Needle Navigation Research Articles

Quantitative Analysis of Needle Navigation under Ultrasound Guidance in s Simulated Central Venous Line Procedure

Complications in ultrasound-guided central line insertions are associated with the expertise level of the operator. However, a lack of standards for teaching, training and evaluation of ultrasound guidance results in various levels of competency during training. To address such shortcomings, there has been a paradigm shift in medical education toward competency-based training, promoting the use of simulators and quantitative skills assessment. It is therefore necessary to develop reliable quantitative metrics to establish standards for the attainment and maintenance of competence. This work identifies such a metric for simulated central line procedures. The distance between the needle tip and ultrasound image plane was quantified as a metric of efficacy in ultrasound guidance implementation. In a simulated procedure, performed by experienced physicians, this distance was significantly greater in unsuccessful procedures (p = 0.04). The use of this metric has the potential to enhance the teaching, training and skills assessment of ultrasound-guided central line insertions.

A radiopaque 3D printed, anthropomorphic phantom for simulation of CT-guided procedures.

To develop an anthropomorphic phantom closely mimicking patient anatomy and to evaluate the phantom for the simulation of computed tomography (CT)-guided procedures. Patient CT images were printed with aqueous potassium iodide solution (1 g/mL) on paper. The printed paper sheets were stacked in alternation with 1-mm thick polyethylene foam layers, cut to the patient shape and glued together to create an anthropomorphic abdomen phantom. Ten interventional radiologists performed periradicular infiltration on the phantom and rated the phantom procedure regarding different aspects of suitability for simulating CT-guided procedures. Radiopaque printing in combination with polyethylene foam layers achieved a phantom with detailed patient anatomy that allowed needle placement. CT-guided periradicular infiltration on the phantom was rated highly realistic for simulation of anatomy, needle navigation and overall course of the procedure. Haptics were rated as intermediately realistic. Participants strongly agreed that the phantom was suitable for training and learning purposes. A radiopaque 3D printed, anthropomorphic phantom provides a realistic platform for the simulation of CT-guided procedures. Future work will focus on application for training and procedure optimisation. • Radiopaque 3D printing combined with polyethylene foam achieves patient phantoms for CT-guided procedures. • Radiopaque 3D printed, anthropomorphic phantoms allow realistic simulation of CT-guided procedures. • Realistic visual guidance is a key aspect in simulation of CT-guided procedures. • Three-dimensional printed phantoms provide a platform for training and optimisation of CT-guided procedures.

Robust path planning for flexible needle insertion using Markov decision processes.

Flexible needle has the potential to accurately navigate to a treatment region in the least invasive manner. We propose a new planning method using Markov decision processes (MDPs) for flexible needle navigation that can perform robust path planning and steering under the circumstance of complex tissue-needle interactions. This method enhances the robustness of flexible needle steering from three different perspectives. First, the method considers the problem caused by soft tissue deformation. The method then resolves the common needle penetration failure caused by patterns of targets, while the last solution addresses the uncertainty issues in flexible needle motion due to complex and unpredictable tissue-needle interaction. Computer simulation and phantom experimental results show that the proposed method can perform robust planning and generate a secure control policy for flexible needle steering. Compared with a traditional method using MDPs, the proposed method achieves higher accuracy and probability of success in avoiding obstacles under complicated and uncertain tissue-needle interactions. Future work will involve experiment with biological tissue in vivo. The proposed robust path planning method can securely steer flexible needle within soft phantom tissues and achieve high adaptability in computer simulation.

4:12 PM Abstract No. 219 Barriers to adoption of fusion and navigation tools for biopsy and ablation

