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As the prevalence of image-guided interventions increases, electromagnetic tracking (EMT) systems play an important role in modern patient care, as they enable real-time instrument positioning and navigation inside the human body without line-of-sight restrictions. Miniature-size inductive coils are the gold standard in clinical settings, as they provide accurate, passive sensing of the magnetic field. To compensate for their small dimensions, such sensors are designed with an elongated shape, where the coil length is usually 10 to 20 times larger than the diameter. In this article, the benefits of a field model based on the magnetic scalar potential formulation are demonstrated for EMT applications where elongated tracking sensors are used. The novel method resolves the single-point approximation error when the coil length is not negligible, and demonstrates improvements in terms of speed and storage requirements. A detailed analysis is proposed where alternative formulations of the magnetic model used in the tracking algorithm are compared. Although this work does not resolve any substantial limits of EMT used in a clinical environment, which are mainly caused by the presence of magnetic distortions, the proposed method is an improvement over existing EMT systems because it enables more accurate and faster tracking. The method might facilitate the use of longer tracking sensor coils which can achieve high sensitivities without the requirement of a magnetic core. In the envisioned application, such coils may be wound around flexible instruments, such as endoscopes or catheters.

Purpose: Accuracy of image-guided liver surgery is challenged by deformation of the liver during the procedure. This study aims at improving navigation accuracy by using intraoperative deep learning segmentation and nonrigid registration of hepatic vasculature from ultrasound (US) images to compensate for changes in liver position and deformation. Methods: This was a single-center prospective study of patients with liver metastases from any origin. Electromagnetic tracking was used to follow US and liver movement. A preoperative 3D model of the liver, including liver lesions, and hepatic and portal vasculature, was registered with the intraoperative organ position. Hepatic vasculature was segmented using a reduced 3D U-Net and registered to preoperative imaging after initial alignment followed by nonrigid registration. Accuracy was assessed as Euclidean distance between the tumor center imaged in the intraoperative US and the registered preoperative image. Results: Median target registration error (TRE) after initial alignment was 11.6 mm in 25 procedures and improved to 6.9 mm after nonrigid registration (p = 0.0076). The number of TREs above 10 mm halved from 16 to 8 after nonrigid registration. In 9 cases, registration was performed twice after failure of the first attempt. The first registration cycle was completed in median 11 min (8:00–18:45 min) and a second in 5 min (2:30–10:20 min). Conclusion: This novel registration workflow using automatic vascular detection and nonrigid registration allows to accurately localize liver lesions. Further automation in the workflow is required in initial alignment and classification accuracy.

Purpose: Accuracy of image-guided liver surgery is challenged by deformation of the liver during the procedure. This study aims at improving navigation accuracy by using intraoperative deep learning segmentation and nonrigid registration of hepatic vasculature from ultrasound (US) images to compensate for changes in liver position and deformation. Methods: This was a single-center prospective study of patients with liver metastases from any origin. Electromagnetic tracking was used to follow US and liver movement. A preoperative 3D model of the liver, including liver lesions, and hepatic and portal vasculature, was registered with the intraoperative organ position. Hepatic vasculature was segmented using a reduced 3D U-Net and registered to preoperative imaging after initial alignment followed by nonrigid registration. Accuracy was assessed as Euclidean distance between the tumor center imaged in the intraoperative US and the registered preoperative image. Results: Median target registration error (TRE) after initial alignment was 11.6 mm in 25 procedures and improved to 6.9 mm after nonrigid registration (p = 0.0076). The number of TREs above 10 mm halved from 16 to 8 after nonrigid registration. In 9 cases, registration was performed twice after failure of the first attempt. The first registration cycle was completed in median 11 min (8:00–18:45 min) and a second in 5 min (2:30–10:20 min). Conclusion: This novel registration workflow using automatic vascular detection and nonrigid registration allows to accurately localize liver lesions. Further automation in the workflow is required in initial alignment and classification accuracy.

Purpose: Surgical navigation techniques can guide surgeons in localizing pelvic–abdominal malignancies. For abdominal navigation, accurate patient registration is crucial and is generally performed using an intra-operative cone-beam CT (CBCT). However, this method causes 15-min surgical preparation workflow interruption and radiation exposure, and more importantly, it cannot be repeated during surgery to compensate for large patient movement. As an alternative, the accuracy and feasibility of tracked ultrasound (US) registration are assessed in this patient study. Methods: Patients scheduled for surgical navigation during laparotomy of pelvic–abdominal malignancies were prospectively included. In the operating room, two percutaneous tracked US scans of the pelvic bone were acquired: one in supine and one in Trendelenburg patient position. Postoperatively, the bone surface was semiautomatically segmented from US images and registered to the bone surface on the preoperative CT scan. The US registration accuracy was computed using the CBCT registration as a reference and acquisition times were compared. Additionally, both US measurements were compared to quantify the registration error caused by patient movement into Trendelenburg. Results: In total, 18 patients were included and analyzed. US registration resulted in a mean surface registration error of 1.2 ± 0.2 mm and a mean target registration error of 3.3 ± 1.4 mm. US acquisitions were 4 × faster than the CBCT scans (two-sample t-test P < 0.05) and could even be performed during standard patient preparation before skin incision. Patient repositioning in Trendelenburg caused a mean target registration error of 7.7 ± 3.3 mm, mainly in cranial direction. Conclusion: US registration based on the pelvic bone is accurate, fast and feasible for surgical navigation. Further optimization of the bone segmentation algorithm will allow for real-time registration in the clinical workflow. In the end, this would allow intra-operative US registration to correct for large patient movement. Trial registration: This study is registered in ClinicalTrials.gov (NCT05637359).

Accurate in vivo measurement of finger joint kinematics is important for evaluation of treatment methods, implant designs, and for the development and validation of computer models of the hand. The main objective of this project was to develop a standardized finger kinematic measurement system employing electromagnetic (EM) tracking to measure in vivo finger motion pathways. A landmark digitization protocol was developed and used in vivo, in a biomechanical study using EM trackers secured to the finger segments. In vivo results for finger flexion/extension showed no significant differences between EM and goniometer results, 5°±3°; p = 0.735.

Purpose An auditory brainstem implant (ABI) represents an alternative for patients with profound hearing loss who are constrained from receiving a cochlear implant. The positioning of the ABI electrode influences the patient’s auditory capacity and, therefore, quality of life and is challenging even with available intraoperative electrophysiological monitoring. This work aims to provide and assess the feasibility of visual-spatial assistance for ABI positioning. Methods The pose of the forceps instrument that grasps the electrode was electromagnetically navigated and interactively projected in the eyepieces of a surgical microscope with respect to a target point. Intraoperative navigation was established with an experimental technique for automated nasopharyngeal patient registration. Two ABI procedures were completed in a human specimen head. Results An intraoperative usability study demonstrated lower localization error when using the proposed visual display versus standard cross-sectional views. The postoperative evaluations of the preclinical study showed that the center of the electrode was misplaced to the planned position by 1.58 mm and 3.16 mm for the left and the right ear procedure, respectively. Conclusion The results indicate the potential to enhance intraoperative feedback during ABI positioning with the presented system. Further improvements consider estimating the pose of the electrode itself to allow for better orientation during placement.

