Autonomous Medical Needle Steering In Vivo

The use of needles to access sites within organs is fundamental to many interventional medical procedures both for diagnosis and treatment. Safe and accurate navigation of a needle through living tissue to an intra-tissue target is currently often challenging or infeasible due to the presence of anatomical obstacles in the tissue, high levels of uncertainty, and natural tissue motion (e.g., due to breathing). Medical robots capable of automating needle-based procedures in vivo have the potential to overcome these challenges and enable an enhanced level of patient care and safety. In this paper, we show the first medical robot that autonomously navigates a needle inside living tissue around anatomical obstacles to an intra-tissue target. Our system leverages an aiming device and a laser-patterned highly flexible steerable needle, a type of needle capable of maneuvering along curvilinear trajectories to avoid obstacles. The autonomous robot accounts for anatomical obstacles and uncertainty in living tissue/needle interaction with replanning and control and accounts for respiratory motion by defining safe insertion time windows during the breathing cycle. We apply the system to lung biopsy, which is critical in the diagnosis of lung cancer, the leading cause of cancer-related death in the United States. We demonstrate successful performance of our system in multiple in vivo porcine studies and also demonstrate that our approach leveraging autonomous needle steering outperforms a standard manual clinical technique for lung nodule access.Comment: 22 pages, 6 figure

Robotic System Development for Precision MRI-Guided Needle-Based Interventions

This dissertation describes the development of a methodology for implementing robotic systems for interventional procedures under intraoperative Magnetic Resonance Imaging (MRI) guidance. MRI is an ideal imaging modality for surgical guidance of diagnostic and therapeutic procedures, thanks to its ability to perform high resolution, real-time, and high soft tissue contrast imaging without ionizing radiation. However, the strong magnetic field and sensitivity to radio frequency signals, as well as tightly confined scanner bore render great challenges to developing robotic systems within MRI environment. Discussed are potential solutions to address engineering topics related to development of MRI-compatible electro-mechanical systems and modeling of steerable needle interventions. A robotic framework is developed based on a modular design approach, supporting varying MRI-guided interventional procedures, with stereotactic neurosurgery and prostate cancer therapy as two driving exemplary applications. A piezoelectrically actuated electro-mechanical system is designed to provide precise needle placement in the bore of the scanner under interactive MRI-guidance, while overcoming the challenges inherent to MRI-guided procedures. This work presents the development of the robotic system in the aspects of requirements definition, clinical work flow development, mechanism optimization, control system design and experimental evaluation. A steerable needle is beneficial for interventional procedures with its capability to produce curved path, avoiding anatomical obstacles or compensating for needle placement errors. Two kinds of steerable needles are discussed, i.e. asymmetric-tip needle and concentric-tube cannula. A novel Gaussian-based ContinUous Rotation and Variable-curvature (CURV) model is proposed to steer asymmetric-tip needle, which enables variable curvature of the needle trajectory with independent control of needle rotation and insertion. While concentric-tube cannula is suitable for clinical applications where a curved trajectory is needed without relying on tissue interaction force. This dissertation addresses fundamental challenges in developing and deploying MRI-compatible robotic systems, and enables the technologies for MRI-guided needle-based interventions. This study applied and evaluated these techniques to a system for prostate biopsy that is currently in clinical trials, developed a neurosurgery robot prototype for interstitial thermal therapy of brain cancer under MRI guidance, and demonstrated needle steering using both asymmetric tip and pre-bent concentric-tube cannula approaches on a testbed

Expanding the use of real-time electromagnetic tracking in radiation oncology.

In the past 10 years, techniques to improve radiotherapy delivery, such as intensity-modulated radiation therapy (IMRT), image-guided radiation therapy (IGRT) for both inter- and intrafraction tumor localization, and hypofractionated delivery techniques such as stereotactic body radiation therapy (SBRT), have evolved tremendously. This review article focuses on only one part of that evolution, electromagnetic tracking in radiation therapy. Electromagnetic tracking is still a growing technology in radiation oncology and, as such, the clinical applications are limited, the expense is high, and the reimbursement is insufficient to cover these costs. At the same time, current experience with electromagnetic tracking applied to various clinical tumor sites indicates that the potential benefits of electromagnetic tracking could be significant for patients receiving radiation therapy. Daily use of these tracking systems is minimally invasive and delivers no additional ionizing radiation to the patient, and these systems can provide explicit tumor motion data. Although there are a number of technical and fiscal issues that need to be addressed, electromagnetic tracking systems are expected to play a continued role in improving the precision of radiation delivery

A narrative review on endopancreatic interventions: an innovative access to the pancreas

