Accuracy and efficacy of percutaneous biopsy and ablation using robotic assistance under computed tomography guidance: a phantom study

Puncture Accuracy of Robot-Assisted CT-Based Punctures in Interventional Radiology: An Ex Vivo Study

OBJECTIVES

The purpose of this study was to assess the performance of an optically tracked robot for computed-tomography (CT)-guided needle placements in a phantom study.

METHODS

In total, 240 needle punctures were carried out with the help of an optically tracked robotic device (Micromate) based on CT image datasets at three different slice thicknesses (1, 3, and 5 mm). Conically shaped targets inside a gelatin-filled plexiglass phantom were punctured. The target positioning error between the planned and actual needle trajectory was assessed by measuring the lateral positioning error (ND) between the target and the puncture needle and the Euclidean distance (ED) between the needle tip and target in control CTs.

RESULTS

The mean ND and ED for the thinnest CT slice thickness were 1.34 mm (SD ± 0.82) and 2.1 mm (SD ± 0.75), respectively. There was no significant impact of target depth on targeting accuracy for ND (p = 0.094) or ED (p = 0.187). The mean duration for the planning of one trajectory and for needle positioning were 42 s (SD ± 4) and 64 s (SD ± 7), respectively.

CONCLUSIONS

In this ex vivo study, the robotic targeting device yielded satisfactory accuracy results at CT slice thicknesses of 1 and 3 mm. This technology may be particularly useful in interventions where the accurate placement of needle-like instruments is required.

Robotic Assistance in Percutaneous Liver Ablation Therapies: A Systematic Review and Meta-Analysis

Objective

The aim of this systematic review and meta-analysis is to identify current robotic assistance systems for percutaneous liver ablations, compare approaches, and determine how to achieve standardization of procedural concepts for optimized ablation outcomes.

Background

Image-guided surgical approaches are increasingly common. Assistance by navigation and robotic systems allows to optimize procedural accuracy, with the aim to consistently obtain adequate ablation volumes.

Methods

Several databases (PubMed/MEDLINE, ProQuest, Science Direct, Research Rabbit, and IEEE Xplore) were systematically searched for robotic preclinical and clinical percutaneous liver ablation studies, and relevant original manuscripts were included according to the Preferred Reporting items for Systematic Reviews and Meta-Analyses guidelines. The endpoints were the type of device, insertion technique (freehand or robotic), planning, execution, and confirmation of the procedure. A meta-analysis was performed, including comparative studies of freehand and robotic techniques in terms of radiation dose, accuracy, and Euclidean error.

Results

The inclusion criteria were met by 33/755 studies. There were 24 robotic devices reported for percutaneous liver surgery. The most used were the MAXIO robot (8/33; 24.2%), Zerobot, and AcuBot (each 2/33, 6.1%). The most common tracking system was optical (25/33, 75.8%). In the meta-analysis, the robotic approach was superior to the freehand technique in terms of individual radiation (0.5582, 95% confidence interval [CI] = 0.0167-1.0996, dose-length product range 79-2216 mGy.cm), accuracy (0.6260, 95% CI = 0.1423-1.1097), and Euclidean error (0.8189, 95% CI = -0.1020 to 1.7399).

Conclusions

Robotic assistance in percutaneous ablation for liver tumors achieves superior results and reduces errors compared with manual applicator insertion. Standardization of concepts and reporting is necessary and suggested to facilitate the comparison of the different parameters used to measure liver ablation results. The increasing use of image-guided surgery has encouraged robotic assistance for percutaneous liver ablations. This systematic review analyzed 33 studies and identified 24 robotic devices, with optical tracking prevailing. The meta-analysis favored robotic assessment, showing increased accuracy and reduced errors compared with freehand technique, emphasizing the need for conceptual standardization.

Percutaneous Lung Biopsies With Robotic Systems: A Systematic Review of Available Clinical Solutions

Objectives: This systematic review aims to assess existing research concerning the use of robotic systems to execute percutaneous lung biopsy. Methods: A systematic review was performed and identified 4 studies involving robotic systems used for lung biopsy. Outcomes assessed were operation time, radiation dose to patients and operators, technical success rate, diagnostic yield, and complication rate. Results: One hundred and thirteen robot-guided percutaneous lung biopsies were included. Technical success and diagnostic yield were close to 100%, comparable to manual procedures. Technical accuracy, illustrated by needle positioning, showed less frequent needle adjustments in robotic guidance than in manual guidance (P < .001): 2.7 ± 2.6 (range 1-4) versus 6 ± 4 (range 2-12). Procedure time ranged from comparable to reduced by 35% on average (20.1 ± 11.3 minutes vs 31.4 ± 10.2 minutes, P = .001) compared to manual procedures. Patient irradiation ranged from comparable to reduced by an average of 40% (324 ± 114.5 mGy vs 541.2 ± 446.8 mGy, P = .001). There was no significant difference in reported complications between manual biopsy and biopsies that utilized robotic guidance. Conclusion: Robotic systems demonstrate promising results for percutaneous lung biopsy. These devices provide adequate accuracy in probe placement and could both reduce procedural duration and mitigate radiation exposure to patients and practitioners. However, this review underscores the need for larger, controlled trials to validate and extend these findings.

Innovations in Image-Guided Procedures: Unraveling Robot-Assisted Non-Hepatic Percutaneous Ablation

Interventional oncology is routinely tasked with the feat of tumor characterization or destruction, via image-guided biopsy and tumor ablation, which may pose difficulties due to challenging-to-reach structures, target complexity, and proximity to critical structures. Such procedures carry a risk-to-benefit ratio along with measurable radiation exposure. To streamline the complexity and inherent variability of these interventions, various systems, including table-, floor-, gantry-, and patient-mounted (semi-) automatic robotic aiming devices, have been developed to decrease human error and interoperator and intraoperator outcome variability. Their implementation in clinical practice holds promise for enhancing lesion targeting, increasing accuracy and technical success rates, reducing procedure duration and radiation exposure, enhancing standardization of the field, and ultimately improving patient outcomes. This narrative review collates evidence regarding robotic tools and their implementation in interventional oncology, focusing on clinical efficacy and safety for nonhepatic malignancies.

Robotic systems in interventional oncology: a narrative review of the current status

Interventional oncology offers minimally invasive treatments for malignant tumors for curative and palliative purposes based on the percutaneous insertion of needles or catheters into the target location under image guidance. Robotic systems have been gaining increasing attention as tools that provide potential advantages for image-guided interventions. Among the robotic systems developed for intervention, those relevant to the oncology field are mainly those for guiding or driving the needles in non-vascular interventional procedures such as biopsy and tumor ablation. Needle-guiding robots support planning the needle path and align the needle robotically according to the planned trajectory, which is combined with subsequent manual needle insertion by the physician through the needle guide. Needle-driving robots can advance the needle robotically after determining its orientation. Although a wide variety of robotic systems have been developed, only a limited number of these systems have reached the clinical phase or commercialization thus far. The results of previous studies suggest that such interventional robots have the potential to increase the accuracy of needle placement, facilitate out-of-plane needle insertion, decrease the learning curve, and reduce radiation exposure. On the other hand, increased complexity and costs may be a concern when using robotic systems compared with conventional manual procedures. Further data should be collected to comprehensively assess the value of robotic systems in interventional oncology.

