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Biomedical Engineering (Medical Equipment's) - Mathankumar.S - VMKVC, SALEM, TAMILNADU


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Biomedical Engineering (Full Details) - Mathankumar.S - VMKVC, SALEM, TAMILNADU

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Biomedical Engineering (Medical Equipment's) - Mathankumar.S - VMKVC, SALEM, TAMILNADU

  1. 1. 7/25/2014 1
  2. 2. 2/1/2015 2 Solving problems in biology and medicine using engineering methods and technology (e.g., research, design and development of biomedical instrumentation.)
  3. 3.  Image is an Artifact that reproduce the likeness of some subjects usually a physical object.
  4. 4.  Images are pictures! A picture that represents visual information.  Used to save visual experiences.  A picture is worth a 1000 words…I think more!!!  How are non-digital images stored? Photographic film Canvas/paint Digitally
  5. 5.  Imaging is the process of acquiring images.  Shorthand for image acquisition.  Process of sensing our surroundings and then representing the measurements that are made in the form of an image.
  6. 6.  Passive imaging – employs energy sources that are already present in the scene.  Active imaging – involves use of artificial energy sources to probe our surroundings. 6
  7. 7.  Passive imaging is subject to the limitations of existing energy sources. Passive Imaging
  8. 8.  Active imaging is not restrictive in this way but is invariably a more complicated & expensive procedure.  Active imaging predominates in medical field, where precise control over radiations sources is essential.  Active imaging is also an important tool in remote sensing. 8 Active Imaging
  9. 9. DICOM - Digital Imaging and Communications in Medicine 9
  10. 10. 10
  11. 11.  User Consortia (e.g., HL7)  Organizations (e.g., NEMA, IEEE)  US Government Agencies (e.g., ANSI, NIST)  Foreign Government Agencies (e.g., CEN)  United Nations (e.g., ISO, CCITT)
  12. 12.  The name was changed to separate the standard from the originating body  1991 - Release of Parts 1 and 8 of DICOM  1992 - RSNA demonstration, Part 8  1993 - DICOM Parts 1-9 approved, RSNA demonstration of ALL parts  1994 - Part 10: Media Storage and File Format  1995 - Parts 11,12, and 13 plus Supplements
  13. 13. MAGN ETOM Information Management System Storage, Query/Retrieve, Study Component Query/Retrieve, Patient & Study Management Query/Retrieve Results Management Print Management Media Exchange LiteBox
  14. 14. SOP Data Dictionary Real-World Object Information Object DIMSE Service Group
  15. 15.  Composite Verification Storage Query/Retrieve Study Content Notification  Normalized Patient Management Study Management Results Management Basic Print Management
  16. 16.  Joint CEN-DICOM development  Medicom = DICOM  MIPS 95 work is underway with JIRA  IS&C Harmonization is also in progress  HL7 Harmonization continuing interest  New DICOM organization  Companies: NEMA and non-NEMA  ACR, ACC, CAP, ...  individuals
  17. 17. Networking is a critical component of all medical imaging systems Support for Open Communication Standards is a MUST DICOM is here, NOW DICOM products exist on the market DICOM is emerging as THE common protocol for medical image communication - WORLD WIDE!
