robotics in medical...

25Robotics in Medical

Applications

Chris A. RaanesAccuray Incorporated

Mohan BodduluriRestoration Robotics, Inc.

25.1 Introduction 25.2 Advantages of Robots in Medical Applications 25.3 Design Issues for Robots in Medical Applications 25.4 Research and Development Process 25.5 Hazard Analysis

Hazard Identification • Verification and Validation• Initial and Final Risk Legend • Likelihood Determination• Severity Determination • Risk Acceptability

25.6 Medical Applications Noninvasive Robotic Surgery — CyberKnife® StereotacticRadiosurgery System • Minimally Invasive Robotic Surgery —

da Vinci® Surgery System • Invasive Robotic Surgery —

ROBODOC® Surgical Assistant • Upcoming Products

25.1 Introduction

The use of robots in medical applications has increased considerably in the last decade. Today, there arerobots being used in complex surgeries such as those of the brain, eye, heart, and hip. By one survey, 2285medical robots were estimated to be in use at the end of 2002, and that number is expected to rise to over8000 medical robots by 2006. It is also estimated that medical robots may, in the end, have the largestmarket value among all types of robots.

Complex surgeries have complex requirements, such as high precision, reliability over multiple and longprocedures, ease of use for physicians and other personnel, and a demonstrated advantage, to the patient,of using a robot. Furthermore, all new technologies in the medical area have to undergo strict regulatoryclearance procedures, which may include clinical trials, as outlined by various government regulatoryagencies. In the U.S., the Food and Drug Administration (FDA) has jurisdiction over medical devices. Asmore and more devices get through the regulatory procedures, there will be more and more robots in themedical world.

25.2 Advantages of Robots in Medical Applications

Before one can consider the usage of robots in medical applications, it is important to understand thatmedical applications have unique requirements, different from general, or “traditional,” robot design.Some of the design issues and associated advantages are described below.

1. High precision: Modern robots are demonstrated to be highly precise. The precision range dependson the robot and the application, of course, but it is generally accepted that for a given application,

Copyright © 2005 by CRC Press LLC

25-2 Robotics and Automation Handbook

a robot can be designed to meet or exceed the precision requirements of the application. A typicalindustrial robot has repeatability specifications measured in tenths of a millimeter. A representativeratio of motion in robotic assisted surgery is that a 1 cm movement of a doctor’s hand translates toa 0.1 cm movement of the robotic tool.

2. Heavy payloads: Modern robots can carry heavy payloads over large workspaces, at high speeds,with high precision. Industrial robots are available with payload capacity of a few ounces to over1000 lb.

3. Workspace: Medical robot workspace requirements tend to be significantly larger than industrialneeds because of patient related factors, such as uncertainty in patient location during the procedureand safety requirements. There is an obvious overriding need to avoid any hazard to the patient,physician, and other medical personnel; this drives an exclusionary zone around the patient, doctor,and other equipment that may be attached to the patient. Thanks to the advances driven by industrialapplications, the workspace of most available robots is significant and can be utilized for medicalapplications.

4. High Speed: Most new robots have been designed and optimized for industrial automation, en-abling them to move at high speeds with high precision. The majority of medical applications donot require robots to move at high speeds as these robots are working on a patient. Reassurance,comfort, and safety dictate the robot’s speed in medical applications.

5. Reliability: Industrial robots are designed to work round the clock without stopping; their medicalcounterparts work only a few hours a day. The nature of medical applications is that most of the timeis taken up by other parts of the surgery, such as operating room preparation, patient preparation,and postoperative procedures. The robots actually perform surgeries for only a limited time, around10% of surgery time. The resulting reliability numbers for medical work are excellent, leading tovery limited downtime.

6. Tedium: Most of the medical applications where robots are sought involve repetitive tasks overa very long period of time. Some surgeries last for many hours, during which the operators arerequired to repeat tasks hundreds or thousands of times. Obviously, robots do not have any problemswith tedium.

7. High Quality: Robotic assisted surgery can help a wide variety of doctors perform complex surg-eries with the same high quality previously achieved only by some accomplished surgeons. Addi-tionally, most medical procedures cannot tolerate any degradation in quality due to trembling orunsteadiness of hands. Robotic systems in the operating room can compensate for imperfectionsin the user due to age, fatigue, or other factors, without degrading the quality of care administeredto the patient.

