Accurate Needle Placement Research Articles

PP06 Presentation Time: 10:50 AM: Needles in T.A.R.G.I.T.: "Tandem Anchored Radially Guiding Interstitial Template" Enabling Simplified Needle Insertion for Optimized Dosimetry

Purpose: It is well established in cervical brachytherapy that the addition of interstitial (IS) needles to intra-cavitary (IC) applicators can significantly enhance dosimetry by improving target coverage without increasing normal tissues doses. Accurate placement of interstitial needles requires significant skill and imaging guidance proficiency, thereby limiting the benefits to a subset of practitioners and patients. Available commercial combined IC/IS applicators restrict the available needle positions to often unsatisfactory locations for optimized dosimetry.

Development and placement accuracy evaluation of an MR conditional robot for prostate intervention.

Robot-assisted prostate intervention under magnetic resonance imaging (MRI) guidance is a promising method to improve the clinical performance compared with the manual method. An MR conditional 6-DOF prostate intervention serial robot is developed and a binocular vision system (BVS) is established to evaluate the needle placement accuracy and located the penetration point precisely. The robot is designed by the MR conditional criteria. The serial configuration of the robot provides adequate flexibility and large workspace and excellent friendliness to the physicians. The kinematics are deduced and the needle placement control flow is proposed according to the configuration of the robot. The robot-assisted prostate intervention is divided into two phases including needle placement and needle penetration. A custom-made robust BVS is developed to obtain the needle tip position automatically in the needle placement phase where the needle cannot be detected by the MRI for lack of hydrogen atom. A simple and general algorithm used for needle tip camera coordinate estimation is proposed. Experiments on the BVS validation and robot accuracy evaluation are performed. The experiment results show that the errors of the BVS are under 0.3621 mm and the position error of the proposed robot is 2.815 mm which indicate the adequate accuracy for the prostate intervention. Graphical abstract.

Time-aware deep neural networks for needle tip localization in 2D ultrasound.

Accurate placement of the needle is critical in interventions like biopsies and regional anesthesia, during which incorrect needle insertion can lead to procedure failure and complications. Therefore, ultrasound guidance is widely used to improve needle placement accuracy. However, at steep and deep insertions, the visibility of the needle is lost. Computational methods for automatic needle tip localization could improve the clinical success rate in these scenarios. We propose a novel algorithm for needle tip localization during challenging ultrasound-guided insertions when the shaft may be invisible, and the tip has a low intensity. There are two key steps in our approach. First, we enhance the needle tip features in consecutive ultrasound frames using a detection scheme which recognizes subtle intensity variations caused by needle tip movement. We then employ a hybrid deep neural network comprising a convolutional neural network and long short-term memory recurrent units. The input to the network is a consecutive plurality of fused enhanced frames and the corresponding original B-mode frames, and this spatiotemporal information is used to predict the needle tip location. We evaluate our approach on an ex vivo dataset collected with in-plane and out-of-plane insertion of 17G and 22G needles in bovine, porcine, and chicken tissue, acquired using two different ultrasound systems. We train the model with 5000 frames from 42 video sequences. Evaluation on 600 frames from 30 sequences yields a tip localization error of [Formula: see text] mm and an overall inference time of 0.064s (15fps). Comparison against prior art on challenging datasets reveals a 30% improvement in tip localization accuracy. The proposed method automatically models temporal dynamics associated with needle tip motion and is more accurate than state-of-the-art methods. Therefore, it has the potential for improving needle tip localization in challenging ultrasound-guided interventions.

The video demonstrates transbronchial access using CrossCountryTM tool. After ENB navigation to the proximity of a lung nodule which requires transbronchial access, the locatable guide is removed and replaced with the CrossCountryTM needle. The nodule is marked by yellow tracings, and accurate placement of needle is guided by real-time fluoroscopy.

The video demonstrates transbronchial access using CrossCountryTM tool. After ENB navigation to the proximity of a lung nodule which requires transbronchial access, the locatable guide is removed and replaced with the CrossCountryTM needle. The nodule is marked by yellow tracings, and accurate placement of needle is guided by real-time fluoroscopy.

In vivo evaluation of angulated needle-guide template for MRI-guided transperineal prostate biopsy.

