scholarly journals A Compact, Bone-Attached Robot for Mastoidectomy

2015 ◽  
Vol 9 (3) ◽  
Author(s):  
Neal P. Dillon ◽  
Ramya Balachandran ◽  
J. Michael Fitzpatrick ◽  
Michael A. Siebold ◽  
Robert F. Labadie ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Compact Bone ◽  
Target Volume ◽  
Surgical Workflow ◽  
The Mean ◽  
Milling Robot ◽  
High Level ◽  
Temporal Bones

Otologic surgery often involves a mastoidectomy, which is the removal of a portion of the mastoid region of the temporal bone, to safely access the middle and inner ear. The surgery is challenging because many critical structures are embedded within the bone, making them difficult to see and requiring a high level of accuracy with the surgical dissection instrument, a high-speed drill. We propose to automate the mastoidectomy portion of the surgery using a compact, bone-attached robot. The system described in this paper is a milling robot with four degrees-of-freedom (DOF) that is fixed to the patient during surgery using a rigid positioning frame screwed into the surface of the bone. The target volume to be removed is manually identified by the surgeon pre-operatively in a computed tomography (CT) scan and converted to a milling path for the robot. The surgeon attaches the robot to the patient in the operating room and monitors the procedure. Several design considerations are discussed in the paper as well as the proposed surgical workflow. The mean targeting error of the system in free space was measured to be 0.5 mm or less at vital structures. Four mastoidectomies were then performed in cadaveric temporal bones, and the error at the edges of the target volume was measured by registering a postoperative computed tomography (CT) to the pre-operative CT. The mean error along the border of the milled cavity was 0.38 mm, and all critical anatomical structures were preserved.

scholarly journals High-Speed Railway Clearance Intrusion Detection with Improved SSD Network

2019 ◽  
Vol 9 (15) ◽  
pp. 2981 ◽  
Author(s):  
Baoqing Guo ◽  
Jiafeng Shi ◽  
Liqiang Zhu ◽  
Zujun Yu
Keyword(s):  
Intrusion Detection ◽  
High Speed ◽  
Rapid Development ◽  
Single Shot ◽  
L1 Norm ◽  
Low Level ◽  
Model Size ◽  
Public Dataset ◽  
The Mean ◽  
High Level

With the rapid development of high-speed railways, any objects intruding railway clearance will do great threat to railway operations. Accurate and effective intrusion detection is very important. An original Single Shot multibox Detector (SSD) can be used to detect intruding objects except small ones. In this paper, high-level features are deconvolved to low-level and fused with original low-level features to enhance their semantic information. By this way, the mean average precision (mAP) of the improved SSD algorithm is increased. In order to decrease the parameters of the improved SSD network, the L1 norm of convolution kernel is used to prune the network. Under this criterion, both the model size and calculation load are greatly reduced within the permitted precision loss. Experiments show that the mAP of our method on PASCAL VOC public dataset and our railway datasets have increased by 2.52% and 4.74% respectively, when compared to the original SSD. With our method, the elapsed time of each frame is only 31 ms on GeForce GTX1060.

scholarly journals Whole-Body Operational Space Control for Locomotion and Manipulation

2015 ◽  
Vol 137 (06) ◽  
pp. S2-S6
Author(s):  
Luis Sentis
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Humanoid Robots ◽  
Rigid Body Dynamics ◽  
Joint Torque ◽  
Whole Body ◽  
Operational Space ◽  
Body Dynamics ◽  
Service Oriented ◽  
High Level

This article discusses the various researches being undertaken to study and develop Whole-Body Operational Space Control (WBOSC). The WBOSC emerges as a capable framework for real-time unified control of motion and force of humanoid robots. It could theoretically outperform high-speed industrial manipulators while providing the grounds for new types of service-oriented applications that require contact, by exploiting the rigid body dynamics of systems. By relying on joint torque sensors, WBOSC opens up the potential to interact with the physical environment using any part of the robot’s body while regulating the effective mechanical impedances to safe values. With ControlIt!, the developers provide a strict and easy way to use the WBOSC API consisting of compound tasks which define the operational space, and constraint sets that define the contacts with the environment as well as dependent degrees of freedom. ControlIt! is easy to connect to high level planners.

