Journal of Computer Aided Surgery Vol.3 No.3
Abstract：This paper describes a concept of an assistive health－care
robot for holding and carrying a bedridden patient．The robot has multi－dimensional
robot arms using of offset rotary Joints. The characteristics of the arm
are slender Joint shape，and stick－like shaped configuration.These characteristics
are useful for the robot arm insertion between a bed and patient．Pressure
sense sheets are furnished to arms to control arm angles to fit a patient
shape at holding action for painless holding．
KeyWords：Offset joint，Holding Robot Arm，Health－Care Robot Multi-joint manipulator，Co－operative
【Abstract］
Miniaturized prototype of master-slave Hyper Finger applicable for minimal
invasive surgery is developed．By using a couple of the Hyper Finger with
7 D．O.F,smooth control of the surgical toolis verified experimentally．Both
feasibility and problems for clinical application are made clear by in
vivo surgical expenments with anesdletized pig
【KeyWords】
Hyper Finger，Laparoscopic Surgery，Minimally Invasive Surgery，Medical
Robotics，Hyper redundant degrees of freedom manupulator
【Abstract】
We developed improvement Microsurgery System which solved varioussproblems of first prototype of Remote Microsurgery System．And we verified effectiveness of this system by in vivo surglcal experiments which followed the procedure of new operation method we proposed and developed．
Key words：Remote Microsurgery，Decoupled wire drive，Minimally invasive
surgery
Abstract：We have improved the 2D.O.F.bending forceps mmipulator that had
been developed for laparoscopic sulgery.Each D．O．F. of the manipulator
was driven with one motor and onespring in 1D.O.F.In current system，we
used two motors an a tension regulator for each D．O．F．We also studied
a new method for measurement of bending angle with Light Emitting Diode（LED）and
Photo Transistor(PT）.Then we evaluated validity of this rmethod.In the
future we will measure bending angle of forceps and control position with
this.
Key Word:forceps mamipulator，laparoscopic surgery，wire driven，bending angle control，optical sensing
Abstract：Targeting and approaching to a certain point in the brain is
an important method in neurosurgery，and mechanical stereotactic devices
have been nused for this purpose for many years.We recently intrduced a
robotic system "Neuromate"to improve theaccuracy．The robot communicates
with the host computer through a infrared transmitter to obtain three dimensional
information of the patient's brain．The robot arm automatically moves to
target the operation point.It also has fail－safe mechanisms．The concept
of this robot system is excellent，but it has still many problems．It requlres
whole brain scanning with MR or CT scan，special operators，and head fixation．The
motion speed of the robot is not rapid enough resulting in longer time
for operation．Compared with the traditional stereotactic devices，there
are still few advantages in using the robot system in the actual clinical
setting in Japan．This may have to do with the hospital systems in Japan
where they can not afford enough time and man－power．The Neuromate robot
is theoretically a good device but there are many problems to be solved．
Key words：stereotxis，robbotic surgery，neurosurgery
Mechanical support system is needed for minimally invasive surgery，since
it enables precise manipulation of surgical instruments beyond human ability
in a small operation space．In this approach，we are developing micro－forceps
manipulator for neurosurgery．However，since the wire is used，the micro－forceps
cannot perform a precise manipulation．Therefore，instead of a wire，pushing
a rigid body stick bends tip of forceps．Moreover，in recent years，MRI
came to be used for surgical assistance．So it is necessary to make micro－forceps
for MR compatibility．We manufactured the prototype，and evaluated it．
Key words：Neurosurgery，Manipulator，Minimally invasive surgery，MR compatibility
【Abstract】
We have developed a novel system of 4-dimensional motion analysis to
estimate risk of dislocation and daily motion that greatly influences wear
of hip joint for the patients who underwent total hip arthroplasty（THA)．This
system consists of skeletal structure data from CT and motion capture data from
infrared position sensor for each patient．3-D models reconstructed from
CT data was combined with the motion capture data．By using this system，we
analysed 8 patients who underwent THA．The objective motion of this study
was level walking，getting up and down from a chair and climbing stairs．
Average angle from the point of maximum hip flexion to the point of
impingement between skeletal bones or implants was 87±31°for flexion，42±12°for
adduction，and 97 ±35°for internal rotation during level walking，respectively．The
angle was46±17°， 53±12°，and 54±11°during getting up and down from
a chair，and 66±22°，51±13°and 83±31° during climbing stairs．Average
distance of articulating surface movement in one cycle was28士7．2mm for
level walking，40 ±8．3mm for standing up from a chair，and 54 ±12．8mm
for climbing stairs，respectively． More investigation of daily motion
will reveal the safe motion preventing hip dislocation and the daily
motion greatly affecting wear of hip joint in detail，leading to precise
guidance of each patient in postoperative daily motion．
Abstract：We have developed a novel system，Which can analyze the movement
of the patient who underwent total hip arthroplasty（THA）.In total hip
arthroplasty，reducing complications such as dislocating，loosening，or
wearing of the joint are important．However，it is difncult even for a
doctor and also the patient himself to recognize the situation of the artififial
joint and to predict its movement，Therefore，We have created the system
thatcan reveal the motion of the patient's skeleton and estimate therisk
of dislocation or the collision between bones．At first we constructed
the 3－dimensional skeletal model of the patient's lower limb from CT data，Due
to the metal artifact，the model around the artificial hip joint was not
accurate enough to analyze the movement．So，as for the artificial joint，we
replaced the model with the CAD data by using the method of 3－D surface
registration（ICP algorithm）．Then we acquired motion capture data by an optical 3D tracking system（VICON，Oxford Metrics）.Therefore，we could drive the skeletal model corresponding to the captured data．Thus by using this system，we were able to predict the prognosis after the installation of the artificial hip joint．
Keywords：motion analysis，total hip arthorplasty（THA），motioncapture
Abstract：We propose a new concept of a unified system for supporting
both surgical treatment and intrasurgical diagnosis of heart diseases under
a magnetic resonance imaging environment．The system consists of three
main parts：multimodal diagnostic devices（an optical endoscope，an ultrasonic
scanner and a Magnetic Resonance Imager（MRI）as the intrasurgical imagers），an
intrasurgical information support system，and a master－slave manipulator
system．As a part of development，We designed the manipulator system according
to the following requirements；it must have MR compatibility so that the
manipulators and the MRI do not interfere with each other，and it also
must have high maneuverability for anastomosis．We expect that the quality
of treatmentWill become higher by this unined support system．
KeyWords：MRI，MRcompatibility，master-slave manipulator system，heart diseases
Abstract：It is the information-guided stereotaxis assisted by visualization
of medical information hat becoms the next generation system．We performed
90 open MRI surgeries at Tokyo Wbmen's Medical University between March
3，2000 and July 25，2001．Of them，comparisons of the pre-and pos-operative
MR images for malignant gliomas in 22 cases revealed that an average resection
rate achieved 90．3％（the maximum100％，the minimum 80％）．In this article
we describe realtime up-date navigation,augmented reality navigation，three-dimensional
navigation,chemical navigation，information guided navigation system（High
definition visual Computer Aided Surgery System：HivisCAS），and open MRI-guided
surgery that we are developing.
