Biomedical subjects

Dumitru Mazilu

Publications and source records attributed to Dumitru Mazilu.

7 recordsLinked to original sources

PubMed2006

An evaluation method for the mechanical performance of guide-wires and catheters in accessing the upper urinary tract.

The placement of guide-wires and catheters to gain access to the upper urinary tract can induce undesirable stresses on tissues. Previous studies have characterized the performance of wires and catheters by evaluating their physical properties such as stiffness and friction coefficient. However, the results of these studies do not directly quantify the wire's effects on tissues. Furthermore, the individual physical properties of wires and catheters investigated in previous studies cannot be simply summed up to characterize the behavior of an entire wire/catheter ensemble. This paper presents an objective method for testing guide-wires and catheters that estimates the forces applied by these instruments to anatomical structures during urological procedures. Our model utilizes a computer-controlled test stand that simulates a urological environment by including a tortuous path and a stone obstruction. Experimental results using this model show significant promise in reflecting the performance of guide-wires and catheters measuring the stress exerted upon relevant anatomical structures. Furthermore, due to the modularity of the approach, the model can be easily reconfigured to simulate environments relevant to other medical fields.

Catheterization↗

PubMed2006

Magnetic resonance imaging compatible robotic system for fully automated brachytherapy seed placement.

OBJECTIVES: To introduce the development of the first magnetic resonance imaging (MRI)-compatible robotic system capable of automated brachytherapy seed placement. METHODS: An MRI-compatible robotic system was conceptualized and manufactured. The entire robot was built of nonmagnetic and dielectric materials. The key technology of the system is a unique pneumatic motor that was specifically developed for this application. Various preclinical experiments were performed to test the robot for precision and imager compatibility. RESULTS: The robot was fully operational within all closed-bore MRI scanners. Compatibility tests in scanners of up to 7 Tesla field intensity showed no interference of the robot with the imager. Precision tests in tissue mockups yielded a mean seed placement error of 0.72 +/- 0.36 mm. CONCLUSIONS: The robotic system is fully MRI compatible. The new technology allows for automated and highly accurate operation within MRI scanners and does not deteriorate the MRI quality. We believe that this robot may become a useful instrument for image-guided prostate interventions.

Brachytherapy↗

PubMed2006

Synthetic torso for training in and evaluation of urologic laparoscopic skills.

BACKGROUND: The expanding use of advanced minimally invasive surgical techniques demands more advanced training methods, objective measures of resident performance, and more realistic and anatomically correct training models. MATERIALS AND METHODS: A new synthetic torso for urologic laparoscopy training was developed and assessed. The trainer, Lapman, was based on the Visible Human Model and has the exact shape of a human torso. The torso models the outer shape of the body and the abdominal and pulmonary cavities. Animal or synthetic models of the abdominal organs may be placed in the abdominal cavity. An abdominal wall provides access and seals the cavity and can be replaced after repeated punctures with laparoscopic instruments. The thoracic cavity connects to a pneumatic pump to simulate breathing. In order to render realistic mechanic properties, the torso is cast of materials with elastic properties similar to those of soft tissue and incorporates a synthetic skeleton. These similar mechanical properties and the thoracic insufflation create realistic ventilatory motion simulation. RESULTS: Twenty-five individuals--medical students, residents, and attending urologists--participated in a study comparing Lapman with a standard training box. Lapman presented several advantages over the traditional training box, specifically with regard to internal and external views and the incorporation of a realistically shaped abdominal wall. A significant and recurrent theme was the value of the synthetic wall as a tool to gain a greater appreciation of the importance of port placement. Study participants at all levels of training appreciated that Lapman gives a more realistic approximation of the operative procedure. CONCLUSIONS: The novelty of the trainer consists in its anatomic shape, realistic mechanical properties, and ventilatory simulation. This paper reports on its design, construction, and preliminary tests.

Humans↗

PubMed2004

Overview and fundamentals of urologic robot-integrated systems.