Assessing Tissue Damage Around a Tape Spring Steerable Needle With Sharp Turn Radii

Steerable needles are a novel technology that offers a wide range of uses in medical diagnostics and therapeutics. Currently, there exist several steerable needle designs in the literature, however, they are limited in their use by the number of possible turns, turn radius, and tissue damage. We introduce a novel design of a tape spring steerable needle, capable of multiple turns, that minimizes tissue damage. In this study, we measure the turning radius of our steerable needle in porcine liver tissue in vitro with ultrasound and estimate tissue damage in gel blocks using image analysis and 3D plaster casting. We were able to demonstrate our steerable needle's ability to steer through biological tissue, as well as introduce a novel method for estimating tissue damage. Our findings show that our needle design showed lower damage compared to similar designs in literature, as well as tissue stiffness being a protective factor against tissue damage.

Laser Target System in Combination with an Aiming Device for Percutaneous CT-Guided Interventions - An Accuracy Study

RATIONALE AND OBJECTIVES

To evaluate the targeting accuracy of laser-guided punctures in combination with an aiming device for computed tomography (CT) interventions during in vitro experiments. MATERIALS AND METHODS: A total of 600 CT-guided punctures were performed using a laser target system, half of them with the additional help of an aiming device. Conically shaped targets in a plexiglass phantom were punctured. The planning CT data sets were acquired with 1.25, 2.5 and 5 mm slice thickness. Needle placement accuracy, as well as procedural time, was assessed. The Euclidean (ED) and normal distances (ND) were calculated at the target point.

RESULTS

Using the aiming device, the accomplished mean ND at the target for the 1.25, 2.5 and 5 mm slice thickness was 1.76 mm (SD ± 0.92), 2.09 mm (SD ± 1.06) and 1.93 mm (SD ± 1.38), respectively. Without aiming device, the corresponding results were 2.55 mm (SD ± 1.42), 2.7 mm (SD ± 1.43) and 2.31 mm (SD ± 1.64). At a slice thickness of 1.25 mm and 2.5 mm, punctures with the aiming device were significantly more accurate for both the ED and ND as compared to the punctures without aiming device (p < 0.001). The mean time required to complete the procedure, including image acquisition, trajectory planning, the placement of 10 needles, and the control-CT scan was 24.8 min without and 29.8 min with the aiming device.

CONCLUSION

The additional use of the aiming device in combination with the commercially available laser guidance system significantly increased the level of accuracy during this in vitro experiment compared to freehand passes.

Robotic versus freehand CT-guided radiofrequency ablation of pulmonary metastases: a comparative cohort study

PURPOSE

Radiofrequency ablation (RFA) is a curative treatment option for small lung metastases, which conventionally involves multiple freehand manipulations until the treating electrode is satisfactorily positioned. Stereotactic and robotic guidance has been gaining popularity for liver ablation, although has not been established in lung ablation. The purpose of this study is to determine the feasibility, safety, and accuracy of robotic RFA for pulmonary metastases, and compare procedures with a conventional freehand cohort.

METHODS

A single center study with prospective robotic cohort, and retrospective freehand cohort. RFA was performed under general anesthesia using high frequency jet ventilation and CT guidance. Main outcomes were (i) feasibility/technical success (ii) safety using Common Terminology Criteria for Adverse Events (iii) targeting accuracy (iv) number of needle manipulations for satisfactory ablation. Robotic and freehand cohorts were compared using Mann-Whitney U tests for continuous variables, and Fisher's exact for categorical variables.

RESULTS

Thirty-nine patients (mean age 65 ± 13 years, 20 men) underwent ablation of 44 pulmonary metastases at single specialist cancer center between July 2019 and August 2022. 20 consecutive participants underwent robotic ablation, and 20 consecutive patients underwent freehand ablation. All 20/20 (100%) robotic procedures were technically successful, and none were converted to freehand procedures. There were 6/20 (30%) adverse events in the robotic cohort, and 15/20 (75%) in the freehand cohort (P = 0.01). Robotic placement was highly accurate with 6 mm tip-to-target distance (range 0-14 mm) despite out-of-plane approaches, with fewer manipulations than freehand placement (median 0 vs. 4.5 manipulations, P < 0.001 and 7/22, 32% vs. 22/22, 100%, P < 0.001).

CONCLUSIONS

Robotic radiofrequency ablation of pulmonary metastases with general anesthesia and high frequency jet ventilation is feasible and safe. Targeting accuracy is high, and fewer needle/electrode manipulations are required to achieve a satisfactory position for ablation than freehand placement, with early indications of reduced complications.

Percutaneous Robotics in Interventional Radiology

The accuracy of the robotic device not only relies on a reproducible needle advancement, but also on the possibility to correct target movement at chosen checkpoints and to deviate from a linear to a nonlinear trajectory. We report our experience in using the robotic device for the insertion of trocar needles in CT guided procedures. The majority of procedures were targeted organ biopsies in the chest abdomen or pelvis. The accuracy of needle placement after target adjustments did not significantly differ from those patients where a linear trajectory could be used. The steering capabilities of the robot allow correction of target movement of the fly.

Evaluation of the performance of robot assisted CT-guided percutaneous needle insertion: Comparison with freehand insertion in a phantom

PURPOSE

To evaluate the performance of a novel robot for CT-guided needle positioning procedures and compare it to the freehand technique in an abdominal phantom.

METHODS

One interventional radiology fellow and one experienced interventional radiologist (IR) performed twelve robot-assisted and twelve freehand needle positionings in a phantom over predetermined trajectories. The robot automatically aimed a needle-guide according to the planned trajectories, after which the clinician manually inserted the needle. Using repeated CT scans, the needle position was assessed and adjusted if the clinician deemed it necessary. Technical success, accuracy, number of position adjustments, and procedure time were measured. All outcomes were analyzed using descriptive statistics and were compared between the robot-assisted and freehand procedures using the paired t-test and Wilcoxon signed rank test.

RESULTS

Compared with the freehand technique, the robot system improved the number of technically successfully needle targeting (20/24 vs 14/24), with higher accuracy (mean Euclidean deviation from target center: 3.5 ± 1.8 mm vs 4.6 ± 2.1 mm, p = 0.02) and required fewer needle position adjustments (0.0 ± 0.2 steps vs 1.7 ± 0.9 steps, p < 0.001), respectively. The robot improved the needle positioning for both, the fellow and the expert IR, compared to their freehand performances, with more improvement for the fellow than for the expert IR. The procedure time was similar for the robot-assisted and freehand procedures (19.5 ± 9.2 min. vs 21.0 ± 6.9 min., p = 0.777).

CONCLUSIONS

CT-guided needle positioning with the robot was more successful and accurate than freehand needle positioning and required fewer needle position adjustments without prolonging the procedure.

Developing and testing a robotic MRI/CT fusion biopsy technique using a purpose-built interventional phantom

BACKGROUND

Magnetic resonance imaging (MRI) can be used to target tumour components in biopsy procedures, while the ability to precisely correlate histology and MRI signal is crucial for imaging biomarker validation. Robotic MRI/computed tomography (CT) fusion biopsy offers the potential for this without in-gantry biopsy, although requires development.

METHODS

Test-retest T1 and T2 relaxation times, attenuation (Hounsfield units, HU), and biopsy core quality were prospectively assessed (January-December 2021) in a range of gelatin, agar, and mixed gelatin/agar solutions of differing concentrations on days 1 and 8 after manufacture. Suitable materials were chosen, and four biopsy phantoms were constructed with twelve spherical 1-3-cm diameter targets visible on MRI, but not on CT. A technical pipeline was developed, and intraoperator and interoperator reliability was tested in four operators performing a total of 96 biopsies. Statistical analysis included T1, T2, and HU repeatability using Bland-Altman analysis, Dice similarity coefficient (DSC), and intraoperator and interoperator reliability.