Magnetic resonance imaging (MRI)-guided transperineal prostate biopsy has been practiced since the early 2000s. The technique often suffers from targeting error due to deviation of the needle as a result of physical interaction between the needle and inhomogeneous tissues. Existing needle guide devices, such as a grid template, do not allow choosing an alternative insertion path to mitigate the deviation because of their limited degree-of-freedom (DoF). This study evaluates how an angulated needle insertion path can reduce needle deviation and improve needle placement accuracy. We extended a robotic needle-guidance device (Smart Template) for in-bore MRI-guided transperineal prostate biopsy. The new Smart Template has a 4-DoF needle-guiding mechanism allowing a translational range of motion of 65 and 58mm along the vertical and horizontal axis, and a needle rotational motion around the vertical and horizontal axis and a vertical rotational range of , respectively. We defined a path planning strategy, which chooses between straight and angulated insertion paths depending on the anatomical structures on the potential insertion path. We performed (a) a set of experiments to evaluate the device positioning accuracy outside the MR-bore, and (b) an in vivo experiment to evaluate the improvement of targeting accuracy combining straight and angulated insertions in animal models (swine, ). We analyzed 46 in vivo insertions using either straight or angulated insertions paths. The experiment showed that the proposed strategy of selecting straight or angulated insertions based on the subject's anatomy outperformed the conventional approach of just straight insertions in terms of targeting accuracy (2.4mm [1.3-3.7] vs 3.9mm [2.4-5.0] {Median ); p=0.041 after the bias correction). The in vivo experiment successfully demonstrated that an angulated needle insertion path could improve needle placement accuracy with a path planning strategy that takes account of the subject-specific anatomical structures.

Influence of clinical experience on accuracy and safety of obliquus capitus inferior dry needling in unembalmed cadavers

ABSTRACT Background Suboccipital myofascial trigger points are common in tension-type headaches. Objectives Compare the influence of clinical experience on the accuracy and safety of dry needle placement on the C2 laminar arch using a cranial-medial and caudal-medial technique to target obliquus capitus inferior in unembalmed cadavers. Methods Three physical therapists inserted three 50 mm dry needles, per technique, individually toward the C2 laminar arch targeting the obliquus capitus inferior. Ultrasound video of each trial was recorded, and an investigator trained in ultrasound interpretation and blinded to experience level recorded needling accuracy. Results The novice, experienced and expert clinicians were accurate on 73.8%, 59.5% and 71.4% of caudal-medial trials, and 14.3%, 16.7% and 66.7% of cranial-medial trials, respectively, with each clinician striking the spinal cord at least once. The expert clinician was 10 times more likely to accurately reach the C2 laminar arch using the cranial-medial direction than the experienced and novice clinicians. Conclusion Increased clinical experience improved accuracy reaching the C2 laminar arch, with all investigators being more accurate with the caudal-medial technique. Greater experience did not eliminate risk as all investigators recorded at least one incident of striking the spinal cord. Fewer spinal cord strikes occurred with the cranial-medial than the caudal-medial technique.

High Accuracy of Digital Tomosynthesis-Guided Bronchoscopic Biopsy Confirmed by Intraprocedural Computed Tomography

Background: Digital fluoroscopic tomosynthesis-guided electromagnetic navigational bronchoscopy (F-ENB) is a novel adjunct to ENB associated with higher diagnostic yield. The likelihood of F-ENB allowing accurate placement of a biopsy needle within a target remains unclear. Objective: This study intends to determine the accuracy of F-ENB as confirmed by cone-beam computed tomography (CBCT) scan. Methods: Patients undergoing CBCT-assisted ENB for lung nodule biopsy were prospectively enrolled. ENB was performed followed by digital tomosynthesis correction. Once optimal F-ENB alignment was achieved, and a needle was advanced into the expected location of the nodule followed by CBCT. The primary outcome was the percentage of “needle-in-lesion” hits, defined as needle tip within the nodule in 3 planes. Secondary outcomes were diagnostic yield, procedure and room time, complications, radiation, and distance between the needle tip and nodule. Results: Twenty-six patients with a total of 29 nodules were enrolled. Mean nodule size was 13 mm (±4 mm) in maximal axial dimension, 83% (n = 24) were located in the peripheral third of the chest, and 17% (n = 5) had a bronchus sign. F-ENB guidance resulted in needle-in-lesion in 21 of 29 nodules (72%). Mean needle tip-to-nodule distance for nonhits was 1.75 mm (±1.35 mm). There were no complications. Conclusion: F-ENB resulted in a needle-in-lesion biopsy in greater than 70% of nodules despite features traditionally associated with poor diagnostic yield (size, absence of bronchus sign). Mean distance between needle tip and target for nonhits was less than 2 mm. These data suggest F-ENB alignment is accurate for small peripheral nodules.