8. Computer control: Robotic surgery is able to capitalize on available diagnostic data to calculate anoptimized approach to treatment. Most modern systems use fusion of multiple imaging modalitiessuch as CT, PET, and MRI.

9. Remote operation: Finally, because robots are typically controlled by computers and/or remoteelectrical signals, the option exists to remotely operate the units over large distances through directdata links, or even over the internet (telerobotics).

People have recognized many of these obvious advantages; therefore, we have seen a considerableincrease in usage of robots in medical applications in recent times. As these advantages are general andapply to many medical procedures, the authors believe that it is just a matter of time before more robotsare employed in automating a variety of procedures, ultimately increasing the quality while reducing thecost of medical care in the future.

25.3 Design Issues for Robots in Medical Applications

Using robots in medical applications presents a unique set of challenges. This section briefly discusses thedesign issues that should be considered in many medical applications.


Robotics in Medical Applications 25-3

1. Safety: Safety of patients and users is the ultimate concern when using robotics in medical applica-tions. In the industrial world, safety is addressed, most typically, by ensuring that humans are notpresent in the robot’s workspace. Considerable precautions are taken so that no one inadvertentlyenters the workspace of a working robot, and if someone does enter the area, the robot is automati-cally stopped. In the case of a medical application, by definition, a human being (the patient) needsto be in the workspace. Moreover, the physician and other medical personnel generally need to bein the workspace as well to attend to other needs of the patient and the surgery. A robotic system,therefore, has to be designed so that it is safe for the patient, physician, and other personnel in theroom while it is effectively operating on the patient.

2. Uncertainty of position: Most medical applications have a higher level of uncertainty in the posi-tion of the target (patient) than their industrial counterparts do. In a typical industrial application,one can expect the workpiece to be aligned and mounted precisely in the same location and ori-entation. In a typical surgery, the patient and the specific organ that needs to undergo surgerycannot practically be located in the same location and orientation. Furthermore, various steps inthe procedure will likely have to be modified and adapted based on the patient’s condition.

3. Fail-safe: It is required that the medical robotic system operates in a fail-safe mode. By fail-safe,one means that if and when any component fails, the system reaches a safe state, thus minimizingchance for injury or death to the patient or other personnel.

4. Power/System Failure: The system needs to be designed in such a way that in case of a power/systemfailure, the physician can move the robot away to keep the patient safe and be able to attend to thepatient.

5. Record Keeping: All records related to an operation need to be kept and protected for future use.This issue has become more acute in recent times with current U.S. and international regulationsregarding patient data privacy. The opposing needs of the system are to maintain confidentiality,while ensuring that the patient on the table matches the program in the robotic system.

6. Regulatory Issues: All design, development, and production activity needs to be done in a con-trolled fashion following the appropriate regulatory guidelines.

The issues outlined above are in addition to the technical issues one has to deal with for any productdesign. It is obvious that these additional requirements add a significant cost in terms of time and resourcesto successfully design, develop, and deploy a product in the field.

25.4 Research and Development Process

It is essential, as well as required (by FDA regulations in the U.S.), that an organization strictly adheresto a process in the design, development, and manufacturing stages of a product. The specificity of theprocess varies from organization to organization, but all the different processes follow good manufacturingpractices (GMP) and good laboratory practices (GLP). See FDA’s document Title 21, Part 820 for theguidance on quality systems regulation. Figure 25.1 shows an example of a research and developmentprocess.

The research and development process shown in Figure 25.1 shows four stages of the development:

1. Requirements Definition2. Concept Development3. Feasibility Studies4. Product Development

While it is important to maintain good documentation throughout each of these stages of development,design control procedures are especially necessary during the product development phase. Please refer toTitle 21, Part 820.30 for guidance from the FDA on design control procedures.



Product Research and Development Process

User Requirements Definition

Collect and review• Market opportunities• Customer expectations• Clinical advice• Safety requirements• Regulatory requirements

Initiate Project

Project Initiation Memo:• Goal statement• Initial requirements

Concept Development Concept Selection

Project Feasibility Plan:• Preliminary requirements• Preliminary design

Evaluate Design Alternatives• Technical challenges/risks• Resource needs• Schedule and costs• Refine requirements• Review and report

Design History File

Product Development

Engineering and Manufacture• Software specifications• Hardware specifications• Design Reviews (PDR, CDR)• Engineering qualification• Initial engineering release• Verification test plans• Human use studies

Commit to Development

Project Management Plan:• Requirements• Feasible design• Cost and schedule

Medical Input

Feasibility Studies

Prototype Development• Draft requirements• Resolve technical issues• Refine schedule• Refine resource needs• Refine cost estimates• Review and report

FIGURE 25.1 An example of research and development process.