To describe the different clinical systems for needle navigation and fusion image guidance for needle biopsy and ablation, and to better understand barriers to adoption. The different methodologies are described for guiding needle-based biopsy and ablation. The basic principles and differentiating mechanistic features are reviewed, as well as the workflow and clinical indications. Selected representative clinical cases are presented to demonstrate principles and barriers to adoption, such as setup processes, learning curves, complex interface buttons and sequence, cost, and workflow impact. TRUS + MRI fusion-guided prostate biopsy is used as an example to show these principles in fusion biopsy. Costs for in-MRI vs out-of-MRI biopsy are compared. Biopsy and ablation may benefit from facilitated needle navigation or multi-parametric guidance and real-time feedback. The ability to spatially combine morphometric (or anatomic) with functional (or metabolic) information may enable clinical procedures that would otherwise not be possible. Procedure time, patient throughput, equipment ergonomics, cost, and risk may be facilitated by familiarity with common barriers to adoption. Training tools to reduce learning curves include training videos, slides and bulky hardware setup flow charts. Registration hardware and techniques also differ in underlying mechanisms. These include: electromagnetic tracking, optical tracking, mechanical position sensing, stereotactics or robotics, image-based registration, and camera-on-ultrasound. Both PET and MRI data can be imported to the patient, instead of performing the procedure inside the PET or MRI environment, which can reduce cost. TRUS + MRI fusion-guided prostate biopsy hardware and software approaches demonstrate representative paradigms that differ in terms of underlying mechanisms, rationale, goals, cost, ease of use, and impact upon workflow. Many different registration and fusion systems and navigation techniques are useful for specific biopsy and ablation clinical scenarios, with variable indications, cost, ease of use, and impact on workflow. Better understanding of barriers to adoption may help realize theoretical benefits.

AngleNav: MEMS Tracker to Facilitate CT-Guided Puncture.

As a low-cost needle navigation system, AngleNav may be used to improve the accuracy, speed, and ease of CT-guided needle punctures. The AngleNav hardware includes a wireless device with a microelectromechanical (MEMS) tracker that can be attached to any standard needle. The physician defines the target, desired needle path and skin entry point on a CT slice image. The accuracy of AngleNav was first tested in a 3D-printed calibration platform in a benchtop setting. An abdominal phantom study was then performed in a CT scanner to validate the accuracy of the device's angular measurement. Finally, an in vivo swine study was performed to guide the needle towards liver targets (n=8). CT scans of the targets were used to quantify the angular errors and needle tip-to-targeting distance errors between the planned needle path and the final needle position. The MEMS tracker showed a mean angular error of 0.01° with a standard deviation (SD) of 0.62° in the benchtop setting. The abdominal phantom test showed a mean angular error of 0.87° with an SD of 1.19° and a mean tip-to-target distance error of 4.89mm with an SD of 1.57mm. The animal experiment resulted in a mean angular error of 6.6° with an SD of 1.9° and a mean tip-to-target distance error of 8.7mm with an SD of 3.1mm. These results demonstrated the feasibility of AngleNav for CT-guided interventional workflow. The angular and distance errors were reduced by 64.4 and 54.8% respectively if using AngleNav instead of freehand insertion, with a limited number of operators. AngleNav assisted the physicians to deliver accurate needle insertion during CT-guided intervention. The device could potentially reduce the learning curve for physicians to perform CT-guided needle targeting.

Assistive system based on nerve detection and needle navigation in ultrasound images for regional anesthesia

The development of Ultrasound-Guided Regional Anesthesia (UGRA) is of great help to practitioners of regional anesthesia as it enables real time visualization of the needle, the targeted nerve, and different anatomic structures. However, the clinician has to perform a complex hand coordination to keep the needle, the nerve and some key regions visible in the ultrasound image plane. Daily clinical practice therefore requires a high degree of training and practical skill to identify the nerve block and steer the needle to it. There are two critical steps in UGRA: the recognition of anatomical structures and steering the needle to the target region. An intelligent system, with the ability to identify the regions of interest and to provide the needle insertion trajectory in ultrasound images, can significantly improve UGRA practice and generalize it to medical facilities that lack practitioners. It would also make the UGRA procedure safer (i.e., reducing the risk of nerve trauma). This work presents the first fully automatic system for the detection of regions of interest and generation of the needle trajectory for UGRA. Several problems were addressed, in two stages. The first one consisted in the automatic localization and segmentation of the nerve (target) and arteries (obstacles) in ultrasound images. A new method based on a machine learning algorithm with a multi-model classification process using a sliding window for localization, then an active contour was applied to delineate the localized regions. In the second stage, an algorithm for path planning was also developed to obtain the optimal trajectory for needle insertion based on the result of the first stage (target and obstacle detection). To check the effectiveness of the proposed system, firstly, experiments were performed over individual modules of the detection framework. Secondly, a comparison between the overall framework and the existing method was performed. Two data-sets were acquired in real conditions at different times to prove the robustness of our method. The first data-set contained eight patients and the second data-set, acquired one year later, contained five patients. Experimental results demonstrate the robustness of the proposed scheme and the feasibility of such an assistive system.