  18. 18. Electro-Magnetic Spectrum
  19. 19. IR Imaging (Performance) Fig. Thermal / IR view of a Chip
  20. 20. IR Imaging (Natural Calamity) Fig. IR satellite view of Augustine volcano
  21. 21. IR Imaging (Night Vision) Fig. IR image of a sloth at night
  22. 22. IR Imaging (Night Vision) Fig. Night vision system used by soldiers
  23. 23. Ultrasound imaging (Medical) Fig. Fetus and Thyroid using ultrasound
  24. 24. Seismic imaging (Earthquake) Fig. Detecting Earthquakes and its cause using cross sectional view
  25. 25. UV imaging (Ozone) Fig. Detect ozone layer damage
  26. 26. X-Ray imaging (Medical) Fig. X - Ray of neck
  27. 27. X-Ray imaging (Medical) Fig. X - Ray of head
  28. 28. Gamma-Ray imaging (Medical) Fig. Gamma ray exposed images
  29. 29. Remote Sensing Fig. Satellite images of Mumbai suburban(Left) and Gateway of India (Right)
  30. 30.  Images stored in digital form! Many ways of acquiring images Scanner Digital Camera Others… Many ways of storing images Gif Tiff BMP JPG Others…
  31. 31. JPEG (Joint Photographic Experts Group) GIF (Graphic Interchange Format) PNG (Portable Network Graphics) TIFF (Tagged Image File Format) PGM (Portable Gray Map) FITS (Flexible Image Transport System) BMP (Bitmap Format)
  32. 32. JPEG - Joint Photographic Experts Group JPEG is designed with photographs in mind.  It is capable of handling all of the colors needed. JPEGs have a lossy way of compressing images. At a low compression value, this is largely not noticeable, but at high compression, an image can become blurry and messy. .jpg
  33. 33. JPEG cautions: • Images with hard edges, high contrasts, angular areas, and text suffer from JPEG compression. • Scanned “natural” photographs do not lose much, especially at High or Maximum quality. • Only save finished images as JPEGs, every time you open and save again, even if you don’t edit, you lose quality. • Always keep the original non-JPEG version (the native .psd format). So why use JPEG? • It is the best format for photographic images on the Web. • It’s compression ability is very great.
  34. 34. 34
  35. 35. GIF - Graphics Interchange Format GIF is the most popular on the Internet, mainly because of its small file size. It is ideal for small navigational icons and simple diagrams and illustrations where accuracy is required, or graphics with large blocks of a single color. The format is loss- less, meaning it does not get blurry or messy. The 256 color maximum is sometimes tight, and so it has the option to dither, which means create the needed color by mixing two or more available colors. GIF use a simple technique called LZW compression to reduce the file sizes of images by finding repeated patterns, but this compression never degrades the image quality. .GIF
  36. 36. 36  The GIF format is one of the most commonly used graphic file formats, especially on the Internet.  The GIF format is exceedingly useful in that it can contain animations. Its internal structure is such that it can store multiple images and the controls to make them appear as real time animation  animated GIF.  The GIF format also allows a special color as to be specified as "using the background." This results in the image looks like transparent  transparent GIF.
  37. 37. 37  Portable Network Graphic (PNG) which is pronounced as “Ping”.  Alternative to GIF, a lossless compression scheme is used.  Support three image type: true color, grayscale, palette-based (8-bit).  JPEG supports the first 2.  GIF supports the 3rd one.
  38. 38. 38  Advantages  Better Compression ○ Deflate is an improved version of the Lempel-Ziv compression algorithm.  Improve Interlacing ○ Display image quicker than Interlaced GIF.  True Color and Transparency ○ Support 16-bit (Grey scale) or 48-bit (True Color) ○ 16-bit for alpha channel (Transparency).  Gamma storage ○ Store the gamma setting of the platform of the creator.  Disadvantages  Not support by old browsers (Netscape 2,3,4 and IE 2,3,4)
  39. 39. TIFF - Tagged Image File Format  Widely used cross platform file format also designed for printing.  A bitmap image format.  TIFF supports lossless LZW compression which also makes it a good archive format for Photoshop documents.
  40. 40.  A popular format for grayscale images (8 bits/pixel)  Closely-related formats are:  PBM (Portable Bitmap), for binary images (1 bit/pixel)  PPM (Portable Pixelmap), for color images (24 bits/pixel) - ASCII or binary (raw) storage
  41. 41. FITS - Flexible Image Transport System  Format of a FITS file (  Primary Header: metadata describing instrument, observation & file contents  Primary Data Array: array of 0-999 dimensions – usually a 2D image + none or more Extensions:  Array, ASCII Table or Binary Table, each with Header (New FITS-inspired XML format – VOTable)
  42. 42. 42 BMP - Bitmap Format uses a pixel map which contains line by line information. It is a very common format, as it got its start in Windows.  This format can cause an image to be super large.