25.5 Hazard Analysis

As mentioned in the previous sections, safety is the first and foremost concern of using robots in medicalapplications. To address this issue, a formal hazard analysis is done during the design process. This sectiondescribes a typical hazard analysis (based on EN60601-1-4).

25.5.1 Hazard Identification

Preliminary hazards are identified from

� Requirements specifications� Architecture and design descriptions� Previous hazard analysis results

The preliminary hazard list is updated into the final hazard list by the addition of hazards identifiedduring fault tree analysis. The final hazard list is revised from time to time as the product undergoeschanges.

25.5.2 Verification and Validation

Fault tree analysis (FTA) will be done on the hazards identified. This will identify states within the systemthat could cause a hazard. Recommendations will be made to test these states. Code or design changerecommendations will also be made if necessary.



25.5.3 Initial and Final Risk Legend

The risk codes used in the hazards list initial and final risk columns are composed of a letter indicatinglikelihood and a number indicating severity.

25.5.4 Likelihood Determination

Likelihoods of hazards are defined according to the table below. Entries here follow the EN 60601-1-4suggested rankings for a programmable electrical medical system (PEMS).

ID Likelihood Description

A Frequent Likely to occur frequently or continuously during the product lifetimeB Probable Likely to occur several times during the product lifetimeC Occasional Likely to occur sometime during the product lifetimeD Remote Unlikely to occur during the product lifetimeE Improbable Possible but extremely unlikely to occur during the product lifetimeF Impossible Cannot occur given the current product makeup

25.5.5 Severity Determination

Severities of hazards are defined according to the table below. Entries here follow the EN 60601-1-4suggested rankings for a PEMS.

ID Severity Description

1 Catastrophic Potential for multiple deaths or serious injuries2 Critical Potential for death or serious injury3 Marginal Potential for minor injury4 Negligible Little or no potential for injury

Hazard severities are assigned according to the anticipated severity of a single incident or accident resultingfrom that hazard. In particular, the severity rating does not reflect the possibility that the hazard couldcause multiple incidents or accidents over the life of the product or at multiple product installations. Theseaspects of the hazard are reflected in the likelihood rating.

25.5.6 Risk Acceptability

Acceptability of risk is assessed according the following table:

Likelihood

A - Frequent ALARP Unacceptable Unacceptable UnacceptableB - Probable ALARP ALARP Unacceptable UnacceptableC - Occasional ALARP ALARP ALARP UnacceptableD - Remote Acceptable ALARP ALARP ALARPE - Improbable Acceptable Acceptable ALARP ALARPF - Impossible Acceptable Acceptable ALARP ALARP

4 - Negligible 3 - Marginal 2 - Critical 1 - CatastrophicSeverity Level

ALARP: As low as reasonably practical.



25.6 Medical Applications

As pointed out earlier in the chapter, Robots in medicine offer several potential advantages:

� They do not tire.� They do not become inattentive.� They do not suffer from human “frailties” such as shaking or jittering.� They are more accurate.

Studies have shown that a surgeon’s skill is one of the most significant factors in predicting patientoutcomes. One of the goals of medical robotics is to minimize this difference between surgeons.

In the remainder of this chapter, we review three different products as examples of robotics in medicineas well as provide an insight into new and upcoming medical products. The three products highlightedbelong to the categories of noninvasive surgery, minimally invasive surgery, and invasive surgery in termsof the procedure being automated. We study noninvasive applications in more detail than others, as theauthors believe that noninvasive surgery will bring unique opportunities in advancing the state of medicinein the future.

25.6.1 Noninvasive Robotic Surgery --- CyberKnife®

Stereotactic Radiosurgery System

25.6.1.1 Introduction to Stereotactic Radiosurgery

Radiation has been widely used over many decades to treat cancerous tumors and other malformations invarious parts of the body in a noninvasive fashion. There are two forms of radiation treatments, radiotherapyand radiosurgery. Radiotherapy treats the tumors with low amounts of radiation per session over manysessions, while radiosurgery treats the tumors with high amounts of radiation per session over one or afew sessions. Radiotherapy relies on the differential response of the tumor and the surrounding normaltissue, whereas the radiosurgery relies on very high, ablative doses of radiation delivered accurately to thetumor while minimizing the radiation to the surrounding normal tissue.