Abstract：We started MR guided surgery using a vertically oriented open
MR system，0．5 T GE Signa SP／i．Since this procedure is now in progress，developments
of new device and software are required.The hand piece for the image plane
navigation system caused artihcts on MR images and its LEDs were frequently
blocked．To soIve these problems，we have developed new assistive device
for the hand piece．A noise fi1ter was installed in the microwave coagulator
to eliminate noises during thermal ablation therapy．MR－compatible endoscopic
system was constructed and utilized in MR-guided surgely. An image navigation
software，“3D Slicer”was installed and modified to combine with real－time
MR image guidance．To increase the safety and availability of this procedure，these
new device and software were quite useful．
Keywords：MR－guided surgery，image navigation，thermal ablation．
Junichi TOKUDA＊，Shigehiro MORIKAWA＊＊，Takeyoshi DOHI＊＊＊，Nobuhiko HATA＊＊＊
＊Department of Mechano－Informatics，Faculty of Engineering，The University of Tokyo
＊＊Molecular Neuroscience Research Center，Shiga University of Medical Science
＊＊＊Graduate School of Information Science and Technology,The University of Tokyo
Abstract－This paper proposes a fast motion correction method for magnet resonance image（MRI）－guided surgery by matching projection data along two axis．The projection data can be obtained by applying one pulse echo without phase encoding，thus making the data acqllisition time much shorter than previously reported volumetric image registration approaches.Cornputing Mutual Information frorn two projections befbre and after the motion canestimate the motion of offset along the two axis and rotation around the other axis．We conducted a set of performance study by applying the synthesized offset to abdominal MR images and used the proposed method to estimate the offset．The results indicated that the method could correct up to approximately 20－30 pixels of offset．The method was also implemented to the 2．0 tesla MRI scanner to successfully prove the applicability of the method in MRI-guided surgery setting．In summery，it is safe to saythat the newly proposed method can perform a real-time motion correction to correct organ motion in MRI-guided surgery.
Key Wbrds：MR－guided surgery，Motion correction，Projection matching
Abstract：There are always some limitations that meet the condition for
catching visual image even common inventions such as cameras or video cameras．Thus
the given images are subordinated to the relation of cause and effect of
an object at the point of filming，and it always makes hidden visual information
under the object．Currently，the method called view－independent scene
acquisition using multiple cameras has been developed，and now we are creating
a new extended filming method to make capable of voluntary viewpoints that
can move during observations．However,most of researches upon the this
methods are pointed to acquisitionof visual information for communication
such as tele-presence．Thus there is no fixed quantity for the object at
the present condition．Then，we focused on time-spacial measurements of
human movement at the maximum of the whole body and developed Dynamic
Spacial Video Camera（DSVC）to analyze it quantitatively．
Keywords：view－independent scene aquisition，4 D image，human locomotion，dynamic spatial video camera
Abstract：Our aim is to develop a simulation system which enableto perform High Tibia Osteotomy planning using real time Computer Graphics（CG）.For this simulation system we developed a suructural model of the knee containing ligaments and meniscus．ln the simulation model，these ligaments and meniscus are respond as elastic obiects according to the moving of knee joint．In this simulation system，the user able to determine the way of High Tibia Osteotomy according to the condition of load on the meniscus．
Keywords：skeletal and muscular model，physical interference，Knee，High Tibia Osteotomy
Abstract：We have aimed to develop a virtual surgery system thatrealizes
to perform surgical maneuvers on elastic organs．And we tried to construct
an elastic organ model by the name of sphere－filled model．This model
is reconstructed by filling patient data with spheres automadcally after
three-dimensional segmentation and its defomation depends on behavior of
each sphere due to external force．Once sphere－filled model was applied
to surface organ model and suited for real-time simulation.In this paper
we describe a method to deform volu,e data by using sphere-filled model．We
adopted a kind of dodecahedron as the form of a mass of voxels assigned
to sphere so it is adjacent to one another without spacc． Furthermore
we modified this model to take the interference between soft tissue and
rigid one to considradon．By these modifications our vittual surgery system
can be loaded with two types of elastic organ model,"surface"and"volume”,and
its function will expand．
Keywords：virtual surgery system，sphere-filled model，volume data deformation
Abstract：Simulation for needle penetration requires the mechanical properties of soft tissue．The viscoelasticity of soft tissue appears in the force of static friction on needle penetration．In this study we proposed a viscoelastic model of soft tissue which includs a non－linear spring．The performance of this model was evaluated by comparing the resistance force of a needle generated computationally by the model with that measured at the invitro experiment with pigis hip muscle．The model could represent both the relaxation of the force at the time the needle stops and the linear reduction of the force along with the needle motion at constant speed．
Keywords：simulation，soft tissue，needle penetration，friction，viscoelasticity
Abstract：A technique for intra－operative non－rigid registrationwas
developed aimed at suppport of liver surgery.In the method，a liver model
constructed pre－operatively including internal vasculature is deformed
and is registered to intra－operative liver surface data obtained by using
a range sensor．In addition to geometric modal representation for fast
deformation basedon free－form deformation，physically－based modes were
imported for the purpose of improving registration accuracy．
Keywords：free－form deformation，finite element method，modal analysis，and non－rigid registration
Abstract：Surgical navigation for abdominal organs has difficulties，such as dynamic deformation，compared with other organs （i.e.brain，bone）.Organ deformations prevent surgical navigators from performing accurate navigation based on preoperative information.We are studying on a method for deforming preoperative organ models so that the models are matched to intraoperative shapes．The method is based on the ICP（iterative closest point）algorithm and modal representation of shape deformation.In this paper;we describe preliminary experiments for rigid parameter estimation in the entire registration process，by using range data andsurface model reconstructed from X－ray CT of a liver phantom．
Keywords：surface measurement，ICP algorithm，range data，and registration error．
This paper describes the development of mixed reality type 3－D display system.This system is made up of 3－D video－monitoring of the surgical field and 3D images which are reconstructed by preoperative MRI／CT data．Projected images of tumor，bile duct and the main pancreatic duct can be observed on the real time video monitor.This mixed reality system enable surgeon to perceive the tumor which is actually invisible in solid organ，such as liver and pancreas．
Abstract：Our objective is to evaluate the accuracy of an augmented reality
system for laparoscopic surgery．In this system，themagneto－optic hybrid
sensor which was combined primary optical sensor with secondary magnetic
sensor by tracking the latter with the former was used．Accuracy of the
optical sensor depends on the layout of markers attached to measurement
objects from its measurement method，which affects measurements with the
secondary sensor．In order to evaluate the effects of the layout of markers
on the overall accuracy of the system，we made experiments using Monte
Calro simulation．As a result，the overall accuracy was about 3 mm under
theavailable configuration in the operating room．Attaching more marker
or using more accurate prlmary sensor，the accuracy of about 2 mm was achieved．
Keywords：Augmented reality，Hybrid sensor，Accuracy evalllation，Computer
assisted surgery，Monte Carlo simulation
Abstract
In order to solve the problem for identifying the tip position oflexible fiber scopes under the endoscopic surgery，we propose an image association system.The proposed system is realized by combining complex－valued associative memories with a 2－dimensional discrete Fourier transform，for facilitatiny rotation－invariant image association.Simulation results using intracramial images observed through endoscope are also presented.