Friesen, KB, Barfield, JW, Murrah, WM, Dugas, JR, Andrews, JR, and Oliver, GD. The association of upper-body kinematics and earned run average of national collegiate athletic association Division I softball pitchers. J Strength Cond Res 35(11): 3145-3150, 2021-Although recent literature has increased examination of the association of injury and biomechanics, there remains a lack of evidence supporting optimal windmill pitch mechanics. Therefore, the purpose of this study was to investigate trunk and pitching arm kinematics and their association with performance outcome: earned run average (ERA), in collegiate softball pitchers. Twenty-three NCAA Division I collegiate softball pitchers (20.14 ± 1.07 years; 173.93 ± 6.68 cm; and 85.79 ± 11.06 kg) performed 3 maximal effort rise ball pitches to a catcher located at a distance of 43 ft. (13.11 m). Kinematic data of the trunk and pitching arm were collected using an electromagnetic tracking system. A multiple regression analysis was performed at each pitch event: top of backswing, foot contact, ball release, and follow-through. The multiple regression at foot contact showed an overall statistically significant regression equation (F6, 16 = 3.7, p = 0.017) and explained approximately 42% of the variance in ERA (R = 0.579, Adj. R2 = 0.421). Results revealed that those pitchers who had greater trunk (SE = 0.018, t = -2.5, p = 0.023) and elbow flexion (SE = 0.006, t = -4.2, p = 0.001) at the event of foot contact had lower ERAs. This study supported previous research on the importance of trunk and elbow angle at front foot contact on rise ball pitch performance. These key technique points and the importance of elbow flexors should be explored in future research and potentially visually attended to by coaches and strength professionals.

Introduction: Clinicians typically observe and describe abnormal head postures (AHPs) and may also measure them. Depth cameras have been suggested as a reliable measurement device for measuring head position using face-tracking technology. This study compared a depth camera (Microsoft Kinect) to a gold standard electromagnetic tracking system (Polhemus device) to measure head position.\ud \ud \ud \ud Method: Twenty healthy volunteers (mean age 21 years) had their head position simultaneously recorded using the depth camera (Kinect) and the electromagnetic tracking system (Polhemus). Participants were asked to make 30-degree head movements into chin up, chin down, head turn and head tilt positions. The head movement made and the stability of the head at each position were recorded and analysed.\ud \ud \ud \ud Results: Compared to the electromagnetic tracking system (Polhemus), the depth camera (Kinect) always measured a smaller head movement. Measurements with the two devices were not statistically significantly different for turn right (P = 0.3955, p > 0.05), turn left (P = 0.4749, p > 0.05), tilt right (P = 0.7086, p > 0.05) and tilt left (P = 0.4091, p > 0.05) head movements. However, the smaller depth camera measurement of chin up and chin down head movements were statistically significant, chin up (P = 0.0001, p < 0.01) and chin down (P = 0.0005, p < 0.001). At each eccentric position, the depth camera (Kinect) recordings were more variable than the electromagnetic tracking system (Polhemus).\ud \ud \ud \ud Conclusions: Compared to the electromagnetic tracking system (Polhemus), the depth camera (Kinect) was comparable for measuring head turns and tilts but was less accurate at measuring chin up and chin down head positions. Further research is needed before the depth cameras are considered for clinical recordings of head position.

The standard treatment for rectal cancer is surgical resection of the entire rectum with its surrounding fat. Despite this radical procedure, local recurrence may still occur in up to 10% of patients and is often due to incomplete resection of the tumor area. To better assess tumor borders, image-guided navigation (IGN) can be used. A common form of IGN is where the surgeon uses tracked surgical tools that are visualized on a screen in real-time, relative to a 3D anatomical model created from preoperative imaging. To maintain sufficient navigation accuracy, when operating on the non-rigid rectum, the 3D model should be updated upon tumor motion. It was investigated if including real-time tumor tracking, using electromagnetic (EM) trackers placed close or inside the tumor, can facilitate this. Using an IGN system with wired EM tumor tracking, surgeons assessed proximal rectal tumor borders with a low median error of 3mm. Tumor tracker placement and linking it to the 3D model, however, took 30 minutes of intraoperative time. With implantable wireless trackers these steps can be done preoperatively. It was investigated if a commercially available system for wireless EM tumor tracking in radiotherapy (WL-EMTS) can also be used for IGN surgery. An IGN system was developed using the WL-EMTS for tumor tracking and an optical tracking system for tool tracking. With this IGN system it was possible to reduce incomplete resections of non-palpable breast phantom tumors by a factor of 3, compared to a clinically used wireless localization technique. The IGN system was upgraded using only the WL-EMTS for tumor ánd tool tracking. Accurate navigated resections were possible on virtual lesions in ex vivo liver specimens, where surgeons cut with 0.1±2.3mm accuracy along a planned resection margin. Ideally, the 3D model is projected onto the actual anatomy, such that the navigation screen can be omitted, improving usability. In laparoscopic surgeries this requires laparoscope camera calibration. With oblique-viewing laparoscopes, often used in rectal surgery, camera calibration parameters change when rotating their telescope. Therefore, a camera model was developed modeling these changes, resulting in reprojection accuracies of about 4 pixels (0.4mm) independent on telescope rotation.

With the continuous development of digital medicine, minimally invasive precision and safety have become the primary development trends in hepatobiliary surgery. Due to the specificity and complexity of hepatobiliary surgery, traditional preoperative imaging techniques such as computed tomography and magnetic resonance imaging cannot meet the need for identification of fine anatomical regions. Imaging-based three-dimensional (3D) reconstruction, virtual simulation of surgery and 3D printing optimize the surgical plan through preoperative assessment, improving the controllability and safety of intraoperative operations, and in difficult-to-reach areas of the posterior and superior liver, assistive robots reproduce the surgeon’s natural movements with stable cameras, reducing natural vibrations. Electromagnetic navigation in abdominal surgery solves the problem of conventional surgery still relying on direct visual observation or preoperative image assessment. We summarize and compare these recent trends in digital medical solutions for the future development and refinement of digital medicine in hepatobiliary surgery.

Femoral derotation osteotomy (FDO) is a well-established procedure for the correction of internal rotation gait in children with cerebral palsy. Various studies have demonstrated good results for FDO both in short-term and long-term evaluation with some describing recurrence and over- or under-corrections. The present study evaluates the use of an objective intraoperative derotation measurement through electromagnetic tracking. We report the static and dynamic results of 11 cases with internal rotation gait (8 male, 3 female, mean age 22.2 years), that underwent FDO with intraoperative electromagnetic tracking and conventional goniometric measurement of the correction. The dynamic and static changes were assessed through three-dimensional gait analysis after a mean of 12 months after surgery and rotational imaging preoperative and after a mean of eleven days postoperatively. Mean hip rotation in stance significantly decreased from 20.9° (SD 5.9) to 5.8° (SD 4.7°) after FDO. The mean amount of derotation quantified by electromagnetic tracking was 23.2° (16.5°-28.8°) and 25.1° (20.0°-33.0°) for goniometric measurement. Both measurement modalities showed small differences to rotational imaging (electromagnetic bone tracking [EMT]: 0.72°; goniometer: 1.19°) but a large deviation when compared to three-dimensional gait analysis (EMT: 8.5°, goniometer: 9.1°). In comparison to the static changes and EMT measurement, the dynamic changes measured during 3-D-gait analysis reflected only 66% of the actual derotation performed during surgery. Although electromagnetic tracking allows a precise intraoperative assessment of the derotation during FDO, the amount of intraoperative correction is not reflected in the improvements in three-dimensional gait analysis.