Delivering high amounts of radiation into a tumor while minimizing the radiation to the surroundingtissue is achieved by radiosurgery systems by delivering narrow beams from numerous (hundreds) anglesall pointed into the tumor. The cumulative dose in the tumor where all the beams cross will thus bevery high to eradicate the tumor, while the surrounding tissue where the beams are not overlappingreceives low amounts of radiation. This technique was pioneered by Leksell (1951) and Larsson et al.(1958).

Because delivering high amounts of radiation in order to knock out the tumor is the primary focus ofthe radiosurgery, it is important to understand that accuracy immediately becomes a big issue. The errorin the delivery system of this high amount of radiation directly increases the amount of surrounding tissuedamaged in order for the entire tumor to receive the prescription dose.

25.6.1.2 Project Background

In the early 1990s, a project was launched to develop frameless radiosurgery, which, in principle, can thenbe applied anywhere in the body (including brain treatments), as the frame limitation would not existanymore. As described above, radiosurgery is characterized by the following attributes:

1. Narrow beams2. Numerous (hundreds) beams from various approach angles3. High accuracy4. Single or few treatments



FIGURE 25.2 CyberKnife® stereotactic radiosurgery system. (Source: Accuray, Inc.)

25.6.1.3 CyberKnife® System

The CyberKnife stereotactic radiosurgery system, produced by Accuray, Incorporated, of Sunnyvale,California, achieves frameless stereotactic radiosurgery using robotics and image guidance (seeFigure 25.2). The CyberKnife system has the following major components:

1. Linear accelerator (radiation source)2. Six axis robotic manipulator3. Stereo x-ray imaging system4. Patient positioning system5. Computer software

The linear accelerator produces a 6 MeV radiation beam which can be collimated to various sizes (5 to60 mm diameter) based on the size of the tumor to be treated. The linear accelerator is mounted as thetool of the robot manipulator; therefore, it can be positioned and aimed at the patient arbitrarily as per thetreatment needs. Two x-ray sources and cameras are used to monitor the patient, and patient movementsare calculated and communicated to the robot which then compensates for the patient movement. Thetreatment delivered is accurate, frameless, effective, and elegant.

We briefly describe the major components in the following sections.

25.6.1.3.1 Radiation SourceThe radiation source consists of a pulsed electron gun combined with a waveguide that uses microwaveenergy to accelerate the electrons into a tungsten target. The result is a 6 MeV x-ray beam that can becollimated into a diameter as small as 5 mm. This radiation source is known as a linear accelerator and iscommonly called a “linac.” The weight of the linac is approximately 165 kg and must be manipulated bythe robot to accommodate tumor movement.

25.6.1.3.2 Robot ManipulatorAn industrial robot (KUKA KR210), typically used in the automotive industry, is adapted for this medicaldevice. The robot can carry a tool of weight up to 210 kg, with a maximum speed of 2 m/sec and arepeatability specification of 0.2 mm. This robot has a reach of 2.5 m or more which makes it morethan adequate for positioning the linear accelerator to precisely aim at the patient from various differentapproach angles.



25.6.1.3.3 Stereo X-ray Imaging SystemThe imaging system consists of two x-ray sources mounted to the ceiling of the treatment room and a pairof x-ray cameras mounted in a “V”-shaped frame and fixed to the floor. Amorphous silicon detectors areused to provide 20 × 20 cm x-ray images. The distance between the camera and patient is approximately65 cm, which eliminates most of the scatter radiation. The distance between the patient and the x-raysource is approximately 260 cm, which provides the robot ample access to the patient during the patienttreatment.

25.6.1.3.4 Patient Positioning SystemThe patient positioning system provides precise location of the patient relative to the imaging system.

Appropriate location of the tumor and landmarks in the field of view of the cameras, with appropriatex-ray illumination, enhances tracking performance. However, once in position the system remains fixedthroughout treatment. Patient movement during treatment is accommodated by the robot manipulator.

25.6.1.3.5 Computer SoftwareA high-end computer provides software integration to the system. It supports both the treatment planningand the treatment delivery software. The system is designed to have a fixed set of nodes on a sphere,from which treatment beams can be delivered. A treatment plan consists of a dose rate, duration, anddirection at each node. The robot moves sequentially through each of the nodes and delivers the requireddose.