High－Intensity Focused Ultrasound（HIFU）has the potential to provide
a valuable method for minimal invasive liver cancer treatment because of
its thermal ablation effbct．For successful HIFU therapy，we require accurate
targeting and treatment monitoring．During this treatment，3D ultrasound
image is effective for operator to irradiate HIFU to liver cancer．We integrate
HIFU applicator and ultrasound probe rotating unit mechanically so as toacquire
3D volume dataset based on 2D scanning rotating unit with stepping motor．The
current 3－dimensional visualization method enables for both HIFU focal
point and target tissue to be displayed in the same spatial coordinate，Therefore，operator
can acquire overall 3D information of liver cancer and HIFU focal point，and
can be considered to support liver cancer．
Keywords：Liver Cancer，High.Intensity Focused Ultrasound（HIFU），3D Ultrasound Image
【Abstract】
In this study，we assessed the change of lower limb alignment inrelation to preoperative and operative lower limb rotation using3D CT simulation program for High Tibial Osteotomy（HTO）．The change of femorotibial angle（FTA）in preoperative radiography，between the position of lO°internal rotation and lO° external rotation,was 4．1° and the change of hip－knee－ankle angle（HKA）was 1．9°．The lower limba lignment of preoperative radiography was influenced by the position of lower limb rotation．The change of FTA was larger than that of HKA．In closed wedge osteotomy of HTO，the change of FTA was0．4° and of HKA was 0．3° by 20°rotation at a bone cutting surface．A wedge bone was resected and the distal bone fragment was reattached to the proximal bone fragment at the proximal tibia in the closed wedge osteotomy，the change of FTA was 0．9° and of HKA was 0・4°by the 20°rotation of the distal bone fragment．Both the changes of FTA and HKA was within 1°，so the lower limb alignment was not innuenced by rotation of bone cutting surface and reattachment of distal bone fragment in closed wedge osteotomy．
【Keywords】 high tibial osteotomy，surgical planning，3D simulation program，FTA，HKA
Abstract：This paper presents the use of volume rendering in theprocess of camera motion tracking of real endoscope and comparison of its performance with the method using surface rendering．We have already proposed a method for tracking flexible endoscopebased on image－based registration between real and virtual endoscopic images．To reduce the computation time during the tracking，we generated a virtual endoscope image by using conventional 3－D graphics hardware．However，in the surface rendering method，several artifacts，which occurred during the traingulation process and are not observed in volume－rendered images，affected the tracking performance．In this paper we replace the surface renderig with the volume rendering in the process of generating virtual endoscopic images. We employ fast software volume rendering method developed by authors’group.The result showed result showed that utilization of volume rendering improves the performance of tracking significancantly.
KeyWords：virtual endoscopy，camera motion estirnation，endoscope navigation system，volume rendering，surface rendering
【Abstract】
Multi－detector CT（MD－CT）allows shorter acquisition times，greater coverage，and
superior image resolution.MD－CT enable us to observe abdominal 3－D image
more precisely．In this study，we presented 3D－CT images for pancreas
tumors of three patients．MD－CT images were useful for difference diagnosis
of pancreas tumors and for recognition of nutrient artery．
Keywords：Multi－detector CT，Pancreas Tumor
Abstract：A high-speed image processing system that superimposesthe real，intuitive 3－D image for medical diagnosis and operation was developed．This system creates 3－D image based on the principle of integral photography，named “Integral Videography（Ⅳ）”，which can be observed following the operator's movement of the field of vision via a half－mirror as if they could be seen through the body．Moreover，a high－speed image processing method was used for calculating a high quality integral videography．Because of the simplicity and the accuracy of real－tlme prqjected point location，this system will be practically usable in the medical field by introducing a display device with higher density．
KeyWords：integral videography，high quality，image processing，integral photography
［Abstract］
Background Recently，virtual operation planning and navigation systems
have been introduced in the field of neurosurgery and orthopedic surgery.