The natural connection between the duodenum and the pancreatic duct enables a minimally invasive access to the pancreas. Endoscopically this access is already regularly used, mainly for diagnostic and even for certain therapeutic purposes. With per-oral pancreatoscopy the endopancreatic approach allows the direct visualization of the pancreatic duct system potentially improving the diagnostic work-up of pancreatic cystic neoplasms, intrapancreatic strictures and removal of pancreatic duct stones. However, the endopancreatic access can equally be applied for surgical interventions. The objective of this review is to summarize endoscopic and surgical interventions using the endopancreatic access. Endopancreatic surgery stands for a further development of the endoscopic technique: a rigid endoscope is transabdominally introduced over the duodenum and the papilla to enable resections of strictures and inflamed tissue from inside the pancreas under visual control. While the orientation and localization of target structures using this minimally invasive approach is difficult, the development of an accurate image guidance system will play a key role for the clinical implementation and widespread use of endoscopic and surgical endopancreatic interventions

Cone-beam Computed Tomography-guided Stereotactic Liver Punctures: A Phantom Study

Purpose: Images from computed tomography (CT), combined with navigation systems, improve the outcomes of local thermal therapies that are dependent on accurate probe placement. Although the usage of CT is desired, its availability for time-consuming radiological interventions is limited. Alternatively, three-dimensional images from C-arm cone-beam CT (CBCT) can be used. The goal of this study was to evaluate the accuracy of navigated CBCT-guided needle punctures, controlled with CT scans. Methods: Five series of five navigated punctures were performed on a nonrigid phantom using a liver specific navigation system and CBCT volumetric dataset for planning and navigation. To mimic targets, five titanium screws were fixed to the phantom. Target positioning accuracy (TPECBCT) was computed from control CT scans and divided into lateral and longitudinal components. Additionally, CBCT-CT guidance accuracy was deducted by performing CBCT-to-CT image coregistration and measuring TPECBCT-CT from fused datasets. Image coregistration was evaluated using fiducial registration error (FRECBCT-CT) and target registration error (TRECBCT-CT). Results: Positioning accuracies in lateral directions pertaining to CBCT (TPECBCT=2.1±1.0mm) were found to be better to those achieved from previous study using CT (TPECT=2.3±1.3mm). Image coregistration error was 0.3±0.1mm, resulting in an average TRE of 2.1±0.7mm (N=5 targets) and average Euclidean TPECBCT-CT of 3.1±1.3mm. Conclusions: Stereotactic needle punctures might be planned and performed on volumetric CBCT images and controlled with multidetector CT with positioning accuracy higher or similar to those performed using CT scanner

Cone-beam computed tomography-guided stereotactic liver punctures: a phantom study

PURPOSE Images from computed tomography (CT), combined with navigation systems, improve the outcomes of local thermal therapies that are dependent on accurate probe placement. Although the usage of CT is desired, its availability for time-consuming radiological interventions is limited. Alternatively, three-dimensional images from C-arm cone-beam CT (CBCT) can be used. The goal of this study was to evaluate the accuracy of navigated CBCT-guided needle punctures, controlled with CT scans. METHODS Five series of five navigated punctures were performed on a nonrigid phantom using a liver specific navigation system and CBCT volumetric dataset for planning and navigation. To mimic targets, five titanium screws were fixed to the phantom. Target positioning accuracy (TPECBCT) was computed from control CT scans and divided into lateral and longitudinal components. Additionally, CBCT-CT guidance accuracy was deducted by performing CBCT-to-CT image coregistration and measuring TPECBCT-CT from fused datasets. Image coregistration was evaluated using fiducial registration error (FRECBCT-CT) and target registration error (TRECBCT-CT). RESULTS Positioning accuracies in lateral directions pertaining to CBCT (TPECBCT = 2.1 ± 1.0 mm) were found to be better to those achieved from previous study using CT (TPECT = 2.3 ± 1.3 mm). Image coregistration error was 0.3 ± 0.1 mm, resulting in an average TRE of 2.1 ± 0.7 mm (N = 5 targets) and average Euclidean TPECBCT-CT of 3.1 ± 1.3 mm. CONCLUSIONS Stereotactic needle punctures might be planned and performed on volumetric CBCT images and controlled with multidetector CT with positioning accuracy higher or similar to those performed using CT scanners

On uncertainty propagation in image-guided renal navigation: Exploring uncertainty reduction techniques through simulation and in vitro phantom evaluation