A Randomized Crossover Study Comparing a Novel Needle Guidance Technology for Simulated Internal Jugular Vein Cannulation

Despite ultrasound guidance for central line placement, complications persist, as exact needle location is often difficult to confirm with standard two-dimension ultrasound. A novel real-time needle guidance technology has recently become available (eZono, Germany) that tracks the needle during insertion. This randomized, blinded, crossover study examined whether this needle guidance technology improved cannulation of a simulated internal jugular (IJ) vein in an ultrasound phantom. One hundred physicians were randomized to place a standard needle in an ultrasound neck phantom with or without the needle guidance system. Video cameras were placed externally and within the lumens of the vessels to record needle location in real time. The primary outcome measured was the rate of posterior wall puncture. Secondary outcomes included number of carotid artery punctures, number of needle passes, final needle position, time to cannulation, and comfort level with this new technology. The incidence of posterior vessel wall puncture without and with needle guidance was 49 and 13%, respectively (P < 0.001, odds ratio [OR] = 7.33 [3.44 to 15.61]). The rate of carotid artery puncture was higher without needle navigation technology than with needle navigation 21 versus 2%, respectively (P = 0.001, OR = 12.97 [2.89 to 58.18]). Final needle tip position being located within the lumen of the IJ was 97% accurate with the navigation technology and 76% accurate with standard ultrasound (P < 0.001, OR = 10.42 [2.76 to 40.0]). Average time for successful vessel cannulation was 1.37 times longer without guidance technology. This real-time needle guidance technology (eZono) shows significant improvement in needle accuracy and cannulation time during simulated IJ vein puncture.

Real-time epidural anesthesia guidance using optical coherence tomography needle probe.

Epidural anesthesia is one of the most widely used anesthesia methods. Due to lack of visual feedback to guide needle navigation, failure rate of epidural anesthesia is up to 20%, and the complication rate of peripheral nerve block approaches 10%, with the potential of permanent nerve damage. To address these difficulties, needle insertion under ultrasound guidance and fluoroscopy has been introduced. However, they do not provide adequate resolution and contrast to distinguish the tissue layers that the needle travels through or to specifically identify the epidural space. To improve the accuracy of epidural space identification, we developed a small hand-held optical coherence tomography (OCT) forward-imaging needle device for real-time epidural anesthesia surgery guidance and demonstrated its feasibility through ex vivo and in vivo animal experiments. With tissue structures visualized and differentiated at the needle tip, OCT needle imaging device will enhance clinical outcomes with regards to complication rates, induced pain, and procedure failure when compared to standard practice. Furthermore, this technology could be used in combination with ultrasound/fluoroscopy to enhance outcomes.

Tracked ultrasonography snapshots enhance needle guidance for percutaneous renal access: a pilot study.

Although ultrasonography-guided percutaneous nephrostomy is relatively safe, a number of factors make it challenging for inexperienced operators. A computerized needle navigation technique using tracked ultrasonography snapshots was investigated to determine whether performance of percutaneous nephrostomy by inexperienced users could be improved. Ten operators performed the procedure on a phantom model with alternating needle guidance between conventional ultrasonography and tracked ultrasonography snapshots. The needle was reinserted until fluid backflow confirmed calyceal access. Needle trajectories were recorded using the real time needle navigation system for offline evaluation of operator performance. Recorded needle trajectories were used to measure needle motion path length inside the phantom tissue, number of reinsertions, total procedure time, and needle insertion time as end points of this study. Needle path length measured inside the phantom tissue was significantly lower with ultrasonography snapshots guidance (295.0±23.1 mm, average±standard error of the mean) compared with control procedures (977.9±144.4 mm, P<0.01). This was associated with a significantly lower number of needle insertion attempts with ultrasonography snapshots (average 1.27±0.10 vs 2.83±0.31, P<0.01). The total procedure time and the needle insertion time were also significantly lower with ultrasonography snapshots guidance. Tracked ultrasonography snapshots appear to improve the performance of percutaneous nephrostomy in these preliminary investigations, justifying further validation studies. The presented navigation system is reproducible because of commercially available hardware and open-source software components, facilitating its potential role in clinical practice.

MR-guided vertebroplasty with augmented reality image overlay navigation.