Advances in technology have revolutionized urology. Minimally invasive tools now form the core of the urologist's armamentarium. Laparoscopic surgery has become the favored approach for treating many complicated urologic ailments. Surgical robots represent the next evolutionary step in the fruitful man-machine partnership. The introduction of robotic technology in urology changes how urologists learn, teach, plan, and operate. As technology evolves, robots not only will improve performance in minimally invasive procedures, but also enhance other procedures or enable new kinds of operations.

Equipment Design↗

PubMed2002

System for robotically assisted prostate biopsy and therapy with intraoperative CT guidance.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess the work-in-progress prototype of an image-guided, robotic system for accurate and consistent placement of transperineal needles into the prostate with intraoperative image guidance inside the gantry of a computed tomographic (CT) scanner. MATERIALS AND METHODS: The coach-mounted system consists of a seven-degrees-of-freedom, passive mounting arm: a remote-center-of-motion robot; and a motorized, radiolucent needle-insertion device to deliver 17-18-gauge implant and biopsy needles into the prostate with the transperineal route. The robot is registered to the image space with a stereotactic adapter. The surgeon plans and controls the intervention in the CT scanner room with a desktop computer that receives DICOM images from the CT scanner. The complete system fits in a carry-on suitcase, does not need calibration, and does not utilize vendor-specific features of the CT scanner. RESULTS: In open air, the average accuracy was better than 1 mm at a 5-8-cm depth. In various phantoms, the average orientation error was 1.3 degrees, and the average distance between the needle tip and the target was 2 mm. CONCLUSION: Results of preliminary experiments indicate that this robotic system may be suitable for transperineal needle placement into the prostate and shows potential in a variety of other percutaneous clinical applications.

Biopsy, Needle↗

PubMed2002

Robotically assisted nerve and facet blocks: a cadaveric study.

RATIONALE AND OBJECTIVES: This study was performed to evaluate the feasibility of using a joystick-controlled robotic needle driver to place a 22-gauge needle for nerve and facet blocks. MATERIALS AND METHODS: Biplane fluoroscopy and a robotic needle driver were used to place 12 needles into the lumbar paraspinal region of an embalmed female cadaver (age at death, 98 years). Small metal BB nipple markers (1 mm in diameter) were inserted percutaneously to serve as targets. Six needles were then placed near the nerve root, and six were placed near the facet root. Anteroposterior and lateral radiographs were obtained after each needle placement to assess its accuracy. RESULTS: All needles were placed within 3 mm of the target BB. The average distance was 1.44 mm +/- 0.66 (standard deviation). DISCUSSION: A robotic needle driver can be used to place needles accurately in the nerve and facet regions. Clinical studies are required to investigate the advantages and disadvantages of this system for interventional procedures involving needles.

Aged↗

PubMedDate not supplied

Robotically assisted prostate brachytherapy with transrectal ultrasound guidance--Phantom experiments.

PURPOSE: To report the preliminary experimental results obtained with a robot-assisted transrectal ultrasound (TRUS)-guided prostate brachytherapy system. METHODS AND MATERIALS: The system consists of a TRUS unit, a spatially coregistered needle insertion robot, and an FDA-approved treatment planning and image-registered implant system. The robot receives each entry/target coordinate pair of the implant plan, inserts a preloaded needle, and then the seeds are deposited. The needles/sources are tracked in TRUS, thus allowing the plan to be updated as the procedure progresses. RESULTS: The first insertion attempt was recorded for each needle, without adjustment. All clinically relevant locations were reached in a prostate phantom. Nonparallel and parallel needle trajectories were demonstrated. Based on TRUS, the average transverse placement error was 2 mm (worst case 2.5 mm, 80% less than 2 mm), and the average sagittal error was 2.5 mm (worst case 5.0 mm, 70% less than 2.5 mm). CONCLUSIONS: The concept and technical viability of robot-assisted brachytherapy were demonstrated in phantoms. The kinematically decoupled robotic assistant device is inherently safe. Overall performance was promising, but further optimization is necessary to prove the possibility of improved dosimetry.

Brachytherapy↗