RESULTS

T1, T2, and HU repeatability had 95% limits-of-agreement of 8.3%, 3.4%, and 17.9%, respectively. The phantom was highly reproducible, with DSC of 0.93 versus 0.92 for scanning the same or two different phantoms, respectively. Hit rate was 100% (96/96 targets), and all operators performed robotic biopsies using a single volumetric acquisition. The fastest procedure time was 32 min for all 12 targets.

CONCLUSIONS

A reproducible biopsy phantom was developed, validated, and used to test robotic MRI/CT-fusion biopsy. The technique was highly accurate, reliable, and achievable in clinically acceptable timescales meaning it is suitable for clinical application.

Image-guided percutaneous ablation for lung malignancies

Image-guided percutaneous lung ablation has proven to be an alternative and effective strategy in the treatment of lung cancer and other lung malignancies. Radiofrequency ablation, microwave ablation, and cryoablation are widely used ablation modalities in clinical practice that can be performed along or combined with other treatment modalities. In this context, this article will review the application of different ablation strategies in lung malignancies.

Comparison of a Robotic and Patient-Mounted Device for CT-Guided Needle Placement: A Phantom Study

Background: Robotic-based guidance systems are becoming increasingly capable of assisting in needle placement during interventional procedures. Despite these technical advances, less sophisticated low-cost guidance devices promise to enhance puncture accuracy compared with the traditional freehand technique. Purpose: To compare the in vitro accuracy and feasibility of two different aiming devices for computed-tomography (CT)-guided punctures. Methods: A total of 560 CT-guided punctures were performed by using either a robotic (Perfint Healthcare: Maxio) or a novel low-cost patient-mounted system (Medical Templates AG: Puncture Cube System [PCS]) for the placement of Kirschner wires in a plexiglass phantom with different slice thicknesses. Needle placement accuracy as well as procedural time were assessed. The Euclidean (ED) and normal distances (ND) were calculated at the entry and target point. Results: Using the robotic device, the ND at the target for 1.25 mm, 2.5 mm, 3.75 mm and 5 mm slice thickness were 1.28 mm (SD ± 0.79), 1.25 mm (SD ± 0.81), 1.35 mm (SD ± 1.00) and 1.35 mm (SD ± 1.03). Using the PCS, the ND at the target for 1 mm, 3 mm and 5 mm slices were 3.84 mm (SD ± 1.75), 4.41 mm (SD ± 2.31) and 4.41 mm (SD ± 2.11), respectively. With all comparable slice thicknesses, the robotic device was significantly more accurate compared to the low-cost device (p < 0.001). Needle placement with the PCS resulted in lower intervention time (mean, 158.83 s [SD ± 23.38] vs. 225.67 s [SD ± 17.2]). Conclusion: Although the robotic device provided more accurate results, both guidance systems showed acceptable results and may be helpful for interventions in difficult anatomical regions and for those requiring complex multi-angle trajectories.

Robotic computed tomography-guided celiac plexus neurolysis: our experience of technique and outcomes

Aim: We report the use of robot assistance for computed tomography-guided celiac plexus neurolysis for the first time. Materials & methods: Four patients of upper abdominal cancer with intractable pain despite opioids were positioned prone on the PET-computed tomography scanner, which measured the accurate coordinates for the entry, depth and angle of the target point. The robot positioned its arm over the patient in accordance with the set needle path. The physician manually inserted needle through it and injected 20 ml of 0.75% alcohol after dye confirmation. Results: Significant reduction in pain scores and oral morphine consumption were observed in patients during 3 months follow-up. Conclusion: The robot precisely orients and helps in accurate placement of the needle through the robotic arm.

Starting CT-guided robotic interventional oncology at a UK centre

OBJECTIVE

A commercially available CT-guided robot offers enhanced abilities in planning, targeting, and confirming accurate needle placement. In this short communication, we describe our first UK experience of robotic interventional oncology procedures.

METHODS

We describe the device, discuss installation, operation, and report upon needle insertion success, accuracy (path deviation; PD and tip deviation; TD), number of adjustments, complications, and procedural success.

RESULTS

Nine patients (seven males), median age 66 years (range 43-79) were consented for biopsy or ablation between March and April 2021. Needle placement in biopsy was more accurate than ablation (median 1 vs 11 mm PD and 1 vs 20 mm TD) and required fewer adjustments (median 0 vs 5). No complications arose, and all procedures were successful (diagnostic material obtained or complete ablation at follow-up).

CONCLUSION

Short procedure times and very high levels of accuracy were readily achieved with biopsy procedures, although tumour ablation was less accurate which likely reflects higher procedural complexity.

ADVANCES IN KNOWLEDGE

Achieving highly accurate robotic biopsy with is feasible within a very short time span. Further work is required to maximise the potential of robotic guidance in tumour ablation procedures, which is likely due to higher complexity giving a longer learning curve.

Efficacy of Shadow-Based Needle Positioning System in Performing CT Image-Guided Percutaneous Biopsy of Lung Lesions: Our Initial Experience

Context  Computerized tomography (CT) is widely used for various interventions and there is a need for an effective navigation tool, for best outcomes.

Aim  The study was performed to evaluate the efficacy of light- and shadow-based needle positioning assistance device, an innovative navigation tool over the conventional freehand technique, in performing CT image-guided percutaneous interventions.

Settings and Design  This randomized control trial was performed among patients undergoing CT-guided percutaneous intervention for lung pathologies.

Methodology  A total of 60 participants were randomized into an intervention group and a control group. The accuracy of needle insertion and other efficacy parameters were assessed for both groups. Post needle placement, CT images were used to evaluate the study endpoints.

Statistical Analysis  Statistical analysis was performed using SPSS ver. 20 software.

Results  The mean needle positioning accuracy was 2.1 mm in the experimental group compared with 7.2 mm in the control group freehand procedures. The average time to position the needle at the desired target location was 2.5 minutes in the assisted procedure as compared with 5.3 minutes in the freehand procedure ( p  < 0.05). The total number of check scans required to position the needle was 1.3 for assisted procedures and 1.9 for freehand procedures.

Conclusion  The use of shadow-based assistance device for CT-guided interventions is proven to be efficient and safer with high needle positioning accuracy.

Robotic assistance for percutaneous needle insertion in the kidney: preclinical proof on a swine animal model

Background

We evaluated the accuracy, safety, and feasibility of a computed tomography (CT)-guided robotic assistance system for percutaneous needle placement in the kidney.

Methods

Fiducials surgically implanted into the kidneys of two pigs were used as targets for subsequent robotically-assisted needle insertion. Robotically-assisted needle insertions and CT acquisitions were coordinated using respiratory monitoring. An initial scan volume data set was used for needle insertion planning defining skin entry and target point. Then, needle insertion was performed according to robot positioning. The accuracy of needle placement was evaluated upon the distance between the needle tip and the predefined target on a post needle insertion scan. A delayed contrast-enhanced CT scan was acquired to assess safety.

