Medical Cyclotron

1. Principles and Applications of
Medical Cyclotrons
M.R.A. Pillai
Molecular Cyclotrons Pvt. Ltd
Cochin, India
Pillai.m.r.a@gmail.com
Sri Lanka Atomic Energy Board
International Atomic Energy Agency (SRL 6308)
27-31 March 2023

2. Topics
• Genesis of medical cyclotron
• Atomic Physics
• Nuclear Physics
• Accelerator
• Cyclotron
• Classification of Cyclotrons
• Application of Medical Cyclotrons
2

3. Twentieth Century is the Century
of Physics
• Discoveries
• Electron, Proton, Neutron, Positron, Alpha particles and
list goes on
• Theory of relativity
• Matter can be converted to energy
• E= mc2
• Invention of machines
• Particle accelerators
• Cyclotron
3

4. Exploring the atom
• The size of an atom is 10-8 cm (Å )
• The wavelength of X-rays is 0.1 to 1 Å
• X rays could be used for studying atomic structure
• X-ray diffraction
• X-ray crystallography

5. Exploring the Nucleus
• Size of the nucleus is 10-12 cm
• X-rays could not be used to study the nucleus because
the wavelength is too large
• Needed something which has wavelength smaller than
that of the nucleus
• Particles have wavelength smaller than the nucleus

6. Atomic Nucleus
• Discovery of Atomic Nucleus by Rutherford by alpha
scattering
• The alpha particles got deflected when came close to
the nucleus.

7. Discovery of Artificial Radioactivity
Irène Joliot-Curie and Frédéric Joliot
• Alpha particles of Polonium
were impinged to aluminum
• The emission persisted even
after removing Polonium
source
• 27Al + 4He → 30P +1n
• Alchemie became true in
1934
1935 Nobel prize in chemistry

8. Nobel Laureate Family
Five Nobel Prizes among four Individuals out of
the 954 Nobel Laureates
1903 Physics
1911 Chemistry
Marie Curie
1869-1934
Pierre Curie 1859-1906
Irene Curie 1897-1956 Frederic Joliot Curie 1900-1958

9. Charged Particles: The need
• Particles cannot enter the nucleus of an atom unless
the coulomb barrier is overcome
• Hence, higher energy particles were needed

10. A particle Accelerator
A positively charged particle enters a negative electrode and
gets accelerated. The polarity of the electrode is reversed in
order to push the particle to the next electrode.

11. Particle Accelerator
• An accelerator is a machine which can make high
energy particles
• An electron if removed from hydrogen atom it
becomes a proton
• The proton is pulled through a series of electrodes
kept at higher and higher voltages
• The polarity of the electrode keep flipping from
negative to positive to negative
• As the particle passes through the electrodes it
becomes energetic or charged particles

12. European Organization for Nuclear
Research (CERN) Particle Physics
Laboratory

13. Cyclotron
• As the energy of the particle increased the length
of the electrodes increased
• A brilliant idea stuck to one of the physicists, Ernest
Orlando Lawrence
• Can I apply a magnetic field to bend the particle
and keep it in a circular path?

14. E.O. Lawrence (1901-1958)
Nobel Laureate 1939
5- inch tiny cyclotron built in 1931

15. Berkeley Cyclotrons
15
37 Inch cyclotron 1932 60 Inch Cyclotron 1939

16. 16
The magnet yoke for the 37-inch cyclotron on
display at the Lawrence Hall of Science,
Berkeley California

17. Principle of Cyclotron:
Two Ds in between two Electromagnets

18. Cyclotrons:
The size increases as the energy increases

19. Application of Cyclotrons
• Nuclear Physics Studies!!!!
• But the most important use is to make
radioisotopes
• The major application of cyclotrons today is to
make FDG and other PET radiopharmaceuticals
• ~There are over 1500 cyclotron facilities
around the world
• IAEA has a database featuring 1300 of these
cyclotron facilities from 95 countries.

20. Radionuclide Production
Accelerators
Proton
Neutron
𝟗
𝟏𝟖
𝐅
𝟖
𝟏𝟖
𝐎
(+)
(+)
18O(p,n)18F

21. Type of Cyclotrons
• Low energy cyclotrons, 11-20 MeV
• For (p,n) reaction
• PET radiopharmaceuticals production
• 11C,13N, 15O, 18F, 68Ga etc.
• Medium Energy Cyclotrons 20-30 MeV
• (p,2n) (p,3n) reactions
• SPECT radiopharmaceuticals
• 67Ga,111In, 123I, 201 Tl, 68Ge etc.
• High Energy 70 MeV and upwards
• (p,xn) reactions
• Spallation reaction for making several isotopes
21

22. Beams available in cyclotrons
• Proton beam (H+)
• Made by ionization of hydrogen
• Deuteron beam (d+)
• Deuterium beam made by ionization of deuterium gas
• Alpha beam (3He+ and 4He+)
• We are happy with a proton beam only when it
comes to most nuclear medicine applications
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23. PET-CT Imaging is the modern
tool for Cancer Staging
23
a b c
68Ga-PSMA-11

24. Cancer Management
• Diagnosis
• Staging
• Monitoring the Response to Therapy and
• Recurrence Evaluation
Staging cancer is the most crucial as treatment
option is decided based on the stage
• Surgery, Chemotherapy, Targeted Therapy,
Radiation Therapy or a combination of the above?
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25. 25
Positron Emission Tomography
(PET)- Computed Tomography (CT)
PET-CT imaging
PET-CT imaging in progress at the
DDNMRC, Trivandrum

26. 26
PET-CT images
PET and CT Images of a woman with breast
cancer before and after treatment with four
courses of chemotherapy
Whole-body PET-CT imaging of a Prostate
Cancer Patient using Na18F

27. PET in Neurology
Courtesy: Dr. Shanmuga Sundaram , Amrita Hospital

28. 28
Thank you