Image-guided interventions (IGIs) entail the use of imaging to augment or replace direct vision during therapeutic interventions, with the overall goal is to provide effective treatment in a less invasive manner, as an alternative to traditional open surgery, while reducing patient trauma and shortening the recovery time post-procedure. IGIs rely on pre-operative images, surgical tracking and localization systems, and intra-operative images to provide correct views of the surgical scene. Pre-operative images are used to generate patient-specific anatomical models that are then registered to the patient using the surgical tracking system, and often complemented with real-time, intra-operative images. IGI systems are subject to uncertainty from several sources, including surgical instrument tracking / localization uncertainty, model-to-patient registration uncertainty, user-induced navigation uncertainty, as well as the uncertainty associated with the calibration of various surgical instruments and intra-operative imaging devices (i.e., laparoscopic camera) instrumented with surgical tracking sensors. All these uncertainties impact the overall targeting accuracy, which represents the error associated with the navigation of a surgical instrument to a specific target to be treated under image guidance provided by the IGI system. Therefore, understanding the overall uncertainty of an IGI system is paramount to the overall outcome of the intervention, as procedure success entails achieving certain accuracy tolerances specific to individual procedures. This work has focused on studying the navigation uncertainty, along with techniques to reduce uncertainty, for an IGI platform dedicated to image-guided renal interventions. We constructed life-size replica patient-specific kidney models from pre-operative images using 3D printing and tissue emulating materials and conducted experiments to characterize the uncertainty of both optical and electromagnetic surgical tracking systems, the uncertainty associated with the virtual model-to-physical phantom registration, as well as the uncertainty associated with live augmented reality (AR) views of the surgical scene achieved by enhancing the pre-procedural model and tracked surgical instrument views with live video views acquires using a camera tracked in real time. To better understand the effects of the tracked instrument calibration, registration fiducial configuration, and tracked camera calibration on the overall navigation uncertainty, we conducted Monte Carlo simulations that enabled us to identify optimal configurations that were subsequently validated experimentally using patient-specific phantoms in the laboratory. To mitigate the inherent accuracy limitations associated with the pre-procedural model-to-patient registration and their effect on the overall navigation, we also demonstrated the use of tracked video imaging to update the registration, enabling us to restore targeting accuracy to within its acceptable range. Lastly, we conducted several validation experiments using patient-specific kidney emulating phantoms using post-procedure CT imaging as reference ground truth to assess the accuracy of AR-guided navigation in the context of in vitro renal interventions. This work helped find answers to key questions about uncertainty propagation in image-guided renal interventions and led to the development of key techniques and tools to help reduce optimize the overall navigation / targeting uncertainty

IMAGING DI FUSIONE E NUOVE TECNOLOGIE ABLATIVE IN ONCOLOGIA INTERVENTISTICA

Le terapie oncologiche interventistiche stanno entrando sempre più nella pratica clinica quali efficaci terapie alternative o complementari per molte malattie tumorali. Tali terapie, per definizione mini-invasive, sono effettuate sotto la guida delle metodiche per immagine. L’imaging di fusione consente di allineare e sovrapporre in tempo reale le immagini ottenute mediante metodiche diverse, allo scopo di sfruttare al meglio le caratteristiche di ognuna, superandone i rispettivi limiti. La prima fase del progetto ha dimostrato la fattibilità e la accuratezza della guida di procedure interventistiche mediante un sistema di fusione di immagini di tomografia computerizzata e ultrasuoni in un modello ex-vivo. Nella seconda e terza fase del progetto sono state valutate fattibilità e sicurezza di nuove procedure ablative per il trattamento di neoplasie polmonari, in un modello animale in-vivo. Nella seconda fase sono stati trattati con successo e senza complicanze 10 conigli New Zealand White, mediante agoelettrodo ad uncini per fusi. Nella terza fase è stata dimostrata la fattibilità e sicurezza della termoablazione polmonare mediante micro-onde in 10 conigli New Zealand White , paragonando i risultati con quelli ottenuti in un gruppo di 10 animali trattati con la termoablazione a radiofrequenza

CT-Guided Interventions Using a Free-Hand, Optical Tracking System: Initial Clinical Experience

Purpose: The present study was designed to evaluate the geometrical accuracy and clinical applicability of a new, free-hand, CT-guided, optical navigation system. Methods: Fifteen procedures in 14 consecutive patients were retrospectively analyzed. The navigation system was applied for interventional procedures on small target lesions, in cases with long needle paths, narrow access windows, or when an out-of-plane access was expected. Mean lesion volume was 27.9ml, and mean distance to target measured was 107.5mm. Eleven of 15 needle trajectories were planned as out-of-plane approaches regarding the axial CT plane. Results: Ninety-one percent of the biopsies were diagnostic. All therapeutic interventions were technically successful. Targeting precision was high with a mean distance of the needle tip from planned target of 1.98mm. Mean intervention time was 1:12h. A statistically significant correlation between angular needle deviation and intervention time (p=0.007), respiratory movement of the target (p=0.008), and body mass index (p=0.02) was detected. None of the evaluated parameters correlated significantly with the distance from the needle tip to the planned target. Conclusions: The application of a navigation system for complex CT-guided procedures provided safe and effective targeting within a reasonable intervention time in our serie