Cost-effective 3D documentation device in forensic medicine.

3D documentation in forensics and forensic medicine is being introduced more frequently in various institutes around the world. However, several institutes lack capacity in finances as well as staff to perform 3D documentations regularly. This technical paper aims to present a 3D documentation device that is low cost and easy to use and is a viable entry level solution for forensic medical departments. For this the small single-board computer Raspberry Pi 4 was used in conjunction with its high quality (HQ) camera module to create the 3DLamp - a flexible, low cost and easy to use documentation device. Besides a detailed description of the device this paper also presents four case examples where a 3D documentation was performed and analyses the acquired data and the created 3D models. It was found that the device returns feasible 3D models that appear usable for forensic 3D reconstructions.

Simultaneous T2 -weighted real-time MRI of two orthogonal slices.

PURPOSE: MR guidance is used during therapy to detect and compensate for lesion motion. T2 -weighted MRI often has a superior lesion contrast in comparison to T1 -weighted real-time imaging. The purpose of this work was to design a fast T2 -weighted sequence capable of simultaneously acquiring two orthogonal slices, enabling real-time tracking of lesions. METHODS: To generate a T2 contrast in two orthogonal slices simultaneously, a sequence (Ortho-SFFP-Echo) was designed that samples the T2 -weighted spin echo (S- ) signal in a TR-interleaved acquisition of two slices. Slice selection and phase-encoding directions are swapped between the slices, leading to a unique set of spin-echo signal conditions. To minimize motion-related signal dephasing, additional flow-compensation strategies are implemented. In both the abdominal breathing phantom and in vivo experiments, a time series was acquired using Ortho-SSFP-Echo. The centroid of the target was tracked in postprocessing steps. RESULTS: In the phantom, the lesion could be identified and delineated in the dynamic images. In the volunteer experiments, the kidney was visualized with a T2 contrast at a temporal resolution of 0.45 s under free-breathing conditions. A respiratory belt demonstrated a strong correlation with the time course of the kidney centroid in the head-foot direction. A hypointense saturation band at the slice overlap did not inhibit lesion tracking in the semi-automatic postprocessing steps. CONCLUSION: The Ortho-SFFP-Echo sequence delivers real-time images with a T2 -weighted contrast in two orthogonal slices. The sequence allows for simultaneous acquisition, which could be beneficial for real-time motion tracking in radiotherapy or interventional MRI.

Technical note: Semiautomated targeted postmortem computed tomography angiography of the pulmonary arteries using a robotic system.

INTRODUCTION: To better depict vascular lesions on postmortem computed tomography (PMCT), whole-body postmortem computed tomography angiography (PMCTA) can be used in forensic diagnostics. Targeted angiography, in which only a specific vessel is filled with contrast agent, might help in cases of traumatic changes that render whole-body PMCTA impossible. Moreover, in targeted PMCTA, the contrast agent does not affect the haptics of any other organs. In this article, we describe automated, CT-guided targeted angiography of the pulmonary artery (PA) using the Virtobot system. MATERIAL AND METHODS: Our study group consisted of 8 deceased persons (3 males, 5 females). We first performed an unenhanced CT scan and used the data obtained to plan the needle trajectories with the Virtobot planning software. Then, the needle was fully automatically placed by the Virtobot system. Subsequently, 50 ml of contrast agent was injected manually, and the CT scan was repeated (targeted PMCTA). RESULTS AND DISCUSSION: We tested a new method for performing semiautomated targeted postmortem angiography of the PAs using a robotic needle placement system (Virtobot). In 6 out of our 8 cases, the injection of contrast agent in the PA was successful. In five of the six successful cases, there was reflux of contrast agent to some extent, but the reflux did not affect the readout. In general, the procedure was easy to plan based on a PMCT data set, and the pulmonary trunk was easy to reach with a robotic needle placement system.

Development of a miniaturized robotic guidance device for stereotactic neurosurgery.