  43. 43. Image Processing is any form of signal processing for which our input is an image, such as photographs or frames of video and our output can be either an image or a set of characteristics or parameters related to the image.
  44. 44.  Image Processing generally refers to processing of two dimensional picture and by two dimensional picture we implies a digital image.  A digital image is an array of real or complex numbers represented by a finite number of bits.  But now in these days optical and analog image processing is also possible.
  45. 45.  Is enhancing an image or extracting information or features from an image.  Computerized routines for information extraction (eg, pattern recognition, classification) from remotely sensed images to obtain categories of information about specific features.
  46. 46. Image processing are of two aspects.. improving the visual appearance of images to a human viewer preparing images for measurement of the features and structures present. 2/1/2015 46
  47. 47. ❶ Acquisition of Image  Medical image data is acquired one slice at a time.  Resulting data set comprises n slices, each containing w x h pixels. Basic Steps for Image Processing
  48. 48. ❷ Data Storage  Array starts with the first row of the first slice and so on until the end of the first slice.  Next, the array continues with the first row of the second slice, then the second row of the second slice, and so on.
  49. 49.  A single slice corresponds to a k space plane acquired in real-time  The “K-Space” undergoes an Inverse Fourier Transform.  Following this mathematical step, we finally have an image ❸ Image Formation
  50. 50. ❹ Data Visualisation  Medical image data is commonly visualised by two methods.  Reslicing  Surface rendering
  51. 51. Since the digital image is “invisible” it must be prepared for viewing on one or more output device (laser printer, monitor, etc.,) It might be possible to analyze the image in the computer and provide cues to the radiologists to help detect important/suspicious structures (e.g.: Computed Aided Diagnosis, CAD) 2/1/2015 51 Why do we need Image Processing
  52. 52. Image processing can be done using various software's and languages such as:- Language VHDL C/C++ Software Matlab Adobe Photoshop Irfan view How Image Processing is done?
  53. 53. 53  Early 1920’s: One of the first applications of digital imaging was in the newspaper industry  The Bartlane cable picture transmission service  Images were transferred by submarine cable between London and New York  Pictures were coded for cable transfer and reconstructed at the receiving end on a telegraph printer Early digital image
  54. 54.  Mid to late 1920’s: Improvements to the Bartlane system resulted in higher quality images Improved digital image Early 15 tone digital image New reproduction processes based on photographic techniques Increased number of tones in reproduced images
  55. 55. 1960’s: Improvements in computing technology and the onset of the space race led to a surge of work in digital image processing A picture of the moon taken by the Ranger 7 probe minutes before landing  1964: Computers used to improve the quality of images of the moon taken by the Ranger 7 probe  Such techniques were used in other space missions including the Apollo landings
  56. 56. 1970’s: Digital image processing begins to be used in medical applications Typical head slice CAT image 1979: Sir Godfrey N. Hounsfield & Prof. Allan M. Cormack share the Nobel Prize in medicine for the invention of tomography, the technology behind Computerised Axial Tomography (CAT) scans
  57. 57. 1980’s - Today: The use of digital image processing techniques has exploded and they are now used for all kinds of tasks in all kinds of areas  Image enhancement/restoration  Artistic effects  Medical visualisation  Industrial inspection  Law enforcement  Human computer interfaces
  58. 58.  Face detection  Feature detection  Non-photorealistic rendering  Medical image processing  Microscope image processing  Morphological image processing  Remote sensing  Automated Sieving Procedures  Finger print recognization Applications
  59. 59.  Primary purpose is to identify pathologic conditions.  Requires recognition of normal anatomy and physiology.  Create image of body part  Disease Monitoring
  60. 60. Medical imaging is the technique and process used to create images of the human body or it’s parts for clinical purposes . Non-invasive visualization of internal organs, tissue, etc.
