Imaging with Positron Emission Tomography/ Computed Tomography (PET/CT)

Lisa Rhoden (RT)(R) B.S. CNMT

PETPET permits investigation and comparison of

events occurring at the molecular and cellular level.This data is not attainable by other modalities.

PET is especially useful in the detection of cancer, coronary heart disease, and brain disease.

The basis of PET is the positronThe positron is a positively charged beta particle

emitted from neutron-poor radionuclides.The result of this emission are annihilation

photons that create 2 gamma rays of exactly 511 keV each, at 180 degrees to each other.

Positron Decay

Annihilation - two photons

-+

511 keV

511 keV

180oPositronium

For more on Positron Decay click

PET/CT vs. PETThe ability to have the CT localization makes

interpretations more accurate PET/CT has advantages to the patient in

making the acquisition time shorterThere is more accurate attenuation

correction with PET/CT

PET/CT Machine

Protocol:Dose Receiving

•Upon receiving a dose shipment from the pharmacy, the technologist must check it in

•This includes measuring the radioactivity in mR at the surface of the box and at one meter away.

•All measurements are recorded and kept

Protocol: Patient Prep (at UAMS)Patient is to be held

NPO (with the exception of water) a minimum of six hours prior to injection time

No insulin or Dextrose-5 should be given to the patient for a minimum of six hours prior to injection

The patient may receive 5-10 mg of Valium before the injection is given

The patient should be made comfortable and relaxed

Did the patient follow the prep

correctly? YES NO

Protocol: Blood Glucose LevelA blood glucose level will be obtained prior to

injection and recordedOptimum blood glucose level is below 150

mg/dL

Below 150 mg/dL

Above 150 mg/dL

Select the patient’s blood

glucose level

Next: Assay the Dose

The tech will then do background counts and a wipe test

Next the dose will be assayed, or measured for radioactivity in the dose calibrator

Protocol: Isotope InjectionAn IV will be started and used to administer the

radioactive tracerPatient will wait 2-3 hours to allow the isotope to

be taken into the cells

Protocol Cont.Patient will drink

approximately 300 cc of contrast containing Omnipaque (iohexol) 300 mgI/ml

Remove metallic objects

Empty bladder

Protocol Cont.Position for scanningPatient position will be determined based

on area being scanned

Data Acquisition and Processing

Colorectal Carcinoma

CT PET FUSED

Breast Cancer

CT PET Fused

Review Basic PET Process

Isotopeproduction(cyclotron)

Tracerlabeling

(radiochemistry)

Tracerinjection &

data acquisition

Imagereconstruction Interpretation

Datasynthesis

Thank you for your time

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