To evaluate the feasibility of magnetic resonance imaging (MRI)-guided vertebroplasty at 1.5 Tesla using augmented reality image overlay navigation. Twenty-five unilateral vertebroplasties [5 of 25 (20%) thoracic, 20 of 25 (80%) lumbar] were prospectively planned in 5 human cadavers. A clinical 1.5-Teslan MRI system was used. An augmented reality image overlay navigation system and 3D Slicer visualization software were used for MRI display, planning, and needle navigation. Intermittent MRI was used to monitor placement of the MRI-compatible vertebroplasty needle. Cement injections (3 ml of polymethylmethacrylate) were performed outside the bore. The cement deposits were assessed on intermediate-weighted MR images. Outcome variables included type of vertebral body access, number of required intermittent MRI control steps, location of final needle tip position, cement deposit location, and vertebroplasty time. All planned procedures (25 of 25, 100%) were performed. Sixteen of 25 (64%) transpedicular and 9 of 25 (36%) parapedicular access routes were used. Six (range 3-9) MRI control steps were required for needle placement. No inadvertent punctures were visualized. Final needle tip position and cement location were adequate in all cases (25 of 25, 100%) with a target error of the final needle tip position of 6.1 ± 1.9 mm (range 0.3-8.7 mm) and a distance between the planned needle tip position and the center of the cement deposit of 4.3 mm (range 0.8-6.8 mm). Time requirement for one level was 16 (range 11-21) min. MRI-guided vertebroplasty using image overlay navigation is feasible allowing for accurate vertebral body access and cement deposition in cadaveric thoracic and lumbar vertebral bodies.

Ultrasound-based tumor movement compensation during navigated laparoscopic liver interventions

Image-guided navigation aims to provide better orientation and accuracy in laparoscopic interventions. However, the ability of the navigation system to reflect anatomical changes and maintain high accuracy during the procedure is crucial. This is particularly challenging in soft organs such as the liver, where surgical manipulation causes significant tumor movements. We propose a fast approach to obtain an accurate estimation of the tumor position throughout the procedure. Initially, a three-dimensional (3D) ultrasound image is reconstructed and the tumor is segmented. During surgery, the position of the tumor is updated based on newly acquired tracked ultrasound images. The initial segmentation of the tumor is used to automatically detect the tumor and update its position in the navigation system. Two experiments were conducted. First, a controlled phantom motion using a robot was performed to validate the tracking accuracy. Second, a needle navigation scenario based on pseudotumors injected into ex vivo porcine liver was studied. In the robot-based evaluation, the approach estimated the target location with an accuracy of 0.4 ± 0.3 mm. The mean navigation error in the needle experiment was 1.2 ± 0.6 mm, and the algorithm compensated for tumor shifts up to 38 mm in an average time of 1 s. We demonstrated a navigation approach based on tracked laparoscopic ultrasound (LUS), and focused on the neighborhood of the tumor. Our experimental results indicate that this approach can be used to quickly and accurately compensate for tumor movements caused by surgical manipulation during laparoscopic interventions. The proposed approach has the advantage of being based on the routinely used LUS; however, it upgrades its functionality to estimate the tumor position in 3D. Hence, the approach is repeatable throughout surgery, and enables high navigation accuracy to be maintained.

Hand gesture guided robot-assisted surgery based on a direct augmented reality interface

Radiofrequency (RF) ablation is a good alternative to hepatic resection for treatment of liver tumors. However, accurate needle insertion requires precise hand-eye coordination and is also affected by the difficulty of RF needle navigation. This paper proposes a cooperative surgical robot system, guided by hand gestures and supported by an augmented reality (AR)-based surgical field, for robot-assisted percutaneous treatment. It establishes a robot-assisted natural AR guidance mechanism that incorporates the advantages of the following three aspects: AR visual guidance information, surgeon's experiences and accuracy of robotic surgery. A projector-based AR environment is directly overlaid on a patient to display preoperative and intraoperative information, while a mobile surgical robot system implements specified RF needle insertion plans. Natural hand gestures are used as an intuitive and robust method to interact with both the AR system and surgical robot. The proposed system was evaluated on a mannequin model. Experimental results demonstrated that hand gesture guidance was able to effectively guide the surgical robot, and the robot-assisted implementation was found to improve the accuracy of needle insertion. This human–robot cooperative mechanism is a promising approach for precise transcutaneous ablation therapy.

Aportaciones al cálculo de la latitud en la náutica española de principios del siglo XVII contenidas en el manuscrito de Diego Ramírez de Arellano Reconocimiento de los estrechos de Magallanes y San Vicente, con algunas cosas curiosas de navegación (1621)

In 1620, was named chief pilot of the Casa de Contratacion de Sevilla Diego Ramirez de Arellano, author of a manuscript entitled Reconocimiento de los estrechos de Magallanes y San Vicente, con algunas cosas curiosas de navegacion . He had participated in the reconnaissance mission referred by the title of the manuscript, and in that book developed same methods and tools for a nautical understood scientifically, and even used a methodology close to modern science, as in refuting the theory about Figueiredo of the linear relationship between longitude and magnetic variation of the needle navigation. This article is based on some conclusions that can get an analysis of the manuscript. It focuses on the exhibition held at the Diego Ramirez same about a useful procedure for pilots of calculating the latitude of a place by the Sun extrameridianas heights, which meant a breakthrough in navigation methods of the time. It also outlines the motivations and geopolitical interests of the Spanish monarchy to promote scouting expedition that made the manuscript and the innovations it contains.