  61. 61.  Medical imaging has come a long way since 1895 when Röntgen first described a ‘new kind of ray’.  That X-rays could be used to display anatomical features on a photographic plate was of immediate interest to the medical community at the time.  Today a scan can refer to any one of a number of medical-imaging techniques used for diagnosis and treatment. Medical Imaging using Ionising Radiations
  62. 62.  The transmission and detection of X-rays still lies at the heart of radiography, angiography, fluoroscopy and conventional mammography examinations.  However, traditional film-based scanners are gradually being replaced by digital systems  The end result is the data can be viewed, moved and stored without a single piece of film ever being exposed. Digital Systems
  63. 63. Projection X-ray (Radiography) Ultrasound X-ray Computed Tomography (CT) Magnetic Resonance Imaging(MRI)
  64. 64. 1. X-Rays 2. Computer Tomography (CT or CAT) 3. MRI (or NMR) 4. PET / SPECT (Positron Emission Tomography, Single Photon Emission Computerized Tomography
  65. 65. 5. Ultrasound 6. Computational 7. Mammography 8. Angiography 9. Fluoroscopy 65
  66. 66. X-rays: A form of Electromagnetic Energy travelling at the speed of light. Properties *No mass *No charge *Energy Wavelength – Range of 0.01 to 10 nanometer
  67. 67.  X-rays: a form of electromagnetic energy  Travel at the speed of light  Electromagnetic spectrum  Gamma Rays X-rays  Visible light Infrared light  Microwaves Radar  Radio waves
  68. 68.  X-Rays are associated with inner shell electrons  As the electrons decelerate in the target through interaction, they emit electromagnetic radiation in the form of x-rays.  patient is located between an x-ray source and a film -> radiograph  cheap and relatively easy to use  potentially damaging to biological tissue
  69. 69. X-Rays - Visibility  Bones contain heavy atoms -> with many electrons, which act as an absorber of x-rays  Commonly used to image gross bone structure and lungs  Excellent for detecting foreign metal objects  Main disadvantage -> Lack of anatomical structure  All other tissue has very similar absorption coefficient for x-rays
  70. 70. Three things can happen  X-rays can:  Pass all the way through the body  Be deflected or scattered  Be absorbed Where on this image have x-rays passed through the body to the greatest degree?
  71. 71. X-rays Passing Through Tissue  Depends on the energy of the x-ray and the atomic number of the tissue  Higher energy x-ray - more likely to pass through  Higher atomic number - more likely to absorb the x-ray
  72. 72.  X-rays that pass through the body to the film render the film dark (black).  X-rays that are totally blocked do not reach the film and render the film light (white). Air = low atomic no. = x-rays get through = image is dark Metal = high atomic no. = x-rays blocked = image is light (white) How do x-rays passing through the body create an image?
  73. 73. 5 - Basic Radiographic Densities  Air  Fat  Soft tissue/fluid  Mineral  Metal 1. 2. 3. 4. 5.
  74. 74. X-Rays - Images X-Rays can be used in computerized tomography
  75. 75.  Computerized (Axial) Tomography  Introduced in 1972 by Hounsfield and Cormack  Natural progression from X-rays  Based on the principle that a three-dimensional object can be reconstructed from its two dimensional projections From 2D to 3D ! Radon again! CT (or) CAT
  76. 76. • Johan Radon (1917) - Showed how a reconstruction from projections was possible. • Cormack (1963,1964) - Introduced Fourier transforms into the reconstruction algorithms. • Hounsfield (1972) - Invented the X-ray Computer scanner for medical work, (which Cormack and Hounsfield shared a Nobel prize). • EMI Ltd (1971) - Announced development of the EMI scanner which combined X-ray measurements and sophisticated algorithms solved by digital computers.
