Towards Design and Development of an MRI Conditional Robot to Enable Curvilinear Transperineal Prostate Biopsy

BACKGROUND

In-bore MRI prostate biopsy offers improved visualisation and detection of significant prostate cancer; however, it is not widely practiced in cancer diagnosis due to its associated costs.

METHODS

This work introduces the first prototype towards a 7-degrees-of-freedom (DOF) MRI-conditional piezoelectrically actuated robotic system for transperineal prostate biopsy. The robot enables needle insertions in the desired trajectories. Kinematic and static models of the active needle as well as automated control of the robot are presented.

RESULTS

It is shown that the controller can force the needle to realize the reference sine and triangular bending angles with an accuracy of 1.78 and 1.88°, respectively, in air. The trajectory tracking capability of the system in free space is shown with an RMS error of 0.86 mm and a standard deviation of 0.36 mm.

CONCLUSIONS

The robot's capability to steer the needle towards target inside a phantom and extract a sample was evaluated.

Closed-Loop Control of a Tendon-Driven Active Needle for Tip Tracking at Desired Bending Angle for High-Dose-Rate Prostate Brachytherapy

Prostate cancer is the second most common malignancy in American men. High-dose-rate brachytherapy is a popular treatment technique in which a large, localized radiation dose is used to kill cancer. Utilization of curvilinear catheter implantation inside the prostate gland to provide access channels to host the radiation source has shown superiority in terms of improved dosimetric constraints compared to straight needles. To this aim, we have introduced an active needle to curve inside the prostate conformal to the patient's specific anatomical relationship for improved dose distribution to the prostate and reduced toxicity to the organs at risk (OARs). This work presents closed-loop control of our tendon-driven active needle in water medium and air using the position feedback of the tip obtained in real time from an ultrasound (US) or an electromagnetic (EM) tracking sensor, respectively. The active needle consists of a compliant flexure section to realize bending in two directions via actuation of two internal tendons. Tracking errors using US and EM tracker are estimated and compared. Results show that the bending angle of the active needle could be controlled using position feedback of the US or the EM tracking system with a bending angle error of less than 1.00 degree, when delay is disregarded. It is concluded that the actuation system and controller, presented in this work, are able to realize a desired bending angle at the active needle tip with reasonable accuracy paving the path for tip tracking and manipulation control evaluations in a prostate brachytherapy.

A Survey of Needle Steering Approaches in Minimally Invasive Surgery

In virtue of a curved insertion path inside tissues, needle steering techniques have revealed the potential with the assistance of medical robots and images. The superiority of this technique has been preliminarily verified with several maneuvers: target realignment, obstacle circumvention, and multi-target access. However, the momentum of needle steering approaches in the past decade leads to an open question-"How to choose an applicable needle steering approach for a specific clinical application?" This survey discusses this question in terms of design choices and clinical considerations, respectively. In view of design choices, this survey proposes a hierarchical taxonomy of current needle steering approaches. Needle steering approaches of different manipulations and designs are classified to systematically review the design choices and their influences on clinical treatments. In view of clinical consideration, this survey discusses the steerability and acceptability of the current needle steering approaches. On this basis, the pros and cons of the current needle steering approaches are weighed and their suitable applications are summarized. At last, this survey concluded with an outlook of the needle steering techniques, including the potential clinical applications and future developments in mechanical design.

A Model to Predict Deflection of an Active Tendon-Driven Notched Needle Inside Soft Tissue

The last decade has witnessed major progress in the field of minimally invasive and robotic-assisted surgeries. Needle insertion, a minimally invasive technique, has proven its efficacy in procedures such as brachytherapy, ablation, drug delivery, and biopsy. Manual needle steering inside tissue is a challenging task due to complex needle-tissue interactions, needle and tissue movement, lack of actuation and control, as well as poor sensing and visualization. Recently, active tendon-driven notched needles, and robotic manipulation systems have been proposed to assist surgeons to guide the needles in desired trajectories toward target positions. This work introduces a new deflection model for the active tendon-driven notched needle steering inside soft tissue for intention to use in model-based robotic control. The model is developed to predict needle deflection in a single-layer tissue. To validate the proposed deflection model, five sets of needle insertion experiments with a bevel-tipped active needle into single-layer phantom tissues were performed. A real-time robot-assisted ultrasound tracking method was used to track the needle tip during needle insertion. It was shown that the model predicts needle deflection with an average error of 0.58 ± 0.14 mm for the bevel-tipped active needle insertion into a single-layer phantom tissue.

Flexible Needle Steering with Tethered and Untethered Actuation: Current States, Targeting Errors, Challenges and Opportunities

Accurate needle targeting is critical for many clinical procedures, such as transcutaneous biopsy or radiofrequency ablation of tumors. However, targeting errors may arise, limiting the widespread adoption of these procedures. Advances in flexible needle (FN) steering are emerging to mitigate these errors. This review summarizes the state-of-the-art developments of FNs and addresses possible targeting errors that can be overcome with steering actuation techniques. FN steering techniques can be classified as passive and active. Passive steering directly results from the needle-tissue interaction forces, whereas active steering requires additional forces to be applied at the needle tip, which enhances needle steerability. Therefore, the corresponding targeting errors of most passive FNs and active FNs are between 1 and 2 mm, and less than 1 mm, respectively. However, the diameters of active FNs range from 1.42 to 12 mm, which is larger than the passive steering needle varying from 0.5 to 1.4 mm. Therefore, the development of active FNs is an area of active research. These active FNs can be steered using tethered internal direct actuation or untethered external actuation. Examples of tethered internal direct actuation include tendon-driven, longitudinal segment transmission and concentric tube transmission. Tendon-driven FNs have various structures, and longitudinal segment transmission needles could be adapted to reduce tissue damage. Additionally, concentric tube needles have immediate advantages and clinical applications in natural orifice surgery. Magnetic actuation enables active FN steering with untethered external actuation and facilitates miniaturization. The challenges faced in the fabrication, sensing, and actuation methods of FN are analyzed. Finally, bio-inspired FNs may offer solutions to address the challenges faced in FN active steering mechanisms.