OBJECTIVE: Consistently high accuracy and a straightforward use of stereotactic guidance systems are crucial for precise stereotactic targeting and a short procedural duration. Although robotic guidance systems are widely used, currently available systems do not fully meet the requirements for a stereotactic guidance system that combines the advantages of frameless surgery and robotic technology. The authors developed and optimized a small-scale yet highly accurate guidance system that can be seamlessly integrated into an existing operating room (OR) setup due to its design. The aim of this clinical study is to outline the development of this miniature robotic guidance system and present the authors' clinical experience. METHODS: After extensive preclinical testing of the robotic stereotactic guidance system, adaptations were implemented for robot fixation, software usability, navigation integration, and end-effector application. Development of the robotic system was then advanced in a clinical series of 150 patients between 2013 and 2019, including 111 needle biopsies, 13 catheter placements, and 26 stereoelectroencephalography (SEEG) electrode placements. During the clinical trial, constant modifications were implemented to meet the setup requirements, technical specifications, and workflow for each indication. For each application, specific setup, workflow, and median procedural accuracy were evaluated. RESULTS: Application of the miniature robotic system was feasible in 149 of 150 cases. The setup in each procedure was successfully implemented without adding significant OR time. The workflow was seamlessly integrated into the preexisting procedure. In the course of the study, procedural accuracy was improved. For the biopsy procedure, the real target error (RTE) was reduced from a mean of 1.8 ± 1.03 mm to 1.6 ± 0.82 mm at entry (p = 0.05), and from 1.7 ± 1.12 mm to 1.6 ± 0.72 mm at target (p = 0.04). For the SEEG procedures, the RTE was reduced from a mean of 1.43 ± 0.78 mm in the first half of the procedures to 1.12 ± 0.52 mm (p = 0.002) at entry in the second half, and from 1.82 ± 1.13 mm to 1.57 ± 0.98 mm (p = 0.069) at target, respectively. No healing complications or infections were observed in any case. CONCLUSIONS: The miniature robotic guidance device was able to prove its versatility and seamless integration into preexisting workflow by successful application in 149 stereotactic procedures. According to these data, the robot could significantly improve accuracy without adding time expenditure.

Frameless Stereotactic Brain Biopsies: Comparison of Minimally Invasive Robot-Guided and Manual Arm-Based Technique.

BACKGROUND: Most brain biopsies are still performed with the aid of a navigation-guided mechanical arm. Due to the manual trajectory alignment without rigid skull contact, frameless aiming devices are prone to considerably lower accuracy. OBJECTIVE: To compare a novel minimally invasive robot-guided biopsy technique with rigid skull fixation to a standard frameless manual arm biopsy procedure. METHODS: Accuracy, procedural duration, diagnostic yield, complication rate, and cosmetic result were retrospectively assessed in 40 consecutive cases of frameless stereotactic biopsies and compared between a minimally invasive robotic technique using the iSYS1 guidance device (iSYS Medizintechnik GmbH) (robot-guided group [ROB], n = 20) and a manual arm-based technique (group MAN, n = 20). RESULTS: Application of the robotic technique resulted in significantly higher accuracy at entry point (group ROB median 1.5 mm [0.4-3.2 mm] vs manual arm-based group (MAN) 2.2 mm [0.2-5.2 mm], P = .019) and at target point (group ROB 1.5 mm [0.4-2.8 mm] vs group MAN 2.8 mm [1.4-4.9 mm], P = .001), without increasing incision to suture time (group ROB 30.0 min [20-45 min vs group MAN 32.5 min [range 20-60 min], P = .09) and significantly shorter skin incision length (group ROB 16.3 mm [12.7-23.4 mm] vs group MAN 24.2 mm [18.0-37.0 mm], P = .008). CONCLUSION: According to our data, the proposed technique of minimally invasive robot-guided brain biopsies can improve accuracy without increasing operating time while being equally safe and effective compared to a standard frameless arm-based manual biopsy technique.

VirtoScan-on-Rails - an automated 3D imaging system for fast post-mortem whole-body surface documentation at autopsy tables.

Two-dimensional photographic documentation is a substantial part of post-mortem examinations for legal investigations. Additional three-dimensional surface documentation has been shown to assist in the visualization of findings and contribute to the reconstruction of the sequence of events. However, 2D photo documentation and, especially, 3D surface documentation, are time-consuming procedures that require specially trained personnel. In this study a 3D imaging system, called VirtoScan-on-Rails, was developed to automate and facilitate 3D surface documentation for photo documentation in autopsy suites. The imaging system was built to quickly acquire photogrammetric image sets of whole bodies during different stages of external and internal examinations. VirtoScan-on-Rails was set up in the autopsy suite of the Zurich Institute of Forensic Medicine at the University of Zurich (Zurich, Switzerland). The imaging system is based on a movable frame that carries a multi-camera array. Data quality and the applicability of the system were analyzed and evaluated within two test series. Up to 200 overlapping photographic images were acquired at consecutive image-capturing positions over a distance of approximately 2000 mm. The image-capturing process took 1 min and 23 s to acquire a set of 200 images for one side of the body. During test series one and two, 53 photogrammetric image sets taken from 31 forensic cases were successfully reconstructed. VirtoScan-on-Rails is an automated, fast and easy-to-use 3D imaging setup for autopsy suits. It facilitates documenting bodies during different stages of forensic examinations and allows standardizing the procedure of photo documentation.