We report here the beneficial effects of 3－dimensional（3D）visualizalion
on hepatic venous reconstructionin Living Donor Liver Transplantation（LDLT）using
right lobe graft.Method. 3D－image reconstruction of the liver was rendered
with 3mm－slices of helical computed tomography（CT）data，using zioM900（Zio
Software Inc.，Tokyo，Japan）.In order to understandthe anatomy of the
donor’s vessels and design an operation plan，an image of the vessels
in and around the liver was constructed.ResulLs.The 3D image demonstrated
two short hepatic veins nextto the right inferior hepatic vein（RIHV）as
well as a large RIHV.The 3D image showed a more precise diameter of the
right hepatic vein（RHV）and the RIHV and a more accurate distance between
the two hepatic veins than did images measured by 2－dimensional（2D）－CT
.This preoperative information allowed the donor surgeon to dissect inferior
vena cava（IVC）and hepatic veins with reduced blood loss，due to reduced
risk of irjury to the blood vessels．The 3D image revealed that both the
RHV and the RIHV branched off at the same angle from cylindrical IVC.Preoperative
planning based on this information secured smooth anastomosis．Conclusion.3D
visualization is useful for hepatic venous reconstruction of the recipient
as well as for donor surgery in LDLT using right lobe graft．
KeyWords：Preoperative planning”visualization
Abstract：We present the work in progress prototype of an accurateimage overlay guidance system for accurate placement of biopsy（orother kinds）needles into patient's body under quasi-acquired image guidance，inside the gantry of a CT scanner．The image overlay system is mounted directly on the CT scanner，and consists of a seven degrees-of-freedom passive mounting arm，a 2D flat LCD display，and a light brown acrylic plate as a half mirror．The position of the display and a half-mirror are registered to the image planeof the CT scanner with a simple triangle registration marker．Once registered，the surgeon takes a transverse image and sends animage via DICOM，and sees overlaid slice image accurately appearing inside the patient to control the intervention in the scanner room．The complete system fits in a carry on suitcase（except the mounting adapter），with easy calibration，and does not utilize vendor-specific features of the CT scanner．
Keywords:Image Overlay,Augumented Reality,X-lay CT
【Abstract】
Virtual Endoscope System consists of a miniaturized haptic mechanism to provide force sensation to the doctor，micro computer and LCD display．Allof these components are built in tower-type computer case and implemented to simulate large deformable intes－tine and endoscope．
＜Abstract＞AIMS：Virtual endoscopy is a new method of diagnosisusing computer processing of three－dimensional images data sets．However,there are few reports about the clinical application of virtual endoscopy for the pancreas.In this study，we evaluated the feasibility of surface－rendered magnetic resonance virtual endoscopy for pancreatic tumor.
METHODS：Twenty－six cases of panreatic cancer and fourteen cases（21 lesions）of Intraductal papillary mucinous tumor of pancreas（IPMT）were studied．Twelve patients with pancreatic cancer and five patients with IPMT underwent surgical resection of the pancreas．MRI data were acquired with a 1．5－T clinical imager（Signal．5；GE Medical Systems，U．S．A）．We used a multislab single shot fast spin－echo sequence．Section thickness was between 2 and 3 mm in the coronal plane．Three－dimensional reconstructed images and virtual endoscopic images were generated with Advantage Wndows by GE．
RESULTS：Virtual endoscopic images could be generated in 20 patients with pancreatic cancer（76．9％）．In these cases， we could observe the inner surface of the pancreatc duct and the stricture from not only the pancreatic head but also the pancreatic tail．Clear virtual images could not be generated in 6 cases．We were able to divide the 20 cases in which images could be generated into groups according to the appearance of the stricture．Theedge of the stricture appeared to be protruding in 4 cases（15.44％），and appeared polygonal in 13 cases（50．0％）．In 3 cases（11．5％），we recognized the existence of a stricture，but thedetail of the stricture was unclear.And virtual endoscopic images of IPMTs could be generated in 19 lesions of 21 lesions（90．1％）．We divided the 19 lesions into 3 groups according to the tumor size.8 lesions belonged to the small-size group（＜2cm），5 lesions belonged to the middle－size group（2～3cm），and 6 lesions belonged to the large－size group（≧3cm）．In the small－size group，inner surface of all lesion appeared smooth，3 lesion appeared rough（60％）in the middle－size group，4 lesion（66．7％）appeared rough in the large－size size group．There was
a tendency that inner surface of cystic lesions was more rough in proportion to its size．3 lesions of IPMTs werw intraductal adenocarcinoma．Inner surface of these 3 lesions were rough．
CONCLUSIONS：Virtual endoscopy caused minimal discomfort compared to real endoscopic examination，and it can access cystic lesions and the pancreatic duct behind the stricture．It is concludedthat virtual endoscopy for pancreatic tumor has potental clinical utility.
Abstract：We have been developing some virtual surgery systems using force
feedback devices.The system enabled to simulate surgical manipulation with
tactile sensations．However,the user could not immerse to virtual surgical
space because of the way of presentation of simulation results using conventional
computer display and head mount display.Then，we developed a new surgical
simulation system composed of a large prqiection display with a high resolutionand
a large field of view, an elevator which the user stands on，force feedback
devices and a graphic workstation.