The treatment planning system (see Figure 25.3) allows the physician to specify radiation dose distribu-tions in the tumor and surrounding tissue. The planning algorithm translates this into dose rate, duration,and direction at each of the treatment nodes.

On the day of the treatment, the patient lies on the couch of the patient positioning system. The treatmentplan is selected and the system assists the operator in aligning the patient in the center of the imagingsystem. This is done by acquiring x-ray images using the diagnostic x-ray sources and cameras. Once thepatient is aligned the treatment begins.

FIGURE 25.3 Treatment planning system for CyberKnife®. (Source: Accuray, Inc.)



During the patient treatment, the robot moves the linear accelerator through each beam position andorientation. Before each irradiation, a pair of orthogonal x-ray images of the patient is obtained and themovement of the patient is calculated. This information is transmitted to the robot, which compensatesfor the patient movement before the therapeutic beam is turned on. This process is repeated through allthe nodes to complete an entire treatment.

25.6.1.4 Patient Safety

The system is designed with patient safety in mind, from treatment planning all the way through thetreatment delivery. The treatment planning system limits the use of the robot to its known safe positions(nodes), so the treatment planned by a physician is always guaranteed to be safe during delivery. Further-more, the treatment planning system provides a computer simulation of treatment and automatically flagsany potentially dangerous movements of the equipment close to the patient.

During treatment delivery, the system monitors the robot movement in real time, and if any impendingcollisions are detected, the machine is stopped immediately. Furthermore, an operator is required tomonitor the treatment through multiple video monitors and can issue an emergency stop to the systemwhen any out-of-the-ordinary movements of the system or the patient are observed. Any stopped treatmentcan be resumed and completed with no adverse effects to the patient.

Fail-safe operation of the CyberKnife has also been designed in. For example, any fault condition, eitherdetected by the system automatically or issued by the operator, immediately stops all the radiation andany robotic movement, thus causing the system to reach a safe condition during a failure. Furthermore,the operator can use the pendant to move the robot away in order to attend to the patient, if necessary.

25.6.1.5 System Accuracy and Calibration

A system centerpoint called the isocenter is identified in order to calibrate the installation of the imagingsystem and the robot in the treatment facility. The alignment of the cameras and location of the sourcesplaces the image of the isocenter within 5 mm of the center of both cameras. A calibration process identifiesvariations in location over the face of the camera to account for small variations. The imaging system’saccuracy is better than 1 mm.

The installation of the robot determines the orientation of the user frame which has its origin at theisocenter. The tool frame is identified by measuring the position and orientation of the line from thelaser-mounted coaxial to the therapeutic beam in the linear accelerator. Further calibration involves anautomated process in which the robot illuminates an isocrystal and searches for the position and orientationthat provides the maximum signal. A correction look-up table is maintained by the system. The residualerror of the robot positioning system is less than 0.5 mm.

The total clinically relevant system accuracy, from treatment planning through delivery, is measured byexposing a film cube in a phantom and is found to be within 0.95 mm.

25.6.1.6 Robotic Advantages

Using a robot in the CyberKnife brings distinct advantages to the system. The ability to deliver a beam thatcan originate at an arbitrary point and can be aimed arbitrarily, brings an enormous level of flexibility indesigning the treatments. Complex treatments can be generated that conform to the oddly shaped tumors(see Figure 25.4).

In addition, robotics makes the CyberKnife the only technology that is able to treat a moving tumor.Thanks to the advancement of robotics and computer vision, the CyberKnife is able to track a lung tumoraccurately through the entire breathing cycle to deliver treatments.

25.6.2 Minimally Invasive Robotic Surgery --- da Vinci® Surgery System

As opposed to the CyberKnife system, which is a noninvasive robotic medical device, the da Vinci systemis a minimally invasive robotic system. The term “minimally invasive” in the medical world means that thesurgery is performed with small incisions (also called laparoscopic surgery) in place of traditional surgery.



FIGURE 25.4 The dose radiation and dose distributions are planned on the CT slices directly. Simulation of thetreatment allows verification of the dose distributions. (Source: Accuray, Inc.)

The da Vinci, a product of Intuitive Surgical, Inc., of Sunnyvale, California, brings telerobotics into theworld of medicine. Telerobotics was originally developed to perform remote tasks by the robots. It enablesa human to remain in a safe environment while directing the robots to perform complex and dangeroustasks in a remote and/or dangerous environment.

