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Radiotherapy for Pediatric Central Nervous System Tumors – Techniques and Strategies
Published in David A. Walker, Giorgio Perilongo, Roger E. Taylor, Ian F. Pollack, Brain and Spinal Tumors of Childhood, 2020
Modern facilities employ robotic couches with carbon fiber tabletops which allow six degrees of freedom, with corrections possible in all three spatial dimensions (superior/inferior, anterior/posterior, and laterally), as well as along the corresponding rotational axes. Although image guidance solutions in proton therapy have historically lagged behind linear accelerator technology, more recent installations have built in image guidance systems (2D kilovoltage and CBCT) to ensure accurate treatment delivery (Figure 7.10).126
3D Augmented Reality-Based Surgical Navigation and Intervention
Published in Terry M. Peters, Cristian A. Linte, Ziv Yaniv, Jacqueline Williams, Mixed and Augmented Reality in Medicine, 2018
Zhencheng Fan, Cong Ma, Xinran Zhang, Hongen Liao
Tracking surgical tools is of importance for surgical navigation and intervention. Commercial optical tracking systems use reflective balls or flat “chessboard” patterns as tracking markers. In some surgical treatments, such as cutting during an operation, detecting the tool with six degrees-of-freedom (6-DOF) is important for surgical safety. To ensure 6-DOF detection, markers are arranged in a noncollinear fashion, with the result that current surgical tools with such markers are difficult to use in a limited space due to their large spatial volume. A novel 3D spatial position measurement system using 3D image markers has been designed especially for surgical scenes with limited space (Fan et al. 2017a). The 3D image marker, which is a 2D image with encoded spatial information, has a compact size while providing spatial position measurement. The 3D image marker can be attached on the target for positioning and can be employed in a surgical tool. A novel surgical tool designed with collinear 3D image markers can generate a virtual, noncollinear set of markers (Figure 17.6) (Fan et al. 2015). Combined with the image acquisition device and the image processing method, the proposed surgical tool can be used for tracking and positioning in a limited space.
Physiology of Equilibrium
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Floris L. Wuyts, Leen K. Maes, An Boudewyns
Every motion in space can be broken down into three rotational degrees of freedom (yaw, pitch and roll) and three translational degrees of freedom (left–right, up–down, fore–aft). No event in one degree of freedom can be described by the others, hence every movement is uniquely and appropriately described by a combination of all six degrees of freedom. The anatomical design of the motion sensors in the peripheral vestibular system in the inner ear reflects these six degrees of freedom. The semicircular canals (SCCs) measure predominantly rotations whereas the maculae of the utricle and saccule detect mainly translations.
Propagation of registration errors into the change in maximum total point motion for determining stability of tibial baseplates
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Abigail E. Niesen, Maury L. Hull
To quantify the bias and precision in ΔMTPM for stable baseplates, migration defined as the movement which occurs between a time zero reference exam and a single follow-up time point (e.g. 1 year) must be computed. Since migration can only be determined in the presence of random error due to registration in the clinical setting (thus making it apparent migration rather than true migration), a simulation which propagates the random error due to registration in six degrees of freedom under different cases of true displacement and true rotation is necessary to determine the impact of registration error on ΔMTPM. An important input to the simulation is the registration error in six degrees of freedom, which can be identified from double examinations. Double examinations involve acquiring two independent pairs of images at the same follow-up exam and can be used to compute either registration error (also termed measurement error) or repeatability (Ranstam et al. 1999). A single publication which computed the registration errors using marker-based and model-based RSA was selected to provide inputs for the random errors in six degrees of freedom (van Hamersveld et al. 2019). Since the registration errors for marker-based RSA differ from those for model-based RSA, the methods described below were first applied for marker-based RSA followed by model-based RSA.
Computer-assisted surgery in medical and dental applications
Published in Expert Review of Medical Devices, 2021
Yen-Wei Chen, Brian W. Hanak, Tzu-Chian Yang, Taylor A. Wilson, Jenovie M. Hsia, Hollie E. Walsh, Huai-Che Shih, Kanako J. Nagatomo
ROSA® utilizes a robotic arm comprised six degrees of freedom to guide the surgeon to the anatomic target with flexibility and dexterity for precise surgical targeting. The device may be registered using bone fiducials or laser facial scanning, with studies showing similar accuracy between both methods [16]. The ROSA® robot is designed to assist neurosurgeons in planning and execution of procedures in a minimally invasive manner. As such, the device is most often utilized for minimally invasive stereotactic procedures, although the device may also be used as a navigation system for open cranial surgery and endoscopic procedures. The most common stereotactic procedures performed with ROSA® include the placement of deep brain stimulation (DBS) electrodes for movement disorders, lasers for laser interstitial thermal therapy neuroablative procedures, and stereoelectroencephalography (SEEG) electrode placement used for precise mapping and localization of epileptogenic foci. Studies using the ROSA® robot have demonstrated improved accuracy and precision with decreased operative time for robotic-assisted DBS and SEEG electrode placement, compared with conventional frame-based stereotactic placement [16,17].
Sensitivities of lumbar segmental kinematics and functional tissue loads in sagittal bending to design parameters of a ball-in-socket total disc arthroplasty prosthesis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Unlike spinal fusion, an important design objective of TDA prosthesis is to reproduce natural segmental motion (Galbusera et al. 2008). To describe the biofidelity of segmental motion, the instantaneous center of rotation (ICR) pattern is commonly adopted (Galbusera et al. 2008). Due to different definitions of the segmental ICR, inconsistent ICR patterns of intact lumbar segments have been reported in the literature (Rousseau et al. 2006; Schmidt et al. 2008; Liu et al. 2016). However, in all definitions, a single ICR location is calculated based on relative rotations and translations of adjacent vertebrae. Therefore, postoperative segmental kinematics should be more directly evaluated using the segment motions in all six degrees of freedom (DOFs). Furthermore, lumbar TDA using the anterior surgical approach, in which the anterior longitudinal ligament (ALL), anterior annulus fibrosis (AF) and the whole nucleus pulposus (NP) are dissected to create the surgical window (Galbusera et al. 2008), inevitably causes instability allowing excessive segmental motions (Marchi et al. 2012; Mobbs et al. 2017) and consequently increases the risk of overloading in intersegment tissues such as spinal ligaments and FJs (Shim et al. 2007; Ellingson et al. 2016). Hence, it is also indispensable to perform TDA performance evaluation considering load patterns of all spinal tissues.