Keywords：Virtual surgery，surgical sirnulation，virtual reality
○星野好昭 森健策＊ 末永康仁 鳥脇純一郎
名古屋大学大学院工学研究科
＊名古屋大学難処理人工物研究センター
Abstract This paper describes an improved method for generating a virtual
pathological specimen based on deformation of 3－D CT image．In the previous
method，the cutting line of organs cannot be inputted freely because the
cutting line is constrained on edges of the patches．Since a virtual pathological
specimen has only the information of the difference in height with the
organs surface，the fold regions can not be observed clearly on extended
images．We propose the methods to input free cutting lineand enhanced fold
regions on virtually stretChed organ images．The proposed methods were
applied to 3－D abdominal CT images，and the result showed that by the
proposed method free cutting lines could be given and the fold regions
of virtual pathological specimen could be observed more clearly．
Keywords：Virtual pathological specimen，3－D abdominal CT image，stretched organs image，stomach
Abstract：Force feedback is one of the most essential functions in surgical training．To avoid unnecessary and inJurious force to the organs in OR，trainees must precisely know for the mselves how much force they give in handling surgical tools．Our goal is to develop an ESS training system that quantitatively evaluates the trainee's basic surgical skills．In this paper,we presentan ESS training system with 6 degree-of-freedom（DOF）force sensor for surgical skill evaluation．
Keywords：surgical training，endoscopic sinus surgery
Abstruct：This paper describes a method for tracking the camera motion
of a real endoscope for the endoscope navlgation system．The proposed method
estimates the 3D camera motion using opticalflow analysis and image－based
registration．We estimate the camera motion（translation and rotation）roughlyfrom
the measured optical flow，and then determine the camera position by image－based
registration．We applied the proposed method to three cases of real endoscopic
videos and X－ray CT images．The experimental results showed that the proposed
method could estimate the motion satisfactorily．
Keywords：endoscope navigation，virtual endoscopy，registration of endoscope image，epipolar
Abstract：The newly developed computerized computer enhanced surgical system"da Vinci”has been used to perform cardiac operations and digestive surgery and gynecological operations，and it was found to be safe and efftctive in Europe and America．In our department，we have used this system for digestive surgery．A 45years－old Japanese man，who had undergone distal partial gastrectomy one year ago，was revealed superficial esophageal cancer
by endoscopic examination．Five port sites for two assistants’arms，two
da Vinci’s arms and camera were made．Middle and lower esophagus was easily
and smoothly dissected from mediastial tissues with the advantage of da
Vinci arms’flexibility．Because of adhesion of abdominal cavlty due to
previous operation．laparoscope has not been used abdominal procedure．The
computer enhanced surgical system "da Vinci”enabled our surgeons
to do the safe and minimally invasive operation and will open the men field
in endoscopic surgery．
Keywords：esophageal cancer．esohagectomy．computer enhanced surgical system
Abstract：The purpose of this study is to evaluate clinically the accuracy
of femoral canal preparation using the ROBODOC system.Sixty－eight cementless
total hip arthroplasties（THA）were performed using the ROBODOC system
in sixty－four patients.The meanage of the patients at the time of the
operation was fifty－eight years（range，twenty－seven to eighty－one years）．A
VerSys femoral component（Zimmer）that has two design variations of theproximal
metaphysis（both STD and LM）was inserted．Preoperatively，after pin implantation，CT
images were taken.Preoeplative planning was made on the workstation（ORTHODOC）with
the CT data．After registration based on two locater pins，the robot milled
the inside of the femoral canal according to the plan.Surgeons inserted
and impacted the femoral component manually.CT images were taken again
a month after surgery.
Anteroposterior and lateral synthetic radiographs of the proximal femur and axial images of the femur at five levels were reconstructed from both preoperative and postoperative CT data using the ORTHODOC.The synthetic radiographs and axial images at the five levels were evaluated for fit and fill.The synthetic radiographs were also evaluated for alignment of the femoral component.The results showed that the differences in fit，fill，and alignment were very small between the preoperative plan and postoperative images.The robot can mill the femoral canal accurately clinically as surgeons planned preoperatively.
Keywords：ROBODOC，Clinical accuracy evaluation，Femoral canal preparation
【Abstract】
A master－slave manipulator，da Vinci were introduced to thoracoscopic
surgery in patients with mediastinal masses．In two patients，thymoma and
bronchogenic cyst were completely and safely extirpated．There were nocomplications．The
computer－enhanced thoracoscopicsurgery would be well indicated for non－invasive
mediastinal tumor．
Key Words: Master－slave manipulator， thoracoscopic surgery，mediastinal tumor，computer－enhanced surgery
Abstract：We report a case of gastric devascularization for the gastric varix assisted with a computer－enhanced surgical system“da Vinci TM”．It was successfully completed with no complication．In the operation we could perform gastric devascularizaionsafely and smoothly by tremor removing function and viewing 3D irnaging of the vascular system．Two weeks later，gastrointestinal fiberscopy showed the gastric varix reduced in size．In conclusion，gastric devascularizaton assiste dwith "da Vinci TM "can be a safe and effective therapy for the gastric varix．
Keyword：Computer－Enhaced Surgical System“da Vinci TM”，Gastric devascularization，Gastricvarix
Radiofrequency Ablation（RFA）における
Abstract：Radiofrequency Ablation（RFA），using ultrasound guidance to
insert an electrode delivering radiowaves and heat the tumor,is generally
being performed as a liver neoplasm therapic procedure these days.In RFA
in dealing with large or plural tumors，RFA electrode needles are inserted
more than twice for their limitation of their ablation range，which often
leads to the recurrence of incompletely ablated tumors．In these cases，microbubbles
made in the firrst ablation，Which behave as artifacts in the ultrasound
images，can prevent the successive insertions of electrode needles from
being inserted correctly．Therefore we propose the developmentof a navigation
system for RfA based on computer followed with the preoperative information.The
system mainly consists of three－dimensional optical tracking device to
get the information about the position and thep osture of the inserted
electrode needleand a personal computer to provide navigating information
to the surgeons．
Abstract：In this paper we report a new implant lens power prediction method using computer－simulated ocular optic analysis with skew ray tracing．A postoperative refractive power of the eye could be predicted by preoperative optic measurements，curvatureof anterior cornea surfaces，corneal thickness，corneal width，curvatures of anterior and posterior implant lens，lens thickness，and axial length．201 lays run through into the eye were simulated on each optic layer by skew ray tracing，the optimal implant lens was automatically estimated．The proposed method perfbrmed better than SRK／T and SRK－Ⅱdoes．Mean absolute spherical equivalent error of this method was 0．2928 diopter（D），where SRK／T0．4790 D and SRK-Ⅱ0．9174 D on N＝10 patients．Under 土 0．5000 D error appeared 8／10 in this method，6／10 in SRK／T，2／10 in SRK－Ⅱ．This method had real anatomical structures andgave accurate simulation of light courses in the eye，where SRK／T and SRK－Ⅱ uses some experimental modifications and approximations．
Abstract：A computer－assisted navigation system was initially developed to provide neurosurgeons with an accurate guidance during surgical procedures．Endoscopic sinus surgery（ESS）is a common technic to the chronic sinusitis and cystic desease，but it causes sirious complications such as intracranial penetration and loss of vision．We would report the application of navigation system to theESS for more accurate and safty surgery and reducing complications．Up to now，we have used this system to the 80 patients with chronic sinusitis and maxillary cyst．By using an optical navigation
