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Computer-Assisted Surgery Medical Robotics
Medical Image Processing
LECTURE 1
1. What‘s in a surgery
2. Technical tools in CS
3. CAS systems
CAS, Spring 2001 © L. Joskowicz 3
PAST: Cut, then see
CAS, Spring 2001 © L. Joskowicz 4
PRESENT: See, then cut
CAS, Spring 2001 © L. Joskowicz 5
FUTURE: Combine, see, minimally cut
CAS, Spring 2001 © L. Joskowicz 6
How do surgeries proceed?• Diagnosis
– based on physical exams, images, lab tests
• Preoperative planning– determine the surgical approach– elaborate intraoperative plan (path, tools, implants)
• Surgery– prepare patient and assess condition– acquire intraoperative images, adapt and execute plan
• Postoperative follow-up– exams, lab tests, images to be corroborated
CAS, Spring 2001 © L. Joskowicz 7
Treatment procedures• Invasive
– neurosurgery: tumor removal– hear surgery: clogged arteries, transplants– orthopaedic surgery: spine, hip replacement, knee,
fractures– gall bladder removal, prostate, various cancers
• Non-invasive– radiation therapy– kidney stone pulverization
CAS, Spring 2001 © L. Joskowicz 8
Medical imaging modalities
• Preoperative– Film X-rays, Digital X-rays, Ultrasound,
Angiography, Doppler, ….– Computed Tomography (CT), Magnetic Resonance
(MR), Nuclear Medicine (PET, SPECT, …)
• Intraoperative– X-ray fluoroscopy, ultrasound– video images (laparoscopy, arthorscopy)– Open MR
CAS, Spring 2001 © L. Joskowicz 9
Medical imaging modalities: X-rays
Film or Digital X-ray X-ray Fluoroscopy
CAS, Spring 2001 © L. Joskowicz 10
Medical imaging modalities: continuous X-ray angiography
CAS, Spring 2001 © L. Joskowicz 11
Medical imaging modalities: Ultrasound
CAS, Spring 2001 © L. Joskowicz 12
Medical imaging modalities: CT
Single slice
Series of parallel slices 2mm apart
CAS, Spring 2001 © L. Joskowicz 13
Medical imaging modalities: MRI
Good imaging of soft tissue
CAS, Spring 2001 © L. Joskowicz 14
Medical imaging modalities: Nuclear medicine (PET, SPECT, NMR)
Functional imaging: colors indicate
electrical activity
CAS, Spring 2001 © L. Joskowicz 15
Medical imaging modalities: video
TV quality image from small camera (laparoscope or endoscope)
CAS, Spring 2001 © L. Joskowicz 16
Surgical approaches• Open surgery
– area of interest directly exposed by cutting– direct sight and touch of anatomy by surgeon– direct access but causes additional damage
• Closed surgery not always feasible– indirect access to anatomical area of interest– no direct visual sight or tactile feel– catheterization, biopsies– intraoperative imaging is often required– require more skills: lengthier, more difficult
• Diagnostic surgery
CAS, Spring 2001 © L. Joskowicz 17
Minimally invasive surgery
• Provides treatment through small incisions
• Uses imaging equipment for seeing and instruments for touching
• Advantages: less damage, faster recovery
• Disadvantages: hand/eye coordination, time
• Examples: – brain tumor removal, laparoscopic surgery
CAS, Spring 2001 © L. Joskowicz 18
Laparoscopic surgery
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Brain surgery
CAS, Spring 2001 © L. Joskowicz 20
Total Hip replacement -- principle
CAS, Spring 2001 © L. Joskowicz 21
Total hip replacement procedure
CAS, Spring 2001 © L. Joskowicz 22
What is required to perform surgery?