scholarly journals Custom Focal Trough in Cone-Beam Computed Tomography Reformatted Panoramic Versus Digital Panoramic for Mental Foramen Position to Aid Implant Planning

2020 ◽  
Vol 10 ◽  
pp. 34
Author(s):  
Khaled Beshtawi ◽  
Emad Qirresh ◽  
Mohamed Parker ◽  
Shoayeb Shaik
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Mental Foramen ◽  
Reference Points ◽  
Cone Beam ◽  
Vertical Position ◽  
Linear Measurements ◽  
Mean Values ◽  
The Mean ◽  
High Level

Objectives: To compare the linear measurements from digital panoramic (DP) radiographs and cone-beam computed tomography (CBCT) volumes for the localization of the mental foramen (MF). Material and Methods: Thirty-one patients with panoramic and CBCT radiographs depicted on the same machine were analyzed. The vertical and horizontal positions of the MF were compared by the differences in distances measured from reference points to the boundaries (tangents) of the MF in digital panoramic (DP) and CBCT reformatted panoramic (CRP) views. The vertical position of MF was also analyzed on CBCT oblique coronal views (CORO) and compared with its corresponding distances on DP and CRP views. Results: Statistically significant differences (P < 0.05) were found in all compared measurements between CRP and DP views. In addition, the vertical distance (Y1) compared between DP, CRP, and CORO views also showed a statistically significant measurement discrepancy in the mean distance (P < 0.000) with the highest mean difference of 1.59 mm (P < 0.05) was attained from Y1 (DP-CORO). Inter- and intra-examiner analysis indicated a high level of agreement for all measurements. Conclusion: The mean values of discrepancies in measurements between DP and CRP views for horizontal and vertical linear measurements were clinically tolerable. Nevertheless, significant differences in the vertical MF position were detected between the panoramic views (DP, CRP) and the coronal views (CORO). This implies that the use of coronal view measurements during implant planning might reduce the risk of neurovascular injuries.

scholarly journals Fusion of intra-oral scans in cone-beam computed tomography scans

2020 ◽  
Vol 25 (1) ◽  
pp. 77-85 ◽  
Author(s):  
F. Baan ◽  
R. Bruggink ◽  
J. Nijsink ◽  
T. J. J. Maal ◽  
E. M. Ongkosuwito
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Gold Standard ◽  
Degrees Of Freedom ◽  
Cone Beam ◽  
Intra Class Correlation ◽  
Six Degrees Of Freedom ◽  
Software Packages ◽  
High Level ◽  
Intra Class Correlation Coefficient

Abstract Purpose The purpose of this study was to evaluate the clinical accuracy of the fusion of intra-oral scans in cone-beam computed tomography (CBCT) scans using two commercially available software packages. Materials and methods Ten dry human skulls were subjected to structured light scanning, CBCT scanning, and intra-oral scanning. Two commercially available software packages were used to perform fusion of the intra-oral scans in the CBCT scan to create an accurate virtual head model: IPS CaseDesigner® and OrthoAnalyzer™. The structured light scanner was used as a gold standard and was superimposed on the virtual head models, created by IPS CaseDesigner® and OrthoAnalyzer™, using an Iterative Closest Point algorithm. Differences between the positions of the intra-oral scans obtained with the software packages were recorded and expressed in six degrees of freedom as well as the inter- and intra-observer intra-class correlation coefficient. Results The tested software packages, IPS CaseDesigner® and OrthoAnalyzer™, showed a high level of accuracy compared to the gold standard. The accuracy was calculated for all six degrees of freedom. It was noticeable that the accuracy in the cranial/caudal direction was the lowest for IPS CaseDesigner® and OrthoAnalyzer™ in both the maxilla and mandible. The inter- and intra-observer intra-class correlation coefficient showed a high level of agreement between the observers. Clinical relevance IPS CaseDesigner® and OrthoAnalyzer™ are reliable software packages providing an accurate fusion of the intra-oral scan in the CBCT. Both software packages can be used as an accurate fusion tool of the intra-oral scan in the CBCT which provides an accurate basis for 3D virtual planning.