system（Evans：Tomiki Medical Instruments Co．Ltd．Japan），we could be
guided with an accuracy of about 0．8 mm through the critical point of
sinuses such as orbital wall，ethmoid tegmen and optic canal．Based on
our experiences，this system has the potential to make more accurateand
safty operation and particularly to improvethe surge's confidence．
Keywords：navigation system，endoscopic sinus surgery
Abstract：In this paper we described a method of puncture the hepatic tumor using a 0．5 Tsuperconducting MR system“SIGNASP／Ⅰ”（General Electric Medical Systems，USA）．3D Slicer（Harvard Medical School，Boston，USA）is helpful for navigation as well as to demonstrate the tumor margins to achieve a complete and safe microwave ablation of hepatic tumor．
Keywords：Navigation system，Open MR system，3D Slicer
Abstract
We developed intraoperative laparoscopic 3－dimensional（3D）echoic image
using the information of 2－dimensional echo and image analzing system（SAS－200）．The
principle of SAS－200 is that magnetic field sensor，whish is setting on
outer position of laparoscopic echo probe，recognizes the position of the
probe as 3D coordinatation.This method was adopted to the patients with
liver tumor．Using this method，the relation between a main tumor and feeding
vessels was visualized as 3D－US image although the image was worse than
open 3D－US image．Inspite of some problems，a laparoscopic 3D－US was
useful to make an accurate navigation forliver surgery．
High Intensity Focused Ultrasound（HIFU）is expected as one of the least minimally invasive thermal abaltion therapy，since it is applied without any needle puncture or invasive procedure，byfocusing the ultrasound from an eXtra－corporeal spherical transducer.Since 1995，We have studied HIFU，and finally developed a new HIFU apparatus，which can be applied intra－operatively by surgeons with its handheld applicator．Our improvement of HIFU are 1）Cavitation Suppression Technique that could reduce the micro－bubble formation and makeaccuracy ablation，2）Phased Array Drive by unbalanced checker method that enlarge the ablation area to 10x10x15 mm ／shot，3）Intermittently Imaging Methd that could observe US image by avoidance of noise from HIFU and 4）manufacturing the HIFU Generator and Handheld Applicators．All works well in animal expenments. 12 cases of the pnmary and secondary liver tumor with various kinds of background of liver disorder；normal，fatty changed，fibrotic and cirrhotic livers were treated by our HIFU apparatus pnor to surgical removal.Histo－pathologlcal examination of surgical specimens showed complete ablation of the tumors．
Abstract：Interface of the electric surgical unit was investigatedfrom
the view of population stereotypes in this paper．The cognitive integrity
of the interface design was generally favorable，but more quantitative
study on the effect of electric cautery is required for the user-friendly
design of power controller of electric surgical unit．Cognltlve investlgation
is essential for the designof ME devices．
Keywords：Electric surgical unit，Man－machine interface，Population stereotypes
【abstract】
We proposed and developed new type of micro valve for micro pneumatic drive．By
using this valves，we produced safety active catheter of micro pneumatic
drive．Moreover we betterment and small-sizedthis valve and bellows of
joint．High safety and good drive performance were verified experimentally．
【Keywords】
Minimally invasive surgery,Micro active catheter，Band pass valve，Pneumatic
actuator
Abstract：A new device to harvest human bone marrow cell（BMC Harvester）for
the bone marrow transplantation is presented on this research．By using
this device，bone marrow is harvested from donors within minimal puncture．Additionally，the
time needed to carry out BMC harvesting and contamination of T cells can
be minimized．
In this paper，we developed an experimental model of BMC Harvester for femora．The device is inserted intc madullary space from greater trochanter，discharge physiologlcal saline and aspirate bone marrow.We found that the device can be inserted into madullary space of the pig femure asily and harvest a phantom of bone marrow．Farthe consideration especially about whether this equipment can harvest stem cells should be considered through experiments of laboratory animals．
KeyWords：bone marrow transplantation，minimally invasive surgery，bone marrow harvesting device
【Abstract】Today surgeons cut the bone with a surgical saw in an operation of Rotational Acetabular Osteotomy（RAO）．However，lots of difficulty is inevitable when cutting the part which is not visible.The method which uses ablation of the bone tissue bylaser as an alternative of the current method is studied，and ithas many advantages，such as being able to cut arbitrary parts exactly and not giving vibration to a bone.In this paper，we investigated the state of a cutting plane and the cutting speed using the Er：YAG laser widely used for dentistries.
When cooling water was used，there was no denaturation accordingto heat，on any organization which constitutes a bone．It was cut evenly，and the ablation depth was so much enough to under gothe operation of RAO．Surgeons can undergo an operation safely，without blocking bone tissue reproduction by using Er：YAG laser．
【Keywords】Rotational Acetabular Osteotomy（RAO），Er：YAG laser，ablation
Abstract：In this paper we describe a method of border marking on brain tumors by laser． It is considered that the accurate recognition of the border on malignant brain tumors and normal tissue in enucleation make advantage of survivalrate．We propose touse a λ＝2．8 μm micro－laser which can perform less invasive ablation on living tissue，as a marking equipment．From our resent experiment，the micro－laser could form a marking line on pigbrain surface by ablation process with less damage．
KeyWords：λ＝2．8 μm，micro－laser，brain tumor，border marking
Abstract：To understand the relationships between stress and saturation of oxygen（SO2）in the retracted brain tissue，animal experiments using piglets were carried out.In the expenment，an indentor was pushed into the cerebrum.The indentor was made from ablack painted block of Plexiglas and optical fibers were built in．The force from the cerebrum were measured with a load cell and SO2 of the brain tissue were measured with a tissue oxygen monitor，and both were measured simultaneously．The decrease of SO2with increasing stress in the tissue was observed during the pushing．
KeyWords：hemoglobin，oxygenation monitor，spatially resolved spectroscopy
Abstract：In this research，we calculated the shape of a constraint sucker for soft tissue deformation during minimally invasivesurgery，especially needle insertion．When the load actson the living soft tissue，the transformation of the skin produces the highest influence on the transformation of the entire soft tissue．Therefore，the shape of the constraint sucker to causea high stress in the skin beforehand was considered．It has been understood to be able to cause a high stress in the skin by increasingthe number of suck parts．The simulation of the sucker and the skin is expanded into an overall simulation including needle insertion and the method of designing the constraint sucker will be established in the future．
Keywords：Minimally invasive surgery，needle insertion，constraint sucker，FEM
Abstract：Real－time update navigation uses positional informtion in intraoperative Open MRI in real time，and is being high lighted in the world as a method of solution for a brain shift．Butthen there are many cases that the stereotactic approach enablesmore accturate operation，since it is important for neurosurgeryto approach to the lesion simply and easily ．So we have develoPed MRI－guided Hitchcock stereotactic surgery frame provided with receiver coil fo rintraoperative Open MRI．This stereotactic surgery frame omits time to attach and remove the coil when shooting MRI imges，and the optimzation of the process in MRI can be attemped．
Keyword：intraoperative Open MRI，MRI－guided stereotactic surgery frame，receiver coil
Abstract：We present a ner method for estimating the 3-D positionof the endoscope and the 3-D motion of the forceps from endoscopic image sequence.The proposed method requires no additional optical /magnetic 3-D sensor systems but only uses image information obtained from endoscopic camera itself to acquire the 3-D information of the camera (endoscope)and surgical instruments (forceps).A prliminary experimental result is also shown.
