Data Set ◽

Normalized Mutual Information ◽

Registration Errors ◽

Positron Emission ◽

Tau Pet

Abstract Purpose Fusion images of positron emission tomography ( PET and magnetic resonance image MRI are effective to evaluate pathological changes using anatomical information. Registration of PET and MRI based on normalized mutual information (NMI) is widely used , where PET images change a lot depending on not only the choice of tracers but also disease progress ion , but the co registration accuracy has not been confirmed well yet. The aim of this study is to clarify the accuracy of NMI based registration between MRI and PET (amyloid PET and tau PET). Methods We obtained PET and MRI data from 69 participants (ages from 47 to 87 ) who underwent PET using one of the following four tracers 11 C PiB, 18 F Florbetapir, 11 C PBB3 or 18 F THK5351. T he ground truth (i .e .., a set of registered MRI PET images) was manually made by two experts. For each data set, 40 set of perturbed parameters were given to MR image s . Then each perturbed MR I was registered to the PET image using the statistical parametric mapping (SPM) tool. The differences between the given and the estimated shifts and rotates were calculated as registration errors. Results We found the registration errors were around 2 mm in the shift and around 1 deg in the rotation. These registration errors were independent of the amount of the perturbation given. Conclusion Although negative subjects of tau tracers showed higher error than other tracers, the registration error was less than PET spatial resolution, which supported a proof of the stability of the SPM.

Download Full-text

An Integrated Computer-Aided Robotic System for Dental Implantation

10.54294/9z73p5 ◽

2011 ◽

Author(s):

Xiaoyan Sun ◽

Yongki Yoon ◽

Jiang Li ◽

Frederic D. McKenzie

Keyword(s):

Preoperative Planning ◽

Robotic System ◽

Integrated System ◽

Patient Specific ◽

Registration Accuracy ◽

Coordinate Measurement ◽

Registration Errors ◽

Dental Implantation ◽

Computer Aided ◽

Preoperative Plan

This paper describes an integrated system for dental implantation including both preoperative planning utilizing computer-aided technology and automatic robot operation during the intra-operative stage. A novel two-step registration procedure was applied for transforming the preoperative plan to the operation of the robot, with the help of a Coordinate Measurement Machine (CMM). Experiments with a patient-specific phantom were carried out to evaluate the registration error for both position and orientation. After adopting several improvements, registration accuracy of the system was significantly improved. Sub-millimeter accuracy with the Target Registration Errors (TREs) of 0.38±0.16 mm (N=5) was achieved. The target orientation errors after registration and after phantom drilling were 0.92±0.16 ° (N=5) and 1.99±1.27 ° (N=14), respectively. These results permit the ultimate goal of an automated robotic system for dental implantation.

Download Full-text

Image Registration for Multimodal Inspection of Mechanical Parts

Volume 1: 23rd Computers and Information in Engineering Conference, Parts A and B ◽

10.1115/detc2003/cie-48175 ◽

2003 ◽

Author(s):

Yanyan Wu ◽

Chunhe Gong

Keyword(s):

Image Registration ◽

Point Cloud ◽

Computational Algorithm ◽

Iterative Closest Point ◽

Research Focus ◽

Registration Accuracy ◽

Multimodal Registration ◽

Mechanical Parts ◽

Iterative Closest Point Algorithm ◽

Inspection Data

Image registration is the process of aligning the corresponding features of images in the same coordinate system. Multimodal registration has been widely used in medical imaging and geographic imaging. However, it has not been broadly applied in the inspection imaging of mechanical parts. Multimodal registration can improve inspection accuracy and quality by combining complementary inspection data from different inspection methods, or “modalities”. The research focus of this work is to develop a computational algorithm to register a CMM point cloud with a CT image in the 2-D (planar) domain. Dealing with outliers is the major concern for achieving required registration accuracy. Targeting solving this problem, a new registration metric is proposed in this work, which makes application of the traditional ICP (Iterative Closest Point) algorithm robust, by optimizing the search for closest points.

Download Full-text

High-Detail Animation of Human Body Shape and Pose From High-Resolution 4D Scans Using Iterative Closest Point and Shape Maps

Applied Sciences ◽

10.3390/app10217535 ◽

2020 ◽

Vol 10 (21) ◽

pp. 7535

Author(s):

Marta Nowak ◽

Robert Sitnik

Keyword(s):

Computer Animation ◽

Point Clouds ◽

The Body ◽

Iterative Closest Point ◽

Surface Geometry ◽

Virtual Character ◽

Pose Tracking ◽

3D Point Clouds ◽

Shape Mapping ◽

3D Scans

In this article, we present a method of analysis for 3D scanning sequences of human bodies in motion that allows us to obtain a computer animation of a virtual character containing both skeleton motion and high-detail deformations of the body surface geometry, resulting from muscle activity, the dynamics of the motion, and tissue inertia. The developed algorithm operates on a sequence of 3D scans with high spatial and temporal resolution. The presented method can be applied to scans in the form of both triangle meshes and 3D point clouds. One of the contributions of this work is the use of the Iterative Closest Point algorithm with motion constraints for pose tracking, which has been problematic so far. We also introduce shape maps as a tool to represent local body segment deformations. An important feature of our method is the possibility to change the topology and resolution of the output mesh and the topology of the animation skeleton in individual sequences, without requiring time-consuming retraining of the model. Compared to the state-of-the-art Skinned Multi-Person Linear (SMPL) method, the proposed algorithm yields almost twofold better accuracy in shape mapping.

Download Full-text

Registration of Dental Tomographic Volume Data and Scan Surface Data Using Dynamic Segmentation

Applied Sciences ◽

10.3390/app8101762 ◽

2018 ◽

Vol 8 (10) ◽

pp. 1762 ◽

Cited By ~ 2

Author(s):

Keonhwa Jung ◽

Sukwoo Jung ◽

Inseon Hwang ◽

Taeksoo Kim ◽

Minho Chang

Keyword(s):

Computer Aided Design ◽

Automatic Segmentation ◽

Iterative Closest Point ◽

Data Sets ◽

Volume Data ◽

Metal Artifacts ◽

Registration Method ◽

Dynamic Segmentation ◽

Surface Data ◽

Edge Points

Over recent years, computer-aided design (CAD) has become widely used in the dental industry. In dental CAD applications using both volumetric computed tomography (CT) images and 3D optical scanned surface data, the two data sets need to be registered. Previous works have registered volume data and surface data by segmentation. Volume data can be converted to surface data by segmentation and the registration is achieved by the iterative closest point (ICP) method. However, the segmentation needs human input and the results of registration can be poor depending on the segmented surface. Moreover, if the volume data contains metal artifacts, the segmentation process becomes more complex since post-processing is required to remove the metal artifacts, and initially positioning the registration becomes more challenging. To overcome these limitations, we propose a modified iterative closest point (MICP) process, an automatic segmentation method for volume data and surface data. The proposed method uses a bundle of edge points detected along an intensity profile defined by points and normal of surface data. Using this dynamic segmentation, volume data becomes surface data which can be applied to the ICP method. Experimentally, MICP demonstrates fine results compared to the conventional registration method. In addition, the registration can be completed within 10 s if down sampling is applied.

Download Full-text