Asli yildirim
Download
1 / 29

ASLI YILDIRIM - PowerPoint PPT Presentation


  • 189 Views
  • Uploaded on

ASLI YILDIRIM. Medical applications of particle physics General characteristics of detectors (5 th Chapter). APPLICATIONS OF PARTICLE PHYSICS. Medical applications such as producing X rays, protons, neutrons for diagnostic or treatment purposes. Security such as nuclear waste monitoring

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 ' ASLI YILDIRIM' - lynley


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
Asli yildirim

ASLI YILDIRIM

Medical applications of particle physics

General characteristics of detectors (5th Chapter)


Applications of particle physics
APPLICATIONS OF PARTICLE PHYSICS

  • Medical applications such as producing X rays, protons, neutrons for diagnostic or treatment purposes.

  • Security such as nuclear waste monitoring

  • Industry

  • Biomedicine


Medical imaging
MEDICAL IMAGING

  • X Rays

  • Computational Tomography

  • Magnetic Resonance Imaging

  • Ultrasound

  • Positron Emission Tomography


Medical imaging1
MEDICAL IMAGING

  • X Rays

  • Computational Tomography

  • Magnetic Resonance Imaging

  • Ultrasound

  • Positron Emission Tomography


Positron emission tomography
Positron Emission Tomography

* After injecting radiotracer to human body, gamma rays produced and detected.

* This information is transformed into images by using tomography tecniniques.



Examples of radiotracer
Examples of radiotracer

  • Radioactive chemical that can be injected into vein, swallowed or inhaled

  • Produced in cyclotron



Compton scattering and photoelectric absorption
Compton scattering and photoelectric absorption

  • Photon can loose energy through Compton scattering and scattering changes direction of photon

  • Under certain energy levels, photon can be absorbed by an atom.



Scattered coincidence
Scattered coincidence

After first detection, one of detected photons has undergone Compton scattering


Random coincidence
Random coincidence

Two photon from different annihilation


Pet detector
PET Detector

Gamma rays

Photo sensor

Scintillation

crystal

Pre-Amplifier

Electronics

Its converts gamma rays to optical photons

It converts light into electrical signal

It prepares the signal for computational processing


Scintillatior
Scintillatior

  • Spatial resolution


Thicker detectors improve sensitivity, but spatial resolution becomes worse

Thinner detectors give better resolution and better images but they have lower sensivity


Detectors
Detectors resolution becomes worse

  • PMT

  • Solid state detectors

  • Photodiodes

  • Silicon PMT

    Photodiodes

    Avalanche photodiodes

PMT

PD

SPMT

SSD


Properties of system
Properties of system resolution becomes worse

  • Spatial resolution is 1- 5 mm

  • Detection efficiency is higher than 30 %

  • Time resolution is 1-10 ns

  • Energy resolution is about 20 %

  • Can detect 107-108events

  • Expensive


Computed tomography
Computed Tomography resolution becomes worse

  • Computed x-ray tomography is a technique in which the x-ray source and detector screen are moved in opposite directions

  • Also system moves around object to produce images slices that can be converted into 3d picture


General characteristics of detectors (5 resolution becomes worseth Chapter)



Sensivity
Sensivity we can observe it.

  • Capability of producing signal for a given radiation

    • Cross section for ionizing reactions

    • Detector mass

    • Detector noise

    • Protective material


Detector response
Detector response we can observe it.

Response is relation between radiation energy and output signal.

Energy Resolution

Ability of distinguish very close energy levels


Response function
Response function we can observe it.

  • Spectrum of pulses observed in detector when monoenergetic beam is sent to detector

  • Related to different interactions , design and geometry


Example
Example we can observe it.


Dead time
Dead time we can observe it.

  • Required time for detector to process an event

  • All other electronics have their own dead times


Extendable nonextendable dead times
Extendable- we can observe it.Nonextendable dead times

Non-extendable occurs when detector looses its sensitivity during dead time

Extendable occurs when detector does not loose its sensitivity during dead time


Detector efficiency
Detector we can observe it.efficiency

  • Intrinsic Efficiency

    • Related to radiation interacting with detector

  • Geometric Efficiency

    • Related to part of the radiation which is intercepted by detector.


References
References we can observe it.

  • W.R Leo, Techiniques for nuclear and particle physics experiments, pages 107-118

  • http://depts.washington.edu/nucmed/IRL/pet_intro/toc.html, accessed on 11/14/2010

  • www.bnl.gov/ncss/files/.../NucChemSummerSchool-072106-v2.ppt, accessed on 11/14/2010

  • www.physics.usyd.edu.au/astromed09/Talks/Day2/Cherry_invited.ppt, accessed on 11/14/2010

  • www.fnal.gov/gridfest/pdfs/benefits_factsheet.pdf, accessed on 11/14/2010

  • www.physics.ucla.edu/~arisaka/.../Physics89_PET.pdf, accessed on 11/14/2010

  • http://serc.carleton.edu/research_education/geochemsheets/techniques/CT.html, accessed on 11/14/2010

  • http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm115317.htm#5, accessed on 11/14/2010

  • www.jsgreen.tamu.edu/427%205%20Medical%20imaging.ppt, accessed on 11/14/2010


ad