  77. 77.  measures the attenuation of X-rays from many different angles  a computer reconstructs the organ under study in a series of cross sections or planes  combine X-ray pictures from various angles to reconstruct 3D structures
  78. 78.  Linear advancement (slice by slice)  typical method  tumor might fall between ‘cracks’  takes long time  Helical movement  5-8 times faster  A whole set of trade-offs
  79. 79. 1. Scanning the patient 2. Data Acquisition  Tube and detector move  Multiple attenuation measurements are taken around object. 3. Image reconstruction 4. Image Display 5. Image archival (recording)
  80. 80.  Conventional CT  Axial  Start/stop 1.X-ray tube and detector rotate 360° 2.Patient table is stationary with X-ray’s “on” 3.Produces one cross-sectional image 4. Once this is complete patient is moved to next position Process starts again at the beginning 1.X-ray tube and detector rotate 360° 2.Patient table moves continuously With X-ray’s “on” 3.Produces a helix of image information 4.This is reconstructed into 30 to 1000 images  Volumetric CT  Helical or spiral CT  Continuous acquisition
  81. 81. One 256-Slice CT Scan 256 x 0.5 MB = 178 MB
  82. 82. Medical Applications Type of Tomography Full body scan X-ray Respiratory, digestive systems, brain scanning PET Positron Emission Tomography Respiratory, digestive systems. Radio-isotopes Mammography Ultrasound Whole Body Magnetic Resonance (MRI, NMR) PET scan on the brain showing Parkinson’s Disease MRI and PET showing lesions in the brain.
  83. 83. Non Medical Applications Type of Tomography Oil Pipe Flow Turbine Plumes Resistive/Capacitance Tomography Flame Analysis Optical Tomography ECT on industrial pipe flows
  84. 84.  Significantly more data is collected  Superior to single X-ray scans  Far easier to separate soft tissues other than bone from one another (e.g. liver, kidney)  Data exist in digital form -> can be analyzed quantitatively  Adds enormously to the diagnostic information  Used in many large hospitals and medical centers throughout the world
  85. 85.  significantly more data is collected  soft tissue X-ray absorption still relatively similar  still a health risk  MRI is used for a detailed imaging of anatomy – no X rays involved.
  86. 86. 1979 “For the Development of computer assisted tomography (CAT)” – Hounsfield & Cormack 2003 “For the Discoveries concerning magnetic resonance imaging (MRI)” - Paul Lauterbur & Peter Mansfield
  87. 87.  Nuclear Magnetic Resonance (NMR) (or Magnetic Resonance Imaging - MRI)  Most detailed anatomical information  High-energy radiation is not used, i.e. this is “safe method”  Based on the principle of nuclear resonance  (medicine) Uses resonance properties of protons MRI (or) NMR
  88. 88. Magnetic resonance imaging (MRI), Magnetic resonance imaging (MRI), is a non-invasive method used to render images of the inside of an object. It is primarily used in medical imaging to demonstrate pathological or other physiological alterations of living tissues.
  89. 89. Hydrogen nuclei(protons) under a strong magnetic field in phase with one another and align with the field. Relaxed protons induce a measurable radio signal. 1952  Main modality for image guided surgery.  Ability to discriminate between subtle surfaces.  Very safe. --Not effective for bone scanning.
  90. 90.  Positron Emission Tomography Single Photon Emission Computerized Tomography  recent technique  involves the emission of particles of antimatter by compounds injected into the body being scanned  follow the movements of the injected compound and its metabolism  reconstruction techniques similar to CT - Filter Back Projection & iterative schemes
  91. 91. •Positron Emission Tomography (PET) is a nuclear medicine medical imaging technique which produces a three-dimensional image or map of functional processes or Metabolic Activities in the body.