Steerable needles for radio-frequency ablation in cirrhotic livers

Accurate needle placement in deep-seated liver tumours can be difficult. In this work, we disclose two new manually controlled steerable needles for 17G radio-frequency ablation probe placement. The needles contain stylets with embedded compliant joints for active tip articulations, and concentric tubes for (curved-path) guidance. Needle steering was evaluated sequentially by intended users and in intended-use tissue types. Six interventional radiologists evaluated the needle in repeated ultrasound-guided steering tasks in liver-mimicking phantoms. Targets were located at a 100 mm depth and 20 mm lateral offset from the initial insertion line. The resulting mean absolute tip placement error was 1.0 ± 1.0 mm. Subsequently, steering-induced tissue damage was evaluated in fresh cirrhotic human liver explants. The surface area of puncture holes was estimated in scanned histology slides, using a connected-components analysis. The mean surface area was 0.26 ± 0.16 mm2 after steering with a median radius of curvature of 0.7 × 103 mm, versus 0.35 ± 0.15 mm2 after straight-path insertions with the steerable needle and 0.15 ± 0.09 mm2 after straight-path RFA probe insertions. The steering mechanisms proposed enable clinically relevant path corrections for 17G needles. Radiologists were quickly adept in curved-path RFA probe placement and the evaluation of histological tissue damage demonstrated a potentially safe use during liver interventions.

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 ± 1:43min. Time for needle placement decreased with subsequent attempts, with average third placement taking 2:29 ± 1:51min less than the first attempt. The average vector distance from the target was 2.3 ± 1.2mm. 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.

SabreSource™: a novel percutaneous nephrolithotomy apparatus to aid collecting system puncture - a preliminary report

Successful percutaneous nephrolithotomy (PCNL) relies on a technically challenging, precise needle puncture of the renal collecting system. We aimed to compare, in an ex vivo model, the use of a real time image guidance system (the SabreSource™) and a mechanical stabilising device with conventional manual techniques for the accuracy of needle placement. The SabreSource™ system (Minrad International Inc.; New York, USA) is a real time image guidance system. The system platform is mounted on a C-arm fluoroscope. It employs targeting cross hairs on the fluoroscopic image that can be easily positioned to target the desired renal calyx. The system directs a visible laser beam onto the patient which is precisely aligned with the cross hairs on the fluoroscopic image. This provides the correct "bull's-eye" angle of approach to the calyx, even after the x-ray source is turned off. The locator then stabilises the needle in the "bull's-eye" position so that only screening for depth is required. Objective assessment using a simulated PCNL puncture was performed by 7 urologic trainees on a kidney phantom with and without using the SabreSource™. Fluoroscopy screening time (FST) and amount of radiation (mGy) used to achieve successful puncture were compared. Simulated PCNL puncture was quicker and resulted in reduced radiation exposure when the apparatus was used. The mean FST for traditional "bull's-eye" vs SabreSource™ puncture was 17 vs 5 seconds (p = 0.01), and the mean radiation exposure to puncture was 0.7 vs 0.2 mGy (p = 0.03), respectively. The SabreSource™ is a novel assistant to achieving successful PCNL puncture. In combination with "the locator" the preliminary in vitro testing suggests that the device reduces fluoroscopy exposure and is quicker. The device warrants further evaluation in the clinical setting.