Results

Eight needle trajectories were performed with a median procedural time measured from turning on the robotic system to post needle insertion CT scan of 21 min (interquartile range 15.5−26.5 min). Blind review of needle placement accuracy was 2.3 ± 1.2 mm (mean ± standard deviation) in lateral deviation, 0.7 ± 1.7 mm in depth deviation, and 2.8 ± 1.3 mm in three-dimensional Euclidian deviation. All needles were inserted on the first attempt, which determined 100% feasibility, without needle readjustment. The angulation and length of the trajectory did not impact on the needle placement accuracy. Two minor procedure-related complications were encountered: 2 subcapsular haematomas (13 × 6 mm and 35 × 6 mm) in the same animal.

Conclusions

Robotically-assisted needle insertion was shown feasible, safe and accurate in a swine kidney model. Further larger studies are needed.

A coordinate positioning puncture method under robot-assisted CT-guidance: phantom and animal experiments

PURPOSE

To evaluate the accuracy of the robot-assisted computed tomography (CT)-guided coordinate positioning puncture method by phantom and animal experiments.

MATERIAL AND METHODS

In the phantom experiment, seven robot-assisted punctures were made to evaluate the accuracy of the method. In the animal experiment, 18 punctures (nine robotic and nine manual) were made in the livers of nine rabbits. The indicators, such as needle-tract length, angle deviation, puncture accuracy, number of scans required, and radiation exposure dose were compared between manual and robotic punctures. The paired-samples t-test was used for analysis.

RESULTS

In the phantom experiment, the mean accuracy of seven punctures was 2.67 mm. In the animal experiment, there was no significant difference in needle-tract length (32.58 mm vs. 34.04 mm, p = .606), angle deviation (17.21° vs. 21.23° p = .557) and puncture accuracy (8.42 vs. 8.77 mm, p = .851) between the two groups. However, the number CT scans required (2.44 vs. 3.33, p = .002), and the radiation exposure dose (772.98 vs. 1077.89 mGy/cm, p = .003) were lower in the robot group than in the manual group.

CONCLUSIONS

The coordinate positioning puncture method under robot-assisted CT-guidance can reach an accuracy that is comparable to that of the traditional manual CT-guided puncture method and with fewer CT scanning times accompanied with a lower radiation dosage.

Image-Guided Robotics for Standardized and Automated Biopsy and Ablation

Image-guided robotics for biopsy and ablation aims to minimize procedure times, reduce needle manipulations, radiation, and complications, and enable treatment of larger and more complex tumors, while facilitating standardization for more uniform and improved outcomes. Robotic navigation of needles enables standardized and uniform procedures which enhance reproducibility via real-time precision feedback, while avoiding radiation exposure to the operator. Robots can be integrated with computed tomography (CT), cone beam CT, magnetic resonance imaging, and ultrasound and through various techniques, including stereotaxy, table-mounted, floor-mounted, and patient-mounted robots. The history, challenges, solutions, and questions facing the field of interventional radiology (IR) and interventional oncology are reviewed, to enable responsible clinical adoption and value definition via ergonomics, workflows, business models, and outcome data. IR-integrated robotics is ready for broader adoption. The robots are coming!

Microwave ablation of lung tumors: A probabilistic approach for simulation-based treatment planning

PURPOSE

Microwave ablation (MWA) is a clinically established modality for treatment of lung tumors. A challenge with existing application of MWA, however, is local tumor progression, potentially due to failure to establish an adequate treatment margin. This study presents a robust simulation-based treatment planning methodology to assist operators in comparatively assessing thermal profiles and likelihood of achieving a specified minimum margin as a function of candidate applied energy parameters.

METHODS

We employed a biophysical simulation-based probabilistic treatment planning methodology to evaluate the likelihood of achieving a specified minimum margin for candidate treatment parameters (i.e., applied power and ablation duration for a given applicator position within a tumor). A set of simulations with varying tissue properties was evaluated for each considered combination of power and ablation duration, and for four different scenarios of contrast in tissue biophysical properties between tumor and normal lung. A treatment planning graph was then assembled, where distributions of achieved minimum ablation zone margins and collateral damage volumes can be assessed for candidate applied power and treatment duration combinations. For each chosen power and time combination, the operator can also visualize the histogram of ablation zone boundaries overlaid on the tumor and target volumes. We assembled treatment planning graphs for generic 1, 2, and 2.5 cm diameter spherically shaped tumors and also illustrated the impact of tissue heterogeneity on delivered treatment plans and resulting ablation histograms. Finally, we illustrated the treatment planning methodology on two example patient-specific cases of tumors with irregular shapes.

RESULTS

The assembled treatment planning graphs indicate that 30 W, 6 min ablations achieve a 5-mm minimum margin across all simulated cases for 1-cm diameter spherical tumors, and 70 W, 10 min ablations achieve a 3-mm minimum margin across 90% of simulations for a 2.5-cm diameter spherical tumor. Different scenarios of tissue heterogeneity between tumor and lung tissue revealed 2 min overall difference in ablation duration, in order to reliably achieve a 4-mm minimum margin or larger each time for 2-cm diameter spherical tumor.

CONCLUSIONS

An approach for simulation-based treatment planning for microwave ablation of lung tumors is illustrated to account for the impact of specific geometry of the treatment site, tissue property uncertainty, and heterogeneity between the tumor and normal lung.

Evolution and Stagnation of Image Guidance for Surgery in the Lateral Skull: A Systematic Review 1989-2020

Objective: Despite three decades of pre-clinical and clinical research into image guidance solutions as a more accurate and less invasive alternative for instrument and anatomy localization, translation into routine clinical practice for surgery in the lateral skull has not yet happened. The aim of this review is to identify challenges that need to be solved in order to provide image guidance solutions that are safe and beneficial for use during lateral skull surgery and to synthesize factors that facilitate the development of such solutions. Methods: Literature search was conducted via PubMed using terms relating to image guidance and the lateral skull. Data extraction included the following variables: image guidance error, imaging resolution, image guidance system, tracking technology, registration method, study endpoints, clinical target application, and publication year. A subsequent search of FDA 510(k) database for identified image guidance systems and extraction of the year of approval, intended use, and indications for use was performed. The study objectives and endpoints were subdivided in three time phases and summarized. Furthermore, it was analyzed which factors correlated with the image guidance error. Factor values for which an error ≤0.5 mm (μ_error + 3σ_error) was measured in more than one study were identified and inspected for time trends. Results: A descriptive statistics-based summary of study objectives and findings separated in three time intervals is provided. The literature provides qualitative and quantitative evidence that image guidance systems must provide an accuracy ≤0.5 mm (μ_error + 3σ_error) for their safe and beneficial application during surgery in the lateral skull. Spatial tracking accuracy and precision and medical image resolution both correlate with the image guidance accuracy, and all of them improved over the years. Tracking technology with accuracy ≤0.05 mm, computed tomography imaging with slice thickness ≤0.2 mm, and registration based on bone-anchored titanium fiducials are components that provide a sufficient setting for the development of sufficiently accurate image guidance. Conclusion: Image guidance systems must reliably provide an accuracy ≤0.5 mm (μ_error + 3σ_error) for their safe and beneficial use during surgery in the lateral skull. Advances in tracking and imaging technology contribute to the improvement of accuracy, eventually enabling the development and wide-scale adoption of image guidance solutions that can be used safely and beneficially during lateral skull surgery.