The da Vinci, being a telerobotic device, is operated by the surgeon remotely (see Figure 25.5). Therobot system is composed of multiple arms manipulating various instruments inserted into the patientthrough tiny ports. One of the instruments is a camera with a light source to see the anatomy as well as thesurgical instruments. The surgeon operates while seated comfortably (away from the patient, yet still inthe operating room) at a console monitoring a 3D image of the surgical field. The surgeon’s fingers graspthe master controls with hands and wrists, and the surgeon’s movements are translated into the actualmovements of the instruments by the robots, thus performing the surgery telerobotically.

FIGURE 25.5 da Vinci® surgery system. (Source: Intuitive Surgical, Inc.)



25.6.3 Invasive Robotic Surgery --- ROBODOC® Surgical Assistant

As a final example in this chapter, we will look at the ROBODOC Surgical Assistant offered by IntegratedSurgical Systems of Davis, California. The ROBODOC system is used currently for procedures that typicallytend to be fully invasive type of surgical procedures—total hip replacement and total knee replacement. Thesystem is designed to aid doctors with hip implants and other bone implants, through more accurate fittingand positioning. The advantage currently offered by ROBODOC system is accuracy, which should translateinto better patient outcomes. According to Integrated Surgical Systems’ own literature, a typical surgicalprocedure without robotic assistance will routinely leave a gap of 1 mm or greater between the bone and theimplant. ROBODOC aids the surgeon in shaping the patient’s bone to match the implant to within 0.5 mm.

The ROBODOC system incorporates a computer planning system combined with a five-axis robot(see Figure 25.6). The robot carries a high-speed end-milling device to do the shaping. One should notethe theme of preplanning, which is pervasive in robotic surgery — given adequate information prior tothe procedure (CT scans, MR scans, PET scans); a good planning component exploits the precision anddegrees of freedom of a robot to offer a better technical option for the procedure.

Follow-up studies on ROBODOC cases support the fundamental thesis of robots in medicine of en-hanced outcomes: better fit and positioning of the implant to the bone (based on x-ray evaluations) withfewer fractures, as one might expect based on better fit and more accurate positioning. With developmentof newer technology, the ROBODOC system offers the potential for performing the surgery through a verysmall incision [Sahay et al. 2004] of about 3 cm compared to standard incision sizes of about 15 cm. Thus,even in the area of joint surgery that is typically an invasive procedure, robotic systems offer the potentialfor reducing invasiveness while maintaining the advantage of precision and accuracy.

FIGURE 25.6 ROBODOC Surgical Assistant System for hip replacement. (Source: Integrated Surgical Systems)



FIGURE 25.7 Artist’s rendering of robotic hair transplantation system. (Source: Restoration Robotics, Inc.)

25.6.4 Upcoming Products

Robotics in medicine has been on the rise. There will be newer products that employ robots in variousdifferent practices of medicine. Two such new products that are in development are described here.

1. Hair Transplantation Robot: A robotic system using image guidance is being developed to performhair transplants. Hair transplantation is a successful procedure that is performed routinely acrossthe world. The procedure involves transplanting 1000 to 2000 individual follicular units from adonor area of the patient (back of the head) to the target area of the patient (bald spot or thinningarea on the head). The procedure is highly tedious, repetitive, and prone to errors due to fatiguein the surgeon as well as the technicians. A robotic system that automates this process is beingdeveloped by Restoration Robotics, Inc., Sunnyvale, California, which will eliminate the tedium,thus enhancing the quality of the transplants (Figure 25.7).

2. Robotic Catheter System: A telerobotic device is being developed to guide catheters in patients.Cardiac surgery has undergone drastic changes in the past decade. There are fewer and fewer openheart surgeries being performed and most of the problems related to the heart are being addressedby delivering the appropriate treatment using catheters. These procedures have become routinein most of the hospitals. However, guiding the catheter through the patient involves tedious workfor the surgeon. Furthermore, in order for the physician to observe the position of the catheter,the patient needs to be monitored using x-rays, which also exposes the surgeon while he or sheis guiding the catheter. Hansen Medical, Palo Alto, California, is developing a robotic cathetersystem with broad capabilities as a standalone instrument or highly-controllable guide catheter tomanipulate other minimally invasive instruments via a working lumen formed by the device. Thesystem has very sophisticated control and visualization aspects to enable an operator to navigateand conduct procedures remotely with high degrees of precision. This system removes the tediumin the procedure as well as enables the surgeon to stay out of the radiation field of the x-ray machine.

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