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“Victor Babes” UNIVERSITY OF MEDICINE AND PHARMACY TIMISOARA

“Victor Babes” UNIVERSITY OF MEDICINE AND PHARMACY TIMISOARA. DEPARTMENT OF MEDICAL INFORMATICS AND BIOPHYSICS Medical Informatics Division www.medinfo.umft.ro/dim 2007 / 2008. COURSE 1. 1. MEDICAL INFORMATICS. MEDICAL INFORMATICS – an interdisciplinary field studying :

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“Victor Babes” UNIVERSITY OF MEDICINE AND PHARMACY TIMISOARA

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  1. “Victor Babes” UNIVERSITY OF MEDICINE AND PHARMACY TIMISOARA DEPARTMENT OF MEDICAL INFORMATICS AND BIOPHYSICS Medical Informatics Division www.medinfo.umft.ro/dim 2007 / 2008

  2. COURSE 1

  3. 1. MEDICAL INFORMATICS MEDICAL INFORMATICS–an interdisciplinary field studying: Old definition: computer applications in medical practice and research Modern definition: generation, acquisition, storage, transmission, processing, protectionand use of medical information

  4. 2. INFORMATION THEORY

  5. 2.1. INTRODUCTORY NOTIONS • a) VARIABLES • deterministic • well defined values • by repeating the measurement the same valueswill be obtained • random (stochastic) • get different values even will keep the conditions • ex: throwing the dice, tossing a coin

  6. b) PROBABILITY: • EVENT = EXPERIMENT’S RESULT • FREQENCES: • ABSOLUTE - ni • RELATIVE - ni / N, S ni = N • FIELD OFEVENTS: • EVENTS X1 X2 . . . Xk • ABS.FREQ. n1 n2 . . . nk • DEFINITION OF PROBABILTY: • EXAMPLES

  7. c) FIELD OFPROBABILITIES: • - EVENTS X1 X2 . . . Xk • - PROBABILITIES p1 p2 . . . pk • TYPES OF EVENTS: • - certain event - - - - p = 1 • - impossible event - - - p = 0 • - equelprobabile events pi = pj

  8. 2.2. NOTION OF INFORMATION • a) Definition: philosophical category (with high degree of generality) definedby properties: Basic property: ‘REMOVING AN UNCERTAINTY’ • b) Information nature: • it’s not substance • it’s not energy

  9. c) Complete approach (triadic): • matter structure • Energy support • information (function) • d) Utility valueof information • dependson the receptor • examples

  10. 2.3. AMOUNT OF INFORMATION • a) FOR ONE EVENT (Shannon) Ii = log2 (1/pi) = - log2 pi • b) UNIT of measure: BIT (Binary digIT): 1 bit removes an uncertainty of 1/2

  11. c) INFORMATIONAL ENTROPY • AVERAGE INFORMATION OF ONE EVENT IN A MESSAGE OF LENGTH “N” Im = (n1I1 + . . . + nkIk) / N Im = H = S piIi H = - S pi log2 pi

  12. d) FOREQUIPROBABLE EVENTS • pi = 1 / k , H = Hmax = log2 k • e) Examples: oneproteic sequence of 100 amino acids • k = 20 aa , p = 1 / 20 • H = 20 ( (1/20) log2 (1/20) ) = 4,5 bit/aa • Itot = 100 x 4,5 = 450 bit • f) The relation with the thermodynamic entropyand order(Maxwell’s demon)

  13. 2.4. REDUNDANCY • a) DEFINITION: - ABSOLUTE REDUNDANCY R = HMAX - HREAL - RELATIVE REDUNDANCY Rr = R / HMAX • b) UTILITY: to decrease perturbations effects in the information transfer process

  14. 2.5. COMMUNICATION SYSTEMS • a) DEFINITIONS: MESSAGE = the informationwhich istransmitted SIGNAL = the physical support forthe message

  15. b) THE COMMUNICATIONSYSTEM SCHEME S = source (emmitter) R = destination (receptor) C = communication channel N = perturbations (noise)

  16. c) TRANSDUCERS = device which changes d) MODEMS = MOdulation / DEModulatione) CODING = translationfrom one alphabettoanotherf) THE CHANNEL CAPACITY = bits/seconds (bps,baud)

  17. 2.6. INFORMATION TRANSFER IN BIOLOGICAL SYSTEMS • a) THEGENETIC CODE: • DNA, 4 bases (A - T / U, C - G) • REPLICATION, CODONS • b) CODINGIN NERVOUS SYSTEM • - FREQUENCY - ONAXONS • - AMPLITUDE - DENDRITES, SYNAPSES • c) EXTERNAL INFORMATION - sense organs • d) INTERNAL INFORMATION - interorceptors

  18. 3. MEDICAL INFORMATION

  19. 3.1. MEDICAL INFORMATION • PACIENT – PHYSICIAN RELATION • ELEMENTARY CYCLE OF MEDICAL ACTIVITY • MEDICAL INFORMATION USED IN MEDICAL ACTIVITY: • DATA – individualcharacter - facts • KNOWLEDGE – generalcharacter - concepts

  20. 3.2. ELEMENTARY CYCLE OF MEDICAL ACTIVITY

  21. Level of medical information Structural level Studied by: Domain Chapter in IM Infra-individual level Molecular / subcellular Molecular Biology and Genetics Life Sciences Bioinformatics Cell / tissue Cell Biology Organ / System Physiology Neuro -informatics Brain Theory Cognitive Sciences Individual level Whole organism (‘pacient’) Paraclinical Disciplines (investigations) Clinical Disciplines (diagnosis, treatment) Medical Sciences Clinical Informatics Supra-individual level Community Public Health Health Sciences Health Informatics Healthcare Activity Healthcare Management 3.3. Medical Information Classificationon Structural Levels

  22. 3.4. TYPES OF DATA • QUALITATIVE – Anamnesis (descriptive) • NUMERICAL – Laboratory investigations • GRAPHICAL – Biosignals (ECG, EEG…) • SOUNDS: Phonocardiogram • STATIC IMAGES: X-Ray, NMR • DYNAMIC IMAGES – movies

  23. 3.5. Operations with information • Generation (biomedical process or action) • Acquisition(collection) – dependson information nature • Storage – data bases, knowledge bases • Processing – for interpretation • Transmission • Protection • Use

  24. 4. CHAPTERS OF MEDICAL INFORMATICS Ist PART. DATA • STORAGE - DATABASES • ACQUISITION & PROCESSING: • NUMERICAL & QUALITATIVE – BIOSTATISTICS • SIGNAL PROCESSING, MEDICAL IMAGING IInd PART. MEDICAL KNOWLEDGE • MEDICAL DECISION SUPPORT • EXTRACTION & FORMALIZATION OF MEDICAL KNOWLEDGE IIIrd PART. HEALTHCARE INFORMATICS • INFORMATION SYSTEMS

  25. END

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