• Knowledge intensive task– anatomy, procedures, cases– experience, skills, customization and generalization
• Manual and cognitive skills– dexterity, precision, strength, tool manipulation– spatial orientation and navigation
• Determination– information integration– judgement, decision, execution
CAS, Spring 2001 © L. Joskowicz 23
Medical and surgical trends• Imaging improved dramatically diagnosis
– started with X-rays last century– 30% of all cases use images
• Move towards minimally invasive procedures– introduced in the mid ‘70s, slow acceptance (laparoscopy)– the method of choice now
• More precise and delicate procedures
• Development of sophisticated surgical hardware
• High degree of craftsmanship and skills
CAS, Spring 2001 © L. Joskowicz 24
Socio-economical medical trends
• Increase of aging population and associated problems: tumors, osteoporosis, Alzheimers
• Larger population volumes
• Universal, first rate, highly specialized care
• Health care costs reduction (managed care)
• Higher patient requirements
• Legal and regulatory aspects
CAS, Spring 2001 © L. Joskowicz 25
Surgical Needs
• Support for image-guided surgery• Passive and active devices for accurate spatial positioning,
tracking, and execution• Modeling, planning, viewing, diagnosis systems• Systems integration: from diagnosis to post-op• Improve current practice and enable new procedures• Simulation and training systems
Augment the surgeon’s capabilities with better quantitative planning, execution, and integration
CAS, Spring 2001 © L. Joskowicz 26
Current clinical status• Imaging
– vast databases of medical images– digitized atlases– mostly uncorrelated unimodal qualitative interpretation
• Devices– mostly passive and non-invasive (supports)– laparoscopic camera, – some real-time tracking
• Planning, modeling, visualization– 3D reconstruction, some registration
Part 2: Computers and Robots
Technology and algorithms
available today
CAS, Spring 2001 © L. Joskowicz 28
How can computers help?(or are already helping…)
• Image processing– single image: enhancement, noise reduction,
segmentation, quantitative measurements– image stacks: 3D reconstruction, segmentation– image sets: registration, comparison, data fusion
• Planning and simulation– integrate medical images and CAD models– planning and simulation programs
• Computer vision and graphics– camera modeling, image registration, rendering
CAS, Spring 2001 © L. Joskowicz 29
Image processing
CAS, Spring 2001 © L. Joskowicz 30
Planning and simulation
CAS, Spring 2001 © L. Joskowicz 31
Virtual man project -- digital model
CAS, Spring 2001 © L. Joskowicz 32
How can robots and sensors help?(or are already helping…)
• Robotic devices– passive, semi-active, active devices – instrument and anatomy positioning and holding– cutting and machining
• Real-time tracking – optical, video, electromagnetic devices– navigation tools
CAS, Spring 2001 © L. Joskowicz 33
Robotic devices
CAS, Spring 2001 © L. Joskowicz 34
Real-time tracking devicescamera
instrument
Passive markers
Instrument has infrared LEDs attached to it Active markers
CAS, Spring 2001 © L. Joskowicz 35
Computer-Assisted Surgery (CAS)
A computer-integrated system to enhance the dexterity, visual feedback, and information
integration of the surgeon
Key points:• The goal is NOT to replace the surgeon• A new paradigm for surgical tools• Address a real clinical need• Prove efficacy and cost-effectiveness
CAS, Spring 2001 © L. Joskowicz 36
Elements of CAS systems
CAS, Spring 2001 © L. Joskowicz 37
Elements of CAS systems• Preoperative planning
– image acquisition, modeling, analysis, simulation– plan elaboration, tool and prosthesis selection– Output: preop images, 3D models, prosthesis type and
position, navigation and cutting plan
• Intraoperative execution– passive, semi-active, active robot– real time tracking– intraoperative imaging (fluoroscopy, ultrasound)
CAS, Spring 2001 © L. Joskowicz 38
State of the Art (1)
• Main clinical procedures– neurosurgery: biopsies, tumor removal– orthopaedics: hip and knee replacement, spine, pelvis
and femur fractures– maxillofacial and cranofacial– laparoscopy: laparoscope holders– new fields: dentistry, ophtalmology, prostate
• Mostly rigid structures: bones!!
CAS, Spring 2001 © L. Joskowicz 39
State of the Art (2)
• Commercial navigation systems– main uses: neurosurgery and spine surgery
• Commercial robotic systems– ROBODOC for total hip replacement– laparoscope arm holders
• Research– very active, very interdisciplinary– a few dozen systems tested in-vitro
CAS, Spring 2001 © L. Joskowicz 40
State of the Art (3)
• Major players– INRIA Sophia Antipolis, Grenoble, Johns Hopkins,
Brigham Women’s H./MIT, Shadyside H./CMU, Imperial College, many places in Germany and Japan
• Interdisciplinary conferences and journals– started in 1994: MRCAS’94; Orthopaedic CAS
meetings, visualization, etc,– Journals: Computer-Aided Surgery, Medical Image
Analysis
CAS, Spring 2001 © L. Joskowicz 41
Examples of CAS systems in use
• Image-guided navigation systems
• ROBODOC: Total hip replacement surgery
• LARS: Laparoscopic assistant
• Radiosurgery
Brief overview follows; will be covered in detail later
CAS, Spring 2001 © L. Joskowicz 42
Image-guide navigation• Purpose
– accurate placement of instruments with respect to imaged anatomy for several procedures
• Problem addressed– provide 3D vision of unseen structures
replace static 2D fluoroscopy or larger openings– improve precision of biopsies, screw placements
