brachytherapy.pptx

the physics and clinical applications of brachytherapy

1. Dr :- OMER HASHIM Radiation oncologist Universal hospital Khartoum brachytherapy

2. brachytherapy Brachytherapy is the treatment of cancer with shot Distance using encapsulated radionuclide sources Usually given by placing the sources directly to the tumor or nearby. The radioactive material will give contuse radiation Dose commonly by gamma rays or few specialized situations b or neutron emitting sources are used

3. Types of brachytherapy By treatment Types :- Intracavitary:- the sources are placed in body cavities close to the tumor volume Interstitial:- in which the sources are implanted within the tumor volume Other less common types include surface plaque, intraluminal , intraoperative and intravascular

4. Brachytherapy types according to the treatment duration :- 1) Temporary :- the dose is delivered over a short period of time and the sources are removed after the prescribed dose has been reached 2) Permanent:- Dose is delivered over the lifetime of the source until complete decay

5. Types of brachytherapy according to source loading:- Preloading: the applicator is preloaded and contains The radioactive sources at time of placement to the patients (old method with high hazer to workers). After loading: The applicator is placed first into the target position and the radioactive sources are loaded later by machine (brachytherapy devices currently in use)

6. AfterloadingI nstrumentation

7. Brachytherapy types according to dose rate:- Remote after Loading Radiation protection

8. After loading Instrumentation Intracavitary BT :- Applicators are inserted in body cavities(rectum, vagina, uterus ( Interstitial BT :- Catheters or needles are implanted in body tissue(breast, prostate, head&neck ( Intraluminal BT:- Applicators are inserted in organs within lumen(esophagus, bronchus ) Superficial BT:- Catheters or needles are embedded in flabs or individually tailored surface molds where they run alongside the are to be treated Surface mold Interstitial implant

9. Interstitial implant

10. CHARACTERISTICS of sources

11. The common sources are :-

12. the less common sources are:-

13. Sources not be used because safety concerns:-

14. Brachytherapy photon sources are available in various forms :-

15. The use fullness of brachytherapy radiation consist:- less therapeutic use

16. Why brachytherapy sources capsulated :-

17. The choice of appropriate radionuclide for brachytherapy depend on: -

18. 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

19. 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

20. Comparison of  60 Co and  192 Ir  These are the most common used radionuclides. Ir-192 was the   preferred option for HDR & afterload for Its small size for temporary use, Recently also  60 Co sources have been made available with identical geometrical dimensions. The result of the studies that compare the clinical aspects are equal While the co60 has longer half-life ( 5.3 years vs. 74 days ) making it an interesting alternative especially in developing countries,

21. 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

22. Brachytherapy treatment done in tow ways

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

24. techniques

25. Dose specification:- the most common does specific systems

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

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

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

29. Fractionations in gynecology caner:-

30. Prostate brachytherapy Prostate cancer:- brachytherapy has important role in the treatment of prostate as monotherapy or boost with EBRT We uses the tow types of brachytherapy LDR & HDR

31. Hdr brachytherapy machine

32. 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 :-

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

34. Doses fractionations in hdr boost in prostate :-

35. 3 D image OF PROSTATE BRACHYTHERAPY

36. THANKS