Feasibility and Accuracy of a Novel Hands-Free Robotic System for Percutaneous Needle Insertion and Steering.

PURPOSE: To assess the performance and accuracy of CT-guided needle insertion for clinical biopsies using a novel, hands-free robotic system that balances accuracy with the duration of the procedure and radiation dose. MATERIALS AND METHODS: A prospective, multi-center study was conducted on 60 clinically indicated biopsies of abdominal lesions at two centers (Center 1, n=26; Center 2, n=34). CT datasets were obtained for planning and controlled placement of 17g and 18g needles using a patient-mounted, CT-guided robotic system with 5 degrees of freedom. Planning included target selection, skin entry point, and predetermined checkpoints where additional imaging was performed to permit stepwise correction of the needle trajectory. Success rate, needle tip-to-target distance, number of checkpoints used, number of trajectory corrections, procedure duration, and effective radiation dose were recorded and compared between centers. RESULTS: In 55 of 60 procedures (91.7%), the robot positioned the trocar needle successfully on target. In the remaining 5 patients, the procedure was manually performed by the operator due to technical failure (n=3) or patient-related factors (n=2). The average lesion size was 2.8 ± 1.7cm with a lesion depth from the skin of 8.7 ± 2.6cm, and there was no difference between centers. The overall accuracy (needle tip-to-target distance) was 1.71 ± 1.49 (range 0.05-7.20mm), with an accuracy of 2.06 ± 1.45 mm at Center 1 and 1.45 ± 1.52 mm at Center 2 (p=0.1358). Center 1 used significantly more checkpoints (4.96 ± 1.08) and performed target adjustments in 20 of 24 (83%) cases compared to Center 2 (2.77 ± 0.6 checkpoints and target adjustments in 13 of 31 cases, 42%) (p=0.0024). Accordingly, the steering duration from skin entry to the target varied between Centers 1 and 2; 13.1min ± 4.25min vs. 5.7min ± 2.7min, respectively (p <0.001). The average DLP for the entire procedure was 1147 ± 820 mGycm, with a slightly lower average at Center 2 (1031 ± 724 mGycm) compared to Center 1 (1297 ± 925 mGycm) (p=0.236). CONCLUSION: Accurate needle-targeting within an error of 2mm can be achieved in patients using a CT-guided robotic system. The variation in the number of checkpoints did not affect system accuracy but was related to shorter steering times and may contribute to a lower radiation dose. Accurate needle insertion using a hands-free CT-guided robotic system may facilitate difficult needle placement and enhance the performance of less-experienced interventionalists.

Clinical evaluation of a robotic system for precise CT-guided percutaneous procedures.

PURPOSE: To assess accuracy and compare protocols for CT-guided needle insertion for clinical biopsies using a hands-free robotic system, balancing system accuracy with duration of procedure and radiation dose. METHODS: Thirty-two percutaneous abdominal and pelvic biopsies were performed and analyzed at two centers (Center 1 n = 11; Center 2 n = 21) as part of an ongoing prospective, multi-center study. CT datasets were obtained for planning and controlled placement of 17 g needles using a patient-mounted, CT-guided robotic system. Planning included target selection, skin entry point, and predetermined checkpoints. Additional CT imaging was performed at checkpoints to confirm needle location and permit stepwise correction of the trajectory. Center 1 used a more conservative approach with multiple checkpoints, whereas Center 2 used fewer checkpoints. Scanning and needle advancement were performed under respiratory gating. Accuracy, radiation dose, and steering duration were compared. RESULTS: Overall accuracy was 1.6 ± 1.5 mm (1.9 ± 1.2 mm Center 1; 1.5 ± 1.6 mm Center 2; p = 0.55). Mean distance to target was 86.2 ± 27.1 mm (p = 0.18 between centers). Center 1 used 4.6 ± 0.8 checkpoints, whereas Center 2 used 1.8 ± 0.6 checkpoints (p < 0.001). Effective radiation doses were lower for Center 1 than for Center 2 (22.2 ± 12.6 mSv vs. 11.7 ± 4.3 mSv; p = 0.002). Likewise, steering duration (from planning to target) was significantly reduced in relation to the number of checkpoints from 43.8 ± 15.9 min for Center 1 to 30.5 ± 10.2 min for Center 2 (p = 0.008). CONCLUSIONS: Accurate needle targeting with < 2 mm error can be achieved in patients when using a CT-guided robotic system. Judicious selection of the number of checkpoints may substantially reduce procedure time and radiation dose without sacrificing accuracy.

Evaluation of a CT-Guided Robotic System for Precise Percutaneous Needle Insertion.

PURPOSE: To assess overall targeting accuracy for CT-guided needle insertion using prototype robotic system for common target sites. MATERIALS AND METHODS: Using CT guidance, metallic (2 × 1 mm) targets were embedded in retroperitoneum (n = 8), kidneys (n = 8), and liver (n = 14) of 8 Yorkshire pigs (55-65 kg). Bronchial bifurcations were targeted in the lung (n = 13). CT datasets were obtained for planning and controlled needle placement of commercially available 17- to 19-gauge needles (length 15-20 cm) using a small, patient-mounted, CT-guided robotic system with 5° of motion. Mean distance to target was 92.9 mm ± 19.7 (range, 64-146 mm). Planning included selection of target, skin entry point, and 4.6 ± 1.3 predetermined checkpoints (range, 2-9) where additional CT imaging was performed to permit stepwise correction of needle trajectory path as needed. Scanning and needle advancement were coordinated with breath motion using respiratory gating. Accuracy was assessed as distance from needle tip to predefined target. RESULTS: Of 45 needle insertions performed, 2 were unsuccessful owing to technical issues. Accuracy of targeting was 1.2-1.4 mm ± 0.6 for kidney, retroperitoneum, and lung (P = .51), with 2.9 mm ± 1.9 accuracy for liver (P = .0003). This was achieved in 39 cases (91%) using a single insertion. Intraprocedural target movement was detected (3.5 mm ± 2.1 in retroperitoneum and 6.4 mm ± 3.9 in liver); the system compensated for 52.9% ± 30.3 of this movement. One pneumothorax was the only complication (8%). CONCLUSIONS: Accurate needle insertion (< 3 mm error) can be achieved in common target sites when using a CT-guided robotic system. Stepwise checks with corrective angulation can potentially overcome issues of target movement during a procedure from organ deformity and other causes.