Anatomy of the Transarcuate Approach to the Petrous Apex

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P98-P98
Author(s):  
Alice D Lee ◽  
Sanaz Hamidi ◽  
Hamid R Djalilian
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Semicircular Canal ◽  
Petrous Apex ◽  
Minimal Risk ◽  
High Resolution Computed Tomography ◽  
Superior Semicircular Canal ◽  
The Mean ◽  
Temporal Bones ◽  
Anterior Posterior

Problem The petrous apex is considered to be one of the most difficult areas of the temporal bone to approach surgically. We present data describing the dimensions of a transarcuate approach to the petrous apex, as measured on high resolution computed tomography. Methods Measurements of the mean dimensions and ranges through the crura of the superior semicircular canal were made. The measurements were obtained from high-resolution computed tomography images of 30 temporal bones in 19 consecutively presenting patients with a pneumatized posterior petrous apex cell tract on CT. Measurements were obtained with the use of the standard PACS (picture archiving and communication system) software. Results The mean anterior-posterior space in the superior semicircular canals without transcrural pneumatization was 4.96±0.39 mm. The mean superior- inferior dimension was 4.98±0.48 mm. The same measurements in canals with pneumatized intercrural tracts were 5.17±0.51 mm and 5.11±0.62 mm respectively. The mean anterior-posterior distance and superior-inferior distance of the intercrural air tracts themselves were 2.09±0.57 and 2.01±0.45mm. There was a statistically significant difference in the anterior-posterior size between the pneumatized and non-pneumatized canals but not in the superior-inferior distance. Conclusion Pneumatized bones demonstrate a slight increase in the subarcuate dimensions as compared to non-pneumatized bones. The transarcuate approach is a viable one for drainage and biopsy of the petrous apex. Significance Our study demonstrates that the transarcuate approach is anatomically possible for drainage of the petrous apex with minimal risk to the superior semicircular canal. This would be especially useful for the drainage of cholesterol granulomas of the petrous apex or biopsy in this area.

scholarly journals Target coverage of daily cone-beam computed tomography in breath-hold image-guided radiotherapy for gastric lymphoma

BJR|Open ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 20200062
Author(s):  
Shigeo Takahashi ◽  
Takamasa Nishide ◽  
Masato Tsuzuki ◽  
Hiroki Katayama ◽  
Masahide Anada ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Gastric Lymphoma ◽  
Target Volume ◽  
Cone Beam ◽  
Breath Hold ◽  
Target Coverage ◽  
Image Guided Radiotherapy ◽  
Image Guided ◽  
The Mean

Objectives: We evaluated retrospectively the daily target coverage using cone-beam computed tomography (CBCT) in breath-hold image-guided radiotherapy (BH-IGRT) for gastric lymphoma. Methods: BH-IGRT was performed using a prescribed dose of 30.6 Gy in 17 fractions for the whole stomach. We assessed the target coverage of the whole stomach on daily CBCT images [daily clinical target volume (CTV)], which was delineated individually by two observers. We evaluated V95% (percentage of volume receiving ≥95% of the prescribed dose) of daily CTV. Results: In total, 102 fractions from 6 patients were assessed. The mean V95% of daily CTV was 97.2%, which was over 95%. In two of six patients, the V95% of daily CTV was over 95% for either observer in all fractions. One patient had significant interobserver variation (p = 0.013). In 95 fractions (93%), the V95% of daily CTV was over 95% for either observer. Conclusion: Daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable, even when using CBCT. Advances in knowledge: A previous study ascertained good daily target coverage in BH-IGRT for gastric lymphoma using in-room CT. Even when using CBCT in our study, daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable.

scholarly journals Inter-observer variations of the tumor bed delineation for patients after breast conserving surgery in preoperative magnetic resonance and computed tomography scan fusion

2021 ◽  
Author(s):  
Jie Jiang ◽  
Jinhu Chen ◽  
Wanhu Li ◽  
Yongqing Li ◽  
Yiru Chen ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Magnetic Resonance ◽  
Breast Conserving Surgery ◽  
Target Volume ◽  
Observer Variability ◽  
Resonance Imaging ◽  
Tumor Bed ◽  
Inter Observer Variability ◽  
Preoperative Magnetic Resonance ◽  
The Mean