Teleoperated and Automated Control of a Robotic Tool for Targeted Prostate Biopsy

This work presents a robotic tool with bidirectional manipulation and control capabilities for targeted prostate biopsy interventions. Targeted prostate biopsy is an effective image-guided technique that results in detection of significant cancer with fewer cores and lower number of unnecessary biopsies compared to systematic biopsy. The robotic tool comprises of a compliant flexure section fabricated on a nitinol tube that enables bidirectional bending via actuation of two internal tendons, and a biopsy mechanism for extraction of tissue samples. The kinematic and static models of the compliant flexure section, as well as teleoperated and automated control of the robotic tool are presented and validated with experiments. It was shown that the controller can force the tip of the robotic tool to follow sinusoidal set-point positions with reasonable accuracy in air and inside a phantom tissue. Finally, the capability of the robotic tool to bend, reach targeted positions inside a phantom tissue, and extract a biopsy sample is evaluated.

Design and Experimental Setup of a Robotic Medical Instrument for Brachytherapy in Non-Resectable Liver Tumors

This paper presents a study regarding the design and the experimental setup of a medical robotic system for brachytherapy using tribology analysis. The robotic system is composed of a collaborative robotic arm and a multi-needle brachytherapy instrument controlled using a unified control system embedding a haptic device and force-feedback. This work is oriented towards identifying the technical characteristics of the system components to determine the accuracy of the procedure, as well as using different scenarios for needle insertion in ex vivo porcine liver tissue in order to determine the forces required for insertion and extraction of the needle and the friction coefficient that accompanies the previously mentioned forces. Subsequent to the computation of the friction forces, the normal forces and the wear during the needle insertion are determined with the scope of predicting the lifecycle of some components of the medical device.

Kinematics modelling and dynamics analysis of an SMA-actuated active flexible needle for feedback-controlled manipulation in phantom

Percutaneous needle-based procedures such as prostate brachytherapy demands for accurate placement of the needle tip at target locations. Recently, robotic needle insertion systems have been made available to help physicians in needle guidance and control inside tissue. It is often challenging to obtain an accurate and real-time position of the needle tip in clinical practice using medical imaging techniques. However, this information is vital for closed-loop control of the needles inside tissue. This work presents an SMA-actuated active flexible needle that is controlled inside a phantom without a need for a position sensor or a medical imaging device. The needle tip position feedback is found using shape sensing capabilities of the embedded SMA-wire actuators and a force sensor at the needle base. Three models were characterized and used to estimate needle tip position in real time. The control scheme was then tested on the active flexible needle to track a desired triangular trajectory in a phantom. It was shown that the control scheme presented in this work was able to manipulate the needle in this path with a reasonable accuracy.

HDR Brachytherapy Planning using Active Needles - Preliminary Investigation on Dose Planning

In this study we present a new approach to plan a high-dose-rate (HDR) prostate brachytherapy (BT) using active needles recently developed by our group. The active needles realize bi-directional bending inside the tissue, and thereby more compliant with the patient's anatomy compared with conventional straight needles. A computational method is presented to first generate a needle arrangement configuration based on the patient's prostate anatomy. The needle arrangement is generated to cover the prostate volume, providing accessible channels for the radiation source during a HDR BT. The needle arrangement configuration avoids healthy organs and prevents needle collision inside the body. Then a treatment plan is proposed to ensure sufficient prescribed dosage to the whole prostate gland. The method is applied to a prostate model reconstructed from an anonymized patient to show the feasibility of this method. Finally, the active needle's capability to generate the required bending is shown. We have shown that our method is able to automatically generate needle arrangement configuration using active needles, and plan for a treatment that meets the dose objectives while using fewer needles (about 20% of conventional straight needles) than the conventional HDR BT performed by straight needles.

3D and 4D Printing in the Fight against Breast Cancer

Breast cancer is the second most common cancer worldwide, characterized by a high incidence and mortality rate. Despite the advances achieved in cancer management, improvements in the quality of life of breast cancer survivors are urgent. Moreover, considering the heterogeneity that characterizes tumors and patients, focusing on individuality is fundamental. In this context, 3D printing (3DP) and 4D printing (4DP) techniques allow for a patient-centered approach. At present, 3DP applications against breast cancer are focused on three main aspects: treatment, tissue regeneration, and recovery of the physical appearance. Scaffolds, drug-loaded implants, and prosthetics have been successfully manufactured; however, some challenges must be overcome to shift to clinical practice. The introduction of the fourth dimension has led to an increase in the degree of complexity and customization possibilities. However, 4DP is still in the early stages; thus, research is needed to prove its feasibility in healthcare applications. This review article provides an overview of current approaches for breast cancer management, including standard treatments and breast reconstruction strategies. The benefits and limitations of 3DP and 4DP technologies are discussed, as well as their application in the fight against breast cancer. Future perspectives and challenges are outlined to encourage and promote AM technologies in real-world practice.