The current study develops an automatic analysis tool of EMT data sets recorded with a solenoid sensor to assure concordance of the source move- ment with the treatment plan. The tool combines machine learning tech- niques such as multi-dimensional scaling (MDS), ensemble empirical mode decomposition (EEMD), singular spectrum analysis (SSA) and particle filter (PF) to precisely detect and quantify any mismatch between the treatment plan and actual EMT measurements.

An open electromagnetic tracking system platform

Understanding the kinematics of the upper extremity during kayak paddling is important for both performance and injury prevention. However, there is a lack of information on scapular and shoulder kinematics in para-kayakers who have additional impairments. This study aimed to clarify the biomechanics of kayak paddling in para-kayakers. We assessed the biomechanics of 5 para-kayakers (included the subjects who competed the 2016 Rio Paralympic Games) and 10 elite able-bodied kayakers (included the subjects who competed the London Olympic Games in 2012 or world championships) during paddling on a kayak ergometer using an electromagnetic tracking device. The stroke rate, scapular motion relative to thorax, humerus motion relative to thorax, and humerus motion relative to scapula during the first 10 cycles of paddling were evaluated. During the first 10 cycles of paddling, para-kayakers showed significantly lower stroke rate compared to elite kayakers. There were also significant differences in scapular upward/downward rotation, humerothoracic plane of elevation, and grenohumeral plane of elevation between the para-kayakers and the elite kayakers. Para-kayakers who have some impairments showed lower kayak paddling performance and different movement patterns compared with elite kayakers. The results of this study could provide some information to guide training programs to improve para-kayakers’ performance.

Purpose Interactive image-guided surgery technologies enable accurate target localization while preserving critical nearby structures in many surgical interventions. Current state-of-the-art interfaces largely employ traditional anatomical cross-sectional views or augmented reality environments to present the actual spatial location of the surgical instrument in preoperatively acquired images. This work proposes an alternative, simple, minimalistic visual interface intended to assist during real-time surgical target localization. Methods The estimated 3D pose of the interventional instruments and their positional uncertainty are intuitively presented in a visual interface with respect to the target point. A usability study with multidisciplinary participants evaluates the proposed interface projected in surgical microscope oculars against cross-sectional views. The latter was presented on a screen both stand-alone and combined with the proposed interface. The instruments were electromagnetically navigated in phantoms. Results The usability study demonstrated that the participants were able to detect invisible targets marked in phantom imagery with significant enhancements for localization accuracy and duration time. Clinically experienced users reached the targets with shorter trajectories. The stand-alone and multi-modal versions of the proposed interface outperformed cross-sectional views-only navigation in both quantitative and qualitative evaluations. Conclusion The results and participants’ feedback indicate potential to accurately navigate users toward the target with less distraction and workload. An ongoing study evaluates the proposed system in a preclinical setting for auditory brainstem implantation.

Purpose: To utilize navigated mandibular (reconstructive) surgery, accurate registration of the preoperative CT scan with the actual patient in the operating room (OR) is required. In this phantom study, the feasibility of a noninvasive hybrid registration method is assessed. This method consists of a point registration with anatomic landmarks for initialization and a surface registration using the bare mandibular bone surface for optimization. Methods: Three mandible phantoms with reference notches on two osteotomy planes were 3D printed. An electromagnetic tracking system in combination with 3D Slicer software was used for navigation. Different configurations, i.e., different surface point areas and number and configuration of surface points, were tested with a dentate phantom (A) in a metal-free environment. To simulate the intraoperative environment and different anatomies, the registration procedure was also performed with an OR bed using the dentate phantom and two (partially) edentulous phantoms with atypical anatomy (B and C). The accuracy of the registration was calculated using the notches on the osteotomy planes and was expressed as the target registration error (TRE). TRE values of less than 2.0 mm were considered as clinically acceptable. Results: In all experiments, the mean TRE was less than 2.0 mm. No differences were found using different surface point areas or number or configurations of surface points. Registration accuracy in the simulated intraoperative setting was-mean (SD)-0.96 (0.22), 0.93 (0.26), and 1.50 (0.28) mm for phantom A, phantom B, and phantom C. Conclusion: Hybrid registration is a noninvasive method that requires only a small area of the bare mandibular bone surface to obtain high accuracy in phantom setting. Future studies should test this method in clinical setting during actual surgery.

Introduction: Endovascular revascularization has become the preferred treatment for most patients with iliac artery obstructions, with a high rate of clinical and technical success.Areas covered: This review will describe novel developments in the diagnosis and treatment of iliac artery obstructions including the augmentation of preprocedural imaging with advanced flow models, image fusion techniques, and state-of-the-art device-tracking capabilities.Expert opinion: The combination of these developments will change the endovascular field within the next 5 years, allowing targeted iliac treatment without the need for radiographic imaging or iodinated contrast media.

Introduction: Endovascular revascularization has become the preferred treatment for most patients with iliac artery obstructions, with a high rate of clinical and technical success.Areas covered: This review will describe novel developments in the diagnosis and treatment of iliac artery obstructions including the augmentation of preprocedural imaging with advanced flow models, image fusion techniques, and state-of-the-art device-tracking capabilities.Expert opinion: The combination of these developments will change the endovascular field within the next 5 years, allowing targeted iliac treatment without the need for radiographic imaging or iodinated contrast media.

Lung cancer is the most common cancer globally with over 2 million new cases diagnosed every year. Fortunately, if caught early, the likelihood of survival is greatly improved. If diagnosed in Stage I, survival rates are >75% over 5 years, vs. just 1% if diagnosed in Stage IV. Early diagnosis requires finding and sampling (biopsy) small, peripheral nodules that are located in the parenchima of the lung and predominately outside small airways. Currently, for early diagnosis a bronchoscope is inserted into the lung airway but due to large size it cannot reach the small airways. Therefore, the doctor has to advance a sharp biopsy needle blindly from the tip of the bronchoscope and into the lung tissue in the approximate direction of the nodule. This blind procedure has low accuracy and carries a high risk of misdiagnosis. Currently, to improve the accuracy, real time x-ray (fluoroscopy) is use which causes exposure of the patient and physician to harmful radiation. Computer and image assisted surgery and medical robotics present viable solutions but are not optimal at present. The scope of our research was to develop a robotic solution for increased precision and accuracy of early diagnosis and treatment of lung cancer, to increase procedure success rate, decrease patient radiation and stress exposure, and reduce the procedure cost. For this purpose, we developed an advanced prototype of a robotic system which is small in size, easy to use and effective. To demonstrate its effectiveness in navigating to peripheral small size lung cancer lesions, we performed laboratory tests or a realistic lung airway model. The preliminary tests of a novel medical robot using a complex lung airway model proved that our catheter driving robotic system is working as designed and allows navigation, through a complex 3D channels structure like the bronchial tree, in both manipulator and robotic modes without fluoroscopy scanning. The robotic system is more precise and stable, and can avoid patient injury and instrument damage due to accidental impact with the airway wall. Because it could be controlled from a different room via the software platform, using this robotic system can drastically reduce radiation exposure of the patient and totally avoid the exposure of the doctor. Another benefit of the proposed robotic system is that it uses currently available catheters in which a reusable electromagnetic guide wire is temporarily inserted to guide the tip of the catheter towards hard to reach targets. After the target is confirmed, the sensor can be retracted and the catheter can be used for its routine function such as biopsy collection. Future development will include placement of a force sensor at the tip of the catheter to “feel” the wall and adapt the speed of insertion in order to avoid wall damage and an improved algorithm to increase the speed in the automatic mode.