• Scope– non-invasive– creates surface model from preop images– registration of images to anatomy by direct contact
CAS, Spring 2001 © L. Joskowicz 43
Image-guided navigation
CAS, Spring 2001 © L. Joskowicz 44
Image-guided navigation (2)pedicle screw insertion
CAS, Spring 2001 © L. Joskowicz 45
Status
• In clinical use
• Over 7,000 neurosurgeries performed with commercial systems
• Gaining popularity in pedicle screw insertion
• Decreased the misplacement rate from 10-40%to 5-18% (clinical study of 700 cases)
• More clinical applications under development
CAS, Spring 2001 © L. Joskowicz 46
ROBODOC: Total hip replacement• Purpose
– precise machining of cementless hip implant canal
• Problem addressed– complications in canal preparation and implant fixation– improve positioning accuracy and surface finish
• Scope– invasive, numerically controled machining– plan from preop CT, registered via pins– adapted commercial robot– custom bone fixator and bone motion detection
CAS, Spring 2001 © L. Joskowicz 47
Artificial hip joint
CAS, Spring 2001 © L. Joskowicz 48
Total hip replacement procedure
CAS, Spring 2001 © L. Joskowicz 49
ROBODOC: Total Hip Replacement
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ROBODOC system diagram
CAS, Spring 2001 © L. Joskowicz 51
ORTHODOC Planning
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ROBODOC robot diagram
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ROBODOC robot
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ROBODOC procedure
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ROBODOC cutting
CAS, Spring 2001 © L. Joskowicz 56
ROBODOC History
• Developed by IBM Research and Integrated Surgical Systems
• First active surgical robot– 1986: feasibility study– 1989: in-vitro testing of dog system– 1990: 26 dog cases– 1992: development of human system– 1994: first human procedure in Frankfurt– 1995- clinical trials in the US for FDA approval
CAS, Spring 2001 © L. Joskowicz 57
ROBODOC current status
• Sold by Integrated Surgical Systems
• Over 3,000 cases performed
• 15 systems installed in Germany, 2 in Austria
• Excellent short term clinical results (3 year study)– no fractures, few failures (continue manually)
• Long-term clinical results to be determined– key issue: does the artificial hip last longer?
• Problems: OR time, pin insertion
CAS, Spring 2001 © L. Joskowicz 58
Laparoscopic assistant: LARS
• Purpose– laparocopic camera holding and precise navigation
• Problem addressed– cumbersome, unintuitive, and unsteady camera
positioning
• Scope– non-invasive intraoperative device – video images interpreted by surgeon
• Benefits– direct camera manipulation; stability, precise targeting
CAS, Spring 2001 © L. Joskowicz 59
Laparoscopic assistant: LARS
CAS, Spring 2001 © L. Joskowicz 60
LARS characteristics
• Designed at IBM Research, 1993. Similar commercial devices available (AESOP)
• Custom redundant 7 degree-of-freedom robot
• Holds laparoscopic camera
• Fulcrum motions: no motion at point of entry
• Mouse-like controls on surgical scissors
• Position memory and replay
CAS, Spring 2001 © L. Joskowicz 61
Stereotactic Radiosurgery• Purpose
– plan and deliver precise radiation doses
• Problem addressed– precise positioning and dosing of radiation to avoid
healthy organ damage
• Scope– non-invasive intraoperative device– active beam postioning and planning– complex preoperative planning based on MRI images– registers preoperative plan with stereotactic frame
CAS, Spring 2001 © L. Joskowicz 62
Stereotactic Radiosurgery
CAS, Spring 2001 © L. Joskowicz 63
CYBERKNIFE system
CAS, Spring 2001 © L. Joskowicz 64
CYBERKNIFE system
CAS, Spring 2001 © L. Joskowicz 65
Stereotactic Radiosurgery: planning
CAS, Spring 2001 © L. Joskowicz 66
Stereotactic Radiosurgery
• Developed at Stanford starting in 1992
• Complex 3D radiation plans
• Currently in clinical use
• Frameless procedure under development follow head with markers, video, or
X-rays
• Company Accuray has performed several clinical trials with frameless procedure
CAS, Spring 2001 © L. Joskowicz 67
Developing CAS systems
• Similarities– understand and address real needs of surgeons– consider established procedures, context, use– work on problems that will make qualitative difference– constant feedback from user; test ideas and prototypes
• Differences– system performace requirements
CAS, Spring 2001 © L. Joskowicz 68
Developing CAS systems
• understand and address real needs of surgeons
• consider established procedures, context, use
• constant feedback from user; test ideas and prototypes
• system requirements– safety and reliability– fail-safe systems: can always stop and proceed as usual– system integration
CAS, Spring 2001 © L. Joskowicz 69
CAS systems design cycle• Prototype development
• In-vitro experiments– system refinement
• Cadaver studies– system refinement
• In-vivo experiments– first animal and human trials
• Clinical trials– double blind studies, Hospital and FDA protocols
• Agency approval and commercial release
CAS, Spring 2001 © L. Joskowicz 70
Summary• Great potential for robots and computers inside
and outside the operating room
• Great research and commercial interest, especially in the past 3 years
• Just the beginning of the road: many things remain to be invented
• Great role for applied computer science:– image processing, geometric planning, registration,
graphics, vision, real-time systems, robotics, etc.