Robotic assistance for quick and accurate image-guided needle placement

Computed tomography (CT) image-guided procedures including biopsy, drug delivery, and ablation are gaining increasing application in medicine. Robotic technology holds the promise for allowing surgeons, and other proceduralists, access to such CT-guided procedures by potentially shortening training, improving accuracy, decreasing needle passes, and reducing radiation exposure. We evaluated surgeon learning and proficiency for image-guided needle placement with an FDA-cleared robotic arm. Five out of six surgeons had no prior CT-guided procedural experience, while one had prior experience with freehand CT-guided needle placement. All surgeons underwent a 60-min training with the MAXIO robot (Perfint Healthcare, Redmond, WA). The robot was used to place needles into three different pre-specified targets on a spine model. Performance time, procedural errors, and needle placement accuracy were recorded. All participants successfully placed needles into the targets using the robotic arm. The average time for needle placement was 3:44 ± 1:43 min. Time for needle placement decreased with subsequent attempts, with average third placement taking 2:29 ± 1:51 min less than the first attempt. The average vector distance from the target was 2.3 ± 1.2 mm. One error resulted in the need for reimaging by CT scan. No errant needle placement occurred. Surgeons (attending fellows and residents) without previous experience and minimal training could successfully place percutaneous needles under CT guidance quickly, accurately, and reproducibly using a robotic arm. This suggests that robotic technology may be used to facilitate surgeon adoption of CT image-guided needle-based procedures in the future.

An Analysis of Free-hand Targeting in Laparoscopic Liver Microwave Ablation

BACKGROUND

Recently, new technologies have been developed for antenna placement in laparoscopic liver tumor ablation (LLTA). At this point, it is important to analyze the efficacy of free-hand targeting to identify deficiencies and opportunities for improvement.

METHODS

This was an institutional review board-approved retrospective study. Video recordings of 30 consecutive patients with 77 lesions who underwent LLTA were reviewed. Tumor-specific anatomic and targeting-related parameters were analyzed using χ2, t test, and regression analyses.

RESULTS

Neuroendocrine metastasis was the dominant tumor type, with median tumor size 1.4 cm (range, 0.5 to 5.2). In total, 41 (53%) tumors were superficial and 36 (47%) deep. In 68 lesions (88%), an optimal targeting was achieved with first attempt, without a need for repositioning; whereas 9 lesions (12%) required repositioning of antenna. For 37% (15/41) of superficial and 56% (20/36) of deep lesions, a straight avascular needle trajectory was not present, requiring steering of the antenna around vascular and biliary structures. All procedures were completed laparoscopically without bleeding or biliary complications. Local treatment recurrence rate in follow-up was 10% (n=8).

CONCLUSIONS

This study shows that in experienced hands, LLTA through free-hand technique is safe and efficacious, providing an accurate targeting with the first pass in 90% of tumors. Although newer technology is being developed to guide less-experienced surgeons in needle targeting, it should be kept in mind that a straight trajectory is not available for 1/3 of superficial and half of deep lesions. Hence, ablation surgeons need to develop free-hand skills to avoid possible hemorrhagic and biliary complications in LLTA.

Preliminary clinical application of the robot-assisted CT-guided irreversible electroporation ablation for the treatment of pancreatic head carcinoma

BACKGROUND

To evaluate the feasibility and safety of a robot-guided irreversible electroporation (IRE) ablation system for the treatment of pancreatic head carcinoma.

METHODS

A total of 20 cases with pancreatic head carcinoma were divided into two groups: 11 cases in group A with manual probe placement and 9 cases in group B with robotic navigated probe placement. The two groups were compared in terms of planning time before puncture, puncture time, the total time of electrode deployment, number of scans, and punctual accuracy of the single electrode.

RESULTS

Each probe was successfully punctured, and no complications were detected. P-values were calculated for all the parameters, using the SPSS 25.0 software and the t test.

CONCLUSIONS

The new robot can reduce the total operating time as compared to the manual probe placement with the same accuracy in the IRE of pancreatic head carcinoma.

Development of a Gripper with Variable Stiffness for a CT-Guided Needle Insertion Robot

In recent years, interventional radiology (IR) as a medical procedure has attracted considerable attention. Among the various IR techniques, computed tomography (CT)-guided IR is performed by inserting a specific needle into a lesion under CT guidance, leading to this medical procedure being less invasive. However, as the procedure requires the doctor to be positioned near the CT, radiation exposure may be a major concern. To overcome this problem, we developed a remote-controlled robotic system for needle insertion during CT-guided interventional procedures. The current needle holder for the robot is risky in that it might hurt a patient since a needle is always held firmly even when the patient moves. To solve this problem, we designed and fabricated a gripper with variable stiffness through jamming transition. Subsequently, we conducted experiments to investigate the effect of elements constituting the gripper to improve its performance.

Improvement of the primary efficacy of microwave ablation of malignant liver tumors by using a robotic navigation system

Background The aim of the study was to assess the primary efficacy of robot-assisted microwave ablation and compare it to manually guided microwave ablation for percutaneous ablation of liver malignancies. Patients and methods We performed a retrospective single center evaluation of microwave ablations of 368 liver tumors in 192 patients (36 female, 156 male, mean age 63 years). One hundred and nineteen ablations were performed between 08/2011 and 03/2014 with manual guidance, whereas 249 ablations were performed between 04/2014 and 11/2018 using robotic guidance. A 6-week follow-up (ultrasound, computed tomography and magnetic resonance imaging) was performed on all patients. Results The primary technique efficacy outcome of the group treated by robotic guidance was significantly higher than that of the manually guided group (88% vs. 76%; p = 0.013). Multiple logistic regression analysis indicated that a small tumor size (≤ 3 cm) and robotic guidance were significant favorable prognostic factors for complete ablation. Conclusions In addition to a small tumor size, robotic navigation was a major positive prognostic factor for primary technique efficacy.

The comparison of the process of manual and robotic positioning of the electrode performing radiofrequency ablation under the control of a surgical navigation system

This study is aimed at the comparison of the process of manual and robotic positioning of the electrode performing radiofrequency ablation under the control of a surgical navigation system. The main hypothesis of this experiment was that the use of a collaborative manipulator (KUKA iiwa) will allow to position the active part of the electrode relative to the center of the tumor more accurately and from the first attempt. We also monitor the stability of the electrode′s velocity during insertion and consider some advantages in ergonomics using the robotic manipulator. We use three more criteria to compare the surgeon's and robotic performance, unlike other studies, where only the target point's accuracy criterion is observed. The main idea is to examine the movement parameters of the electrode that can lead to potential patient trauma. Sphere-shaped tumor phantoms measuring 8 mm in diameter were filled with contrast and inserted in bovine livers. 10 livers were used for the robotic experiment and an equal quantity for manual surgery. The livers were encased in silicone phantoms designed to imitate the liver position in a real patient's abdominal cavity. Analysis of CT data gave the opportunity to find the entry and the target point for each tumor phantom. This data was loaded into a surgical navigation system that was used to track and record the position of the RF-electrode during the operation for further analysis. The standard deviation of points from the programmed linear trajectory totaled in the average 0.3 mm for the robotic experiment and 2.33 mm for the manual operation with a maximum deviation of 0.55 mm and 7.99 mm respectively. Standard deviation from the target point was 2.69 mm for the collaborative method and 2.49 mm for the manual method. The average velocity was 2.97 mm/s for the manipulator and 3.12 mm/s for the manual method, but the standard deviation of the velocity relative to the value of the average velocity was 0.66 mm/s and 3.05 mm/s respectively. Thus, in two criteria out of three, the manipulator is superior to the surgeon, and equality is established in one. Surgeons also noticed advantages in ergonomics performing the procedure using the manipulator. This experiment was produced as part of the work on the developing of a robotic multifunctional surgical complex. We can confirm the potential advantages of using collaborative robotic manipulators for minimally invasive surgery in case of practice for cancer treatment.

