the physics and clinical applications of brachytherapy

2. BRACHYTHERAPY

3. TYPES OF BRACHYTHERAPY

8. Brachytherapy types according to dose rate:-
HDR LDR
Remote after
Loading
Radiation
protection

11. CHARACTERISTICS OF SOURCES
The choice of an
appropriate photon emitting
radionuclide for a specific
brachytherapy treatment
depends on several
relevant physical and
dosimetric characteristics

12. 60Co
137Cs
192Ir
103Pd
90Sr/9
0Y

15. Brachytherapy photon sources are available in
various forms :-
pellets

16. The use fullness of brachytherapy radiation consist:-
less therapeutic
use
g rays
X rays
Alpha rays
Pitta rays

17. Why brachytherapy sources capsulated:-
*
*
*

18. The choice of appropriate radionuclide for
brachytherapy depend on: -
;
Inverse square
fall-off of dose

19. The source HVL The form Half life Photon
energy
Dose rate
Ir-192 3 wires 73.8 d 0.38 1.12
co60 11 pellets 5.26 yrs 1.25 1.11
Cs-137 6.5 needles, 30 yrs 0.66 1.11
Au-198 2.5 seeds 2.7 d 0.41 1.13
I-125 0.02 seeds 60 d 0.028
Pd-103 0.01 seeds 17 d 0.021

20. Ir-192
co60
Suitable for HDR BT specific activity indirect proportional to
half life
specific activity too low
Cs-137 half life too short
I-125 energy too low
Pd-103 energy too low
Ra226 gaseous daughter product
Sm145 energy too low
Yd159 energy too low

21. COMPARISON OF 60CO AND 192IR

22. The EBRT representing about 80% of the radiotherapy
treatment while BART representing about 20% but
currently brachytherapy become more popular specially
with discover machine (HDR) and elimination of hazers

23. • Brachytherapy treatment done in tow ways
•
brachytherapy
Mono-therapy boost

24. Monotherapy
common
uses
Endometrial stage 1B option
Oral cancer /nasal
carcinoma/T1N0&T2N0 option
Prostate cancer T1-2Ta option
Recurrent NPH/OPH/Oral cancer
Option
Selective Localized breast cancer N0
After BCS option

25. Common BARTBoost
After EBRT
Breast cancer after BCS option
Cervical cancer stage 1B1--IVA
Endometria cancer stage 1C—111C
Prostate cancer options
Low—intermediate risk
sarcoma

26. CLINICAL USE AND DOSIMETRY
SYSTEMS
• Gynecology:- commonly Intracavitary brachytherapy
• A cervix applicator consists
• of a central tube (tandem)
• and lateral capsules
• (avoids or colpostats)

27. techniques

28. Dose specification:- the most common does specific systems
The dose to four points: A, B,
bladder and rectum. The
duration of the implant is based
on the dose rate at point A,
which is located 2 cm superior to
the cervical os and 2 cm lateral
to the cervical canal.Point B is
defined 3 cm laterally to point A
Manchester
ICRU system is relates the
dose distribution to the
target volume rather than to
a specific point.
ICRU

31. Tandem -1/3 of the way
between S1 –S2 and the
symphysis pubis
2D IMAGI OF
PANNING IN CA
CERVIX

32. The axis of the tandem
should be central
between the ovoids
2D IMAGI OF CA-
CERVIX PANNING
AP VIEW

33. For imagi guided HDR
Brachytherapy
Doses not for just points
But for all GTV.CTV and
Organs at risk and DVH
Analysis
3D IMAGI

34. FRACTIONATIONS IN GYNECOLOGY
CANER:-
common
FRACTIONATIONS
6GY X 5FRS
7GY X 4FRS
8GY X 3FRS
common
FRACTIONATIONS
6GY X 5FRS
7GY X 4FRS
8GY X 3FRS

35. PROSTATE BRACHYTHERAPY
LDR
I125
pd103
Cs137
Migration of seeds/edema
Urinary &Powel
toxicity
Permanent

36. HDR BRACHYTHERAPY MACHINE

37. CT after accurate implant taken and transferred to the TPS
CTV= prostate, PTV—pm = prostate + 3mm.
In high risk patients PTV can be 5mm
Planning can be 2D or 3D and image guided
LDR
dosimetry:-

38. LDR
I125
Mono –therapy
145 GY
Boost
110
Pd130
Mono-therapy
115GY
Boost
100GY

39. HDR
Boost
With EBRT
Dosimetric advantage VS
LDR/High source activity so
treatment in a few munities
/No radiation exposure
Mono-low
risk
studies??
co60
IR192

42. URUS or CT guided implantation. Then planning in
2D
Or 3D with image guided
HDR technique:-

43. HDR
Boost with EBRX
15--25GY X 1—2 fRS
Boost
10--12YG X 3 FRS
Boost
9.5GY X 4 FRS
Doses fractionations in hdr boost in prostate:-

44. 3D IMAGE OF PROSTATE BRACHYTHERAPY