Proton therapy is a type of particle therapy that uses a beam of protons to treat cancerous tumors. Protons deposit most of their energy at the tumor site in a phenomenon known as the Bragg peak, which allows for high radiation doses to be delivered to the tumor while minimizing exposure of surrounding healthy tissue. Proton therapy offers advantages over photon therapy for tumors located near critical structures due to its ability to more precisely target the tumor site. While proton therapy is an effective treatment, it requires highly specialized and expensive equipment and its use is currently limited to treating certain cancer types. However, its use is expected to grow as costs decrease and more treatment centers are established.

1. 1

2. Author : Moslem( Michael) Najmi Nezhad , M-Sc
student in Shahid Sadoughi university of medical
science.
Supervisor : Dr Ali Parach , Faculty member of
Shahid Sadoughi university of medical science.

3. Radiotherapy
Tele Therapy
Brachy Therapy
BNCT
Targeted Therapy
2

4. Hadron therapy
Hadron: A composite particle made by
quarks heled together
HADRON
Mesunes
(1QUARKS &1ANTIQUARKS)
(Pions)
Baryons
(3 QUARKS)
(P &N)

5. Hadron Therapy
Neutron Proton Ions
(positive ions)
Particle therapy

6. Proton therapy
Proton therapy or proton beam therapy:
In the field of medical procedures is a type of
particle therapy that uses a beam of protons to
irradiate diseased tissue, most often in the
treatment of cancer.
A subdivison of hadron therapy and the most
common type of that.

7. History of Proton Therapy
Suggested by Robert R Wilson in 1946.
In 1950 experiments on uroupian patients
1955 in California .
The results was promissing but …

8. 1970 Progress in computers and cyclotrons.
1990 The first hospital-based proton treatment center
in the United States is built at Loma Linda.
70000 patients around the world treated with proton
therapy.
Half of them in america.

9. Source of proton beam
A machine called a synchrotron or cyclotron speeds up
the protons. The protons’ speed determines the
energy level. High-energy protons travel deeper in the
body than low-energy ones.
The protons go to the targeted place in the body.
There, they deposit the specific radiation dose in the
tumor.

10. Bragg peak
The distinct Bragg peak is a result of the energy
transferred in electromagnetic interactions being
inversely proportional to the velocity of the proton i.e.
as the protons slow down they lose more energy per
path length.This causes an increase in linear energy
transfer(LET) .
LET : The energy absorbed in tissue per unit length
Physics of proton-beam radiation therapy

11. figure1 : Protonrange (inwater) in cm as a function of protonenergyin MeV

12. Losing energy , together with the decreasing number
of protons as a function of depth, causes the Bragg-
peak . The number of primary protons (beam
intensity) is decreasing with depth because they stop
once they run out of energy or because they undergo
a nuclear interaction, which happens mostly in the
entrance region before reaching the Bragg peak area.
On average, about 1% of the protons undergo a nuclear
interaction event per cm range in water.

13. Figure 2: Bragg peak and beam broadening

14. Range straggling:
For a single proton, the peak would be extremely
sharp but the combination of many protons, all
having statistically slightly different ranges due to
their interactions along the path (range straggling),
causes a peak with a width of a few mm. This
phenomenon is called
range straggling.

15. Figure3 : range straggling

16. Multiple Coulomb scattering leads to a
lateral broadening of the beam as a function of depth
For large ranges in tissue (more than ∼15 cm), this can
cause the lateral penumbra of proton beams.
This is also the reason why It is desirable to have the
treatment-head exit as close to the patientas possible
(so as to reduce beam broadening due to scatter in
air).

17. Dose shaping
As with other radiation modalities, proton beams have
to be ‘modulated’ in order to conform the dose
distribution as close as possible to the target. For
instance, a tumor is typically larger than the tip of the
Bragg peak, so that the Bragg peak has to be
broadened by stacking several peaks with different
energies.
This named Range modulation or SOBP ( spread out
bragg peak)

18. Figure 4: SOBT

19. How to do the modulation
Range modulation i.e the stacking of Bragg curves
of different energies is achieved by placing
absorbers in the beam path. By using a fast rotating
absorber with individual steps of absorber
thickness to reduce the energy, the whole spread
out Bragg peak can be delivered within the time of
one rotation (which at a rotation speed of typically
around 10 Hz is more or less instantaneous).

20. The widths of the absorber step controls the beam
fluence and thus the height of each Bragg peak.
Such rotating absorbers (‘range modulator wheels’)
act like a propeller with blades that the beam goes
through, the thinnest blade resulting in the largest
range of the beam.

21. Figure 5: The range modulator wheels

22. Advantages of Proton therapy
Secondary malignancies and side effects:
Patients experience few side effects because
damage to healthy tissue and organs can be
limited and studies have even shown that
compared to traditional radiation treatments
proton therapy may significantly decrease the
estimated risk of developing secondary
malignancies.

23. Figure 6:

24. Figure 7 : Proton therapy vs photon therapy absorbing in healthy
tissue.

25. More effective than photon therapy in
destroying cancer cells.
No need for hospitalization.
Fast and non-invasive.
….

