Radiology Book

Approach

  • Cat Scan

Miscellaneous

http://www.fpnotebook.com/

Cat ScanAka: CT, CT-associated Radiation Exposure

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  1. Adverse Effects: Radiation Exposure
    1. CT Radiation Exposure (average, in MilliSieverts)
      1. High dose protocols: 3-27 mSv
      2. Low dose protocols: 0.3-0.55 mSv
    2. CT radiation exposure varies by CT type
      1. CT Electron beam (EBT): 11 mSv Chest, 26 mSv Abdomen
      2. CT Sequential: 4 mSv Chest, 20 mSv Abdomen
      3. CT Spiral: 2 mSv Chest, 7 mSv Abdomen
      4. Becker (1998) Radiologe 38:726
    3. CT radiation exposure during episodic care
      1. Average radiation exposure during a trauma admission: 22.7 mSv
      2. Tien (2007) j Trauma 62:151
    4. CT Chest Radiation Exposures (in milliSieverts)
      1. Newborn: 1.7 mSv
      2. Five year old (on low dose CF protocol): 0.55 mSv
      3. Adults: 5.4 mSv
        1. Equivalent of 20 to 90 Chest XRays
      4. Huda (2007) Proc Am Thorac Surg 4:316
    5. Comparisons
      1. Standard Chest XRay (2 view) Radiation Exposure: 0.06 to 0.25 mSv
      2. Radiation from natural sources in an entire year (Germany): 2.4 mSv/year
      3. Survivors of Hiroshima and Nagasaki Atomic bombings: 50 to 150 mSv
    6. Interpretation
      1. Each 1 mSv increase in exposure leads to 5 extra malignancies per 100,000 people
      2. Thyroid radiation exposure is proportionally much higher in Chest CT
      3. Diederich (2000) Cancer 89:2457
  2. Background: Current technology
    1. 256 slice scanner
    2. 0.5 sec to complete Head CT (full body in <1 minute)
    3. 6-7 gigabytes/sec acquired
    4. 3D reconstruction
    5. CT angiography (brain, carotids, aorta, lung, coronary)
      1. CT Pulmonary agngiography
      2. CT Peripheral angiography
      3. CT Renal angiography
      4. CT Urology (stone, Hematuria, Renal Mass protocols)
      5. CT Sinus
      6. CT brain perfusion
      7. CT Aortic aneurysm
      8. CT Cardiac Imaging
        1. Gated - synchronized to EKG
        2. Real time (4D) functional study
      9. CT orthopedic trauma

X-Ray Computed Tomography (C0040405)

Definition (MSH)Tomography using x-ray transmission and a computer algorithm to reconstruct the image.
Definition (CSP)radiography in which a three dimensional image of a body structure is constructed by computer from a series of plane cross sectional images made along an axis.
Definition (NCI)A series of detailed pictures of areas inside the body; the pictures are created by a computer linked to an x-ray machine.
Definition (NCI)A method of examining body organs by scanning them with X rays and using a computer to construct a series of cross-sectional scans along a single axis.
Definition (HL7V3.0)Computed axial tomography
ConceptsDiagnostic Procedure (T060)
ICD988.38
MSHD014057
EnglishCAT, CAT - Computerised axial tomography, CAT - Computerized axial tomography, CAT scan, computed axial tomography, computed tomography, Computed X-Ray Tomographies, computed x-ray tomography, computer assisted tomography, Computerised axial tomography, Computerised tomograph scan, Computerised tomography, Computerised transaxial tomography, Computerized axial tomography, Computerized tomograph scan, Computerized tomography, Computerized tomography without IV contrast, Computerized transaxial tomography, Computerized transaxial tomography without IV contrast, CT, CT - Computerised tomography, CT - Computerized tomography, CT scan, CT scan without IV contrast, CT X Ray, CT X Rays, CT XRAY, EMI scan, Tomodensitometries, Tomodensitometry, tomography, X-Ray CAT Scan, X-Ray CAT Scans, X-Ray Computed Tomographies, X-Ray Computed Tomography, X-Ray Computerized Tomographies, X-Ray Computerized Tomography, Xray Computed Tomographies, Xray Computed Tomography
SpanishTAC, TAC - SAI, TC - SAI, tomografia axial computarizada, tomografia axial computarizada - SAI, tomografia computada, tomografia computarizada - SAI, tomografia transaxial computarizada
Parent ConceptsRadiographic Image Enhancement (C0034564), tomography (C0040395), Diagnostic Radiology Modality (C1547664), ObservationMethod - CodeSystem (C1553848), Image Interpretation, Computer-Assisted (C0020910), Tomography, X-Ray (C0040404), Diagnostic Imaging (C0011923), X-Ray Computed Tomography (C0040405), Radiographic imaging procedure (C1962945), Duplicate concept (C1274013)
SourcesAOD, CSP, HL7V2.5, HL7V3.0, LNC, MEDLINEPLUS, MSH, MTH, MTHICD9, NCI, PDQ, SCTSPA, SNOMEDCT
Derived from the NIH UMLS (Unified Medical Language System)



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