Ultrasound-guided intervention and hand tenosynovitis in patients with diabetes mellitus

Background: Flexor tenosynovitis is a frequent cause of hand pain in diabetic patients, and corticosteroid (CS) injection is usually efficiently used in the treatment protocol. Ultrasound (US) guidance is usually helpful for accurate needle placement and improves the outcome. Aim of the Work: The aim of the work was to evaluate the efficacy of US-guided injections compared to clinically guided injections, the treatment of flexor tenosynovitis in diabetic hands. Patients and Methods: Patients were divided into two matched groups of diabetic patients with flexor tenosynovitis: Group 1 – treated with local CS injection under US guidance and Group 2: treated with local CS injection under clinical guidance. Both the groups were assessed twice for pain and tenderness using visual analog scale (VAS) and Richie index, respectively, one before the injection and the second 1 month after. All affected tendons were assessed and graded by US and power Doppler at baseline and 1 month after the injection. Results: Both the groups were matched as regards the disease duration, age, and glycated hemoglobin A1c. The mean VAS for Group 1 was 8.1 ± 0.8 cm at baseline and 3.4 ± 0.7 cm in the second visit; greyscale US showed improvement in 16 patients (61%). The mean VAS was 8.3 ± 0.7 cm at visit one, while it dropped down to 4.5 ± 0.9 cm in visit two. Conclusion: US-guided injections of CSs are statistically superior to clinically guided in treating flexor tenosynovitis in diabetic patients.

A Novel Robotic Guidance System With Eye-Gaze Tracking Control for Needle-Based Interventions

The robotic technologies have been widely used in the operating room for decades. Among them, needle-based percutaneous interventions have attracted much attention from engineering and medical communities. However, the currently used robotic systems for interventional procedures are too cumbersome, requiring a large footprint in the operating room. Recently developed light-weight puncture robotic systems for needle positioning are able to reduce the size, but has the limitation of awkward ergonomics. In this article, we design a compact robotic guidance system that could accurately realize the needle position and orientation within the operating room. The eye-gaze tracking-based approach is proposed to control the position and orientation of the needle toward the desired location in a more intuitive manner, and the forward and inverse kinematics of this 4-DoF robot are analyzed. The robot operating system (ROS)-based experimental studies are performed to evaluate the needle placement accuracy during interventional therapy. The result indicated the effectiveness of the proposed robotic hardware and the eye-gaze-based control framework, which can achieve a distance error of the robot’s end effector to the target point within 1 mm.

Angular needle tracker and stabilizer for image-guided interventions

Introduction Minimally invasive image-guided interventions have changed the face of procedural medicine. For these procedures, safety and efficacy depend on precise needle placement. Needle targeting devices help improve the accuracy of needle placement, but their use has not seen broad penetration. Some of these devices are costly and require major modifications to the clinical workflow. In this article, we developed a low-cost, disposable, and easy-to-use angulation tracking device, which was based on a redesigned commercial passive needle holder. Material and methods The new design provided real-time angulation information for needle tracking. In this design, two potentiometers were used as angulation sensors, and they were connected to two axes of the passive needle holder’s arch structure through a 3 D-printed bridge structure. A control unit included an Arduino Pro Mini, a Bluetooth module, and two rechargeable batteries. The angulation was calculated and communicated in real time to a novel developed smartphone app, where real-time angulation information was displayed for guiding the operator to position the needle to the planned angles. Results The open-air test results showed that the average errors are 1.03° and 1.08° for left–right angulation and head–foot angulation, respectively. The animal cadaver tests revealed that the novel system had an average angular error of 3.2° and a radial distance error of 3.1 mm. Conclusions The accuracy was comparable with some commercially available solutions. The novel and low-cost needle tracking device may find a role as part of a real-time precision approach to both planning and implementation of image-guided therapies.

The application of thermal oscillation method to augment the effectiveness of autologous platelet rich plasma in treating elderly patients with knee osteoarthritis.

Elderly patients with knee osteoarthritis (OA) are often troubled with joint soreness, swelling, weakness, and pain. Knee intra-articular (IA) injection of autologous platelet rich plasma (PRP) is one of the options that can be used in treating knee OA. However, there are doubts on the effect of PRP when used in treating elderly patients with moderate to severe degrees of knee OA. In this study, 47 elderly patients with moderate degree of knee OA combined with supra-patellar bursitis were recruited. Musculoskeletal ultrasound was used for accurate needle placement for the aspiration of bursa synovial fluid SF followed by PRP injections. In group 1, 23 patients received conventional liquid-form IA PRP injections. In group 2, 24 patients received IA injections of thermal oscillation prepared PRP injectants. It was discovered that when the liquid-form PRP was heated up to a temperature of 75°C and simultaneously oscillated under 200 revolutions per minute (rpm) for 15min, the end product became paste-form like and with a viscosity similar to that of an anti-cough syrup. Under incubation, the highest number of platelet-derived growth factor (PDGF) was obtained on the 8th day. At one month after the completion of PRP injections, group 2 patients revealed significant decreases in SF total protein concentrations, SF volumes, and Lequesne index values. Proteins associated with inflammation, such as apolipoprotein A-I, haptoglobin, immunoglobulin kappa chain, transferrin, and matrix metalloproteinase also decreased significantly. Therefore, the thermal oscillation preparation method can augment the effectiveness of autologous PRP in treating elderly patients with moderate knee OA. It may be recommended that the PRP injectant should be prepared first using the thermal oscillation method to increase its viscosity, enabling prolonged release of growth factors once it is injected into the knee joint.