  92. 92. 93 To conduct the scan, a short-lived radioactive tracer isotope, which decays by emitting a positron, which also has been chemically incorporated into a metabolically active molecule, is injected into the living subject (usually into blood circulation). The data set collected in PET is much poorer than CT, so reconstruction techniques are more difficult (see section below on image reconstruction of PET).
  93. 93.  the use of high-frequency sound (ultrasonic) waves to produce images of structures within the human body  above the range of sound audible to humans (typically above 1MHz)  piezoelectric crystal creates sound waves  aimed at a specific area of the body  change in tissue density reflects waves  echoes are recorded
  94. 94.  Delay of reflected signal and amplitude determines the position of the tissue  still images or a moving picture of the inside of the body  there are no known examples of tissue damage from conventional ultrasound imaging  commonly used to examine fetuses in utero in order to ascertain size, position, or abnormalities  also for heart, liver, kidneys, gallbladder, breast, eye, and major blood vessels
  95. 95.  by far least expensive  very safe  very noisy  1D, 2D, 3D scanners  irregular sampling - reconstruction problems
  96. 96. 97
  97. 97.  Mammography is a radiographic examination that is specially designed for detecting early breast cancer, yielding a significant improvement in breast cancer survival.  Mammography has been used in clinical practice since 1927 in the diagnosis of breast abnormalities.  In the late 1950s, the pioneering work of Gershon – Cohen and Egan demonstrated that even clinically occult cancers of early detection of breast cancer by screening asymptotic women. 98
  98. 98.  Since the first mammography units (xeromammography and screen-film mammography in the 1970’s) became available, both the equipment and the examination procedure have changed and progressed.  A high degree of accuracy was developed with this technique to differentiate between Benign and Malignant disease. 99
  99. 99. Past Present ANALOGICAL TECHNOLOGY DIGITAL TECHNOLOGY  Screening  Clinical mammography  Computed radiography (CR)  Digital direct  Computed Aided Diagnosis (CAD)  Tomosynthesis - 3D  CESM Mammography 100
  100. 100. 101
  101. 101.  Improved detection efficiency  A linear dynamic range  Increased signal-to-noise ratio (SNR)  Excellent Image Handling  Data in Digital form  Computer Aided Detection  Compatibility with PACS and Telemammography 102
  102. 102. Early Detection Is Your BEST PROTECTION If breast cancer is found and treated early, the five-year survival rate is 98 percent. The social prejudices and stigma associated in screening of breast is to be sensitized. The success of the scheme depends upon the involvement of radiologists and lab attendants who have to handle with delicate and humane. Another success of the scheme rests upon instead of bringing the people to lab, the lab itself has to go in search of the patient. For which a handy and portable mammogram has to developed for instant and hassle free Service. 103
  103. 103. Portable Mammography  GE unveiled an impressive portable mammography concept as part of a portfolio of integrated technologies aimed at combating cancer.  The SenoCase is mobile mammography system which can be folded and easily stored in a car boot. 104
  104. 104.  According to GE, such portability could remove geographical barriers to regular breast screening for many women on a global scale.  The system could also be more cost effective than conventional mammography systems, making it more accessible to smaller practices and clinics. A standard field of view Cesium Iodide detector Similar image quality to a full-field digital mammography system A user-friendly interface, operable by a single clinician 105
  105. 105. Digital Portable Mammography model was preferred in employee surveys.  Employee feedback confirmed that Women Diagnostic Center mammograms are more convenient, private and familiar because employees feel more comfortable. 106
  106. 106. Digital mammography has proven to be an essential tool in the diagnosis, treatment and fight against breast cancer. And studies have shown that routine mammograms can help reduce breast cancer mortality. The important thing is that you make annual mammography screening a top priority for yourself and the women you care about. 107
  107. 107. As defined at the beginning of this chapter, angiography refers to radiologic imaging of blood vessels after injection of a contrast medium. To visualize these low-contrast structures, contrast media is injected by a catheter that is placed in the vessel of interest. Positive contrast media are more commonly used, but there are instances when use of negative contrast media is indicated. Highly specialized imaging equipment is required for these procedures.