26. Treatment planning
proton treatment
requires planning Like
other external-beam
radiation therapy.

27. Treatment is delivered in a special room
Before treatment, you receive another
x-ray or CT scan

28. Time needed for each treatment
about 15 to 30 minutes once after patient enter the
treatment room
Depend on
part(s) of the body
Number of treatment segments
Number of x-rays or CT scans
Number of cyclotron or synchrotron

29. Cancers treated with proton therapy
Tumors that are near important parts of the body.
For example, tumors near the eye, brain, and spinal
cord.
Childhood cancers of the eye, brain, and spinal cord.
Proton therapy lessens the chance of harming healthy,
developing tissue.

30. May be used in treat these cancers :
Lung cancer
Liver cancer
Prostate cancer
Noncancerous brain tumors

31. Drawbacks
Proton therapy effectively treats only certain
cancer types.
highly specialized and expensive equipment …

32. Conclusion
Proton therapy feasible and effective
It Is approved by FDA .
Proton therapy experiencing a revolutionary
transition in the last few years .
In the next decade improvement in efficiency and
accuracy.

33. Figure : A gantry treatmentroomat the Texas Center for Proton
Therapy at Las Colinas

34. Figure : IBA Proton therapy cyclotron with integratedCT scanner /
with robotized positioning table .

35. References:
Proton Beam Therapy edited by
Professor Harald Paganetti
Proton and Carbon Ion Therapy edited by
C.-m. Charlie ma and Tony lomax

37. ‫سواالت‬:
1-‫چیست؟‬ ‫برگ‬ ‫پیک‬ ‫عمق‬ ‫ی‬ ‫کننده‬ ‫تعیین‬
2-‫است؟‬ ‫چگونه‬ ‫تراپی‬ ‫پروتون‬ ‫ی‬ ‫اینده‬ ‫شما‬ ‫برداشت‬
(‫دالیل‬ ‫و‬ ‫ها‬ ‫دیدگاه‬ ‫شرح‬ ‫با‬)
3-‫فوتون‬ ‫به‬ ‫نسبت‬ ‫تراپی‬ ‫پروتون‬ ‫مواردی‬ ‫چه‬ ‫در‬
‫میشود؟‬ ‫ارجح‬ ‫بسیار‬ ‫تراپی‬

38. 4-‫چیست؟‬ ‫درمانی‬ ‫پرتو‬ ‫اکسترنال‬ ‫ترین‬ ‫متداول‬
5-‫چیست؟‬ ‫تراپی‬ ‫هدرون‬ ‫ترین‬ ‫متداول‬
6-‫پرتو‬ ‫خروجی‬ ‫بودن‬ ‫نزدیک‬ ‫برای‬ ‫ما‬ ‫تمایل‬ ‫دلیل‬
‫چیست؟‬ ‫بیمار‬ ‫به‬ ‫پروتون‬
)‫؟‬ ‫است‬ ‫عبارتی‬ ‫چه‬ ‫مخفف‬ SOBT 7-(

39. ‫سواالت‬ ‫پاسخ‬:
1-‫تابشی‬ ‫پروتون‬ ‫انرژی‬.
2-‫و‬ ‫بوده‬ ‫موثر‬ ‫زیرا‬ ‫پیشرفت‬ ‫به‬ ‫رو‬ ‫همچنان‬ ‫ای‬ ‫اینده‬
‫درمان‬ ‫مراکز‬ ‫افزایش‬ ‫و‬ ‫ها‬ ‫هزینه‬ ‫کاهش‬ ‫زمان‬ ‫گذر‬ ‫در‬
‫بیماران‬ ‫عموم‬ ‫برای‬ ‫تر‬ ‫راحت‬ ‫و‬ ‫بیشتر‬ ‫ی‬ ‫استفاده‬ ‫باعث‬
‫شود‬ ‫می‬.

40. 3-‫و‬ ‫باشد‬ ‫حساس‬ ‫های‬ ‫بافت‬ ‫با‬ ‫ای‬ ‫ناحیه‬ ‫در‬ ‫تومور‬ ‫که‬ ‫وقتی‬
‫باشد‬ ‫حساس‬ ‫تومور‬ ‫از‬ ‫بعد‬ ‫بافت‬ ‫که‬ ‫زمانی‬ ‫مخصوصا‬.
4-‫تراپی‬ ‫رادیو‬ ‫فوتون‬(‫گاما‬ ‫و‬ ‫ایکس‬ ‫با‬ ‫رادیوتراپی‬)
5-‫تراپی‬ ‫پروتون‬
6-‫جانبی‬ ‫نیمسایه‬ ‫بیشتر‬ ‫هرچه‬ ‫کاهش‬
spread out bragg peak 7-

43. ‫مشکالت‬
‫صورت‬ ‫به‬ ‫صفحه‬ ‫شماره‬
‫کل‬ ‫از‬ ‫صفحه‬
‫اولبه‬ ‫کوتاه‬ ‫فهرست‬ ‫و‬ ‫اسکلت‬ ‫نداشتن‬ ‫و‬.