1. Positron Emission Tomography
Near East University
Positron Emission Tomography
BME 350 :Radiology Physics

2. By
Abubakar Yakubu
Hosam Abdulaal
Hadya Mahmoud
Mushtak Ibrahim
Nuhu Abdulhaqq Isa
Sarah Muzenda
Frank Maponga
Mandy Sizalobuhle Mpofu
Muhammad Awadh
Muhammad Bin Munef
Aya Chebib

3. Contents What is Nuclear Medicine ? What is PET-CT ?
Physics Behind the PET
Basic Of Positron Emission Tomography
Physical working principle of PET
PET design & parts
Cost
Advantages Of PET Scan
Disadvantages Of PET Scan
Conclusion

4. What is Nuclear Medicine ?
Fundamental concept Nuclear medicine over others Brief history Role of physics

5. Fundamental concept
Scientifically and clinically defined as the use of a number of trace compounds labelled with radioactivity providing a lot amount of data on the sate of a disease.
Radionuclide decay and emit gamma rays or high energy photons.
External camera detects the gamma rays or photons and create an image

6. http://prospect. rsc. org/metalsandlife/ https://giphy

7. Power and Importance of Nuclear Medicine over others
Sensitivity and specificity to biologic processes underlying diseases.
Modalities in MRI, X-RAY, CT are less in their ability to provide biological data
E.g. MRI has lower limit of detection in millimolar concentration tissue
Nuclear Medicine can detection can range from nano or pico molar concentration per tissue

8. The role of physics in nuclear medicine
A significant part in providing quality images, less cost, and safety.
Physics of nuclear medicine will not change but its technology will

10. Very Brief History and Current Practice
Discovery of radioactivity in 1896 and 1898
Biological foundation laid in 1910 and 1945
Used on humans in 1927
Artificial radionuclide produced in 1930s
In 1950s, we could produce images of the distribution of radionuclide
1951 and 1958 rectilinear scanner and anger camera were developed

11. Very Brief History and Current Practice
Discovery of radioactivity in 1896 and 1898
Biological foundation laid in 1910 and 1945
Used on humans in 1927
Artificial radionuclide produced in 1930s
In 1950s, we could produce images of the distribution of radionuclide
1951 and 1958 rectilinear scanner and anger camera were developed
1960s specificity in radionuclide
Mathematical algorithms lead to PET and SPECT creation

12. What is PET-CT ? WHAT IS A PET SCAN?
PET stands for “positron emission tomography”.
It is a nuclear medicine imaging test in which a small amount of liquid radioactive material is injected into your body and is used to diagnose a variety of diseases, including many types of cancers, heart disease and other diseases.

13. PET-CT IMAGE

14. PET scanners are now commonly combined with computed tomography (CT) scanners, called PET-CT scanners.
CT imaging uses X-ray equipment to create detailed images of slices of the inside of your body.
The PET-CT combination allows any abnormality on the PET scan to be precisely located within the body, allowing for more accurate diagnosis of any problems.
The PET or PET-CT scanner looks like a large box with a circular hole in the middle.

15. Physics Behind the PET

16. Multiple scatter in tissue Annihilation with electron
Decay of radionuclide
Positron Emission
Multiple scatter in tissue
Annihilation with electron
Production of annihilation photons

17. Radioactive isotopes are atoms which are unstable, they possess a lot of energy
In decay, a nuclide transforms one of its protons to a neutron thereby emitting a positron (B+)
At the end of the path the B+ will annihilate with atomic electron. It will then convert the mass to energy then produces a pair of 511 keV photons moving in opposite directions
Annihilation photon interaction with human tissue is known as Compton scatter

18. Basic Of Positron Emission Tomography

19. Pet uses radiotracers which emits positrons(FDG).
Cancer cells absorb more sugar.
They release positrons.
Annihilation process is produced by the Gamma rays
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20. Journal of nuclear medicine technology
Two anti-parallel 511KeV photons.
The line between two an annihilation Is called line of response.
LOS is used for image processing.
Journal of nuclear medicine technology

21. Detects Events In PET
True coincidence: two photons are detected at the same time in opposite direction.
Scatter coincidence: the photons are detected different time.
Random coincidence: detection of two photons from different annihilation.
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22. Physical working principle of PET

23. The scan uses a special dye that has radioactive tracers.
These tracers are injected into a vein in your arm.
Your organs and tissues then absorb the tracer.
When highlighted under a PET scanner, the tracers help your doctor to see how well your organs and tissues are working.
The PET scan can measure blood flow, oxygen use, glucose metabolism (how your body uses sugar), and much more.

