Computed tomography ct retrospective prospective
Download
1 / 18

Computed Tomography (CT) Retrospective/Prospective - PowerPoint PPT Presentation


  • 127 Views
  • Updated On :

Computed Tomography (CT) Retrospective/Prospective. Radiation Protection and Control for New Applications of Existing Technology Robert M. Gagne, Ph.D. Office of Science and Technology. What are the objectives of the presentation?.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Computed Tomography (CT) Retrospective/Prospective' - kosey


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Computed tomography ct retrospective prospective l.jpg

Computed Tomography (CT)Retrospective/Prospective

Radiation Protection and Control for New Applications of Existing Technology

Robert M. Gagne, Ph.D.

Office of Science and Technology

TEPRSSC 2000


What are the objectives of the presentation l.jpg
What are the objectives of the presentation?

  • Update on actions pertaining to Computed tomography fluoroscopy (CTF)

  • Take a retrospective look at CDRH activities in the CT arena

  • Take a prospective look at new applications of CT equipment

  • Identify any unique radiation protection and safety considerations

TEPRSSC 2000


Ctf special interest l.jpg
CTF - Special Interest

  • Dose and imaging performance of computed tomography fluoroscopy (CTF)

    • new real time imaging application for existing technology (CT)

  • similarities between traditional interventional fluoroscopy and CTF

  • sensitize users to exposure levels and possibility of radiation injuries

TEPRSSC 2000


Ctf general description l.jpg
CTF - General Description

  • Continuous scans of a section of the patient

  • 50 seconds of CTF at 1 rotation per second

    • 50 rotations of x-ray tube about the patient

  • Cross-sectional images updated at a rate of 6-9 images per second

    • “real time” imaging

  • If no patient motion during procedure, one strip of skin gets the “full brunt” of the radiation exposure

TEPRSSC 2000


Slide5 l.jpg

Entrance Dose

CTF

1 - pre market submittal

2 - Nawfel et al, AAPM Annual Meeting (1998)

na - not available

TEPRSSC 2000


X ray fluoroscopy or x ray ct l.jpg
X-Ray Fluoroscopy or X-Ray CT?

  • Applicability of requirements in Performance Standard

    • difficult, if not impossible, to fit to CTF

    • how to regulate appropriately?

  • Short and long term actions

    • in process

    • data gathering (NEXT 2000)

    • possible amendments to Performance Standard

TEPRSSC 2000


Ct retrospective look l.jpg
CT - Retrospective Look

  • Amendments to Performance Standard (21CFR1033, Sept 1985)

    • dose labeling in User Manual

    • performance criteria for light localizers and table increment

  • CT characteristics at the time

    • 10 mm slice thickness

    • contiguous scans and consecutive table increment

TEPRSSC 2000


Ct axial scanning 10 mm slice l.jpg
CT - Axial Scanning(10 mm slice)

X,Y

Table motion after scan complete

Tissue Imaged Volume

TEPRSSC 2000


Ct retrospective look9 l.jpg
CT - Retrospective Look

  • Relevance and adequacy of regulations for new applications of CT equipment

  • Helical or spiral CT

    • fast scanning technique

    • new technological considerations

  • New CT applications

    • CTF

    • angiography

    • multiphase contrast studies

TEPRSSC 2000


Ct spiral scan 10 mm slice 2 1 pitch l.jpg
CT - Spiral Scan(10 mm slice, 2:1 pitch)

X,Y

Z

Table Motion

Tissue Imaged Volume

TEPRSSC 2000


Slide11 l.jpg

CT - Prospective Look

  • Multi-slice spiral CT

    • fast volume scanning technique

    • renaissance in CT

TEPRSSC 2000


Ct multi slice spiral scan 2 10 mm slices 1 1 pitch l.jpg
CT - Multi Slice Spiral Scan(2-10 mm slices, 1:1 pitch)

X,Y

Z

Table Motion

Tissue Imaged Volume

TEPRSSC 2000



Radiation protection and safety l.jpg
Radiation Protection and Safety

  • Relative contribution of CT to the dose per capita

  • Fraction of all radiological examinations (3-4 %)

  • 10 - 40 % of total dose contribution

TEPRSSC 2000



Use education and training l.jpg
Use, Education and Training

  • Selection of operating parameters

    • strong dependence on dose

  • User training and education

    • complicated equipment

      • analogy to interventional fluoroscopy

      • sensitivity to possible exposure levels

  • European approach

    • reference dose values and related guidelines

TEPRSSC 2000


Physical and technical aspects l.jpg
Physical and Technical Aspects

  • Added filtration, shaped filters, detector technology

    • improvements by percent not factors

  • Automatic exposure control

    • low attenuation = low mAs

    • for example, pediatric vs adult patients

    • AP vs LAT projections within a scan

    • not available in CT

TEPRSSC 2000


Summary l.jpg
Summary

  • Renaissance in CT

    • new applications with significant benefits

  • Have user and equipment programs kept up with changes?

  • Dose per capita significant

    • fertile area for dose improvement with an impact

  • Open for suggestions

    • not necessarily regulatory approaches

TEPRSSC 2000