Background: This study assessed whether electromagnetic navigation can be of added value during resection of recurrent or post-therapy intra-abdominal/pelvic soft tissue sarcomas (STS) in challenging locations. Materials and Methods: Patients were included in a prospective navigation study. A pre-operatively 3D roadmap was made and tracked using electromagnetic reference markers. During the operation, an electromagnetic pointer was used for the localization of the tumor/critical anatomical structures. The primary endpoint was feasibility, secondary outcomes were safety and usability. Results: Nine patients with a total of 12 tumors were included, 7 patients with locally recurrent sarcoma. Three patients received neoadjuvant radiotherapy and three other patients received neoadjuvant systemic treatment. The median tumor size was 4.6 cm (2.4–10.4). The majority of distances from tumor to critical anatomical structures was

Radiotherapy is highly involved in the management of prostate cancer. Its features and potential applications experienced a radical evolution over last decades, as they are associated to the continuous evolution of available technology and current oncological innovations. Some application of radiotherapy like brachytherapy have been recently enriched by innovative features and multidisciplinary dedications. In this report we aim to put some questions regarding the following issues regarding multiple aspects of modern application of radiation oncology: the current application of radiation oncology; the modern role of stereotactic body radiotherapy (SBRT) for both the management of primary lesions and for lymph-nodal recurrence; the management of the oligometastatic presentations; the role of brachytherapy; the aid played by the application of the organ at risk spacer (spacer OAR), fiducial markers, electromagnetic tracking systems and on-line Magnetic Resonance guided radiotherapy (MRgRT), and the role of the new opportunity represented by radiomic analysis.

Optical and electromagnetic tracking systems represent the two main technologies integrated into commercially-available surgical navigators for computer-assisted image-guided surgery so far. Optical Tracking Systems (OTSs) work within the optical spectrum to track the position and orientation, i.e., pose of target surgical instruments. OTSs are characterized by high accuracy and robustness to environmental conditions. The main limitation of OTSs is the need of a direct line-of-sight between the optical markers and the camera sensor, rigidly fixed into the operating theatre. Electromagnetic Tracking Systems (EMTSs) use electromagnetic field generator to detect the pose of electromagnetic sensors. EMTSs do not require such a direct line-of-sight, however the presence of metal or ferromagnetic sources in the operating workspace can significantly affect the measurement accuracy. The aim of the proposed review is to provide a complete and detailed overview of optical and electromagnetic tracking systems, including working principles, source of error and validation protocols. Moreover, commercial and research-oriented solutions, as well as clinical applications, are described for both technologies. Finally, a critical comparative analysis of the state of the art which highlights the potentialities and the limitations of each tracking system for a medical use is provided.

Brachytherapy has advanced dramatically in the last decade due largely to improvements in applicators, imaging, treatment planning, and use of clinical trials. In addition, current research in brachytherapy technology continues to change how we deliver this treatment modality. The future of brachytherapy lies in the ability of new technologies to overcome real or perceived barriers. The focus for this manuscript is on specific tools that have or are near to being introduced in the clinic. First, we explore the impact electromagnetic tracking technologies can have on brachytherapy implants and planning workflow. This is followed by an overview of the use of 3D printing and its ability to help tailor brachytherapy implants. Next, we discuss advances in self-shielded applicators and intensity-modulated brachytherapy technology. The manuscript closes out with 2 sections on treatment planning. First is a discussion of biological optimization and its potential as compared with current techniques (eg, based on physical dosimetry). And lastly, a section on optimization treatment planning efficiencies in which we explore the potential for machine learning in brachytherapy. As recent clinical evidence continues to show excellent outcomes, this is an exciting time to practice brachytherapy. With the new technologies presented here, the future is even brighter.

Minimally invasive surgical procedures often require needle insertion. For these procedures, efficacy greatly depends on precise needle placement. Many methods, such as optical tracking and electromagnetic tracking, have been applied to assist needle placement by tracking the real-time position information of the needle. Compared with the optical tracking method, electromagnetic tracking is more suitable for minimally invasive surgery since it has no requirement of line-of-sight. However, the devices needed for electromagnetic tracking are usually expensive, which will increase the cost of surgery. In this study, we proposed a low-cost smartphone-based permanent magnet tracking method compatible with CT imaging and designed a 3D printed operation platform to assist with needle placement prior to needle insertion during minimally invasive surgery. The needle positioning accuracy of this method was tested in an open air test and a prostate phantom test in a CT environment. For these two tests, the average radial errors were 0.47 mm and 2.25 mm, respectively, and the standard deviations were 0.29 and 1.92, respectively. The materials and fabrication required for the proposed method are inexpensive. Thus, many image-guided therapies may benefit from the proposed method as a low-cost option for needle positioning prior to needle insertion.

Surgical tool tracking has a variety of applications in different surgical scenarios. Electromagnetic (EM) tracking can be utilised for tool tracking, but the accuracy is often limited by magnetic interference. Vision-based methods have also been suggested; however, tracking robustness is limited by specular reflection, occlusions, and blurriness observed in the endoscopic image. Recently, deep learning-based methods have shown competitive performance on segmentation and tracking of surgical tools. The main bottleneck of these methods lies in acquiring a sufficient amount of pixel-wise, annotated training data, which demands substantial labour costs. To tackle this issue, the authors propose a weakly supervised method for surgical tool segmentation and tracking based on hybrid sensor systems. They first generate semantic labellings using EM tracking and laparoscopic image processing concurrently. They then train a light-weight deep segmentation network to obtain a binary segmentation mask that enables tool tracking. To the authors' knowledge, the proposed method is the first to integrate EM tracking and laparoscopic image processing for generation of training labels. They demonstrate that their framework achieves accurate, automatic tool segmentation (i.e. without any manual labelling of the surgical tool to be tracked) and robust tool tracking in laparoscopic image sequences.

Combining electromagnetic tracking of instruments with preoperatively acquired images can provide detailed visualization for intraoperative guidance and reduce the need for fluoroscopy and contrast. In this study, we investigated the accuracy of a vessel-based registration method designed for matching preoperative image and electromagnetically tracked positions for endovascular therapy.An open-source registration method was used to match the centerline extracted from computed tomography (CT) to electromagnetically tracked positions within a vascular phantom representing the abdominal aorta with bifurcations. The target registration error (TRE) was calculated for 11 fiducials distributed over the phantom. Median and intra-quartile range (IQR) for 30 registrations was reported. TRE5 mm was claimed sufficient for endovascular navigation, evaluated using the Wilcoxon signed-rank test. TRE was also compared to a 3D-3D registration method based on intraoperative cone-beam CT, using the Mann-Whitney U-test.The TRE was 3.75 (IQR: 3.48-3.99) mm for the centerline registration algorithm and 3.21 (IQR: 1.50-3.57) mm for the 3D-3D method (p .001). For both methods, the TRE was significantly5 mm (p .001).The centerline registration method was feasible, with an accuracy sufficient for navigation in endovascular therapy. The centerline method avoids additional image acquisition for registration purpose only.