Robotic CT-guided out-of-plane needle insertion: comparison of angle accuracy with manual insertion in phantom and measurement of distance accuracy in animals

Objectives

To evaluate the accuracy of robotic CT-guided out-of-plane needle insertion in phantom and animal experiments.

Methods

A robotic system (Zerobot), developed at our institution, was used for needle insertion. In the phantom experiment, 12 robotic needle insertions into a phantom at various angles in the XY and YZ planes were performed, and the same insertions were manually performed freehand, as well as guided by a smartphone application (SmartPuncture). Angle errors were compared between the robotic and smartphone-guided manual insertions using Student’s t test. In the animal experiment, 6 robotic out-of-plane needle insertions toward targets of 1.0 mm in diameter placed in the kidneys and hip muscles of swine were performed, each with and without adjustment of needle orientation based on reconstructed CT images during insertion. Distance accuracy was calculated as the distance between the needle tip and the target center.

Results

In the phantom experiment, the mean angle errors of the robotic, freehand manual, and smartphone-guided manual insertions were 0.4°, 7.0°, and 3.7° in the XY plane and 0.6°, 6.3°, and 0.6° in the YZ plane, respectively. Robotic insertions in the XY plane were significantly (p < 0.001) more accurate than smartphone-guided insertions. In the animal experiment, the overall mean distance accuracy of robotic insertions with and without adjustment of needle orientation was 2.5 mm and 5.0 mm, respectively.

Conclusion

Robotic CT-guided out-of-plane needle insertions were more accurate than smartphone-guided manual insertions in the phantom and were also accurate in the in vivo procedure, particularly with adjustment during insertion.

Key Points

• Out-of-plane needle insertions performed using our robot were more accurate than smartphone-guided manual insertions in the phantom experiment and were also accurate in the in vivo procedure.

• In the phantom experiment, the mean angle errors of the robotic and smartphone-guided manual out-of-plane needle insertions were 0.4° and 3.7° in the XY plane (p < 0.001) and 0.6° and 0.6° in the YZ plane (p = 0.65), respectively.

• In the animal experiment, the overall mean distance accuracies of the robotic out-of-plane needle insertions with and without adjustments of needle orientation during insertion were 2.5 mm and 5.0 mm, respectively.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06477-1) contains supplementary material, which is available to authorized users.

Electromagnetic navigation to assist with computed tomography-guided thermal ablation of liver tumors

Purpose: To evaluate the advantages and primary technical efficacy of an electromagnetic (EM) navigation system for computed tomography (CT)-guided thermal ablation of liver tumors.Material and methods: From August 2016 to January 2018, 40 patients scheduled for CT- guided thermal ablation were prospectively enrolled and divided into two groups. Twenty patients underwent CT-guided thermal ablation with an EM navigation system (navigation group), while the other 20 patients underwent conventional CT-guided thermal ablation (control group). Data on skin punctures, instrument adjustments, puncture time to target, CT scans, CT fluoroscopy time and dose-length-product (DLP) were compared between the two groups. Any postoperative complications were recorded and the primary technical efficacy was evaluated four to six weeks after the procedure.Results: All 20 patients in the navigation group successfully underwent EM navigation. Compared to the control group, there were fewer instrument adjustments (mean 2.40 vs. 4.95; p = .003), fewer CT scans (mean 7.10 vs. 10.30; p = .006), less CT fluoroscopy time (mean 40.47 vs. 59.98 s, p = .046), and less DLP (mean 807.39 vs. 1578.67 mGy × cm; p = .001). Although not statistically significant, EM navigation resulted in fewer skin punctures (mean 1.20 vs. 1.25; p = .803) and slightly longer puncture time to target (mean 16.50 vs. 15.20 min; p = .725). No patients experienced major complications and the primary efficacy rate was 90% and 84.21% in the navigation and control groups, respectively (p = .661).Conclusions: EM navigation system optimizes the thermal ablation process and reduces radiation exposure in patients. However, further studies are warranted to determine whether an EM navigation system can improve procedure time, complication rates, and primary technical efficiacy of thermal ablation.

Organic Optoelectronic Diodes as Tactile Sensors for Soft-Touch Applications

The distributed sense of touch forms an essential component that defines real-time perception and situational awareness in humans. Electronic skins are an emerging technology in conferring an artificial sense of touch for smart human-machine interfaces. However, assigning a conformably distributed sense of touch over a large area has been challenging to replicate in modern medical, social, and industrial robots. Herein, we present a new class of soft tactile sensors that exploit the mechanisms of triplet-triplet annihilation, exciton harvesting, and a small Stokes shift in conjugated organic semiconductors such as rubrene. By multiplexing the electroluminescence and photosensing modes, we show that a compact optoelectronic array of multifunctional rubrene/fullerene diodes can accurately measure pressure, position, and surface deformation applied to an overlying elastomeric layer. The dynamic range of sensing is defined by mechanical properties of the elastomer. Such optoelectronic approach paves the way for soft, conformal, and large-area compatible electronic skins for medicine and robotics.

Patient-specific templates for image-guided intervention - a phantom study

Purpose: To evaluate the in vitro accuracy of a new device and method for simultaneous stereotactic CT-guided punctures.Material and methods: 240 needle paths were planned in 1 mm, 1.5 mm and 3 mm slice thickness with a custom-designed software. The data were transferred to a three-axis tabletop CNC machine that then drilled the hole pattern for the needles into square plastic plates. Kirschner wires were slid through the holes of the two parallel fixed plates to aim at the chosen targets inside the phantom. The accuracy was calculated by taking control CTs and measuring the Euclidean distance and the normal distance between the wire and the entry and target point.Results: The mean Euclidean distance of the wire tip to the target for the 1 mm, 1.5mm and 3 mm slice thickness were 2.5 mm (SD ± 0.64), 2.71mm (SD ± 0.78) and 2.8 mm (SD ± 1.0). The mean normal distance was 1.42 mm (SD ± 0.65), 1.43mm (SD ± 0.75) and 1.9 mm (SD ± 1.1), respectively.Conclusion: The system yields satisfactory accuracy comparable to other image-guided intervention systems. Involuntary movements of the patient need to be taken into account in a clinical setting.

Remotely Actuated Needle Driving Device for MRI-Guided Percutaneous Interventions

In this paper we introduce a remotely actuated MRI-compatible needle driving device for pain injections in the lower back. This device is able to manipulate the needle inside the closed-bore MRI scanner under the control of the interventional radiologist inside both the scanner room and the console room. The device consists of a 2 degrees of freedom (DOF) needle driver and an actuation box. The 2-DOF needle driver is placed inside the scanner bore and driven by the actuation box settled at the end of the table through a beaded chain transmission. This novel remote actuation design could reduce the weight and profile of the needle driver that is mounted on the patient, as well as minimize the potential imaging noise introduced by the actuation electronics. The actuation box is designed to perform needle intervention in both manual and motorized fashion by utilizing a mode switch mechanism. A mechanical hard stop is also incorporated to improve the device's safety. The bench-top accuracy evaluation of the device demonstrated a small mean needle placement error (< 1 mm) in a phantom study.