  108. 108. 109
  109. 109.  Fluoroscopy is a technique in which a continuous beam of x-rays is used to produce moving images.  It is used to show movement in the digestive system (which may require ingestion of a high-contrast liquid such as barium) and the circulatory system (angiograms).
  110. 110. 112  X-ray transmitted trough patient  The photographic plate replaced by fluorescent screen  Screen fluoresces under irradiation and gives a live image  Older systems— direct viewing of screen  Screen part of an Image Intensifier system  Coupled to a television camera  Radiologist can watch the images “live” on TV-monitor; images can be recorded  Fluoroscopy often used to observe digestive tract  Upper GI series, Barium Swallow  Lower GI series Barium Enema
  111. 111. 113 (Still in use in some countries) Staff in DIRECT beam
  112. 112. 114 • AVOID USE OF DIRECT FLUOROSCOPY • Directive 97/43Euratom Art 8.4.  In the case of fluoroscopy, examinations without an image intensification or equivalent techniques are not justified and shall therefore be prohibited. • Direct fluoroscopy will not comply with BSS  Performance of diagnostic radiography and fluoroscopy equipment and of nuclear medicine equipment should be assessed on the basis of comparison with the diagnostic reference levels
  113. 113. 115  Remote control systems  Not requiring the presence of medical specialists inside the X Ray room  Mobile C-arms  Mostly used in surgical theatres.
  114. 114. 116  Interventional radiology systems  Requires specific safety considerations. In interventional radiology the physician can be near the patient during the procedure.  Multipurpose fluoroscopy systems  Can be used as a remote control system or as a system to perform simple interventional procedures
  115. 115.  Techniques which are well established in traditional engineering applications need new hardware and software to work efficiently in the biomedical arena. Much of our work includes fusing multiples sources of data, or fusing data with underlying models of movement or tissue properties to improve predictions, sometimes with the development of novel instrumentation.  Current applications are in cancer diagnosis and therapy, stroke rehabilitation and orthopaedics. Recent projects have included monitoring heat distribution and tissue changes from ultrasound images in cancer therapy (HIFU), developing protocols and instrumentation to assess arm movement (with immediate application in stroke rehabilitation), and ultrasound and microwave measurements on soft tissue.  We are pursuing methods to integrate the detection of electrical as well as mechanical properties of tissue. 117
  116. 116. Recognising abnormal states; adaptive stimulation  At present, stimulation is continuous and this gives poor battery usage and can cause habituation.  The goal is to make the next generation of stimulators adaptable to particular patients through demand driven stimulation - altering the pattern and duration of stimulation to the brain's own signals.  Tremor in Parkinson's disease (PD) is clearly detectable in the beta wave brain activity (as well of course from external instrumentation such as accelerometers), but its onset is very rapid.  We have developed methods using autorgressive models, coherence measures and Hidden Markov modelling to detect the change of state associated with onset of tremor from signals received from implanted electrodes in the subthalmic nucelus (which is a prime target for stimulation in PD patients).  More generic work in this area has developed HMM models to identify state transitions between different regions to identify brain networks using MEG imaging. This work is currently been demonstrated on resting state data but will soon be applied to tremor patients. 118
  117. 117. MEG (Magneto encephalography) imaging and application to chronic pain patients  MEG is the only technology suitable for functional imaging for DBS patients as they have metal implanted in the skull so fMRI cannot be used. MEG uses a set of very sensitive magnetic sensors placed around the head to detect the magnetic fields associated with the neuronal activity.  Once the signal have been acquired, an image is formed using a technique known as beam forming which uses them to reconstruct the sources within the brain, a technique known as beam forming.  The signals acquired are typically with low signal to noise ratio, non-Gaussian distribution and correlated. Beam forming is therefore challenging. It is particularly difficult for DBS patients because artefacts arise from the coil of wire left beneath the burr hole (through which wires are taken to the battery. 119