PET-guided biopsy with needle navigation facilitates diagnosis of angiosarcoma in neurofibromatosis type 1

Malignant degeneration frequently arises from preexisting plexiform neurofibroma in patients with neurofibromatosis type 1 (NF1). Image guided biopsy for diagnostic purposes, such as with CT guidance, can be technically challenging in these patients, as CT cannot distinguish malignant from benign areas within the same tumor. Navigation with multi-modality (PET, CT, and ultrasound) image fusion facilitated the successful biopsy and diagnosis of angiosarcoma arising from a pelvic neurofibroma in a patient with NF1. Successful targeting assisted treatment selection in this case. This novel navigation technique may facilitate the otherwise difficult diagnosis of malignancy in patients with NF1.

MO‐D‐144‐01: Ultrasound Guided RT Intervention &amp; Novel Technologies

Significant advances were made over the past decade in ultrasound (US) imaging and new therapeutic applications are emerging. Used alone or in combination with other imaging modalities, US imaging is also well suited for robot‐assisted interventions. This session will feature invited presentations on (1) the use of US and robot for interstitial breast implant high dose rate (HDR) brachytherapy, (2) the possibilities of electromagnetic tracking system for interactive needle navigation, 3D‐printed patient‐specific skewed‐needle template, and co‐robots for interventional brachytherapy, (3), the real time US guidance, dosimetry and treatment optimization for novel HDR brachytherapy such as single fraction partial prostate treatment for early stage disease, and (4) the development of an integrated 3D x‐ray/ultrasound imaging system for on‐board guidance of soft tissue targets for external beam radiation therapy.Learning Objectives:1. Understand the improvements made on ultrasound imaging technology2. Understand the possibilities of real‐time imaging for a wide range of applications3. Identify new applications for medical physicists of ultrasound imaging for image‐guided interventions.Part of this work is supported by NCI R01 CA 161613, and another part by a research contract with Philips Medical Systems.

Abstract No. 382 - High technical success rate for liver needle placement with the CT-guide navigation system

Purpose To evaluate the efficacy of using the ActiViews CT-Guide® navigation system in the accurate placement of needles in liver biopsy and liver ablation. The system allows registration of a CT data set to an optical navigation system allowing free-hand needle placement using a virtual image analogous to CT fluoro. The system easily allows needle placement in off-axial trajectories. Materials and Methods Cohort study of twenty sequential patients undergoing CT guided hepatic needle placement, for either biopsy or thermal ablation, were enrolled in this study. IRB approved. Informed consent. Demographics were captured. Adequacy of needle tip placement was measured. Target parameters such as lesion size and depth from skin were noted. Total navigation time, number of scans performed and radiation dose were noted. Device related adverse events were monitored. All procedures were performed by experienced radiologists. Results Of the 20 patients, there were 7 females/13 males. Average age was 63 (range 43-80 years). All twenty needle placement procedures were technically successful. Average lesion size was 3.3 cm, 3.6 cm for the 14 biopsies biopsies and 1.8cm for the 6 ablations. Lesion depth was 8.1cm on average, 7.2 cm for biopsies and 9.7 cm for ablations. Navigation time was 3.9 minutes on average; 3.3 minutes for biopsies and 5.3 minutes for ablations. Radiation dose, measured as Dose Linear Product, DLP, was 1779 for all, 1675 for biopsies, and 2010 for ablations. There were no device related adverse events in the study group. Conclusion The CT-Guide® navigation system (ActiViews Inc., Wakefield, MA) has proven to be safe and effective in assisting in CT guided needle navigation. Our technical success rate was 100%. The system is easy-to-use after a short learning curve and proved especially useful in situations where lesions are only transiently visible on arterial phase, and in cases requiring multiple ablations. At our institution it has become standard to use this device for almost all ablations and most challenging biopsies.