The aim of this study was to compare cervical spine kinematics in rugby union front row players during machine-based and "live" scrummaging. Cervical spine kinematics was measured via electromagnetic tracking of sensors attached to the head and thorax. Joint angles were extracted from each trial at two time points ("bind" prior to engagement and instant of impact) for comparison between scrummaging conditions. The effect of scrummaging condition on kinematics was evaluated using a mixed effects model and estimations were based on a Bayesian framework. With differences ranging from 38° to 50°, the results show that the cervical spine is consistently more flexed when scrummaging against opponents than against a scrum machine. In contrast, there are little differences in the excursion of lateral-flexion (range 5-8°) and axial rotation (7°) between the two conditions. The findings from this study provide clear information on motion patterns in different scrum formations, and suggest that the current design of scrum machines may not promote the same pattern of movement that occurs in live scrums. The results highlight that findings from previous studies that have investigated kinematics during machine-based scrummaging may not be generalisable to a competitive scrummaging context.

The increase of the aging population brings numerous challenges to health and aesthetic segments. Here, the use of laser therapy for dermatology is expected to increase since it allows for non-invasive and infection-free treatments. However, existing laser devices require doctors’ manually handling and visually inspecting the skin. As such, the treatment outcome is dependent on the user’s expertise, which frequently results in ineffective treatments and side effects. This study aims to determine the workspace and limits of operation of laser treatments for vascular lesions of the lower limbs. The results of this study can be used to develop a robotic-guided technology to help address the aforementioned problems. Specifically, workspace and limits of operation were studied in eight vascular laser treatments. For it, an electromagnetic tracking system was used to collect the real-time positioning of the laser during the treatments. The computed average workspace length, height, and width were 0.84 ± 0.15, 0.41 ± 0.06, and 0.78 ± 0.16 m, respectively. This corresponds to an average volume of treatment of 0.277 ± 0.093 m3. The average treatment time was 23.2 ± 10.2 min, with an average laser orientation of 40.6 ± 5.6 degrees. Additionally, the average velocities of 0.124 ± 0.103 m/s and 31.5 + 25.4 deg/s were measured. This knowledge characterizes the vascular laser treatment workspace and limits of operation, which may ease the understanding for future robotic system development., The authors acknowledge Fundação para a Ciência e a Tecnologia (FCT), Portugal and the European Social Fund, European Union, for funding support through [the “Programa Operacional Capital Humano” (POCH) in the scope of the PhD], grants number [SFRH/BD/136721/2018 (B. Oliveira) and SFRH/BD/136670/2018 (H. Torres)]. Moreover, authors gratefully acknowledge the funding of the projects “NORTE-01-0145-FEDER-000045” and “NORTE-01-0145-FEDER-000059”, supported by [Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER)]. It was also funded by [national funds, through the FCT and FCT/MCTES in the scope of the projects UIDB/05549/2020, UIDP/05549/2020, and LASI-LA/P/0104/2020].

Accurate three-dimensional reconstruction of duodenum is very important in the navigation of ERCP surgery, which helps to improve the success rate of chathete-rization and reduce the difficulty of surgery. Due to the narrow anatomical space of the duodenum, the structure is tortuous, the surface is smooth with few texture features. The existing three-dimensional reconstruction and positioning methods still cannot achieve an effective performance. In this paper, the combination of electromagnetic sensing and ORBSLAM is used for the three-dimensional reconstruction of the duodenal biliary and pancreatic duct. First, we use the accurate tracking performance of electromagnetic sensors to improve the effectiveness of SLAM mapping. Second, we replaced the pose estimation of the camera in SLAM with electromagnetic sensing real-time pose, which improved the real-time performance of 3D reconstruction. The effectiveness and real-time performance of the algorithm in the three-dimensional reconstruction of the duodenum, biliary and pancreatic regions are verified through high-simulation models and real clinical video sequences.

In recent times, the use of electromagnetic tracking for navigation in surgery has quickly become a vital tool in minimally invasive surgery. In many procedures, electromagnetic tracking is used in tandem with X-ray technology to track a variety of tools and instruments. Most commercially available EM tracking systems can cause X-ray artifacts and attenuation due to their construction and the metals that form them. In this work, we provide a novel solution to this problem by creating a new radiolucent electromagnetic navigation system that has minimal impact on -ray imaging systems. This is a continuation of our previous work where we showed the development of the Anser open-source electromagnetic tracking system. Typical electromagnetic tracking systems operate by generating low frequency magnetic fields from coils that are located near the patient. These coils are typically made from copper, steel, and other dense radiopaque materials. In this work, we explore the use of low density aluminum to create these coils and we demonstrate that the effect on X-ray images is significantly reduced as a result of these novel changes in the materials used. The resulting field generator is shown to give at least a 60% reduction in the X-ray attenuation in comparison to our earlier designs. We verify that the system accuracy of approximately 1.5 mm RMS error is maintained with this change in design.