Anatomical study of the human sacral hiatus and implications for successful caudal epidural injection

BackgroundCaudal epidural injection (CEI) is a commonly used procedure to treat back and leg pain secondary to nerve root irritation, predominantly in the context of spinal canal stenosis. Key to a successful outcome is correct needle placement. Although fluoroscopic guidance confirms accurate needle placement, it does not help in determining the starting point, which can lead to multiple needle insertions. ObjectiveThis study aimed to determine the variability in size and position of the sacral hiatus and to identify reproducible surface landmarks to locate its position. Methods and study design250 human sacral bones were examined, measuring morphology and structure. Vernier callipers accurate to 0.1 mm were used for measurements. Results were analysed using SPSS statistical software. ResultsTwo specimens were excluded due to agenesis of the hiatus (0.8%). Of the remaining 248 specimens, it was found that the mean internal diameter of the sacral hiatus was 5.12 mm (SD 1.61). The position of the hiatus was variable but was most commonly found at the level of the fourth sacral vertebrae (62.9%, n = 156). Mean distance between the two superolateral sacral prominences was 64.15 mm (SD 6.5) and between superolateral sacral prominences (left and right) and apex of the hiatus were 63.21 mm (SD 10.9) and 63.34 mm (SD 10.87) respectively. ConclusionAlthough there is a clear anatomical variance in the position and size of the sacral hiatus, this study suggests that surface anatomy landmarks can be used to form an equilateral triangle of which the inferior apex should correspond to the sacral hiatus. Knowledge of this surface anatomy may assist the correct location of the sacral hiatus and hence subsequently improve the efficacy of CEI.

Needle placement accuracy in CT-guided robotic post mortem biopsy

Abstract Forensic autopsies include a thorough examination of the corpse to detect the source or alleged manner of death as well as to estimate the time since death. However, a full autopsy may be not feasible due to limited time, cost or ethical objections by relatives. Hence, we propose an automated minimal invasive needle biopsy system with a robotic arm, which does not require any online calibrations during a procedure. The proposed system can be easily integrated into the workflow of a forensic biopsy since the robot can be flexibly positioned relative to the corpse. With our proposed system, we performed needle insertions into wax phantoms and livers of two corpses and achieved an accuracy of 4.34 ± 1.27 mm and 10.81 ± 4.44 mm respectively.

Shoulder MR Arthrography: Comparative Evaluation of Three Different Contrast Injection Techniques Using an Anterior Approach.

MR arthrography (MRA) is commonly used in the assessment of shoulder internal derangements. Correct intra-articular contrast injection is required for this modality. Anterior injections under fluoroscopic, ultrasound-guidance, or without image-guidance have been described in the literature. However, no simultaneous comparison has been performed between the three techniques. To compare the accuracy and performance of fluoroscopy (FL)-guided, ultrasound (US)-guided and non-image-guided intra-articular contrast injection via an anterior approach for performing shoulder MRA. Prospective. Two-hundred and ten patients (180 men and 30 women; mean age, 33 ± 12 years; range 20-60 years) with clinically suspected shoulder pathology. 1.5T/fat-suppressed T1 -weighted, T2 -weighted, and 3D-gradient-echo images. Patients underwent shoulder MRA after anterior intra-articular contrast injection under FL- or US-guidance or without image-guidance. Patients were randomized among the three techniques with each group comprising 70. The techniques were compared according to the accuracy of intra-articular needle placement, attempts success rate, pain during and 24 hours after injection, procedure times, contrast extravasation rate, joint distension, and MRA diagnostic efficacy. Pain was assessed by the visual analog scale (VAS) pain-score. Pearson's chi-squared and Kruskal-Wallis tests. FL- and US-guided injections (100% accuracy) were significantly more accurate than non-image-guided (85.7% accuracy) (P < 0.05). US-guidance was the least painful, with statistical differences between image-guided and non-image-guided techniques regarding the first attempt success rate (95.7% and 92.8% for FL- and US-guided vs. 78.6% for blinded), VAS-score 24 hours-post-procedure (1.7 ± 1.7, and 1.5 ± 1.4 vs. 2.2 ± 1.4), procedure time (11.9 ± 1.6, and 7.4 ± 1.7 vs. 4.3 ± 0.76 minutes), and contrast extravasation rate (5.7%, and 8.6% vs. 30%) (all P < 0.05). Procedure time was also significantly different between FL and US-guidance (P < 0.05). Imaging-guided injections are more accurate and tolerable than non-image-guided and should be considered to confirm intra-articular needle position, hence adequate capsular distension and good diagnostic quality of shoulder MRA. US guidance is a less painful, rapid, and safe alternative to the FL approach. Evidence Level: 2 Technical Efficacy Stage: 5. J. MAGN. RESON. IMAGING 2021;53:481-490.