A novel robot-guided minimally invasive technique for brain tumor biopsies.

OBJECTIVEAs decisions regarding tumor diagnosis and subsequent treatment are increasingly based on molecular pathology, the frequency of brain biopsies is increasing. Robotic devices overcome limitations of frame-based and frameless techniques in terms of accuracy and usability. The aim of the present study was to present a novel, minimally invasive, robot-guided biopsy technique and compare the results with those of standard burr hole biopsy.METHODSA tubular minimally invasive instrument set was custom-designed for the iSYS-1 robot-guided biopsies. Feasibility, accuracy, duration, and outcome were compared in a consecutive series of 66 cases of robot-guided stereotactic biopsies between the minimally invasive (32 patients) and standard (34 patients) procedures.RESULTSApplication of the minimally invasive instrument set was feasible in all patients. Compared with the standard burr hole technique, accuracy was significantly higher both at entry (median 1.5 mm [range 0.2-3.2 mm] vs 1.7 mm [range 0.8-5.1 mm], p = 0.008) and at target (median 1.5 mm [range 0.4-3.4 mm] vs 2.0 mm [range 0.8-3.9 mm], p = 0.019). The incision-to-suture time was significantly shorter (median 30 minutes [range 15-50 minutes] vs 37.5 minutes [range 25-105 minutes], p < 0.001). The skin incision was significantly shorter (median 16.3 mm [range 12.7-23.4 mm] vs 28.4 mm [range 20-42.2 mm], p = 0.002). A diagnostic tissue sample was obtained in all cases.CONCLUSIONSApplication of the novel instrument set was feasible in all patients. According to the authors' data, the minimally invasive robot-guidance procedure can significantly improve accuracy, reduce operating time, and improve the cosmetic result of stereotactic biopsies.

Automatic entry point planning for robotic post-mortem CT-based needle placement.

INTRODUCTION: Post-mortem computed tomography guided placement of co-axial introducer needles allows for the extraction of tissue and liquid samples for histological and toxicological analyses. Automation of this process can increase the accuracy and speed of the needle placement, thereby making it more feasible for routine examinations. To speed up the planning process and increase safety, we developed an algorithm that calculates an optimal entry point and end-effector orientation for a given target point, while taking constraints such as accessibility or bone collisions into account. TECHNIQUE: The algorithm identifies the best entry point for needle trajectories in three steps. First, the source CT data is prepared and bone as well as surface data are extracted and optimized. All vertices of the generated surface polygon are considered to be potential entry points. Second, all surface points are tested for validity within the defined hard constraints (reachability, bone collision as well as collision with other needles) and removed if invalid. All remaining vertices are reachable entry points and are rated with respect to needle insertion angle. Third, the vertex with the highest rating is selected as the final entry point, and the best end-effector rotation is calculated to avoid collisions with the body and already set needles. DISCUSSION: In most cases, the algorithm is sufficiently fast with approximately 5-6 s per entry point. This is the case if there is no collision between the end-effector and the body. If the end-effector has to be rotated to avoid collision, calculation times can increase up to 24 s due to the inefficient collision detection used here. In conclusion, the algorithm allows for fast and facilitated trajectory planning in forensic imaging.

Virtobot 2.0: the future of automated surface documentation and CT-guided needle placement in forensic medicine.