  118. 118. Microwave imaging to diagnose breast cancer  Microwaves are an attractive imaging method for finding breast tumours as the contrast between healthy tissue and tumour is very high. However the resolution is low.  We are working to improve the interpretation of the data gathered from both phantoms and clinical images using microwave clinical imaging system developed in Bristol University.  A spin out company from Bristol University has one of the few clinical systems in use worldwide, which has been used in trials in Frenchay Hospital. This work is funded by EPSRC. 120
  119. 119. Imaging Modalities  Imaging for medical purposes involves the services of radiologists, radiographers, medical physicists and biomedical engineers working together as a team for maximum output. This ensures the production of high quality of radiological service with consequent improvement of health care service delivery. 121
  120. 120.  Technological advances have made human imaging possible at scales from a single molecule to the whole body.  By linking the anatomical data collected with emerging imaging technologies to computer simulations, researchers now can form truly functional images of individual patients.  These images will allow physicians not only to see what a patient’s organs look like but also how they are functioning even at the smallest dimensions.  A major challenge is how to store, analyze, distribute, understand and use the enormous amount of data associated with thousands of images. 122
  121. 121.  Biomedical engineering stands at the forefront of this effort because its researchers are able to integrate the engineering tools needed to solve the technological problems of image analysis with the deeper knowledge of the underlying biological mechanisms.  Already, members of the Department of Biomedical Engineering, in close collaboration with the Departments of Applied Mathematics and Statistics, Computer Science, Electrical and Computer Engineering, and Radiology, have pioneered the use of imaging technology in computational anatomy, neuropsychiatry, computer-integrated surgery and cardiac procedures. 123
  122. 122.  Now, researchers are expanding their imaging efforts into other modalities and organ systems.  Ultimately, their work will contribute to advancing image-guided therapy and to the early diagnosis and treatment of a host of disorders, including heart disease and brain dysfunction. 124
  123. 123. Included in Medical Imaging Research  Creating new systems and methods for measuring and analyzing imaging data in humans, developing mathematical and computational approaches to compare data across individuals, and applying these techniques to understand, diagnose and treat disease.  Using novel imaging techniques to provide information on three- dimensional structure and function at the molecular, cellular, tissue, organ and organism level.  Improving ways to image blood flow and cardiac motion with magnetic resonance imaging, computed tomography, ultrasound and fluoroscopy.  Finding and modeling the cerebral cortex to understand both normal and abnormal shape and the relation to genetic and environmental disease.  Developing bio-inspired algorithms for recognizing objects and actions in video. 125
  124. 124. Research - Biomedical Imaging  New developments in biomedical imaging provide a window into complex biological phenomena.  Imaging enables researchers to track the movements of molecules, cells, fluids, gases, or sometimes even whole organisms.  Imaging techniques such as x-ray crystallography and magnetic resonance imaging can also yield information about important biological structures from single proteins to the human brain.  The frontiers of biomedical imaging promise to make diagnosis of disease more accurate and less invasive, and to improve our understanding of disease. 126
  125. 125. Imaging research encompasses  Imaging of protein complexes involved in synaptic communication in the brain  Fluorescence tagging of molecules involved in intracellular signalling networks  Non-invasive imaging of cancer  Imaging of human movement using dynamic MR, motion capture systems, and ultrasonic imaging  Molecular and biochemical imaging with PET, SPECT, and optical imaging  Three-dimensional medical imaging of blood flow, blood vessels, and cardiovascular lesions  Functional human brain mapping  Strategies for fusing images across modalities (e.g., CT and MR)  Ultrasonic diagnostic technology in medicine  Computational analysis and reconstruction of complex imaging data 127