Abstract Purpose: Tumor bed (TB) delineation based on preoperative magnetic resonance imaging (pre-MRI) fused with postoperative computed tomography (post-CT) were compared to post-CT only to define pre-MRI may aid in improving the accuracy of delineation. Methods and materials: The pre-MRI imaging of 10 patients underwent radiotherapy (RT) after breast conserving surgery (BCS) were reviewed. Post-CT scans were acquired in the same prone position as pre-MRI. Pre-MRI and post-CT automatically match and then manual alignment was given to enhance fusion consistency. 3 radiation oncologists and 2 radiologists delineated the clinical target volume (CTV) for CT-based. The gross target volume (GTV) of pre-MRI-based was determined by the volume of tumor acquired with 6 sequences: T1, T2, T2W-SPAIR, DWI, dyn-eTHRIVE and sdyn-eTHRIVE, expended 10 mm to form the CTV-pre-MRI. Planning target volume (PTV) for each sequence was determined by CTV extended 15 mm, trimmed to 3mm from skin and the breast-chest wall interface. The variability of the TB delineation were developed as follows: the mean volume, conformity index (CI) and dice coefficient (DC). Results: The mean volumes of CTV and PTV delineated with CT were all larger than those with pre-MRI. The lower inter-observer variability was observed from PTV, especially in sdyn-eTHRIVE in all sequences. For each sequence of pre-MRI, all DCs were larger than post-CT, and the largest DC was observed by sdyn-eTHRIVE sequence fusion to post-CT. The overlap for PTV was significantly improved in the pre-MRI-based compared with the CT-based. Conclusions: TB volumes based on pre-MRI were smaller than post-CT with CVS increased. Pre-MRI provided a more precise definition of the TB with observers performed a smaller inter-observer variability than CT. Pre-MRI, especially in sdyn-eTHRIVE sequence, should help in reducing treatment volumes with the improved accuracy of TB delineation of adjuvant RT of breast cancer. Keywords: Breast cancer, radiotherapy, tumor bed, magnetic resonance imaging, computed tomography

Inlet Distortion Simulations of a Transonic Fan With CFD and Low-Order Methods

2021 ◽  
Author(s):  
Carlo Favaron ◽  
Andrea Magrini ◽  
Alessandro Visentin ◽  
Luca Menegozzo ◽  
Ernesto Benini
Keyword(s):  
High Speed ◽  
Similar Response ◽  
Inlet Distortion ◽  
Speed Flow ◽  
The Mean ◽  
High Level ◽  
Transonic Fan ◽  
Operating Points ◽  
Inflow Conditions ◽  
Low Order

Abstract Future aircraft are expected to have a high level of fuselage-engine integration, exposing the propulsor to non-uniform inflow conditions, in which the performance and stability of the engine fan can be severly affected. This paper proposes a study of a transonic fan subject to inlet distortion by employing steady RANS simulations and mean line calculations. The steady CFD results, although insufficient to correctly measure the interaction of the distortion across the cascade passages, are used as a benchmark to compare the prediction of a leaner low-order tool, adopting a superposition of several 1D calculations in the discretised compressor approach. A continuous total pressure deficit is imposed at the inlet and the distorted operating points are compared to the clean inflow case. The performance drop at the peak efficiency point is similar for the two models, altough the mean-line 1D method fails in closely matching the distribution in the upper span of the blade. The qualitatively similar response of the low-order approach to the distorted inflow should allow for its use in preliminary blade design exploration once improved for high-speed flow prediction.

Computed Tomography Evaluation of Nasal Dimensions among Different Singaporean Ethnicities

2020 ◽  
Vol 36 (05) ◽  
pp. 499-504
Author(s):  
Charmain Liling Zhao ◽  
Suzanne Teo ◽  
Lisa Lim ◽  
Sandeep Uppal
Keyword(s):  
Computed Tomography ◽  
Degrees Of Freedom ◽  
Nasal Bone ◽  
Ct Images ◽  
Lateral Osteotomy ◽  
Significant Difference ◽  
Aperture Width ◽  
Nasal Pyramid ◽  
High Level ◽  
Pyriform Aperture