In this paper we present the second prototype of a robotic system to be used in forensic medicine. The system is capable of performing automated surface documentation using photogrammetry, optical surface scanning and image-guided, post-mortem needle placement for tissue sampling, liquid sampling, or the placement of guide wires. The upgraded system includes workflow optimizations, an automatic tool-change mechanism, a new software module for trajectory planning and a fully automatic computed tomography-data-set registration algorithm. We tested the placement accuracy of the system by using a needle phantom with radiopaque markers as targets. The system is routinely used for surface documentation and resulted in 24 surface documentations over the course of 11 months. We performed accuracy tests for needle placement using a biopsy phantom, and the Virtobot placed introducer needles with an accuracy of 1.4 mm (±0.9 mm). The second prototype of the Virtobot system is an upgrade of the first prototype but mainly focuses on streamlining the workflow and increasing the level of automation and also has an easier user interface. These upgrades make the Virtobot a potentially valuable tool for case documentation in a scalpel-free setting that uses purely imaging techniques and minimally invasive procedures and is the next step toward the future of virtual autopsy.

CT-guided, minimally invasive, postmortem needle biopsy using the B-Rob II needle-positioning robot.

CT-guided, minimally invasive needle biopsy techniques can be used to retrieve tissue or body fluid samples for histologic tissue diagnoses in forensic investigations. The purpose of this study was an evaluation of CT-guided needle-positioning robot B-Rob II. To operate under CT guidance, we adopted the B-Rob II robotic needle placement system and its workflow. The accuracy and speed of the procedure were tested on a gelatin phantom in a series of 21 biopsies. We achieved an average needle placement accuracy of 1.8 mm (±1.1 mm) using robotic assistance. The procedure required an average of 2 min 21 s. The needle placement accuracy for minimally invasive needle biopsies using the B-Rob II biopsy robot is sufficiently accurate and fast for forensic postmortem examinations of focal organ changes. Further tests will be performed to test the feasibility of the robot for performing biopsies of focal organ changes in human bodies.

Virtobot--a multi-functional robotic system for 3D surface scanning and automatic post mortem biopsy.

BACKGROUND: The Virtopsy project, a multi-disciplinary project that involves forensic science, diagnostic imaging, computer science, automation technology, telematics and biomechanics, aims to develop new techniques to improve the outcome of forensic investigations. This paper presents a new approach in the field of minimally invasive virtual autopsy for a versatile robotic system that is able to perform three-dimensional (3D) surface scans as well as post mortem image-guided soft tissue biopsies. METHODS: The system consists of an industrial six-axis robot with additional extensions (i.e. a linear axis to increase working space, a tool-changing system and a dedicated safety system), a multi-slice CT scanner with equipment for angiography, a digital photogrammetry and 3D optical surface-scanning system, a 3D tracking system, and a biopsy end effector for automatic needle placement. A wax phantom was developed for biopsy accuracy tests. RESULTS: Surface scanning times were significantly reduced (scanning times cut in half, calibration three times faster). The biopsy module worked with an accuracy of 3.2 mm. DISCUSSION: Using the Virtobot, the surface-scanning procedure could be standardized and accelerated. The biopsy module is accurate enough for use in biopsies in a forensic setting. CONCLUSION: The Virtobot can be utilized for several independent tasks in the field of forensic medicine, and is sufficiently versatile to be adapted to different tasks in the future.

Robot-assisted biopsy using computed tomography-guidance: initial results from in vitro tests.

PURPOSE: We sought to develop a robotic system for computed tomography (CT)-guided biopsy to validate the feasibility, accuracy, and efficacy of the system using phantom tests. MATERIALS AND METHODS: Ten peas (mean diameter 9.9+/-0.4 mm) embedded within a gel phantom were selected for biopsy. Once the best access was defined on CT images, the position of the phantom was recorded by an optical tracking system. Positional data about the phantom and the corresponding CT image was transferred to the robot planning system (Linux-based industrial PC equipped with video capture card). Once the appropriate position, angulation, and pitch were calculated, the robotic arm moved automatically with 7 degrees-of-freedom to the planned insertion path, aiming the needle-trajectory at the center of the target. Then, the biopsy was performed manually using a coaxial technique. The length of all harvested specimens was measured and short cut pieces of a guidewire were pushed into the target to evaluate the deviation of the actual needle track from the target. RESULTS: In all targets, biopsy specimens (mean length 5.6+/-1.4 mm) were harvested with only 1 needle pass required. The mean deviation of the needle tip from the center of the target in the x and z axes was 1.2+/-0.9 mm and 0.6+/-0.4 mm, respectively. CONCLUSIONS: Robotic-assisted biopsies in vitro, using CT guidance, were feasible and provided high accuracy.