Spinal Needle Navigation by Tracked Ultrasound Snapshots

Ultrasound (US) guidance in facet joint injections has been reported previously as an alternative to imaging modalities with ionizing radiation. However, this technique has not been adopted in the clinical routine, due to difficulties in the visualization of the target joint in US and simultaneous manipulation of the needle. We propose a technique to increase targeting accuracy and efficiency in facet joint injections. This is achieved by electromagnetically tracking the positions of the US transducer and the needle, and recording tracked US snapshots (TUSS). The needle is navigated using the acquired US snapshots. In cadaveric lamb model, the success rate of facet joint injections by five orthopedic surgery residents significantly increased from 44.4% with freehand US guidance to 93.3% with TUSS guidance. Needle insertion time significantly decreased from 47.9 ± 34.2 s to 36.1 ± 28.7 s (mean ± SD). In a synthetic human spine model, a success rate of 96.7% was achieved with TUSS. The targeting accuracy of the presented system in a gel phantom was 1.03 ± 0.48 mm (mean ± SD). Needle guidance with TUSS improves the success rate and time efficiency in spinal facet joint injections. This technique readily translates also to other spinal needle placement applications.

Freehand Biopsy Guided by Electromagnetic Needle Tracking: A Phantom Study

To evaluate the overall accuracy and time spent on biopsy guided by electromagnetic needle tracking in a phantom compared with the standard technique of US-guided biopsy with an attached steering device. Furthermore, to evaluate off-plane biopsy guided by needle tracking. Three different series of biopsy were performed in a phantom: one with a steering device attached to the transducer without needle tracking, simulating the standard ultrasound-guided biopsy procedure (series 1), one freehand in the scan plane using electromagnetic needle tracking (series 2), and one freehand off-the-scan plane using electromagnetic needle tracking (series 3). The phantom contained spheres of 1 cm in diameter filled with red dye. Each time of the phantom surface was perforated counted as an attempt. 180 biopsies were performed. The mean time spent on each biopsy in series one was 19.9 seconds (SD: 9.1), in series two 34.1 seconds (SD: 17.9) and in series three 34.4 seconds (SD: 14.0). The overall rate of success was: 88 % for in-plane needle-guided biopsy, 87 % for in-plane needle tracking, and 92 % for off-plane needle tracking. No statistically significant difference between the methods was shown. Needle navigation is a potentially valuable tool for image-guided biopsy with an equal rate of success compared with conventional image-guided biopsy. Furthermore, it enables off-plane image-guided biopsy.

Biopsy Guided by Needle Navigation: A Phantom Study

Biopsy Guided by Needle Navigation: A Phantom Study

C-arm cone beam computed tomography needle path overlay for image-guided procedures of the spine and pelvis

The aim of this study is to report our early clinical experience using C-arm cone beam computed tomography with fluoroscopic overlay for image guidance during percutaneous needle procedures of the spine and pelvis. Twelve consecutive patients (four female and eight male patients; mean age, 64years; range, 47-74years; SD ± 7.6years) who underwent percutaneous biopsy of the spine and pelvis for suspected metastasis (n = 12), spondylodiscitis (n = 6), abscess (n = 5) or bone tumour (n = 1) were prospectively included between March 2009 and November 2010. The procedures were performed on the Allura Xper FD20/20 (Philips, Best, the Netherlands) using cone beam computed tomography (XperCT) with the C-arm combined with fluoroscopic overlay for needle guidance. Based on an initial XperCT, entry and target points were defined using dedicated guidance software (XperGuide). The needle path was visualised in various reconstructed planes and could be adjusted when considered necessary. For percutaneous interventions, the entry view (overlay of entry and target point in the bull's eye fashion), the progression view (perpendicular to the entry view) as well as two additional views could automatically be piloted to with the C-arm system. Needle navigation was supported by a biopsy guidance device (Seestar, Radi, Uppsala, Sweden). Correct needle positioning was confirmed with a second XperCT acquisition. Technical success was defined as any target point reached via the planned needle trajectory with a distance of final needle tip within 5mm of the planned target point in any direction. In all 12 patients, target areas could be defined based on XperCT data. In 11 of 12 (92%) cases, the target point was successfully reached on the planned trajectory with a mean error of 2.8mm (range, 0.5-9.4mm; SD, 2.4mm). No peri- or post-interventional complications occurred. XperCT-guided interventions with the XperGuide system seem a safe and reliable tool for percutaneous needle interventions of the spine and pelvis. The advantage of the technique when compared to CT- or fluoroscopy-guided interventions needs to be determined in a comparative study of a larger scale.