Tese de Doutoramento Ciências da Saúde, O acesso renal percutâneo (ARP) é importante no tratamento de várias doenças renais, sobretudo na nefrolitíase (cálculos renais) através da nefrolitotomia percutânea (NLPC). O sucesso da NLPC depende do acesso inicial ao rim, sendo que uma correta punção diminui as complicações e facilita as etapas cirúrgicas seguintes. Embora o ARP seja convencionalmente guiado por fluoroscopia e/ou ecografia, continua a ser desafiante aprendê-lo e executá-lo. Recentemente, soluções baseadas em tracking eletromagnético (TEM) têm sido propostas para auxiliar o ARP, permitindo punções rápidas e precisas ao cálice renal. Porém, limitações ainda subsistem, como a falta da perceção tridimensional (3D) da anatomia ou a incapacidade de aceder ao cálice se obstruído por um cálculo. Para mitigar estas limitações, esta tese focou-se em melhorar as soluções baseadas em TEM através da integração de dados de tomografia axial computadorizada (TAC) pré-operatória e de ecografia intra-operatória, e desenvolver um novo sistema de navegação cirúrgica. Para alcançar este objetivo, as seguintes etapas foram realizadas: (1) estudo do impacto dos instrumentos de ureteroscopia e ecografia na precisão dos sistemas de TEM; (2) desenvolvimento de um protocolo para criar fantomas de rim para avaliar estratégias de fusão de imagens; (3) avaliação num ambiente in-silico de uma técnica de registo (baseado em pontos) e de um protocolo de aquisição de imagens intra-operatórias para fundir dados de ecografia e de TAC; (4) proposta de uma nova abordagem intra-operatória para fundir dados de ecografia e TAC, usando uma estratégia de segmentação semi-automática e um algoritmo de registo (baseado em pontos); e (5) integração de todas as contribuições mencionadas num novo sistema de navegação cirúrgica, incluindo características adicionais para melhorar a navegação cirúrgica em tempo real, como: a projeção da trajetória da agulha e da posição do cateter sobre as imagens de ecografia; integração de instrumentos e dados das imagens num ambiente virtual 3D; tracking contínuo dos órgãos (compensando movimentos internos destes); e feedback visual focado na agulha. Este sistema foi avaliado por médicos e comparado com outras soluções baseadas em TEM num fantoma abdominal. O desempenho dos médicos foi superior com o sistema proposto, evitando lesões em órgãos próximos ao rim e destacando-se em cenários mais complexos. O sistema proposto foi classificado como a solução mais segura, obtendo níveis de confiança superiores durante os testes. Globalmente, este sistema provou auxiliar o ARP durante o NLPC. Considerando os excelentes resultados obtidos pela integração de dados pré-operatórios num cenário intra-operatório, o sistema proposto poderá ter aplicabilidade noutras intervenções cirúrgicas., Percutaneous renal access (PRA) has a key role on the treatment of several kidney diseases, particularly in nephrolithiasis (or kidney stone disease) through percutaneous nephrolithotomy (PCNL). The success of PCNL is highly dependent on the initial renal access where an accurate needle puncture decreases the overall complications and facilitates the following surgical steps. Although PRA is conventionally performed under fluoroscopy and/or ultrasonography, it remains challenging to learn and to perform. Recently, electromagnetic tracking (EMT)-based solutions have been proposed to aid PRA, allowing fast and accurate punctures to the renal calyx. However, some limitations still exist, namely the lack of three-dimensional (3D) perception of the anatomy, and the incapacity to achieve the calyx if it is fully occupied by a stone. To mitigate these constraints, this thesis focused on enhancing EMT-based solutions using preoperative computed tomography (CT) and intraoperative tracked ultrasound (US) image data, and, ultimately, deliver a novel surgical navigation system that can be translated to the clinic. To accomplish this goal, the following steps/contributions were fulfilled: (1) study the impact of ureteroscopy and US instruments in the EMT systems’ reliability and accuracy; (2) development of a protocol to create kidney phantom models to assess image fusion strategies; (3) assessment in an insilico environment of a point set registration technique and an US acquisition protocol to fuse twodimensional US and 3D CT data; (4) proposal of a new approach to intraoperatively fuse CT and US data based on a semi-automatic US segmentation strategy and a point set registration algorithm; and (5) gathering of all above-mentioned contributions into a novel surgical navigation system, including additional features to improve real-time guidance, like: needle trajectory and catheter position’ projection over US images; integration of instruments and imaging data into a 3D virtual environment; continuous organtracking (compensating internal organ movements); and needle-based visual feedback. This system was assessed by physicians and compared against other EMT-based solutions in a close-to-real scenario using an abdominal phantom model. The physicians’ performance was superior with the proposed system, preventing injuries to nearby organs and excelling in complex scenarios. The proposed system was classified as the safest solution, obtaining the highest confidence levels during tests. Overall, it proved its added value to assist PRA during PCNL. Considering the applicability of enhancing intraoperative scenarios with preoperative data and guidance feedback, the proposed system may be broadened to other surgical interventions., This work was possible thanks to the financial support provided by FCT - Foundation for Science and Technology, iSurgical3D Lda., and the European Social Fund, through the Programa Operacional Capital Humano (POCH) and, in the scope of the PhD grant PDE/BDE/113597/2015; by funds from the European Regional Development Fund (FEDER) through the Operational Programme Competitiveness Factors (COMPETE) and by National Funds through FCT under the projects POCI-01-0145-FEDER-007038; and by the project NORTE-01-0145- FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through FEDER.

Purpose The surgical navigation system that provides guidance throughout the surgery can facilitate safer and more radical liver resections, but such a system should also be able to handle organ motion. This work investigates the accuracy of intraoperative surgical guidance during open liver resection, with a semi-rigid organ approximation and electromagnetic tracking of the target area. Methods The suggested navigation technique incorporates a preoperative 3D liver model based on diagnostic 4D MRI scan, intraoperative contrast-enhanced CBCT imaging and electromagnetic (EM) tracking of the liver surface, as well as surgical instruments, by means of six degrees-of-freedom micro-EM sensors. Results The system was evaluated during surgeries with 35 patients and resulted in an accurate and intuitive real-time visualization of liver anatomy and tumor's location, confirmed by intraoperative checks on visible anatomical landmarks. Based on accuracy measurements verified by intraoperative CBCT, the system's average accuracy was 4.0 ± 3.0 mm, while the total surgical delay due to navigation stayed below 20 min. Conclusions The electromagnetic navigation system for open liver surgery developed in this work allows for accurate localization of liver lesions and critical anatomical structures surrounding the resection area, even when the liver was manipulated. However, further clinically integrating the method requires shortening the guidance-related surgical delay, which can be achieved by shifting to faster intraoperative imaging like ultrasound. Our approach is adaptable to navigation on other mobile and deformable organs, and therefore may benefit various clinical applications.

Purpose: The purpose of this work was to develop a new method of tracking a laparoscopic ultrasound (LUS) transducer in laparoscopic video by combining the hardware [e.g., electromagnetic (EM)] and the computer vision-based (e.g., ArUco) tracking methods. Approach: We developed a special tracking mount for the imaging tip of the LUS transducer. The mount incorporated an EM sensor and an ArUco pattern registered to it. The hybrid method used ArUco tracking for ArUco-success frames (i.e., frames where ArUco succeeds in detecting the pattern) and used corrected EM tracking for the ArUco-failure frames. The corrected EM tracking result was obtained by applying correction matrices to the original EM tracking result. The correction matrices were calculated in previous ArUco-success frames by comparing the ArUco result and the original EM tracking result. Results: We performed phantom and animal studies to evaluate the performance of our hybrid tracking method. The corrected EM tracking results showed significant improvements over the original EM tracking results. In the animal study, 59.2% frames were ArUco-success frames. For the ArUco-failure frames, mean reprojection errors for the original EM tracking method and for the corrected EM tracking method were 30.8 pixel and 10.3 pixel, respectively. Conclusions: The new hybrid method is more reliable than using ArUco tracking alone and more accurate and practical than using EM tracking alone for tracking the LUS transducer in the laparoscope camera image. The proposed method has the potential to significantly improve tracking performance for LUS-based augmented reality applications.

Background and purpose: To investigate the accuracy of dwell position detection with a combined electromagnetic tracking (EMT) brachytherapy (BT) system for treatment verification, by quantifying positional errors due to EM field interference in typical pelvic BT clinical settings. Materials and methods: Dedicated prostate and cervix BT phantoms were imaged with CT. For the cervix phantom, the Utrecht applicator + interstitial catheters were used. The implants were reconstructed and treatment plans were created with 270/65 dwell positions for the prostate/cervix phantom. Next, EMT experiments were performed in clinical BT settings using a prototype of a combined EMT/BT system. We quantified positional errors due to EM field interference from surrounding equipment by comparing planned and EMT-measured dwell positions. The mean residual error between planned and EMT-measured dwell positions was calculated in the prostate interstitial catheters and in the whole cervix implant including the applicator. For the cervix phantom, the analysis was repeated for only the interstitial catheters. Results: Mean residual errors of less than 0.5/0.4 mm in the prostate/cervix catheters were found. For the whole cervix implant including the applicator, large deviations up to 2.4 mm were found. Compared to the interference free set-up, the CT and patient bed environments showed larger residual errors in the interstitial catheters, but residual errors remained