Keywords:Endoscopic Surgery，Computer Vision，Perspective－Three－Point Problem，Image－based 3－D Measurement
Abstract：We have recently developed a new method to‘virtually，expand the field－of view（FOV）of the video endoscope that is simple and applicable to any endoscopic systems．The system uses a potentiometer attached to the endoscope’s bendiing lever,for real-time tracking of the viewing direction．The endoscopic video image on the monitor moves up and down，whose horizontal position is proportional to the bending angle．An old image remains on the monitorbut is overwritten by the new one．An example shows that the FOV is horizontally expanded by 275％．
Keywords：virtual expansion，field-of-view，endoscope
Abstract
Endoscopic surgery forces surgeons to operate with mental tension under the mechanical and visual constraints．Surgeons are required to extract sense of orientation in the abdominal cavity from the anatomical structure and the direction of laparocope．Laparoscopic surgery would be technologically improved if surgeons are provided with the 3D shape of internal geometry in an intuitive manner．In this paper，we develop the intraoperative 3D shape recovery system for laparoscopic data fusion．And we propose a floating window that enables to provide intuitive comprehension about abdominalspace．
KeyWords：Data Fusion，Endoscope，Laserscanner，High－speed camera，3D geometry
Abstract :This paper describes an improved method to estimate thecamera
motion of flexible endoscopes during endoscopic examination．The cecamera
motion tracking is an important function in theendoscope navigation system.．We
have already reported a camera tracking method based on image registration．This
method failed in tracking when bubbles appeared in real endoscopic views．Thispaper
proposes a method to detect the occurence of bubbles during the tracking
process．This detection is performed by using the difference between an
image with bubbles and the virtual endoscopic image generated from the
image with bubbles．The system suspends the tracking process while the
system is detecting bubbles.We applied the proposed method to three cases
of bronchoscopicvideo images．The experimental results showed that the
proposed method can track the camera motion better than the previous method．
KeyWords：Virtual endoscopy，camera motion estimation，endoscopenavigation system，texture mapping
Abstract
We developed a new three－dimensional endoscopic ultrasonography（EUS）to
safely perform therapeutic and diagnostic proeedures with three－dimensional
image support．Volume data were reconstructed by spatially replacing a
series of two－dimensional imagescorresponding to the position of the ultrasound
probe during scanning．The position of the ultrasound probe was captured
by an electro－magnetic tracking sensor，Which was attached to the tip
of the scope.In the animal study using a plg，the system enabledquick acquisition
of the three－dimensional echoangiography of complex vascular structures
of the hepatic hilum and the spleen．The results of the animal study suggested
the clinical applicability of this system．We believe further improvement
of this study will improve procedural difficulties of endoscopic procedures．
KeyWords：Endocopic ultrasongraphy，animal study，three－dimensional image．
Abstract：We developed new three－dimensional endoscopic ultrasound systems（EUS）with convex scanning echoendoscopes to performvarious procedures with EUS simply and expand their applications.We use optical positioning sensors to detect the position of the probe and the shapes of the scope inside body.These sensors can measure bend and twist of each position along with the scope．Then，these positions were allotted to 2D images，and the systemcan reconstruct and visualize 3D images in real－time.We report results of our experimental studies using phantom and 3D image of vessels in animal studies．
Keywords：3D endoscopic ultrasound，optical positioning sensors，real-time
【Abstract】By the former study, we could confirm the merit of wide－angle
view endoscope using wedge prisms．The system consisted of a laparoscope
with zoom facility and two wedge prisms at the tip．It produced some excellent
characteristics．However，it had some probrems．So we improved the system
as follows．Firstly，we prescribed the angle of the wedge prism so as not
to break a part ofthe field of view because of refraction at the prism．Secondly，weminiaturized
the driving unit to increase efficiency for clinical use.
Keywords：Endoscope，Minimally invasive surgery，
Abstract：In order to visualize the surgery procedure，new surgery event
recording system was developed．Simultaneous patient’svital signs and
images of surgeon’s view field，intraoperative echo cardio graphy were
needed for patient’s monitoring．Patient’s vital signs and 4 images were
brought together in one place．And these recorded with digital video camera．We
succeeded to unify the time series．It becomes easy to check the surgery
procedure and relationship between the medical treatment and the alteration
of patient’s vital signs by bringing the apparatuses together in one place．
Keywords：Visualization of surgery procedure，Event recording system，Unify the time series
Abstract：Touching cardiac muscle provides important informationon its contractility and visco－elastic properties for ventricular plastic surgery．The training system we have developed consists of the virtual heart image based on MRI data and one－dimensional manipulator of a forceps，which transmits reaction force tothe virtual heart muscle．To get real-time response of the virtual heart to the manipulator，equations necessary to compute the reaction force are dynamically activated depending on the finger force applied to the muscle surface．Test runs with a nominal linear cardiac muscle model showed the satisfactory quality of image processing．More realistic mechanical properties need to be embeddedin the cardiac model．
Keywords：left ventricle，cardiac muscle palpation．force feedback
Abstract－This paper presents the performance measurement and evalution
of our system integrated by Common Object Requcst BrokerArchitecture（CORBA）.IN
case of integration with CORBA，existing system can be integrated regardless
of their hardware，operatiin system，or programming language.On RT-Linux
server，the distributed objects are supported on user process and can be
remotelybut transparently invoked from multiple clients．Performance mesurement
results showe that an invocation of distributed object needed about 0.5
millisececonds and irreglarly took 20 times longer than it．In conclusion，the
employment of distributed objects issuitable not to control robot but to
get the status of actuators．
Key Words：CORBA．Performance．Integration
Abstract：In Tokyo Women’s Medical University（TWMU），a navigation system
for brain tumor removal is used for 30 patients in Open MRI operating theater．The
navigation system has been used satisfactory to the operation under supine
position．But，when used navigation system to the operation of prone position，an
accuracy error of navigation system will become a large value．The purpose
of this study is to evaluate quantitatively distortion of MRI image by
