Positron Emission tomography/Computed tomography

positron emission tomography

a medical

imaging technique that allows

quantitative in vivo

measurements of 3D

distributions of

positron-emitting tracers

18F-fluorodeoxyglucose (FDG)

is the most common and widely used

PET tracer in oncological

applications.

FDG basically proves a measure of ____, and it is mainly used to detect malignancies.

PET SCAN

an effective way to help identify a variety of

conditions, including cancer, heart disease and brain disorders.

• detection of cancer

• Revealing spread of cancer

• Check cancer response to treatment

• Cancer recurrence

Which ways is PET scans useful?

PET, pico- or nanthatomoles

• a molecular Principles of imaging technique which measures the PET/CT distribution of a radioactive tracer in vivo.

• Upon administration of very small amounts (______) of a radiotracer to the patient it distributes among and within the organs

positrons

The radioactive atom of the radiotracer emits ____. The

emitted positron combines with an electron after travelling a

distance up to several millimetres in tissue

511 keV

What is the energy value of a photon?

Annihilation coincidence

The process in which positron and electron are converted into two photons which are emitted in nearly opposite directions (180 degreee)

Random coincidence

Coincidence detection of two uncorrelated photons

Scatter coincidence

One or both photons formm a single even produced from compton scattering

True coincidence

Arise form the simultaneous detection of two annihilation photons generated by one positron emission

Random coincidence

arise from the

‘simultaneous’ detection of two uncorrelated photons,

i.e. photons coming from two different positron

emissions.

Causes loss of coincidences

Effect of Attenuation Correction on coincidences

Compton scattering

The main cause of scattering events for 511-keV photons is

______, where the photon interacts with (‘hits’)

an electron.

estimating the scatter distribution/contribution using a single scatter simulation method described by Watson et al

most frequently applied scatter correction

method in PET

O-15, N-13, C-11, and the hydroxyl analog, F-18

Positron-emitting radioisotopes in organinc substances are?

Ann Arbor system

helps guide treatment

decisions and predict prognosis in lymphoma.

As the stage progresses from 1 to 4, the disease

becomes more widespread and complex to

treat

IV insulin administration

Increased insulin secondary to elevated blodd glucose

Interfering drugs