Devices for image-guided lung interventions: State-of-the-art review

Lung cancer is the leading cause of cancer-related death. According to the American Cancer Society, there were an estimated 222,500 new cases of lung cancer and 155,870 deaths from lung cancer in the United States in 2017. Accurate localization in lung interventions is one of the keys to reducing the death rate from lung cancer. In this study, a total of 217 publications from 2006 to 2017 about designs of medical devices for localization in lung interventions were screened, shortlisted, and categorized by localization principle and reviewed for functionality. Each study was analyzed for engineering characteristics and clinical significance. Research regarding interventional imaging equipment, navigation systems, and surgical devices was reviewed, and both research prototypes and commercial products were discussed. Finally, the future directions and existing challenges were summarized, including real-time intra-procedure guidance, accuracy of localization, clinical application, clinical adoptability, and clinical regulatory issues.

Robotic versus Freehand Needle Positioning in CT-guided Ablation of Liver Tumors: A Randomized Controlled Trial

Purpose To compare the accuracy of freehand versus robotic antenna placement in CT-guided microwave ablation (MWA) of liver tumors. Materials and Methods This study was conducted as a prospective single-center nonblinded randomized controlled trial (Netherlands Trial Registry, NTR6023). Eligible study participants had undergone clinically indicated CT-guided MWA of liver tumors and were able to receive a CT contrast agent. Randomization was performed per tumor after identification on contrast material-enhanced CT images. The primary outcome was the number of antenna repositionings, which was compared by using the Mann-Whitney U test. Secondary outcomes were lateral targeting error stratified by in-plane and out-of-plane targets and targeting time. Results Between February 14 and November 12, 2017, 31 participants with a mean age of 63 years (range, 25-88 years) were included: 17 women (mean age, 57 years; range, 25-77 years) and 14 men (mean age, 70 years; range, 52-88 years). The freehand study arm consisted of 19 participants, while the robotic study arm consisted of 18 participants; six participants with multiple tumors were included in both arms. Forty-seven tumors were assessed; five tumors were excluded from the analysis because of technical limitations. In the robotic arm, no antenna repositioning was required. In the freehand arm, a median of one repositioning was required (range, zero to seven repositionings; P < .001). For out-of-plane targets, lateral targeting error was 10.1 mm ± 4.0 and 5.9 mm ± 2.9 (P = .007) for freehand and robotic procedures, respectively, and for in-plane targets, lateral targeting error was 6.2 mm ± 2.7 and 7.7 mm ± 5.9, respectively (P = .51). Mean targeting time was 19 minutes (range, 8-55 minutes) and 36 minutes (range, 3-70 minutes; P = .001) for freehand and robotic procedures, respectively. Conclusion Robotic antenna guidance reduces the need for antenna repositioning in microwave ablation to accurately target liver tumors and increases accuracy for out-of-plane targets. However, targeting time was greater with robotic guidance than with freehand targeting. © RSNA, 2019.

Ablation Planning Software for Optimizing Treatment: Challenges, Techniques, and Applications

Percutaneous ablation can deliver effective anticancer therapy with minimal side effects; however, undertreatment can lead to disease recurrence and overtreatment can lead to unnecessary complications. Ablation planning software can support the procedure during the planning, treatment, and follow-up phases. In this review, 2 examples of microwave ablation software are described with attention to how the software can influence procedural choices. In the future, ablation software will entail larger source datasets and more refined algorithms to better model the in vivo ablation zone. Moreover, ablation simulation has the potential to augment clinical care beyond the interventional suite, such as procedural demonstration for patients, clinical consultation with referring providers, documentation for the medical record, and educational simulation for trainees.

Overlapping radiofrequency ablation planning and robot-assisted needle insertion for large liver tumors

BACKGROUND

We aimed at facilitating percutaneous radiofrequency ablation (RFA) for large tumors with accurate overlapping ablation planning and robot-assisted needle insertion from a single incision port (SIP).

METHODS

We developed a personalized and quantitative RFA planning method to obtain multiple needle overlapping ablation planning through a single incision. A robot with a remote center of motion mechanism was designed to perform needle insertions through a SIP according to the planning.

RESULTS

Numerical and visual evaluation showed that the planning could yield nearly full coverage over large tumors and greatly reduce both ablation times and the ablations of normal tissues. Ex vivo and in vivo experiments showed that our robot-assisted needle insertion system was capable of conducting the RFA procedure in large liver tumors from a SIP.

CONCLUSIONS

Robot-assisted RFA needle insertions from a SIP makes RFA treatment for large tumors more minimally invasive, predictable, and repeatable.

Robotic Insertion of Various Ablation Needles Under Computed Tomography Guidance: Accuracy in Animal Experiments

OBJECTIVE

To evaluate the accuracy of robotic insertion of various ablation needles at various locations under computed tomography (CT) guidance in swine.

MATERIALS AND METHODS

The robot was used for CT-guided insertion of four ablation needles, namely a single internally cooled radiofrequency ablation (RFA) needle (Cool-tip), a multi-tined expandable RFA needle (LeVeen), a cryoablation needle (IceRod), and an internally cooled microwave ablation needle (Emprint). One author remotely operated the robot with the operation interface in order to orient and insert the needles under CT guidance. Five insertions of each type of ablation needle towards 1.0-mm targets in the liver, kidney, lung, and hip muscle were attempted on the plane of an axial CT image in six swine. Accuracy of needle insertion was evaluated as the three-dimensional length between the target centre and needle tip. The accuracy of needle insertion was compared according to the type of needle used and the location using one-way analysis of variance.

RESULTS

The overall mean accuracy of all four needles in all four locations was 2.8 mm. The mean accuracy of insertion of the Cool-tip needle, LeVeen needle, IceRod needle, and Emprint needle was 2.8 mm, 3.1 mm, 2.5 mm, and 2.7 mm, respectively. The mean accuracy of insertion into the liver, kidney, lung, and hip muscle was 2.7 mm, 2.9 mm, 2.9 mm, and 2.5 mm, respectively. There was no significant difference in insertion accuracy among the needles (P = .38) or the locations (P = .53).

CONCLUSION

Robotic insertion of various ablation needles under CT guidance was accurate regardless of type of needle or location in swine.

Percutaneous Liver Tumour Ablation: Image Guidance, Endpoint Assessment, and Quality Control

Liver tumour ablation nowadays represents a routine treatment option for patients with primary and secondary liver tumours. Radiofrequency ablation and microwave ablation are the most widely adopted methods, although novel techniques, such as irreversible electroporation, are quickly working their way up. The percutaneous approach is rapidly gaining popularity because of its minimally invasive character, low complication rate, good efficacy rate, and repeatability. However, matched to partial hepatectomy and open ablations, the issue of ablation site recurrences remains unresolved and necessitates further improvement. For percutaneous liver tumour ablation, several real-time imaging modalities are available to improve tumour visibility, detect surrounding critical structures, guide applicators, monitor treatment effect, and, if necessary, adapt or repeat energy delivery. Known predictors for success are tumour size, location, lesion conspicuity, tumour-free margin, and operator experience. The implementation of reliable endpoints to assess treatment efficacy allows for completion-procedures, either within the same session or within a couple of weeks after the procedure. Although the effect on overall survival may be trivial, (local) progression-free survival will indisputably improve with the implementation of reliable endpoints. This article reviews the available needle navigation techniques, evaluates potential treatment endpoints, and proposes an algorithm for quality control after the procedure.

