Radiation Therapy

1. Radiation Therapy 

2. Radiation Therapy The basic idea behind radiation therapy is to destroy the tumour through high doses of radiation: 

3. Radiation Therapy The Royal College of Radiologists (UK) estimates that, of those cancer patients who are cured: • 49% are cured by surgery • 40% are cured by radiotherapy • 11% are cured by chemotherapy 

4. Radiation Therapy Radiation Therapy - Basics Radiation Therapy - External Radiation Therapy - Internal 

5. Radiation Therapy Radiation Therapy - Basics Radiation Therapy - External Radiation Therapy - Internal 

6. Radiation Therapy – Basics Gamma Rays have a energy high enough to displace an electron from its orbital path. Wavelength [m] low energy high energy This creates an unstable or ionized atom, leading to a changed and dysfunctional molecule. 

7. Radiation Therapy – Basics The main target is the DNA which, when hardly damaged, can lead to cell death and therefore tumour necrosis. 

8. Radiation Therapy – Basics Radiosensitivity and cell cycle The greatest amount of damage occurs during the period of mitosis where one cell divides into two individual cells 

9. Radiation Therapy Radiation Therapy - Basics Radiation Therapy - External Radiation Therapy - Internal 

10. Radiation Therapy – External The radiation is artificially produced by a linear accelerator. The energy of up to 30MeV and more can be 600-fold higher than this of a conventional x-ray machine. 

11. Radiation Therapy – External As the tumour is normally surrounded by normal tissue and often far away from the body surface, collateral damage of this tissue by external radiation cannot be avoided. 

12. A B C Radiation Therapy – External The success depends on the difference between the sensitivity of tumour and surrounding tissue. 

13. Radiation Therapy – External Radiosensitivity of normal and malignant tissue 

14. Radiation Therapy – External Like chemotherapy, external radiation therapy is often given in fractions over a certain time period. For breast cancer for example, a total dose between 40Gy and 60Gy is given in 15-30 fractions over a period of 6 weeks. 

15. Radiation Therapy – External Radical external beam irradiation often requires a multi-field technique employing three or four fields This technique allows to apply higher doses to the tumour without to much collateral damage 

16. Radiation Therapy Radiation Therapy - Basics Radiation Therapy - External Radiation Therapy - Internal 

17. Radiation Therapy – Internal To bring the radiation dose as close as possible to the tumour, several internal radiation methods are used where applicable. Advantages of internal radiation methods: • specific radiation to tumour tissue • less collateral damage • higher doses possible 

18. Radiation Therapy – Internal Examples of internal radiation therapies: • 131I – carcinoma of the thyroid • 32P – bone marrow radiation • 137Cs – needle for local treatment • 125I – brachytherapy seeds 

19. Radiation Therapy – Internal 125I – Brachytherapy seeds 

20. Radiation Therapy Radiation Therapy - Basics Radiation Therapy - External Radiation Therapy - Internal 

21. Radiation Therapy What is most important to remember? Principles of Radiation Therapy Tissue radiosensitivity Differences internal/external 