1. Brachytherapy in Nuclear Medicine
CHEM 464 By
Birendra Adhikari
Rajesh Koirala
Santosh Koirala

2. Outline Introduction Types of Radiation Therapy Brachytherapy
Methods of delivery
Physics of Brachytherapy
Breast Cancer Treatment
Conclusion

3. Radiation therapy
The medical use of ionizing radiation as part of cancer treatment to control or kill malignant cells
Ionizes the atoms of cells which make up the DNA
Can be used in combination with surgery, chemotherapy and hormone therapy
National lung cancer forum for nurses.

4. Types of Radiation Therapy
External beam therapy
Internal beam therapy
Conventional external beam radiotherapy (2DXRT)
Three-dimensional conformal radiotherapy (3DCRT)
Intensity modulated radiation therapy (IMRT)
Intensity Modulated Radiation Therapy (IMRT)

5. Brachytherapy
A form of treatment where a sealed solid source of radiation in the form of seeds, ribbons, or capsules is planted inside the body in or near the cancer cells
High dose of radiation to a smaller part of the body
Treats mostly breast cancer, localized prostate cancer, cervical cancer and cancers of head and neck.
Radium seeds

7. Types of Brachytherapy
High Dose Rate Brachytherapy:
plastic tubes or needles are inserted into the tumor or placed a hollow applicator inside a body cavity
The radioactive source is left in the body for a few minutes and is extracted
Low Dose Rate Brachytherapy:
Between 40 and 100 rice-sized radioactive seeds are implanted into the site of the tumor
the radiation source stays inside the body for a longer time
commonly used to treat prostate cancer.

8. Methods of Delivery Mold Brachytherapy: Strontium plaque
uses sealed sources placed close to the skin to cure superficial tumors
Uses Manchester System to calculate the dose rate of the radiation
Strontium plaque
The plaque is a hollow, thin silver casing that encloses a radioactive strontium-90 powdered salt
used for very superficial tumors less than 1mm
radiation protection issues are slightly less

9. Methods of Delivery Contd…
Interstitial brachytherapy:
radioactive sources are inserted into the tissue
Radium-226 (226Ra) was used as a source in the early days of this kind of treatment which is now replaced by iridium-192 (192Ir)
Intracavitary brachytherapy:
a radioactive source is placed inside a preexisting body cavity
The most common applications of this method are gynecological in nature such as the treatment of cervical cancer

10. Methods of Delivery Contd…
6) Electronic brachytherapy:
A miniature low energy x-ray tube source is placed into a pre-positioned applicator within a body or tumor cavities to rapidly deliver high doses to target tissues while maintaining low doses to healthy cells around the tumor
7) Intravascular brachytherapy:
Sources are sent and returned through a catheter placed inside the vasculature.
most common application is the treatment of coronary in-stent restenosis
Beta-emitting sources of Yttrium-90 (90Yr) or Strontium-90 (90St) are used as a radiation source.

11. Physics of Brachytherapy
Radium was the most commonly used radioactive source
supplied in the form of radium sulfate or radium chloride which is mixed with inner filler and loaded into cells about one centimeter long and one millimeter in diameter
Other sources of radioactivity such as cesium-137, cobalt-60, iridium-192, gold-198 or iodine-125 are also used

12. Physics of Brachytherapy Contd.
The cells are made of mm thick gold foil and are sealed to prevent leakage of radon gas.
The sealed cells are then loaded into platinum sheath.
A radium source contains one to three cells depending upon the source length.
Radium sources are manufactured as needles or tubes in a variety of length and activities.

13. Physics Contd… Radium sources are specified by
active length
physical length
Activity
Filtration
To determine the distribution and types of the radiation sources to provide the optimum dose distribution, the methods used are:
The Paterson-Parker system OR Manchester system
The Quimby system
The Memorial System
Paris System
Computer Dosimetry

14. Physics Contd…
Earlier , computer programs were used to obtain linear source tables, build up factors, and scatter factors
Nowadays, programs are available to calculate isodose distributions for individual patients
Radium and other long-lived isotopes, the dose rates, presented in the form of isodose curves
The dose rate, D0, is calculated to approximate implant duration without decay correction and total dose to be delivered . The cumulative dose, Dc, is given by :

15. Brachytherapy in Breast Cancer Treatment

16. About Breast Cancer Malignant cells in tissue of breast
Breast conservation treatment over Mastectomy
Standard conservation treatment/lumpectomy
External radiation to whole breast for six weeks
Brachytherapy

17. Interstitial Brachytherapy
Used before MammoSite treatment
Breast conservation surgery and a tumor less than three centimeters in diameter
Arrays of thin and flexible catheters (about 25)
Catheters connected to a special machine
Small amount of radioactive sources is transferred
Radioactive source (192Ir) transferred back to machine

18. Interstitial brachytherapy
Source: University of Washington website
High dose after loader
Connector with radioactive source
Radioactive treatment of breast cancer (Radioactive source 192Ir)
Connector

19. MammoSite Treatment Takes five days, two times per day
Spherical dissection cavity
Treat one centimeters of tissue/tumor
Catheter consist a inflation channel and a passage
Saline solution is used for inflation
Inflation volume of balloon depends on cavity
10 fractions 3.4Gy/fractions for the treatment
MammoSite Catheter

20. MammoSite Treatment Surgical Cavity 1. Before surgery Tumor
2. After surgery and use of catheter
Catheter
Balloon
2. Inflation of balloon with saline solution
4. Radioactive source inside catheter/balloon
Radioactive source

21. Conclusion Radioactive sources have great importance in medical field.
Radiotherapy is improving with new technology.
Brachytherapy has been able to treat cancer cells without affecting healthy cells, especially cancers of skin, breast and inner body cavities.
Rate of mastectomy has declined.
MammoSite treatment has been successful.

22. Work Cited
National lung cancer forum for nurses.
Chesapeake potomac Regional Cancer center.
Oak Ridge Associated Universities . Radiotherapy. Wikipedia Website. Available at: Accessed November 16, 2008.
Radiation therapy and you. National Cancer Institute Website. Available at: Accessed November 16, 2008.
Radiation Therapy. American Cancer Society Website. Available at: Accessed November 16, 2008.
Brachytherapy. Wikipedia Website. Available at: Accessed November 16, 2008.
Brachytherapy. Mayo Clinic Website. Available at: Accessed November 16, 2008.
Prostate brachytherapy. Wikipedia Website. Available at: Accessed November 16, 2008.
Khan, FM. The Physics of Radiation Therapy. Baltimore: Williams and Wilkins; 1984.
Breast Cancer Treatment. National Cancer Institute Website. Available at: Accessed November 16, 2008.
Current Applications of Brachytherapy. American Brachytherapy Society Website. Available at: Accessed November 16, 2008.
Brachytherapy (Internal Radiation). Vantage Oncology Website. Available at: Accessed November 16, 2008.
Blackwood MJ. Brachytherapy: Radiation treatment that fits our lives. Focal Spot: Mallinckrodt Institute of Radiology, 2004.
Dickler A, Kirk M, et al. Treatment volume and dose optimization of MammoSite breast brachytherapy applicator. International Journal of Radiation Oncology Biology Physics. 2004; 59:

23. Any Questions?