AbstractOsteotomies in rhinoplasty are performed to correct deformities in nasal contour. The size of osteotome used is dictated by the thickness of the bony nasal pyramid along the osteotomy route. The aim of this study is to determine whether nasal bony dimensions differ between different ethnic groups in Singapore. Randomly selected patients' computed tomography (CT) scans of the face performed between the years 2010 to 2013 in our institution (Khoo Teck Puat Hospital) were evaluated. The setting was a tertiary government hospital. CT images of 309 patients (233 Chinese [147 males, 86 females], 32 Malays [16 males, 16 females], and 44 Indians [33 males, 11 females]) were evaluated. Anthropomorphic measurements of the nasal bone along the track of the lateral, medial, and intermediate osteotomies, as well as the nasal bone length and pyriform aperture width were measured on the CT images by two independent observers. Statistical analysis was performed using Student's t-test and two-way analysis of variance (ANOVA) test. There was no significant difference between the nasal pyramid bone thickness between different ethnicities along the osteotomy tracks (p > 0.05; degrees of freedom [df] = 2). However, there was a significant difference between males and females of the same ethnicity at the low level of the lateral osteotomy (p = 0.003) and the midlevel (p = 0.002) and high-level (p = 0.004) of the intermediate osteotomy. There was a statistically significant difference in nasal pyramid length (p < 0.05, df = 2) and pyriform aperture width (p < 0.05, df = 2) among the races and between the genders (p < 0.05). The mean difference in nasal pyramid length of 2.54 mm and pyriform aperture width of 1.89 mm was particularly significant between the Chinese and the Indians. Gender and ethnic differences in nasal bony dimensions should be considered in surgical planning for rhinoplasty.

scholarly journals Inter-observer variations of the tumor bed delineation for patients after breast conserving surgery in preoperative magnetic resonance and computed tomography scan fusion

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jie Jiang ◽  
Jinhu Chen ◽  
Wanhu Li ◽  
Yongqing Li ◽  
Yiru Chen ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Magnetic Resonance ◽  
Breast Conserving Surgery ◽  
Target Volume ◽  
Conformity Index ◽  
Observer Variability ◽  
Tumor Bed ◽  
Inter Observer Variability ◽  
Preoperative Magnetic Resonance ◽  
The Mean

Abstract Purpose Tumor bed (TB) delineation based on preoperative magnetic resonance imaging (pre-MRI) fused with postoperative computed tomography (post-CT) were compared to post-CT only to define pre-MRI may aid in improving the accuracy of delineation. Methods and materials The pre-MRI imaging of 10 patients underwent radiotherapy (RT) after breast conserving surgery (BCS) were reviewed. Post-CT scans were acquired in the same prone position as pre-MRI. Pre-MRI and post-CT automatically match and then manual alignment was given to enhance fusion consistency. Three radiation oncologists and 2 radiologists delineated the clinical target volume (CTV) for CT-based. The gross target volume (GTV) of pre-MRI-based was determined by the volume of tumor acquired with 6 sequences: T1, T2, T2W-SPAIR, DWI, dyn-eTHRIVE and sdyn-eTHRIVE, expended 10 mm to form the CTV-pre-MRI. Planning target volume (PTV) for each sequence was determined by CTV extended 15 mm, trimmed to 3 mm from skin and the breast-chest wall interface. The variability of the TB delineation were developed as follows: the mean volume, conformity index (CI) and dice coefficient (DC). Results The mean volumes of CTV and PTV delineated with CT were all larger than those with pre-MRI. The lower inter-observer variability was observed from PTV, especially in sdyn-eTHRIVE in all sequences. For each sequence of pre-MRI, all DCs were larger than post-CT, and the largest DC was observed by sdyn-eTHRIVE sequence fusion to post-CT. The overlap for PTV was significantly improved in the pre-MRI-based compared with the CT-based. Conclusions TB volumes based on pre-MRI were smaller than post-CT with CVS increased. Pre-MRI provided a more precise definition of the TB with observers performed a smaller inter-observer variability than CT. Pre-MRI, especially in sdyn-eTHRIVE sequence, should help in reducing treatment volumes with the improved accuracy of TB delineation of adjuvant RT of breast cancer.

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