Purpose: Electromagnetic Tracking (EMT) can partially replace X-ray guidance in minimally invasive procedures, reducing radiation in the OR. However, in this hybrid setting, EMT is disturbed by metallic distortion caused by the X-ray device. We plan to make hybrid navigation clinical reality to reduce radiation exposure for patients and surgeons, by compensating EMT error. Methods: Our online compensation strategy exploits cycle-consistent generative adversarial neural networks (CycleGAN). 3D positions are translated from various bedside environments to their bench equivalents. Domain-translated points are fine-tuned to reduce error in the bench domain. We evaluate our compensation approach in a phantom experiment. Results: Since the domain-translation approach maps distorted points to their lab equivalents, predictions are consistent among different C-arm environments. Error is successfully reduced in all evaluation environments. Our qualitative phantom experiment demonstrates that our approach generalizes well to an unseen C-arm environment. Conclusion: Adversarial, cycle-consistent training is an explicable, consistent and thus interpretable approach for online error compensation. Qualitative assessment of EMT error compensation gives a glimpse to the potential of our method for rotational error compensation., Comment: Conditionally accepted for publication in IJCARS & presentation at IPCAI

The present study investigates awkward human body postures adopted in floor mopping by push and figure-of-eight methods. Three mopping professionals each in three different height categories (5th, 50th and 95th percentile person according to Indian anthropometric data) participated in floor mopping experiments conducted in two different laboratory set-ups. In the first set-up, continuous positional data of participant’s joints (wrist, elbow and shoulder) were recorded using six dimensional electromagnetic tracking system (ETS) and angular variation of the joints were evaluated for the two mopping techniques. In the second set-up, the three-dimensional positional data of body movements were recorded using optical motion capture cameras in mopping experiments to identify Rapid Upper Limb Assessment (RULA) score at extreme postures. The total RULA score obtained in push (4.6–5) for all height categories is less than figure-of-eight (6.4–6.6) method, indicating less postural load during push mopping technique. This research confirms that mopping professionals are highly susceptible to postural loads/discomfort and the need of ergonomic design solutions are essential to reduce the observed risk.

Interventional cardiology procedure is an important type of minimally invasive surgery that deals with the catheter-based treatment of cardiovascular diseases, such as coronary artery diseases, strokes, peripheral arterial diseases and aortic diseases. Ultrasound imaging, also called echocardiography, is a typical imaging tool that monitors catheter puncturing. Localising a medical device accurately during cardiac interventions can help improve the procedure’s safety and reliability under ultrasound imaging. However, external device tracking and image-based tracking methods can only provide a partial solution. Thus, we proposed a hybrid framework, with the combination of both methods to localise the catheter tip target in an automatic way. The external device used was an electromagnetic tracking system from North Digital Inc (NDI) and the ultrasound image analysis was based on UNet, a deep learning network for semantic segmentation. From the external method, the tip’s location was determined precisely, and the deep learning platform segmented the exact catheter tip automatically. This novel hybrid localisation framework combines the advantages of external electromagnetic (EM) tracking and deep-learning-based image method, which offers a new solution to identify the moving medical device in low-resolution ultrasound images. Featured Application This framework can be applied to other medical-device localisation fields to help doctors identify a moving target in low-resolution ultrasound images.

The primary aims of the study were (1) to examine kinematics and kinetics of those pitching with and without lower extremity pain in collegiate softball pitchers, and (2) to determine if there was an association between the lower extremity pain and lower extremity kinematics, trunk kinematics, and shoulder kinetics in collegiate softball pitchers. Thirty-seven NCAA Division I female collegiate softball pitchers (19.8±1.3 yrs,173.7±7.7 cm, 79.0±12.4 kg) participated. Participants were divided into two groups, those who were currently experiencing lower extremity pain and those who were not. Participants threw three rise ball pitches. Kinematic data were collected at 100 Hz using an electromagnetic tracking system. Mann-Whitney U tests revealed no significant kinematic or kinetic differences between pitchers with and without lower extremity pain. Additionally, there were no significant correlations between pain and recorded kinematic and kinetic variables. Considering there were no biomechanical differences observed between pitchers, coaches and athletic trainers should take caution with athlete assessment since athletes may not display altered biomechanics. Further examination into the duration and degree of pain is needed in an attempt to fully understand the implication of pain and pitching mechanics.

Objective: To characterize the effect of a titanium-alloy anchoring system (TAS) on the motion of the cranial cruciate ligament (CrCL) deficient stifle. To compare the motion with the TAS to that of the CrCL-intact and CrCL-deficient stifle.Study Design: Each canine pelvic limb was mounted in a loading jig under 30% body weight. Motion data was collected using an electromagnetic tracking system at stifle angles of 125°, 135°, and 145° with the CrCL-intact, CrCL-deficient and the TAS applied.Results: Total translation of the CrCL-deficient stifle following the TAS was reduced, but remained greater than the CrCL-intact stifle at angles of 125°, 135°, and 145°. Internal rotation of the TAS groups was greater than the CrCL-intact group at 145°, but not 125° and 135°. Varus motion of the TAS group was decreased compared to the CrCL-deficient group, but increased compared to the CrCL-intact group at angles of 125°, 135°, and 145°.Conclusion: Total translation and internal rotation of the CrCL-deficient stifle following the TAS differed from that of the CrCL-intact stifle. However, the TAS reduced total translation and internal rotation of the tibia relative to the femur in the CrCL-deficient stifle to levels that may yield clinically acceptable results.

Dear editor, Jacobson et al 1 keenly examined how a novel electromagnetic tracking system may be safely used to ensure correct placement of small-bore feeding tubes (SBFTs). Clinical practice has shifted such that SBFTs are preferred for short-term feeding due to a reduction in aspiration risk and perceived patient comfort.2 The latter, however, is largely anecdotal and may reflect provider perception rather than reality. In actuality, traditional large-bore feeding tubes (LBFTs) may be the favorable option. SBFTs are commonly placed blindly with a 1%–3% incidence of erroneous airway insertion. A pneumothorax occurs in one-third of pulmonary misplacements with an associated mortality rate reportedly exceeding 20%. Additional pulmonary complications include hemothoraces, pneumonias and broncho-pleural fistulas.1 3 SBFTs employ a rigid guidewire—the suspected culprit …

We designed a virtual reality system which can assist training of vascular interventional surgery. The hardware including electromagnetic navigation, performs real-time guide wire position tracking and display. Through k-dimensional tree data structure we store and calculate the distance between guide wire tip and vascular centerline for security warning, avoiding guide wire tip penetration through vascular wall. The neural network model aims to predict the next operation of guide wire status in real time. The operation information will be displayed by virtual reality devices.

Background Dental implant placement navigation systems based on optical tracking have been widely used in clinics. However, electromagnetic (EM) navigation method that does not suffer from problems of hidden line-of-light has not yet been described. Methods This work proposes an EM-guided navigation method named TianShu-ESNS with virtual calibration. Model (12 implants) and animal experiments (pig head: six implants) were conducted to evaluate its performance and stability. Result The mean virtual calibration error was 0.83 ± 0.20 mm. The mean deviations at the entry point, end point and angle in the phantom experiment of TianShu-ESNS were 1.23 ± 0.17 mm, 1.59 ± 0.20 mm and 1.83 ± 0.27°, respectively. In the animal experiment, the same deviations were 1.25 ± 0.07 mm, 1.57 ± 0.35 mm and 1.90 ± 0.60°, respectively. Conclusions The experimental results show that TianShu-ESNS with the virtual calibration method could serve as a promising tool to eliminate the line-of-light hidden problem and simplify operation procedure in dental implant placement.