Validation of a CT-guided intervention robot for biopsy and radiofrequency ablation: experimental study with an abdominal phantom

PURPOSE

We aimed to evaluate the accuracy of a needle-placement robot for biopsy and radiofrequency ablation on an abdominal phantom.

METHODS

A master-slave robotic system has been developed that includes a needle-path planning system and a needle-inserting robot arm with computed tomography (CT) and CT fluoroscopy guidance. For evaluation of its accuracy in needle placement, a commercially available abdominal phantom (Model 057A; CIRS Inc.) was used. The liver part of the phantom contains multiple spherical simulated tumors of three different size spheres. Various needle insertion trials were performed in the transverse plane and caudocranial plane two nodule sizes (10 mm and 20 mm in diameter) to test the reliability of this robot. To assess accuracy, a CT scan was performed after each trial with the needle in situ.

RESULTS

The overall error was 2 mm (0-2.6 mm), which was calculated as the distance from the planned trajectory before insertion to the actual needle trajectory after insertion. The standard deviations of the insertions on two nodules (10 mm and 20 mm in diameter) were 0.5 mm and 0.2 mm, respectively.

CONCLUSION

The CT-compatible needle placement robot for biopsy and radiofrequency ablation shows relatively acceptable accuracy and could be used for radiofrequency ablation of nodules ≥10 mm under CT fluoroscopy guidance.

MRI-Guided Robotically Assisted Focal Laser Ablation of the Prostate Using Canine Cadavers

OBJECTIVE

a magnetic resonance imaging (MRI)-conditional needle guidance robot is developed to enhance MRI-guided focal laser ablation (FLA) therapy in patients with focal prostate cancer.

METHODS

inspired by the workflow of the manual FLA therapy, we developed an MRI-conditional robot with two degrees of freedom to provide the guidance for laser ablation catheter. This robot is powered by pneumatic turbine motors and encoded with the custom-designed optical encoder. The needle could be inserted manually through the designed robotic system, which keeps the patients inside MRI bore throughout the procedure. The robot hardware is integrated with the custom ablation planning and monitoring software (OncoNav) to provide an iterative treatment plan to cover the whole ablation zone. Virtual tumors were selected in three canine cadavers as targets to validate the performance of the proposed hardware and software system.

RESULTS

phantom studies show that the average targeting error is less than 2 mm and the workflow of the entire procedure lasts for 100 minutes. Canine cadaver experiment results show that all the targets were successfully ablated in no more than three administrations.

SIGNIFICANCE

MRI-guided prostate FLA is feasible using the proposed hardware and software system, indicating potential utility in future human trials.

Performance of Robotic Assistance for Skull Base Biopsy: A Phantom Study

Objectives  This study aims to evaluate the feasibility of a custom robot system guided by optical cone beam computed tomography (CBCT)-based navigation for skull base biopsy. Design  An accuracy study was conducted. Setting  Platform for navigation and robot-aided surgery technology. Participants  Phantom skull. Main Outcome Measures  The primary outcome measure was to investigate the accuracy of robot-assisted needle biopsy for skull base tumors. A 14-gauge needle was automatically inserted by the five degrees of freedom robot into the intended target, guided by optical navigation. The result was displayed on the graphical user interface after matrix transformation. Postoperative image scanning was performed, and the result was verified with image fusion. Results  All 20 interventions were successfully performed. The mean deviation of the needle tip was 0.56 ± 0.22 mm (measured by the navigation system) versus 1.73 ± 0.60 mm (measured by image fusion) ( p  < 0.05). The mean insertion depth was 52.3 mm (range: 49.7-55.2 mm). The mean angular deviations off the x-axis, y-axis, and z-axis were 1.51 ± 0.67, 2.33 ± 1.65, and 1.47 ± 1.16 degrees, respectively. Conclusions  The experimental results show the robot system is efficient, reliable, and safe. The navigation accuracy is a significant factor in robotic procedures.

Instrument flight to the inner ear

Surgical robot systems can work beyond the limits of human perception, dexterity and scale making them inherently suitable for use in microsurgical procedures. However, despite extensive research, image-guided robotics applications for microsurgery have seen limited introduction into clinical care to date. Among others, challenges are geometric scale and haptic resolution at which the surgeon cannot sufficiently control a device outside the range of human faculties. Mechanisms are required to ascertain redundant control on process variables that ensure safety of the device, much like instrument-flight in avionics. Cochlear implantation surgery is a microsurgical procedure, in which specific tasks are at sub-millimetric scale and exceed reliable visuo-tactile feedback. Cochlear implantation is subject to intra- and inter-operative variations, leading to potentially inconsistent clinical and audiological outcomes for patients. The concept of robotic cochlear implantation aims to increase consistency of surgical outcomes such as preservation of residual hearing and reduce invasiveness of the procedure. We report successful image-guided, robotic CI in human. The robotic treatment model encompasses: computer-assisted surgery planning, precision stereotactic image-guidance, in-situ assessment of tissue properties and multipolar neuromonitoring (NM), all based on in vitro, in vivo and pilot data. The model is expandable to integrate additional robotic functionalities such as cochlear access and electrode insertion. Our results demonstrate the feasibility and possibilities of using robotic technology for microsurgery on the lateral skull base. It has the potential for benefit in other microsurgical domains for which there is no task-oriented, robotic technology available at present.

Needle Tip Position Accuracy Evaluation Experiment for Puncture Robot in Remote Center Control

[abstFig src='/00280006/15.jpg' width='300' text='Location of devices in the experiment' ] In recent years, a medical procedure called interventional radiology (IR) has been attracting considerable attention. Doctors can perform IR percutaneously while observing the fluoroscopic image of patients. Therefore, this surgical method is less invasive. In this surgery, computed tomography (CT) equipment is often used for precise fluoroscopy. However, doctors are exposed to strong radiation from the CT equipment. In order to overcome this problem, we have developed a remote-controlled surgical assistance robot called Zerobot. In animal puncture experiment, the operation of Zerobot was based on joint control. Therefore, during a surgery, the tip of the needle moves when a surgeon orders for a change in the direction of the needle. This makes the robot less user-friendly because the surgeon tracks the trajectory of the tip of the needle. This problem can be solved by using remote center control.

Evaluation of a Robotic Assistance-System For Percutaneous Computed Tomography-Guided (CT-Guided) Facet Joint Injection: A Phantom Study

Background

The aim of this study was to compare robotic assisted and freehand facet joint puncture on a phantom model in regards to time requirements and puncture accuracy.

Material/Methods

Forty facet joints were punctured, 20 using a robotic guidance system and 20 using a freehand procedure. Side and height of the facet joints were randomized and identical for both groups. Procedural accuracy, defined as axial and sagittal deviation, as well as the number of corrections were assessed. Procedure times for each step were documented and time requirements for pre-positioning, reconstruction, planning, and total intervention were calculated.

Results

Total procedure time for robotic guidance was 259±111 seconds versus 119±77 seconds for freehand procedure (p=1.0). Procedural accuracy for robotic guidance was significantly higher with 0 corrections versus 1.3 corrections for freehand procedure (p=0.02). Needle deviation in the robotics arm was 0.35±1.1 mm in the axial and 2.15±1.2 mm in the sagittal reconstruction.

Conclusions

Robotic assisted puncture of the facet joint allowed accurate positioning of the needle with a lower number of needle readjustments. Higher procedural accuracy was marginally offset by a slightly longer intervention time.