the position relation between Open MRI and a phantom using the phantom．We
analyzed the resultin the engineering position，and pinpointed the guarantee
space of the navigation system for Open MRI，and worked on the measure
of the navigation system to distortion of MRI image．
Keywords：Open MRI，Navigation System
5－ALA（5－Aminolevulinic Acid）is accumulated on a neoplasm organization in several hours after medication and it changes to Protoporphyrin IX which is fluorescent ultra-violet light excitation．We can identify tumor tissue by fluorescence under ultra－violet illumination when the patient receives oral dose of 5-ALA 2hours before operation.We tried to incorporate this observation system to a neur-endoscope system．We analyzed the requirements for optical system，confirmed its feasibility,and developed a prototype system．In preliminary study,the developed endoscope system could detect fluorescence from Protoporphyrin IX solution．
Abstract：The method of evaluating the surgical operation apparatus which can be used with MR is proposed．In this research，we developed the virtual MR by using FEM．The virtual MR can have an arbitrary performance.The experiment result and the calculation resultwere corresponding well when the test piece was a column．The relation between the distortion of the magnetic field and the distortion of the image can not be considered at this time．We will improve virtual MR to simulate the distortion of the image in the future．
Keywords：MR Compatible，MR Simulator,FE Analysis
Abstract：Laser surgical tools have been widely accepted since it can be applied to coagulation and can precisely localize fieldto be ablated．It is one of important surgical tools in minimally invasive surgery．As the semiconductor laser is light weight and small，it is very useful at the point of use in the medical spot．In this research，we developed the manipulator that manipulate the semiconductor laser. Furthermore，we proposed an interface for the improvement in operability．
Keywords：minimally invasive surgery，semiconductor laser，medical robot
Abstract：During the last years Interventional Magnetic Resonance Imaging（IV－MRI）has
become a significant clinical process．To perform this work，special materials
and processing are required to provide MR－compatible instruments that
are adequately representedin an MRI scan．In this report，we propose a
surgical manipulator system with hydraulic actuators．It is MR－compatible
and enough small to operate in Open－MRI system using MRI scanning．It
has 6 Degrees of Freedom（D．O.F）．The requirements for this MR－compatible
manipulator system are examined，and the design of the manipulator system
is described．
Keywords：MR－compatibility，Interventional MRI，Medical manipulator，Minimally Invasive
Abstract：We have developed a compact manipulator for the Multi－function Forceps．We used two degrees of gimbal mechanism for the rotation of the forceps．For rotation around the axis and back and forth movement，we used friction wheel and ultra-sonic motor．Thismechanism had these characteristics as follows；1）The mechanism
was small in size，which was φ42mm x 90mm．2）The mechanism does not require the forceps any special adapter．
Keywords：Medical Robot，Minimally invasive surgery
Abstract：Present computer－enhanced surgical robot systems unfortunately
occupy a significant amount of space in operating rooms. It sometimes prohibits
a surgeon from accessing to the patient covered with these bulky equipments.
We propose the Active Trocar as an approach to miniaturize the surgical
slave robot system．The miniaturization of the surgical robot system realizes
light weigh and high stifhess．Active Trocar has various uses with replacing
theactive forceps with various surgical instruments．
Keywords：Surgical Robot，Master－Slave Robot
Abstract：In this paper，we would propose an endoscope manipulator for trans－nasal neuro surgery，which is open MRI compatible．The endoscope operation in MR gantry might provide the surgeon（s）with real－time feedback of MR image to endoscopic image and the reverse．This facilitates the comprehensive understanding，because MRI compensates the vision lost through narrow openingof keyhole surgery with global view．For this purpose，aprototype was designed and developed to work around MR gantry and not toaffect MR images.
Keywords：Trans－Nasal Neuro Surgery，Endoscopic Surgery，MRI Compatibility，Medical Robot／Manipulator
Abstract：Image guided spine surgery is gradually spread with the advancement of pre－surgical simulations from X-ray CT or MR images to realize minimally invasive and safer surgery. Especially,in vertebrae cervical bone fixation surgery,the high positioning accuracy is required to avoid injuring dura mater spinalits and major blood vessels inside the vertebrae cervical bone during the drilling．However，when using the image guided navigation system，we meet the difficulties to have an accurate“registration”between the navigation results and the device such as needle，screws and drills，because of surgeon’s tremor and the complicate spatial orientation relations．To solve these problems，we developed the 1st prototype of a simple robot that has only 2 DOF,to navigate the orientation of the device.The characteristics of the robotis‘low DOF’，'restricted moving range’and‘light weight’to realize easy operation considering the medical use.
Abstract：We have developed a laparoscope manipulator system forclinical application．The system consists of a five-bar linkage mechamism，an automatic zoom，and a controller．The mechamism and the automatic zoom are gas sterilizable．A surgeon can operatethe system with a small switch attached on forceps．We determined the setup position through simulated surgical operations．We clinically evaluated the system in a splenectomy．The operation was completed safely without any problems．High operationality ofthe mamipulator mechanism together with zooming mechanism were confirmed．
Keyword：Laparoscopic surgery；Sterilization，Work space，Man－machine interface
Abstract：We have developed the micro－manipulator system for neurosurgery.This system is the surgery support system for minimally invasive neurosurgery．We examined utilities of the micro manipulator system with forceps，a laser scalpel and a monopolar scalpel.We tested handling，suture，ligature，cutting and removal of tissue by surgeons with the manipulator system.Surgeons evaluated to perform easily handling，cutting，and removal.
Keywords：Surgery support system，minimally invasive neuro surgery，micro manipulator
Abstract：Recently，mimimally invasive newosurgery has been developed（1）．In the process of that operation，we have to retract brain tissue and assure the working space for micromanipulator,so we have developed a multiple－DOF brain retract mamipulator ．To retract brain widely and safely ,a multiple degrees of frecdom mechanism is designed with active universal joint and it is operated by passive control in addition to active control．Passive control momitors feedback system all the time and when the system is out of control，controlling valve is closed and cylinder rod never can move．
Keywords：Mimimally invasive surgery，Brain retraction，Mamipulator