There is a growing interest in neonatologists to train in echocardiography. Recommendations for training have been published by medical societies and working groups, but concerns exist on their feasibility in the face of limited resources. Simulators are increasingly used for training in medicine, including echocardiography. They have the potential to help overcome the shortage of training opportunities. We describe the currently available 2 echocardiography simulators designed for neonatology. Both systems are based on real 3-dimensional echocardiographic data and use an electromagnetic tracking system. Although limited data exist proving their effectiveness, deduction from other disciplines support this assumption.

Introduction: Endovascular revascularization has become the preferred treatment for most patients with iliac artery obstructions, with a high rate of clinical and technical success. Areas covered: This review will describe novel developments in the diagnosis and treatment of iliac artery obstructions including the augmentation of preprocedural imaging with advanced flow models, image fusion techniques, and state-of-the-art device-tracking capabilities. Expert opinion: The combination of these developments will change the endovascular field within the next 5 years, allowing targeted iliac treatment without the need for radiographic imaging or iodinated contrast media.

Percutaneous biopsies are popular for extracting suspicious tissue formations (primarily for cancer diagnosis purposes) due to the: relatively low cost, minimal invasiveness, quick procedure times, and low risk for the patient. Despite the advantages provided by percutaneous biopsies, poor needle and tumor visualization is a problem that can result in the clinicians classifying the tumor as benign when it was malignant (false negative). The system developed by the authors aims to address the concern of poor needle and tumor visualization through two virtualization setups. This system is designed to track and visualize the needle and tumor in three-dimensional space using an electromagnetic tracking system. User trials were conducted in which the 10 participants, who were not medically trained, performed a total of 6 tests, each guiding the biopsy needle to the desired location. The users guided the biopsy needle to the desired point on an artificial spherical tumor (diameters of 30, 20, and 10 mm) using the 3D augmented reality (AR) overlay for three trials and a projection on a second monitor (TV) for the other three trials. From the randomized trials, it was found that the participants were able to guide the needle tip 6.5 ± 3.3 mm away from the desired position with an angle deviation of 1.96 ± 1.10° in the AR trials, compared to values of 4.5 ± 2.3 mm and 2.70 ± 1.67° in the TV trials. The results indicate that for simple stationary surgical procedures, an AR display is non-inferior a TV display.

ContextSpiking is one of the most frequently used scoring techniques in volleyball games, and around 80% of shoulder pain in volleyball players is linked with the spiking movement.ObjectiveTo investigate the differences in glenohumeral joint, scapular, and trunk movements during the spiking motion between volleyball players with and those without shoulder pain.DesignCross-sectional study.SettingUniversity laboratory.Patients or Other ParticipantsTwenty amateur volleyball players with shoulder pain (age = 21.8 ± 1.79 years, with an average of 4.0 ± 0.92 years of volleyball experience and 6.0 ± 3.51 months of shoulder pain) and 20 sex-, age-, and experience-matched control participants.Main Outcome Measure(s)The 3-dimensional kinematics of the shoulder joint, scapula, and trunk during spiking were assessed using an electromagnetic tracking system.ResultsCompared with the control group, individuals with shoulder pain demonstrated less scapular posterior tilt (P = .041) and more glenohumeral horizontal abduction (P = .008) and scapular internal rotation (P = .02) at ball contact when performing the cross-body spike.ConclusionsThe decrease in scapular posterior tilt, along with increased glenohumeral horizontal abduction and scapular internal rotation, was associated with shoulder pain in university volleyball players. These changes should be addressed in the training and treatment of young volleyball players.

This work was to devise a comprehensive testing scheme to evaluate the geometric and dosimetric accuracy of the Edge accelerator gating with electromagnetic tracking (EMT) for its safety in clinical application. A CIRS thorax phantom was scanned with four-dimensional cone-beam CT (4D-CBCT) on an Edge accelerator while the simulated tumor was simultaneously tracked with an EMT system using Calypso. The geometric accuracy was validated by comparing the motion trajectories derived from Calypso and 4D-CBCT with the ground truth from motion control software. The two-dimensional and three-dimensional dynamic doses were measured with the Matrixx and ArcCHECK installed on a motion platform, both with and without EMT. For tumor motion with 5, 7.5 mm amplitudes, the average absolute differences of sample position between Calypso and the ground truth were 0.286±0.234 mm, 0.407±0.331 mm respectively. Dosimetric accuracy was validated with 3 mm/3% gamma criterion. The average gamma pass rates of 2D dynamic dose validation based on Matrixx were less than 46% without EMT, 97.3% using 2 mm gating limit, 96% using 3 mm gating limit and 93.4% using 5mm gating limit respectively. The mean 3D dynamic dose validation pass rates based on ArcCHECK were 65.9% without EMT, 96.2% using 3 mm gating limit, and 92.5% using 5 mm gating limit with EMT respectively. The geometric accuracy of the Calypso system in tracking the moving target area was stable at the submillimeter level. The dosimetric accuracy could be improved significantly with EMT using an appropriate gating limit.

Throwing injuries to the shoulder joint often occur during shoulder external rotation. An appropriate combination of thoracic, scapular, and humeral motion during throwing is important to prevent such injuries, but it is unclear how thoracic posture contributes to shoulder motion during throwing.The purpose of this study, therefore, was to clarify the influence of thoracic posture on scapulothoracic and glenohumeral motion during shoulder external rotation.Eccentric external rotation at 90° of shoulder abduction in thoracic flexion and extension postures was performed by 15 asymptomatic participants. Three-dimensional scapulothoracic and glenohumeral movements were measured with an electromagnetic tracking device at 75°, 80°, 85°, and maximum shoulder external rotation. The thoracic angle and maximum shoulder external rotation in absolute coordination were measured with a three-dimensional motion capture system.The results showed that scapular posterior tilting and external rotation in the thoracic extension posture were significantly greater than those in the flexion posture (p 0.05). Glenohumeral horizontal extension was significantly less in the thoracic extension posture than in the flexion posture (p 0.05), whereas maximum shoulder external rotation was significantly greater (p 0.01). Thus, thoracic extension increased scapulothoracic posterior tilting and external rotation and reduced glenohumeral horizontal extension during shoulder external rotation, as well as increasing maximum shoulder external rotation.These findings suggest that thoracic extension may contribute to reduction of mechanical demand in the glenohumeral joint during throwing, potentially reducing shoulder injuries.

As the importance and prevalence of electromagnetic tracking in medical and industrial applications increases, the need for customized sensor design has escalated. This work focuses on AC-based electromagnetic tracking systems where off-the-shelf inductive sensors may not be optimal for many medical instruments or tracking applications. We present a repeatable approach for the design, optimisation and implementation of air-core and ferrite-core inductive sensors suitable for AC-based electromagnetic tracking. Coil-based sensors were designed and tested to investigate the effect of the usual coil parameters such as turn count, geometry and core material on sensor tracking accuracy and precision. Our methodologies were experimentally validated using the Anser EMT system which enabled rapid experimental deployment. Experimental performance is reported compared to off-the-shelf sensors. Static tracking errors of less than 2mm were achieved and close correlation with theoretical design sensitivity and precision was observed. This work may represent a valuable tool in the design of bespoke sensors for electromagnetic tracking where customize sensitivity and form factor are critical.