Spinal cord stimulators and implications for anaesthesia

Spinal cord stimulators and implications for anaesthesia

Augmented Reality-Assisted Biopsy of Soft Tissue Lesions.

Guided biopsy of soft tissue lesions can be challenging in the presence of sensitive organs or when the lesion itself is small. Computed tomography (CT) is the most frequently used modality to target soft tissue lesions. In order to aid physicians, small field of view (FOV) low dose non-contrast CT volumes are acquired prior to intervention while the patient is on the procedure table to localize the lesion and plan the best approach. However, patient motion between the end of the scan and the start of the biopsy procedure can make it difficult for a physician to translate the lesion location from the CT onto the patient body, especially for a deep-seated lesion. In addition, the needle should be managed well in three-dimensional trajectories in order to reach the lesion and avoid vital structures. This is especially challenging for less experienced interventionists. These usually result in multiple additional image acquisitions during the course of procedure to ensure accurate needle placement, especially when multiple core biopsies are required. In this work, we present an augmented reality (AR)-guided biopsy system and procedure for soft tissue and lung lesions and quantify the results using a phantom study. We found an average error of 0.75 cm from the center of the lesion when AR guidance was used, compared to an error of 1.52 cm from the center of the lesion during unguided biopsy for soft tissue lesions while upon testing the system on lung lesions, an average error of 0.62 cm from the center of the tumor while using AR guidance versus a 1.12 cm error while relying on unguided biopsies. The AR-guided system is able to improve the accuracy and could be useful in the clinical application.

Design of an end-effector for robot-assisted ultrasound-guided breast biopsies

PurposeThe biopsy procedure is an important phase in breast cancer diagnosis. Accurate breast imaging and precise needle placement are crucial in lesion targeting. This paper presents an end-effector (EE) for robotic 3D ultrasound (US) breast acquisitions and US-guided breast biopsies. The EE mechanically guides the needle to a specified target within the US plane. The needle is controlled in all degrees of freedom (DOFs) except for the direction of insertion, which is controlled by the radiologist. It determines the correct needle depth and stops the needle accordingly.MethodIn the envisioned procedure, a robotic arm performs localization of the breast, 3D US volume acquisition and reconstruction, target identification and needle guidance. Therefore, the EE is equipped with a stereo camera setup, a picobeamer, US probe holder, a three-DOF needle guide and a needle stop. The design was realized by prototyping techniques. Experiments were performed to determine needle placement accuracy in-air. The EE was placed on a seven-DOF robotic manipulator to determine the biopsy accuracy on a cuboid phantom.ResultsNeedle placement accuracy was 0.3 ± 1.5 mm in and 0.1 ± 0.36 mm out of the US plane. Needle depth was regulated with an accuracy of 100 µm (maximum error 0.89 mm). The maximum holding force of the stop was approximately 6 N. The system reached a Euclidean distance error of 3.21 mm between the needle tip and the target and a normal distance of 3.03 mm between the needle trajectory and the target.ConclusionAn all in one solution was presented which, attached to a robotic arm, assists the radiologist in breast cancer imaging and biopsy. It has a high needle placement accuracy, yet the radiologist is in control like in the conventional procedure.