24. Scan time
The radiotracer typically takes from 45 minutes to 1 hour to travel throughout the body and be absorbed into the organs or tissues to be examined.
The scan may last 30 to 60 minutes. The heart and brain studies take less time for imaging. Patients are required to be still for the entire length of the exam, since motion will reduce the quality of the images.
Depending on which organ is being examined, there may be additional tests and additional dyes or chemicals used that may lengthen the total appointment time up to 2 to 3 hours.
For example, patients being examined for heart disease may undergo a stress test.

25. Typical Scan Procedure
Before the scan, the patient gets tracers via a vein in the arm ,or via a solution ,or via a gas . The body needs time to absorb the tracers.
During the scan, the patient lies on a table attached the PET machine. The table glides slowly into the machine so that the scan can be conducted.
The patient is required lie still during the scan. The patient may be asked to hold your breath for short periods.
When all the necessary images have been recorded, you will slide out of the machine. The test is then complete.

26. After a PET Scan
After the test, you can go about your day unless your doctor gives you other instructions.
Drink plenty of fluids after the test to help flush the tracers out of your system. Generally, all tracers leave your body after two days.
Meanwhile, a trained specialist will interpret the PET images and share the information with your doctor. Your doctor will go over the results with you at your follow-up appointment.

27. PET design & parts

28. What does the PET look like?

29. A PET scanner is a large machine with a doughnut shaped hole in the middle
It is similar to a CT or MRI unit. Within this machine are multiple rings of detectors that record the emission of energy from the radiotracer in your body

32. Cost

33. There is one cost factor that is more telling than any other: slice count. The more slices the CT portion of the machine can capture, the more you'll pay for it.
$95,000 - $125,000
Single-Slice
Dual-Slice
GE Discovery LS4
6-slice
8-slice
$125,000 - $300,000
16-slice
$400,000 - $550,000
64-slice

34. One of the common misperceptions about PET is that it is costly.
PET is generally considered an “expensive” imaging test, yet when compared with the collect charges of contrast-enhanced CT studies of the neck, chest, abdomen, and pelvis, the cost of PET imaging may be quite comparable.

35. Advantages Of PET Scan

36. It’s more effective in diagnosing than other imaging tests because of its ability to study the function of the body through biochemical functions means that it is able to detect disease before changes in the anatomy become apparent.
Is effectively used to diagnose the early stages of neurological illnesses such as Alzheimer’s disease, epilepsy and other dementias.

37. Its ability to distinguish between benign (non-cancerous) and malignant (cancerous) tumours make it a more accurate medical tool that can reduce the number of unnecessary surgeries performed due to incorrect diagnosis and staging data.
By studying metabolic functions in patients, PET imaging is able to be used as an alternative to biopsy and other exploratory surgeries to determine how much a disease has spread.

38. Disadvantages Of PET Scan

39. Risk from radioactive materials used during the procedure
Short period of the radioactive components which will require longer time scanning
It is a very expensive procedure
Difficult treatment to use

40. Poor local tumour description
The scan can cause claustrophobic and discomfort
Invasive use
Has low spatial resolution when compared to other procedures

41. Conclusion

42. Positron emission tomography (PET) is a gamma imaging technique that uses radiotracers that emit positrons.
In PET the gamma rays used for imaging are produced when in-vivo, when an encounter that annihilates both electron and positron to produce two gamma rays travelling in opposite directions.
By mapping gamma rays that arrive at the same time the PET system is able to produce an image with high spatial resolution.

43. Another advantage of PET over procedures that employ gamma emitting tracers is the greater availability of suitable isotopes.
Positron emitting isotopes of biologically active elements such as fluorine, carbon and oxygen are all available.
PET machine is expensive thus the scans are expensive.
PET can also be used to map brain function and the diagnosis of conditions such as Alzheimer’s disease.

44. References www.pancreaticcentre.com.au/wp-content/uploads/PET2.jpg
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Physics in nuclear medicine / Simon R. Cherry, James A. Sorenson, Michael E. Phelps.—4th ed. 2012
42&espv=2&biw=1242&bih=602&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjPi7 n-pazTAhVBjCwKHS3eAz4QsAQIHg#imgrc=CZ-pDTtt_qNkXM